King Faisal University

Faculty of Engineering
Department of Mechanical
Engineering

Prepared by: Eng. Omar Osta

Edition two January / 2014

 ACKNOWLEDGEMENT
Great thanks to Dr.Mohamad Al-Widyan for his valuable review of
the manual.
 CONTENT
Subject Page

Preface a

Lab Policies and Guidelines b

How to Write a Good Lab Report c

Safety Instructions e

Exp. # 1 Fluid Properties 1

Exp. # 2 Submerged plane surface 6

Exp. # 3 Flow Measurement 10

Exp. # 4 Impact of Water Jet 15

Exp. # 5 Friction Loss in Pipes and Fittings 19

Exp. # 6 Parallel and Series Pumps 32

Exp. # 7 Performance of a Positive 39

Displacement Pump [PDP]
Exp. # 8 Open Channel Flow - Sluice Gate 47

Exp. # 9 Water Turbines 50

Exp. # 10 Wind Tunnel [Lift and Drag of an Airfoil] 58

References 65
 PREFACE:
This manual is prepared to cover the material of the fluid mechanics lab
course (Engr 312). The Prerequisite for this lab course is (Engr 309) Fluid
Mechanics. The manual covers a wide range of experiments related to fluid
mechanics concepts and basics, Including fluid properties, fluid statics, fluid
dynamics, and aerodynamics. In more details: forces on submerged planes,
stability of objects, Pascal’s principle, continuity equation, Bernoulli
equation, momentum equation, pumps performance, water turbine
performance are investigated. Also lift and drag forces for an airfoil are
measured in a subsonic wind tunnel.
The overall aim of the laboratory is to strengthen and support the
student knowledge and to provide students with a deeper understanding of
theoretical principles and concepts by observing phenomena, by measuring
physical characteristics and by comparing measured versus calculated results
in the area of fluid mechanics. In addition the lab shall satisfy the following
secondary objectives:
 Acquiring firsthand experience and practical information related to the
apparatus and equipments available on the laboratory.
 Studying and identifying the principle and the concept of operation of
some measurement instruments like thermometers and pressure
gages and some control systems and safety devices.
 Increasing the students’ skills in analyzing data and writing good lab reports.
 Enhancing team work and leadership skills.
Students are encouraged to learn to do all experiments following the
procedures presented in this manual, and to document them in lab reports
using similar styles and format.
The experiments in this manual are designed to give engineering
students an introduction to each experiment followed by theory and physical
principles that will be demonstrated experimentally, in addition to
introducing the laboratory procedures for performing the experiment.
These experiments are also intended to teach students the principles of
laboratory protocol and reporting. In addition to following the procedures
given for a lab, each student will be required to submit a lab report
documenting the experiment and the results. Documenting laboratory
results in a clear and concise manner is just as important as conducting an
experiment properly. The suggested format for the lab report is provided in
this manual. Students are expected to submit neat, professional reports, free
of grammar and spelling errors, one week from the experiment date.

a
 LAB POLICIES AND GUIDELINES
 The class shall be divided into groups of no more than 5 students in
each group.
 The instructor will assign a group leader for each experiment. The
group leader will assign a task to each member in the group.
 Some Programs will perform one experiment only in each lab session,
since the nature of the experiment and the apparatus allow doing this,
also the theoretical course related to the lab taught in the same
semester with the lab course.
 Students will not be required to write and submit a laboratory report
for any experiment they did not perform due to malfunction of the
equipment.
 Attendance:
o Laboratory attendance is mandatory.
o The student will not be allowed to submit a report for an experiment
in which he has not participated.
o In case of excused absences, make-up laboratories will be considered
on a case-by-case basis.
 Reports:
o Individual reports are required for every experiment.
o Reports are type written.
o Reports are due 7 days from the day of the experiment.
o Late report will be subjected to a penalty of 10% per day. Late reports
will be accepted up to 3 days after the due date. No late report will be
accepted after that.
 Grading:
Reports 50% - 60%
Design of experiment 10%
 Exams could be one Exam [Final] OR two
Exams 30% - 40% exams [Mid & Final]
 Exams may be included by verbal part.

b
 HOW TO WRITE A GOOD LAB REPORT
A good lab report should contain the following items:
1. COVER PAGE:
The followings are included in a cover page:
 Name of University, College and Department.
 Student Name and Number.
 Experiment Name and Number.
 Instructor’s Name.
 Date.
2. TITLE:
 Should tell the reader what the report is about.
 Should be as short as possible.
3. OBJECTIVE:
 Should give the reasons for doing the work.
 Should define the problem.
4. THEORY:
 Should state the main assumptions with justifications.
 Should be brief.
 Should number the necessary equations in correct sequence.
5. APPARATUS:
 Describe the experimental rig and the instruments used to
perform the experiment.
 Include sketches of the test setup where appropriate.
6. PROCEDURE:
 Should be brief.
 Should be in short sentences.
 Should be in passive voice.
7. RESULTS:
 Each table should have a number and a title.
 The data should show the proper units.
c
 8. SAMPLE CALCULATIONS:
 Should be clear.
 Should take care of units and make necessary conversions.
 Should present the calculated results in tables that are numbered
and named.
9. GRAPHS:
 Scales and units shown clearly.
 Points shown clearly.
 Graphs should have necessary numerical working such as
determination of slope.
 Title of the graph should explain what the graph shows.
10. DISCUSSION:
 Should make sure that the results are adequate.
 Should give an opinion on the reliability of the results.
 Should state the importance of the experiment on real life, and
mention some applications.
 Should state where the experiment helps to understand the
theory.
11. CONCLUSION:
 Should compare results with what is expected.
 Should estimate possible errors of the work.
 Should justify the conclusions by the results.
12. REFERENCES:
 List all references used in the report.

Note: Lab reports are to be typed, in a neat and orderly fashion, with all
pages numbered at the bottom. Be concise – quality not quantity is important.

d
 SAFETY INSTRUCTIONS
SAFETY FIRST WHILE IN THE LABORATORY

The basic purpose of laboratory safety is to protect students, researchers,

technicians and teachers from the many hazards encountered during the
use of various materials and equipments. Therefore safety in the
laboratory must be of vital concern to all those engaged in experimental
work and thus is the responsibility of everyone to adhere strictly to the
basic safety precautions provided and to avoid any acts of carelessness that
can endanger his, her life and that of others around him, her. It is equally
important to always abide by all the instructions for conducting the
experimental work during the laboratory sessions. A set of information is
presented here to safeguard you while in the laboratory.

1. Smoking is not allowed in the laboratory.

2. Food or beverages are not allowed in the laboratory.
3. Long hair and long sleeved loose clothes are to be avoided, instead, wear
lab coat while conducting experiments to minimize the risk of clothing
getting caught in the machines.
4. Appropriate personal protective equipment should be used at all times,
like Gloves, Safety glasses; Skin Protection, Hearing Protection, and Foot
Protection (don’t wear open sandals)
5. Running, playing, bantering, and kidding in the laboratory are
not allowed.
6. Locations and method of use of first aid and all emergency equipments,
such as fire alarm, water hoses, fire extinguishers, fire blankets, eyewash
stations, and safety showers should be know by all.
7. Laboratory equipment should be used only for its designed purpose.
8. Always follow instructions and use only machines and equipment
that you are authorized and qualified to operate. If you have any
question, consult with your supervisor.
9. Safety rules for specific experiments or tasks should be known
and followed.
10. Potential hazards in your work and ways of working safely to
prevent such hazards should be known.

e
11. Working alone should be avoided. Someone should always be
within call when a laboratory procedure is being performed.
12. Mouth contact with any laboratory equipments including pipettes
should be avoided. Use safety filler to fill pipettes.
13. Exposure to gases, vapors, and particulates by using a properly
functioning laboratory fume hood should be avoided.
14. Ground fault circuit interrupters should be used where there is a risk
of an operator coming in contact with water and electrical equipment
simultaneously.
15. Electrical safety rules should be followed, and make sure your hands
are dry before using electrical equipment, grounding portable electrical
tools. Make sure electrical wires are connected properly without short
circuit before operating. Wear protective clothing, well-insulated groves
and boots, if required.
16. Only trained, qualified personnel may repair or modify electrical or any
equipment.
17. •Properly support glass wares using stand, clamps, etc.
•Use proper rings to place round bottom flasks.
18. •Reduce fire hazard.
•Use shower for fire victims.
•While fire on clothing, do not run or fan flames.
•Smother flames by wrapping in fire blankets.
•Spills of flammable solvents can be a source of fire.
19. Upon hearing fire alarm, you should evacuate the area and
follow emergency procedure.
20. Report all injuries including minor scratches, cuts, and burns for First
Aid treatment. Corrective actions should be taken to prevent future
injuries.
21. Report any damage to equipment or instrument and broken glassware
to the laboratory instructor as soon as such damage occurs.
22. Wash hands upon completion of laboratory procedures and remove all
protective equipment including gloves and lab coats.

PROPER CONDUCT IN THE LABORATORY MINIMIZES ACCIDENTS.

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 COLLEGE OF ENGINEERING
KING FAISAL UNIVERSITY Department of Mechanical Engineering

Exp. # 1

PART ONE: Measurements of Density and Specific Gravity

Objective:
To measure the density and the specific gravity of different liquids

Theory:
Specific gravity is a fluid property defined as the ratio of the density of a fluid to the density
of water. Typical values are 0.8 for paraffin, 1.6 for carbon tetrachloride, 13.6 for mercury
and 1 for water.
Specific gravity can be measured directly using a special -calibrated instrument called
a hydrometer.
A hydrometer is usually made of glass and consists of a cylindrical stem and a bulb weighted
with mercury or lead shot to make it float upright. The liquid to be tested is poured into a
graduated cylinder, and the hydrometer is gently lowered into the liquid until it floats freely.
The point at which the surface of the liquid touches the stem of the hydrometer is noted.
Hydrometers usually contain a scale inside the stem, so that the specific gravity can be read
directly.
For an object partially or completely submerged in a fluid, there is a net upward force
(buoyant force) equal to the weight of the displaced fluid.
The depth to which the hydrometer stem sinks in the liquid is a measure of its density.

With known hydrometer mass and cross section of stem,

density and specific gravity of liquid can be calculated for
any immersed length of stem. The hydrometer stem can be
calibrated for density or specific gravity.
Apparatus:
The setup of this experiment consists of Hydrometer,
Hydrometer Jars and liquids to be tested as shown in Figure 1. Figure 1: Experimental setup

Procedure:
1. Fill the Hydrometer jars with the liquids to be tested.
2. Carefully insert the hydrometer and allow it to settle in the center of the cylinder.
3. Take care not to let it touch the sides; otherwise surface tension effects may cause
errors.
4. When the hydrometer has settled (float freely), read the scale at the level of the free
surface.

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Results:
Atmospheric pressure:……………………………Ambient
temperature:……………………………...
Liquid Experimental density Specific gravity Density from literature % Error

Discussion
1. Compare your results with the available values from literature.
2. Comment on your results.

PART TWO: Capillary Raising Measurement

Objective:
To measure the capillary raising produced in capillary tubes of different sizes

Theory:
According to the theory of molecular attraction, molecules
of liquid considerably below the surface act on each other
by forces that are equal in all directions. However molecules
near the surface have a greater attraction for each other than
they do for the molecules below the surface. This produces a
surface on the liquid that acts like a stretched membrane.
Because of this membrane effect, each portion of the liquid
surface exerts tension on the adjacent portion of the solid
surface or the objects that are in contact with the liquid
surface. The magnitude of this tension force per unit length
of contact surface is defined as surface tension,  , Surface
tension for a water–air surface is 0.073 N/m ( for
o
temperature between 10 – 50 C).
Consider Figure 2, the height of capillary raising water can
be calculated using the force balance in the vertical direction
F , z  weight  o Figure 2: Capillary action in a small tube

 d cos   (h)( d 2 / 4)  0
Thus the raising height h 4

d
Where h is the capillary height
d is the inner diameter of the tube
 is the surface tension
 is the specific weight of the water

Apparatus:

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The capillarity apparatus consists of:

 Three glass capillary tubes having bores of 0.4 mm,
0.8 mm and 1.6 mm.
 Header tank
 Caliper
Procedure:
1- Make sure that the capillary tubes and the header tank
are well cleaned.
2- Fill the header tank with clean water, mixed with ink.
3- Place the capillary tubes in the water and report the
capillary height.
4- If necessary, drain some water from header tank by
means of the drain valve.
Figure 3: Capillarity Apparatus
Results:

Tube diameter Average capillary raising Calculated capillary

% Error
d (mm) h (mm) raising h (mm)

Analysis and Calculations

Calculate the theoretical capillary raising and compare with experimental one.

Discussion
1- What are the sources of error?
2- What are the factors affecting the height to which water rises. Is this agree with
experiment results?

PART THREE: Viscosity Measurement

Objective:

To determine the viscosity of various liquids at atmospheric pressure and temperature, using
Falling Ball Viscometer
Theory:
Viscosity is one of the most important properties of fluids since it determines the behavior
whenever relative movement between fluids and solids occurs. In a simple case in which a
section of fluid is acted on by a shear stress τ, it can be shown that a velocity gradient is
produced which is proportional to the applied shear stress. The constant of proportionality
is the coefficient of viscosity μ and the equation is usually written:

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Where is the velocity gradient normal to the plane of the applied stress.
Equation (1) represents a model of a situation in which layers of fluid move smoothly over
one another. This is termed viscous or laminar flow.
Equation (1) shows that if fluid flows over an object, there will be a velocity gradient in the
flow adjacent to the surface, and a shear force transmitted to the fluid which tends to resist its
motion. Similarly, if an object moves through a fluid, velocity gradients will also be set up
and a force generated on the object which tends to resist its motion. In all such cases,
knowledge of μ is required to calculate the forces involved. It should be noted that μ varies
with temperature, so values for a given fluid are usually tabulated for various temperatures.
2
In the SI system μ has units of Ns/m . In fluid mechanics the term μ/ρ often appears and this
is called the Kinematic Viscosity (ν).
2
Kinematic viscosity is very often more convenient to use and has units of m /s which
are often easier to work with.
There are many experimental methods which can be used to determine μ. One common
method is to consider the rate at which a smooth sphere will fall through a liquid for which it
is required to determine the viscosity [Falling Ball Viscometer].
For a free falling sphere without wall effect (for example: sphere fall in a large diameter
graduated cylinder) the force balance yields
FB + FD = mg
4 3
FB is the buoyancy force = liqud.g. 3 .r
FD is the drag force on the sphere = 6...V .r
Substitute the suitable buoyancy force FB and the Drag force FD
yields the following formula for the dynamic viscosity
 2 (ball  liquid)  g  ………………………………….(2)
 r2
9 V
where V is the speed of ball = Distance of the fall / time taken , m/s
 Density of the ball Kg/m
3
ball

 Density of the liquid

liquid

g 2
acceleration of the gravity 9.81 m/s
r radius of the ball, m

This equation is only applicable for viscous flow, for which a variable called Reynolds
Number is below a certain value
Where: Reynolds Number is given by:

Where : is the density of the liquid

: is the speed of ball
: is ball diameter

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The limiting value of Re is often taken as 0.2 because above this value, the errors in applying
Equation (2) becomes significant.

Apparatus:
The apparatus consists of:
 Graduated Cylindrical Jars.
3
 Steel Spheres [ρ=7800 kg/m ].
 Stop Watch.
 Ball Guide
Procedure:

1- Use the hydrometer to find the density of the oil being tested.
2- Inserting the ball guide.
3- Set the upper timing band marker approximately 20 mm below the level of the base of
the ball guide.
4- Set the lower timing band marker to approximately 200 mm below the first.
5- Drop the ball into the fluid and time the descent between the markers using the
stopwatch.
6- Measure the distance between the markers.
7- Measure the temperature of the liquid.

Results:

Liquid
o
Ambient temperature [ C]
Time [sec]
Radius of the ball [mm]
3
Ball density [kg/m ]
3
Liquid density [kg/m ]
2
Dynamic viscosity µ [Ns/m ]
2
Kinematic viscosity ν [ m /s]
Analysis and Calculations

 Calculate the dynamic viscosity and kinematic viscosity for all liquids.
 Compare your result with the values of the viscosity available in literature and
standard tables.
 Comment on your results.

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Exp. # 2
Submerged Plane Surface
Objective:

To determine the hydrostatic forces on the rectangular face of the partially or entirely
submerged object in the water experimentally and compare with theoretical values.
Theory:

The magnitude of the resultant hydrostatic force on a

plane surface submerged in water (Figure: 1) is the
product of the pressure at the centroid of the surface
and the area of the surface.

F P A y  sin   A (1)


Where  is specific weight of the liquid.
y is slanted distance from the liquid surface
to the centroid of the immerged surface.
 is inclination of the plane surface from the
horizontal
A is the area on the immerged surface
The center of pressure y may be defined as: “The
cp
point in a plane at which the total fluid thrust can be Figure 1: Force on submerged plane
said to be acting normal to that plane.” And is given
by:

ycp  I (2)
 y
y 
A
Where I is the area moment of inertia about the centroidal axis.
Apparatus:
The apparatus consists of a self-contained bench
(Figure 2) complete with all necessary equipment
for a wide range of demonstrations and
experiments in hydrostatics and properties of
fluids.
Experimental setup
The apparatus permits the moment due to the total
fluid thrust on a wholly or partially submerged
plane surface to be measured directly.
Water is contained in a quadrant tank assembly as
part of a balance. The cylindrical sides of the
quadrant have their axes coincident with the
center of rotation of the tank assembly, and
therefore the total fluid pressure acting on these
surfaces exerts no moment about that center. The
only moment present is that due to the fluid
pressure acting on the plane surface. This moment Figure 2: The Hydrostatic Bench
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is measured experimentally by applying weights to a weight hanger mounted on the opposite

side to the quadrant tank. A second tank, situated on the same side of the assembly as the
weight hanger, provides a trimming facility. A scale on the quadrant tank is used to measure
the level of the water below the pivot (h).

Case 1: Plane Partially Submerged

̅ [ = 90 for vertical

plane.]
̅

( )

( )
̅
̅
̅
̅

Take moment at point O

( )

Case 2: Plane Fully Submerged

̅ [ = 90 for vertical

plane.]
̅
̅
̅
̅ ̅

Take moment at point O

( )

Where:
R1[mm] R2[mm] a [mm] b [mm] D [mm]
100 200 75 100 200

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Procedure:
1- Balance the quadrant tank assembly when its empty by adding weights to the hanger.
Fine adjustment for balance is achieved by gently pouring water into the trim tank until
the desired position is achieved.
2- Add 50g weight to the weight hanger. Pour water into the quadrant tank until a 0° balance
is restored. Note the weight and the level of the water (h).
3- Repeat the procedure by adding additional 50g and continue to cover both cases (Partially
and Fully Submerged).
Results:

Case 1: Plane Partially Submerged

M (g) h (mm) 2 4 Ftheo [N]
̅ (m) A(m ) I (m ) ycp (m) Fexp [N] % Error
50

100

150

Case 2: Plane Fully Submerged

M (g) h (mm) 2 4
̅ (m) A(m ) I (m ) ycp (m) Ftheo [N] Fexp [N] % Error

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Analysis and Calculations

1- Calculate ̅
.
2- Calculate .

Discussion
1. Plot yc.p. versus y for both partially and totally immerged.
2. Comment on your results and plots.
3. Explain any source of error.

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Exp. # 3
Flow Measurement
Objective:

The flow measurement experiment familiarizes students with the typical methods of
measuring the discharge of an essentially incompressible fluid, whilst giving applications of
the Steady-Flow Energy Equation and Bernoulli's equation. The discharge is determined using
a Venturi meter, an orifice plate meter and a Rotameter

Theory:
Bernoulli’s Equation Demonstration
Bernoulli’s theorem states that: “The total head of
flowing liquid between two points remains constant
assuming there are no loss due to friction and no gain
due to application of external work between the two
points”.
The total head (Ht) of a flowing liquid is made up of
Elevation head (Hz), pressure head (Hs) and velocity
head (Hv) and according to Bernoulli’s theorem the
total head is constant between any two points along
the streamline of a flowing fluid.
H t  P  V 2  Z ……………………………[1] Figure 1 The Steady Flow energy equation
g 2g
Where: Ht is the total head (m), V is the average
velocity (m/s), P is the pressure (Pa), Z is the
3
elevation (m),  is the density (Kg/m ) and g is the
2
gravitational acceleration (m/s ). Thus between point
1 and 2 for example (Figure 1)

P  V 2 Z1  P  V 2  Z 2  hL (Head loss)

1 1 2 2
………………………………………
g g 2g [2]
2g
If the Bernoulli’s tube is horizontal then Z1 = Z2 and if loss between point 1 and 2 is negligible
then the equation becomes
P P 
1
V2 1 2
V2
2
………………………………………………………………………..[3]
g 2g g 2g
P  P   V2
V2
Or 1 2 2 1
……………………………………………………………[4]
g g 2g 2g
If point 1 and point 2 are of different diameters, then V1 and V2 are different. It is
demonstrated by the difference in manometer water level reading between point 1 and
2. Therefore

From continuity

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Sub equation 6 into equation 5 and rearrange

( )
√
( )

( )
Venturi )between points B and C(

̇
√
( )

Orifice (between points E and F)

For orifice Coefficient of discharge introduced in equation due to high head losses
( )
√
( )

Where C = 0.601
̇

Rotameter

For Rotameter use the calibration curve shown in Figure 2 to find flow rate through the
Rotameter.

Figure 2 Typical Rotameter Calibration Curve

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Apparatus:

Figure 3 shows the Flow Measurement apparatus. Water from the Hydraulic Bench enters the
equipment through a venturi meter, which consists of a gradually converging section,
followed by a throat, and a long gradually diverging section. After a change in cross-section
through a rapidly diverging section, the flow continues along a settling length and through an
orifice plate meter. This is manufactured in accordance with BS1042, from a plate with a hole
of reduced diameter through which the fluid flows[Figure 4]. The H10 has eleven
manometers, nine are connected to tapping's in the pipework and two are left free for other
measurements.

Figure 3 Flow Measurement Apparatus

Figure 4 Explanatory Diagram of the Flow Measurement Apparatus

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Procedure:
1- Connect Power supply of the hydraulic Bench.
2- Check that the valve on hydraulic bench is open and the control valve on the apparatus
are closed.
3- Operate the pump, then open the control valve on the apparatus to give a Rotameter
reading of 25 mm.
4- Check that all pipes and manometers are empty from air bubbles.
5- Record all manometer readings
6- Record the time taken to ‘collect’ a given amount of water in the volumetric tank (with
the drain valve in place). For improved accuracy at greater flow rates, measure a
larger volume. Ensure the water level is at 0 before readings are taken.
7- Drain the water collected in the volumetric tank, simply by lifting the drain valve,
allowing water to return to the sump tank.
8- Repeat the experiment for rotameter readings of 50 mm, 75mm, 100mm, 125mm, and
150mm.
Results:
Test Number
1 2 3 4 5 6
Rotameter (mm) 25 50 75 100 125 150

D
Manometer
E
Level (mm)
F

Water collected (kg)

Time (s)

Venturi

Mass Flow Orifice

Rate ̇(kg/s) Rotameter

Weigh Tank

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Analysis and Calculations

1. Calculate mass flow rate by Weigh tank .

2. Calculate mass flow rate through Venturi [Equations 8 &9].
3. Calculate mass flow rate through orifice [Equations 10 &11].
4. Calculate mass flow rate through Rotameter [Figure 2].
5. Find the difference between the flow rate of each meter and the weigh tank flow rate.
6. Plot the difference of each meter against the flow rate of weigh tank.

Discussion and Conclusions

Compare between the three methods of flow rate measurement in terms of accuracy,
head loss, and ease of use.

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Exp. # 4
Impact of Water Jet
Objectives:
1. To produce and measure force resulted by a water jet when it strikes a target.
2. To compare the results with the theoretical values calculated from the
momentum equation.

Theory:
When a water jet of velocity V0 hits a target plate, its velocity will change direction to V1 as
shown in Figure 1.
Note: The velocity that hits the target plate
is not the same as the velocity at the
nozzle tip. You can calculate the velocity
that hits the target(s) from Bernoulli’s
equation:
(V02  Vnozzle2  2gS ).
Where
V0 is the velocity when hitting the
target plate
S is the distance from the nozzle tip to
the target plate which is designed to be 35
mm for all target plates.
Vnozzle is the velocity at the nozzle tip (the
nozzle tip is 10 mm Diameter)
Assuming that the jet mass flow rate is m
(kg/s) with velocity V0 (m/s). After
striking the target the jet velocity becomes
V1 (m/s) and its direction deviates from
the original direction by angle .
The momentum equation in the Cartesian Figure 1: Water jet acts on target coordinate for
uniform flow across each
flow section and steady state case can be
written as:

 Fexternal  mV0  mVi

c.s c.s
Or the impact force = change in momentum
2
Momentum of jet before hitting the target plate = m V0 (kg-m/s )
2
Momentum of jet after hitting the target plate = m V1 (kg-m/s )
Then the impact force = m V1 cos - m Vo
Then the reaction F by the target plate

F = m ( Vo - V1 cos ) N

For the three targets under consideration the reaction F will be as:
o
 Flat plate ( = 90 )
cos = 0 then F = m V0 (N)

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o o
 120 cone ( = 120 )
cos = -0.5 then
Assume very little energy loss between nozzle (jet) and target (cone) then we can assume
V0=V1
Thus m Vo (1-(-0.5)) = 1.5 m Vo or ( 1.5 times the flat plate)
F = m ( Vo - V1 cos ) =

o
 Hemisphere ( = 180 )
cos = -1 then
Assume very little energy loss between nozzle (jet) and target (Hemisphere) then we can assume
V0=V1
Thus m V0 (1-(-1)) = 2 m V0or ( 2 times the flat plate)
F = m ( V0 - V1 cos ) =

Apparatus:

Figure 2: Impact of water jet apparatus

The equipment consists of:
1. Water supply from the Hydraulic bench which is connected to the inlet pipe at the
bottom of transparent cylinder such that water jet and its target plate can be easily
seen.
2. Water is discharged vertically through a nozzle of 10 mm diameter.
o
3. Three target plates: Flat plate, 120 cone and hemisphere.
4. The target plate is connected to a pivoted beam, which carries a jockey weight [0.6 kg]
and is restrained by a light spring.

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Procedure:
1. The apparatus is first leveled and the lever set to the balanced position (as indicated
by the tally) with the jockey weight at its zero position, and then adjusting the knurled
nut above the spring.
2. Move the jockey weight to ….. and the weight beam is not balanced now.
3. Open the supply valve on hydraulic bench, water is flow and the jet impact the plate.
4. Adjust water flow using valve on hydraulic bench to restores the lever to the
balanced position as indicated by the tally.
5. Measure the amount of water collected during a certain time.
6. Repeat for different positions of the jockey weight.
7. Repeat the experiment using the hemispherical cup and conical plate.

Results:
Diameter of nozzle: 10 mm
Mass of jockey weight: 0.6 kg
Distance from nozzle tip to target: 35 mm
Distance from center of vane to pivot of lever: 150 mm

Target: Flat Plate

Distance Water Time Flow rate Velocity at Velocity at FTheo FExp
Volume nozzle tip Target plate % Error
y (mm) (s) ̇(kg/s) (N) (N)
(Lt) (m/s) Vo (m/s)

Target: Cone
Distance Water Time Flow rate Velocity at Velocity at FTheo FExp
Volume nozzle tip Target plate % Error
y (mm) (s) ̇(kg/s) (N) (N)
(Lt) (m/s) Vo (m/s)

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Target: Hemisphere
Distance Water Time Flow rate Velocity at Velocity at FTheo FExp
Volume nozzle tip Target plate % Error
y (mm) (s) ̇(kg/s) (N) (N)
(Lt) (m/s) Vo (m/s)

Analysis and Calculations

1. Mass flow rate of water:
̇

2. Velocity at target:
√

3. Momentum (theoretical force): ̇

{ ̇
̇

4. Measured force (experimental)

Take moment about pivot

Where y is the distance of jockey

weight from its zero position
5. Calculate % error.
6. Plot the force F (measured) on the
target (for all targets on same figure)
versus the rate of momentum m Vo
and comment on your results.
Discussion
1. How well do the experimental results
fit the theory?
2. Comment on your results and the
accuracy of your experiment.
3. State applications that this experiment
is related.

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Exp. # 5 - A
Friction Loss in Pipes and Fittings
Objectives:
a) To investigate head loss in a straight pipe as a function of volume flow rate or
mean velocity.
b) To determine experimentally the relationship between friction factor and
Reynolds number for flow of water in a straight pipe.
c) To find head loss due to friction and friction coefficient factor in different fittings
experimentally and compare with calculated values.
Theory:
For an incompressible fluid flowing through a pipe from point (1) to point (2), Figure 1. the
following equations apply:
 Continuity equation:

 Bernoulli equation:

Where:
Q Volumetric flow rate
3
(m /s); V Mean velocity (m/s);
A Cross sectional area (m2);
Z Height above datum (m); p
Static pressure (N/m2);
3
ρ Density (kg/m ); Figure 1: flow through a pipe
g Acceleration due to gravity (9.81 m/s ). 2

hL is the head loss (m); which is the total energy lost due to friction between the liquid and
the wall and the interaction of the liquid molecules. The friction head (head loss) between two points can be
expressed by
P P  V 2 V 2  
hL        
Z Z (1)
1 2 1 2

1 2
   

   2g
2g


and the total energy of water at any point may be expressed as the total head at that point ht
where
Total head (ht) = Pressure head +velocity head + static head (elevation)

P V2
= hp + hv + hs =   2g  Z -------------------------------- (2)

Head Loss
The head loss in a pipe circuit falls into two categories:
a) Major head loss (pipe head loss): due to fully developed flow conduits, and it
is caused by shear loss.
b) Minor head loss (component head loss): due to flow through devices such as valves,
bends, and tees.
The overall head loss is a combination of both these categories.

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Head Loss in Straight Pipes [ Major Loss ]

Fluid flows in the direction of decreasing pressure and the decrease in pressure is caused by
the frictional loss in a pipe. The friction loss in a pipe depends on the type of flow (laminar or
turbulent) and the surface roughness of the pipe.
Laminar flow ( for a pipe)
Head loss hf is given by Darcy – Weisbach equation

OR
h V
hf = 32LV Where f
2 L
D
Where V is the average velocity and D is the pipe diameter and L is the pipe length and  is
the specific weight and  is the dynamic viscosity.
Turbulent flow
Also head loss hf is given by Darcy – Weisbach equation

ks
f is a function of Reynolds number, Re, and pipe roughness,
D
f: friction factor
K s: Roughness height

Head Loss for Valves and Pipe Fittings [Minor loss]

There is no established formula for friction of Valves and pipe fittings. However from
experimental results
V2
hL  K Where K is a constant called fittings loss coefficient.
2g
Principles of Pressure Loss Measurement
Considering Figure 2, apply Bernoulli’s equation between
1 and 2:

But

For Piezometer tubes

Rearrange the last equation to get Figure 2: Pressurized piezometer tubes to

measure pressure loss between two points

From equations 1 and 2 we find that

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Considering Figure 3, apply Bernoulli’s equation between

1 and 2:

But

Consider the U-tube. Pressures in both limbs of U-tube are

( )
equal at level 00. Therefore equating pressure at 00:

Considering Equations 3 and 4 and taking the Figure 3: U-tube containing mercury
specific gravity of mercury as 13.6: used to measure pressure loss across
valves
Apparatus:
The setup consists of two separate hydraulic circuits; one painted dark blue, one painted light
blue, each one containing a number of pipe system components. Both circuits are supplied
with water from the same hydraulic bench. The components in each of the circuits are as
detailed at Figure 4 and Table 1.
In all cases (except the gate and globe valves), the pressure change across each of the
components is measured by a pair of pressurized piezometer tubes. In the case of the valves,
pressure measurement is made by U-tube manometers containing mercury.

Figure 4: The setup of friction loss apparatus

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Table 1: Identification of Manometer Tubes and Components

Dark Blue Circuit Light Blue Circuit
A) Straight pipe 13.7 mm bore E) Sudden expansion - 13.6 mm / 26.2 mm
B) 90° Sharp bend (mitre) F) Sudden contraction - 26.2 mm / 13.6 mm
C) Proprietary 90° elbow 12.7 mm radius G) Smooth 90° bend 50.8 mm radius
D) Gate valve H) Smooth 90° bend 100 mm radius
Distance between pressure tappings for straight pipe and J) Smooth 90° bend 152 mm radius
bend experiments = 0.914 m K) Globe Valve
L) Straight Pipe 26.4mm
Unit Manometer tube Unit Manometer tube
o
12.7 mm 90 elbow 1 Contraction 9
2 10
Straight pipe 3 152 mm bend 11
4 12
Mitre bend 5 100 mm bend 13
6 14
Expansion 7 50.8 mm bend 15
8 16
Procedure:
In this experiment, the dark blue circuit only is to be tested
1. Open fully the water control valve on the hydraulic bench.
2. Close fully the globe valve to isolate the Light Blue circuit.
3. Open the gate valve fully to obtain maximum flow through the Dark Blue circuit.
4. Start the pump on the hydraulic bench.
5. Wait until readings are settle down
6. Record the readings on the piezometer tubes and the U-tube.
7. Measure the time needed to collect a quantity of water in the weigh tank [25 Lit].
8. Repeat the above procedure for a total of six different flow rates, obtained by
closing the control valve on the hydraulic bench.
9. With an accurate thermometer, record the water temperature in the sump tank of the
bench at the beginning and at the end of the experiment. Consider the average value as
the water temperature.
10. Close fully the gate valve.
11. Switch off the pump.

Results:
Table 2: Experimental Results
Time to collect Piezometer tube readings (cm) water U-tube (cm) Hg
Test number 25 kg of water
Gate valve
(s) 1 2 3 4 5 6
1

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Table 3: Calculated Results for straight pipe

Test Volume Mean Reynolds Laminar or Friction Friction
flow rate velocity V Log V number turbulent head loss Log hf
number 3 factor f
Q (m /s) (m/s) Re flow hf (m)
1

Table 4: Calculated Results for 90° elbow 12.7 mm radius

Test Volume flow Mean velocity Friction head Minor loss Minor loss
number rate Q (m3/s) (m/s) loss hf (m) coefficient coefficient % Error
KEXP KTHEO
1

Table 5: Calculated Results for 90°Sharp bend (mitre)

Test Volume flow Mean velocity Friction head Minor loss Minor loss
number rate Q (m3/s) (m/s) loss hf (m) coefficient coefficient % Error
KEXP KTHEO
1

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Table 6: Calculated Results for Gate valve

Test Volume flow Mean velocity Friction head Minor loss Minor loss
number rate Q (m3/s) (m/s) loss hf (m) coefficient coefficient % Error
KEXP KTHEO
1

Analysis and Calculations

Head Loss in Straight Pipes [Table 2]

1. Volume flow rate of water ̇ [ ⁄]

2. Mean velocity V
[ ⁄]
̇

3. Reynolds number Re
Classify flow as Laminar or turbulent
4. Friction Head Loss
5. Friction factor Darcy – Weisbach equation
6. Plot a graph of the head loss versus the average velocity and identify the laminar and
turbulent zones on the graph.
7. Confirm that the graph is a straight line for the laminar flow zone and hL~ Vn for the
turbulent flow.
8. Plot a graph of log hf [y-axis] versus log V [x-axis] and confirm that the graph is a straight
line and find the exponent n from the slop of this graph.
9. Plot f [y-axis] versus Re [x-axis]. Compare with moody chart.
Head Loss in fittings (Elbow, Mitre bend, Gate valve) [Tables 4, 5, and 6]
1. Volume flow rate of water
̇ [ ⁄]

2. Mean velocity V
[ ⁄]
̇

3. Friction Head Loss for related manometers

4. Minor loss coefficient KExp h f  K V2
2g
5. Find KStd from literature and find % error
6. Plot a graph of hf [y-axis] versus [x-axis] and confirm that the graph is a straight line
and find the slop of this graph. What the slop represents. Comment on your curve and slop

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Discussion
1. Compare all experimental results with what is expected theoretically.
2. Comment on your % error and discuss any sources of error in the experiment.
3. State the importance of this experiment and mention some related applications.

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Exp. # 5 - B

Objectives:
a) To investigate head loss in a straight pipe as a function of volume flow rate or
mean velocity.
b) To determine experimentally the relationship between friction factor and
Reynolds number for flow of water in a straight pipe.
c) To find head loss due to friction and friction coefficient factor in different fittings
experimentally and compare with calculated values.
Theory:
For an incompressible fluid flowing through a pipe from point (1) to point (2), Figure 1. the
following equations apply:
 Continuity equation:

 Bernoulli equation:

Where:
Q Volumetric flow rate
3
(m /s); V Mean velocity (m/s);
A Cross sectional area (m2);
Z Height above datum (m); p
Static pressure (N/m2);
3
ρ Density (kg/m ); Figure 1: flow through a pipe
g Acceleration due to gravity (9.81 m/s ). 2

hL is the head loss (m); which is the total energy lost due to friction between the liquid and
the wall and the interaction of the liquid molecules. The friction head (head loss) between two points can be
expressed by
P P  V 2 V 2  
hL        
Z Z (1)
1 2 1 2

1 2
   

   2g
2g


and the total energy of water at any point may be expressed as the total head at that point ht
where
Total head (ht) = Pressure head +velocity head + static head (elevation)

P V2
= hp + hv + hs =   2g  Z -------------------------------- (2)

Head Loss
The head loss in a pipe circuit falls into two categories:
a) Major head loss (pipe head loss): due to fully developed flow conduits, and it
is caused by shear loss.
b) Minor head loss (component head loss): due to flow through devices such as valves,
bends, and tees.
The overall head loss is a combination of both these categories.

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 COLLEGE OF ENGINEERING
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Head Loss in Straight Pipes [ Major Loss ]

Fluid flows in the direction of decreasing pressure and the decrease in pressure is caused by
the frictional loss in a pipe. The friction loss in a pipe depends on the type of flow (laminar or
turbulent) and the surface roughness of the pipe.
Laminar flow ( for a pipe)
Head loss hf is given by Darcy – Weisbach equation

OR
h V
hf = 32LV Where f
2 L
D
Where V is the average velocity and D is the pipe diameter and L is the pipe length and  is
the specific weight and  is the dynamic viscosity.
Turbulent flow
Also head loss hf is given by Darcy – Weisbach equation

ks
f is a function of Reynolds number, Re, and pipe roughness,
D
f: friction factor
K s: Roughness height

Head Loss for Valves and Pipe Fittings [Minor loss]

There is no established formula for friction of Valves and pipe fittings. However from
experimental results
V2
hL  K Where K is a constant called fittings loss coefficient.
2g
Principles of Pressure Loss Measurement
Considering Figure 2, apply Bernoulli’s equation between
1 and 2:

But

For Piezometer tubes

Rearrange the last equation to get Figure 2: Pressurized piezometer tubes to

measure pressure loss between two points

From equations 1 and 2 we find that

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 COLLEGE OF ENGINEERING
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Considering Figure 3, apply Bernoulli’s equation between

1 and 2:

But

Consider the U-tube. Pressures in both limbs of U-tube are

( )
equal at level 00. Therefore equating pressure at 00:

Considering Equations 3 and 4 and taking the Figure 3: U-tube containing mercury
specific gravity of mercury as 13.6: used to measure pressure loss across
valves

Apparatus:
The setup consists of two separate hydraulic circuits; one painted dark blue, one painted light
blue, each one containing a number of pipe system components. Both circuits are supplied with
water from the same hydraulic bench. The components in each of the circuits are as detailed at
Figure 4 and Table 1.
In all cases (except the gate and globe valves), the pressure change across each of the
components is measured by a pair of pressurized piezometer tubes. In the case of the valves,
pressure measurement is made by U-tube manometers containing mercury.

Figure 4: The setup of friction loss apparatus

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Table 1: Identification of Manometer Tubes and Components

Dark Blue Circuit Light Blue Circuit
A) Straight pipe 13.7 mm bore E) Sudden expansion - 13.6 mm / 26.2 mm
B) 90° Sharp bend (mitre) F) Sudden contraction - 26.2 mm / 13.6 mm
C) Proprietary 90° elbow 12.7 mm radius G) Smooth 90° bend 50.8 mm radius
D) Gate valve H) Smooth 90° bend 100 mm radius
Distance between pressure tappings for straight pipe and J) Smooth 90° bend 152 mm radius
bend experiments = 0.914 m
K) Globe Valve
L) Straight Pipe 26.4mm
Unit Manometer tube Unit Manometer tube number
o
12.7 mm 90 elbow 1 Contraction 9
2 10
Straight pipe 3 152 mm bend 11
4 12
Mitre bend 5 100 mm bend 13
6 14
Expansion 7 50.8 mm bend 15
8 16

Procedure:
In this experiment, sudden expansion, sudden contraction, and globe valve, in the light
blue circuit is to be tested
1. Open fully the water control valve on the hydraulic bench.
2. Close fully the gate valve to isolate the dark blue circuit.
3. Open the globe valve fully to obtain maximum flow through the light blue circuit.
4. Start the pump on the hydraulic bench.
5. Wait until readings are settle down
6. Record the readings on the piezometer tubes and the U-tube.
7. Measure the time needed to collect a quantity of water in the weigh tank [25 Lit].
8. Repeat the above procedure for six different flow rates, obtained by closing the
control valve on the hydraulic bench.
9. With an accurate thermometer, record the water temperature in the sump tank of the
bench at the beginning and at the end of the experiment. Consider the average value as
the water temperature.
10. Close fully the gate valve.
11. Switch off the pump.
Results:
Table 2: Experimental Results
Time to collect Piezometer tube readings (cm) water U-tube (cm) Hg
Test number 25 kg of water
Globe valve
(s) 7 8 9 10
1

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Table 3: Calculated Results for sudden expansion

Test Volume flow Mean velocity Friction head Minor loss Minor loss
number rate Q (m3/s) (m/s) loss hf (m) coefficient coefficient % Error
KEXP KTHEO
1

Table 4: Calculated Results for sudden contraction

Test Volume flow Mean velocity Friction head Minor loss Minor loss
number 3
rate Q (m /s) (m/s) loss hf (m) coefficient coefficient % Error
KEXP KTHEO
1

Table 5: Calculated Results for globe valve

Test Volume flow Mean velocity Friction head Minor loss Minor loss
number rate Q (m3/s) (m/s) loss hf (m) coefficient coefficient % Error
KEXP KTHEO
1

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Analysis and Calculations

Head Loss in fittings (sudden expansion, sudden contraction, and globe valve) [Tables 3, 4, and 5]

1. Volume flow rate of water ̇ [ ⁄]

2. Mean velocity V
[ ⁄]
̇

3. Friction Head Loss for related manometers

4. Minor loss coefficient KExp h f  KV 2
2g
5. Find KStd from literature and find % error
6. Plot a graph of hf [y-axis] versus [x-axis] and confirm that the graph is a straight line
and find the slop of this graph. What the slop represents. Comment on your curve and slop
Discussion
1. Compare all experimental results with what is expected theoretically.
2. Comment on your % error and discuss any sources of error in the experiment.
3. State the importance of this experiment and mention some related applications.

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 COLLEGE OF ENGINEERING
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Exp. # 6
Parallel and series Pumps

Objective:
1- To study the performance of a single centrifugal pump.
2- To study the performance of two pumps connected in parallel or series.

Theory:
Pumps are used to transfer fluid in a system, either at the same level or to a new height. The
flow rate depends on the height to which the fluid is pumped. The relationship between
“head” and flow rate is called the “pump characteristic curve”. This has to be determined
experimentally for a single pump and two similar pumps connected in Series or Parallel.
The increase in head H between the inlet and outlet
of a pump is a function of the flow rate and
rotational speed N. This relationship is expressed
graphically and called the “pump characteristic”, as
shown in Figure 1.
Head, H, is a height measured in meters of water,
but an alternative convention is to use the pressure
rise across the pump, Δp (N/m2 or bar).
Δp and H are related to each other by:
Δp = ρgH, and
̇
Mass flow rate through pump, ̇
(kg/s)
Hydraulic power generated, is given by:
̇
̇
(W)………………(1)

Electrical power input to pump = ̇

Where ̇is given by manufacturer.

Overall pump efficiency

̇ ̇

Figure 1: Pump characteristics

̇ ̇ ̇

The overall efficiency of a small circulating pump is typically not much greater than 10
to 15%.
Some text books work in terms of Δp, others in terms of H. The two sets of equations
look similar, but differ by the presence of . Never confuse the two systems!
2
For practical convenience, pressure is measured in kN/m and flow rate in kg/sec, but on
2
the experimental equipment the pressure is measured in bars (1 bar = 100 kN/ m ) and the
flow rate measured in liter/sec (1 liter/sec = 1 kg/s).
For input power of the pump manufacturer’s published data may be used. (Table 1)

Two pumps in series

A schematic representation of two pumps in series is shown in Figure 2. Ignoring any losses
that occur between the two pumps, the flow rate through both is the same, but the overall
pressure rise is the sum of the two individual values. If both pumps are identical then the
pressure rise is doubled for a given flow rate. Figure 3 shows the pressure/flow characteristics
for two pumps in series.

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Figure 2: Schematic showing two pumps in series

Figure 3: Pressure-flow characteristics for two pumps in series

Two pumps in parallel
A schematic representation of two pumps in parallel is shown in Figure 4. Ignoring any losses
between the two pumps, the pressure rise across each pump is the same and is the total
pressure rise. The overall flow rate is the sum of the two individual values, as shown in Figure
5. If both pumps are identical, then the total flow rate is twice that of each single pump.

Figure 4: Schematic showing two pumps in parallel

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Figure 5: Pressure-flow characteristics for two pumps in parallel

̇ ̇
The actual pressure-flow characteristic is a curve of the form where A and B are constants which depend on the system. It is therefore useful to plot curves of Δp against
(Figure
6), which should be straight lines.

̇
Figure 6: Curves of Δp against
Bernoulli’s equation is used to estimate the inlet pressure to the pump. Referring to Figures
7 the pressure at the pump inlet is:
( ) …………………………………….(3)

An approximate total value of ΣK = 3.5 will be assumed. Hence:

……………...…………………….(4)
Since

For d=22 mm sub into equation 4

………………………….……..(5)
Wherein [Pa], in[m], and Q in [kg/s]

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Figure 7: Schematic of apparatus to apply Bernoulli’s equation

Apparatus:
The Series and Parallel Pump Test Set, shown in Figure 11, is intended for use with
the Volumetric Hydraulic Bench.
Two similar single-phase multi-speed pump units are connected by a pipe system so that each
pump can be run on its own, combined in series, or combined in parallel. Figures 12, 13, and
14 show the position of the three valves A, B and C required to set up each flow condition.
On the side of each pump, there is a three speed control. The pumps are switched on or off
using the main switch on the control panel at the top of the apparatus.
A single Bourdon gauge is fitted to the top panel which can be switched to measure the
delivery pressure of either pump. The pump inlet pressure can be determined from Bernoulli’s
equation. The water flow rate is adjusted using a gate valve fitted in the return pipe, between
the pump test set and the hydraulic bench. For experiments to determine the pump overall
efficiency, it is necessary to measure the input electrical power with a wattmeter. However,
the input powers quoted by the pump manufacturer will be sufficient to demonstrate how the
efficiency is calculated. Table 1 gives typical input powers and pump speeds.

Figure 11 The Series and Parallel Pump Test Set Figure 12 Setting the three control valves – pump 1
only

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Figure 13 Setting the three control valves – pumps Figure 14 Setting the three control valves – pumps in
in parallel series

Table 1 Typical pump input powers

Speed Input Power (watts)
I 50
II 60
III 70

Procedure:
1) Set the valves for a particular pump test (refer to Figures 12 to 14 if necessary).
2) Set the required pump speed(s).from the three speed control on side of each pump.
3) Measure the difference in height between the water surface in the reservoir and the pump
inlet.
4) Switch on the mains supply switch on the console.
5) Ensure that the valve at inlet is fully open.
6) Set up the delivery flow rate by adjustment of the gate valve on the outlet side of the
pumps. It is convenient to start with a fully open valve. Measure the flow rate using
the Hydraulic Bench.
7) Read the delivery pressure of each pump by switching to either p1 or p2. Ensure the
valve is switched off after each measurement.
8) Enter the results in the table.
9) Repeat for several different flow rates [close the control valve by 1.5 turn] until the control
valve is fully closed.

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Results:

Operation: Single Pump Pump Input Power:

Collected water: :
Time ̇ ̇

(sec) (kg/sec) (bar) (bar) %

Operation: Pumps in Series Pump Input Power:

Collected water: :
̇ ̇

Time (kg/sec)
(sec) (bar) (bar) (bar) % % %

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Operation: Pumps in Parallel Pump Input Power:

Collected water: :
̇ ̇

Time (kg/sec)
(sec) (bar) (bar) (bar) % % %

Analysis and Calculations

1- Calculate the mass flow rate [kg/s]

2- Calculate the inlet pressure. [Equation 5].

3- Calculate the pressure rise across each pump.
For series
For Parallel

4- Calculate the efficiency [Equation 2].

5- Plot graphs of pressure rise against flow
2
rate and (flow rate) .
6- Plot graphs of Efficiency against flow rate.

Discussion
1- What is the source of errors in this experiment?
2-Compare your graphs with what expected theoretically.
3- Comments on all results and analysis
4- State the applications for both series and parallel connections

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Exp. # 7
Performance of a Positive Displacement Pump
Objective:
1) To find how the pump performs for a range of delivery pressures (varied load) at a
constant speed.
2) To find how the pump performs for a range of speeds at a constant delivery pressure (load).
Theory:
Introduction
By definition, Positive Displacement (PD) pumps displace a known quantity of liquid with each
revolution of the pumping elements. This is done by trapping liquid between the pumping elements
and a stationary casing. Pumping element designs include gears, lobes, rotary pistons, vanes, screws
and hoses.
Many applications use positive displacement pumps. They are good for moving fluids at high
pressures.
Uses include hydraulic systems, lubrication systems, medical equipment and sanitation. Positive
displacement pumps come in many different types, in this experiment three most common; piston,
gear, and vane are discussed in this lab session.
Piston Pump
This pump is a twin piston industrial pump.
It has an off-centre cam that pushes two
small vertically opposed pistons up and
down alternately in cylinders. They move oil
through one-way valves from the inlet to the
outlet. The swept volume of each cylinder
determines the volume of fluid moved for
every revolution. Because the pump uses just
two pistons, it creates high pressure pulses in
the fluid at the output. In most applications,
this type of pump has a pulsation damper on
its output. This type of pump is popular and
made in large quantities, so it has a low
relative cost.
Figure 1: Piston Pump

Gear Pump
This pump is basically two helical gears that
move together in a close-fitting housing. It has
a built-in pressure relief valve. As the gears
move they create a low pressure area at the
input port. Fluid moves into the low pressure
area. The gears trap and push small volumes
of the fluid around the walls of the housing
and to the outlet. The output is reasonably
smooth, with small pulses. The size of the
gears determines the volume of fluid moved
in each revolution. Figure 2: Gear Pump

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Vane Pump
This pump has a fixed displacement with a balanced vane. It uses spring loaded vanes to move a fixed
volume of fluid around a chamber, from the inlet to the outlet port. The pump size determines the fixed
volume moved for each revolution. Vane pumps give a pulsed output. Figure below shows two drawings
that explain how two slightly different vane pumps work.

Figure 3: Vane Pump

Useful Equations

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Pump Performance and Efficiency

The pressure increase (or ‘head’) and flow rate caused by a pump are its two most important
qualities. Next most important are its efficiency and power needs.
The pressure increase is simply the difference between the pressures before and after the pump. The
flow rate is the amount of fluid that passes through the pump.
Mechanical Power (into the Pump)
This is simply the shaft power at the pump. The Universal Dynamometer couples directly to the shaft
of the pumps. The shaft power (input power WD) is given by:
( )

Hydraulic Power (from the Pump)

The hydraulic power that the pump adds to the fluid is a product of the flow through the pump and
the increase in pressure (or ‘head’) it gives: ( )

Overall Pump Efficiency

The overall efficiency of the pump is a simple ratio of hydraulic power out against shaft power input
to the pump.

Volumetric Efficiency
Volumetric efficiency is an indication of how well the pump has moved an expected (or theoretical)
volume of fluid. It is the ratio of the actual volume of fluid moved in a given time against the
expected volume of fluid moved. You normally use the total swept volume (Vs) in the pump to find
the expected flow. The expected volume flow is the product of the swept volume per one revolution
-1
(or cc.rev ) and the speed of the pump (NP). The flow-meter measures the actual volume flow (QV).
Expected volume flow = (Vs) × (NP).
From this, the volumetric efficiency:

The swept volumes for the available pumps are:

Piston Pump = 7.16 cc/rev Gear Pump = 10.89 cc/rev Vane Pump = 6.7 cc/rev
Cavitation
When you reduce the inlet pressure to a pump, it can fall to a pressure equal to (or lower than) the
vapour pressure of the fluid that it pumps. This creates bubbles of vapour in the fluid, that collapse
when the pressure increases as the fluid passes through the pump. The collapsing vapour bubbles
cause small pressure waves that can damage the pump. You can usually hear cavitation - the noise
from the pump will change or get louder as the inlet pressure decreases. The low pressure areas
may also occur inside the moving parts of some pumps under low pressure conditions.
Oil Viscosity, Pump and Flow-meter Performance
Temperature affects the oil viscosity. Increasing oil temperature gives decreasing viscosity. Oil
viscosity affects its flow along surfaces and through pipes and pumps. Small changes in viscosity
have less affect on large volume commercial pumps than they do on small pumps, where the fluid
passes through smaller openings and along smaller pipes. As the oil viscosity increases, the pump
uses more power. This affects overall efficiency.

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Apparatus:
The Experimental setup consists of the following components:
1- Positive Displacement Pump Module (figure:4)

Figure 4 shows the main parts of the

Positive Displacement Pump Module.
It shows the Module fitted with the
Universal Dynamometer. The
Universal Dynamometer turns the
pump you fit to the frame. The pump
forces oil around a circuit. The oil
comes from an oil reservoir, through
an inlet valve and through the pump.
It then passes through a pressure
relief valve (for safety) and a delivery
valve. It then passes through a gear-
type flow-meter and back to the oil
reservoir.
Electronic pressure transducers in the
circuit measure the oil pressures at
the inlet to the pump and at the outlet
of the pump. Also, a mechanical
pressure gauge also shows the
delivery pressure. A thermocouple
measures the oil temperature to help Figure 4: Positive Displacement Pump Module
find its viscosity. The flow-meter
measures the oil flow in the circuit.
The electronic pressure transducers, the thermocouple and flow-meter all connect to a digital
display that shows the pressures [inlet and outlet], temperature and flow.
2- The Pumps

The Apparatus includes three positive displacement pumps: Piston Pump, Gear Pump, and
Vane Pump
3- Versatile Data Acquisition System (VDAS) (figure 5)

It is a two-part
product(Hardware and Software)
that will:
• automatically log data
from your tests
• automatically calculate data
for you
• save you time
• reduce errors
• create charts and tables of
your data
• export your data for
processing in other software

figure 5: Versatile Data Acquisition System (VDAS)

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Procedure:

Part one: The Effect of Delivery Pressure at Constant Speed

Aim:
To find how the pump performs for a range of delivery pressures (varied load) at a constant speed.
1. Fit the pump you want to be tested.
2. Fully open the inlet and delivery valves.
3. Use the button on the pressure display to zero all pressure readings.
4. Zero the torque reading of the MFP100 Universal Dynamometer.
5. Press the start button of the Motor Drive and run the speed to 1600 rev/.min (+/- 5 rev/min) for at
least five minutes and monitor the oil temperature until it stabilizes. Check that any air bubbles
have moved away from the flow-meter.
6. Record the speed and oil temperature.
7. Slowly shut the delivery valve and maintain the speed until the delivery pressure reaches 2 bar.
Allow a few seconds for conditions to stabilize. Record the indicated flow and pressures. If you
are using
VDAS, click on the record data values button, to record all data automatically.
8. Continue increasing the delivery pressure in 1 bar steps (while keeping the speed constant) to
a maximum of 15 bar. At each step, allow a few seconds for conditions to stabilize and record
the indicated flow and pressures.

Part two: The Effect of Speed at Constant Delivery Pressure

Aim:
To find how the pump performs for a range of speeds at a constant delivery pressure (load).
1. Fit the pump you want to be tested.
2. Fully open the inlet and delivery valves.
3. Use the button on the pressure display to zero all pressure readings.
4. Zero the torque reading of the MFP100 Universal Dynamometer.
5. Press the start button of the Motor Drive and run the speed to 1600 rev/.min (+/- 5 rev/min) for
at least five minutes and monitor the oil temperature until it stabilizes.
6. Wait for any trapped air bubbles to move away from the flow-meter before you continue.
7. Slowly shut the delivery valve and maintain the speed until the delivery pressure reaches 15 bar.
8. Allow a few seconds for conditions to stabilize, then record the speed, the oil temperature,
the indicated flow (from the display) and pressures. If you are using VDAS, click on the record
data values button, to record all data automatically.
9. Reduce the speed by 100 rev/min while adjusting the delivery pressure to keep it constant at2
bar. Allow conditions to stabilize, and then record the flow and pressures.
10. Continue decreasing the speed in 100 rev/min steps (while keeping the pressure constant)
until you reach 800 rev/min. At each step, record the indicated flow and pressures.

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Results:
Part one: The Effect of Delivery Pressure at Constant Speed
Table 2: Collected Data
Pump type:
N T P1 P2 T1 Flow rate
[RPM] [N.m] [bar] [bar] [°C] [LPM]

Table 3: Calculated Results

∆P Power in Power out η over all Expected flow η Volumetric
[bar] [W] [W] LPM

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Part two: The Effect of Speed at Constant Delivery Pressure

Table 4: Collected Data
Pump type:
N T P1 P2 T1 Flow rate
[RPM] [N.m] [bar] [bar] [°C] [LPM]

Table 5: Calculated Results

∆P Power in Power out η over all Expected flow η Volumetric
[bar] [W] [W] LPM

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Analysis and Calculations

Part one: The Effect of Delivery Pressure at Constant Speed
1. Find the pressure difference across the pump and calculate the hydraulic power.
2. Calculate the expected flow for the speed of your tests, and the overall and
volumetric efficiencies.
3. Plot curves of flow rate (left axis), overall and volumetric efficiencies and shaft (input)
power (right axis) against pressure difference (horizontal axis).

Part two: The Effect of Speed at Constant Delivery Pressure

1. Find the pressure difference across the pump and calculate the hydraulic power.
2. Calculate the expected flow for the speed of your tests, and the overall and
volumetric efficiencies.
3. Plot curves of flow rate (left axis), overall and volumetric efficiencies and shaft (input)
power (right axis) against pump speed (horizontal axis).

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Exp. # 8
Open channel flow - Sluice Gate
Objective:
a) To investigate flow under a sluice gate.
b) To Find flow rate in an open channel using sluice gate and compare it with actual flow.
c) To find the Froude number Fr for open channel flow and its relation to flow.
Theory:
Introduction:
Flow of a liquid in an open channel differs from flow in a closed pipe in that it has a free
surface. In open channel flow a surface of the fluid is exposed to the atmosphere. Although
the theory applies to any liquid, the majority of practical applications are to flow of water in
rivers and canals. The motion is produced essentially by gravity force, so when considering
the mechanics of the flow, the property of specific weight w or ρg of the liquid is of basic
importance. The cross section of the channel may be of different shapes, but in this
experiment we will study flow in open channel of rectangular cross section.
In the laboratory, open channel flow experiments can be used to simulate flow in a river, in a
spillway, in a drainage canal or in a sewer. Such modeled flows can include flow over bumps
or through dams, flow through a venturi flume or under a partially raised gate (a sluice gate).
The flow under a sluice gate, is the subject of this experiment.
Properties of rectangular cross-section
Depth: Distance y from bottom of channel to free surface
Hydraulic Radius R, where
A = Area of cross section = By
P = Wetted perimeter = B+2y
Hydraulic Depth D, where
T = Surface width = B
Therefore Figure 1: Rectangular cross section

Types of flow:
Steady and unsteady flow
The flow is steady if at each position along the length of the channel the depth and velocity is
independent of time. But if depth and velocity changes with time then the flow is unsteady.
Uniform and non-uniform flow
the flow is uniform if depth and cross section are constant along the length of the channel.
But if depth and cross section varies along the channel, then flow is non-uniform.
Froude Number
In analysis of the flow an essential dimensionless parameter known as the Froude number
emerges. This is defined in terms of the velocity V, hydraulic depth D and acceleration due to
gravity g, by the equation:
√
Now the velocity c of an infinitesimal wave, driven by gravity along an open channel, is:
√

So Fr may be regarded as the ratio of flow velocity V to the velocity c of a gravity wave.
For open channel

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So

√
√

Flow Under a Sluice Gate

The sluice gate provides a convenient means of flow regulation,
especially in irrigation and drainage schemes where flow has to be
distributed in networks of interconnected channels.
Figure 2 shows a schematic of the side view of the sluice gate.
Flow upstream of the gate has a depth y1 while downstream
the depth is y2. The objective of the analysis is to formulate an
equation to relate the volume flow rate through(or under) the
gate to the upstream and downstream depths.
Applying the Bernoulli equation to flow about the gate gives
Figure 2: Flow under a sluice gate

Pressures at the free surface are both equal to atmospheric

√
pressure, so they cancel.
√
The left hand side is the Froude number for upstream flow
√

By measuring the depth of liquid before and after the sluice gate, the theoretical flow rate can
be calculated with the above equation. The theoretical flow rate can then be compared to the
actual flow rate obtained by measurements using hydraulic bench.
Apparatus:
The experimental setup consists of:
1- Open Channel Flow Apparatus
(Figure 3): It is a rectangular clear-
sided channel, 2.5 m long, adjustable
in height to give a change in slope,
with the section nominally measuring
53.5 mm wide and 120 mm high.
2- Volumetric Hydraulic Bench: It
supplies the water via the inlet hose
attached, and the channel outlet is
designed to be positioned over the
large volumetric tank of the bench,
enabling the flow rate measurements
when used with the stopwatch supplied
3- Sluice Gate Model
4- Depth gauge Figure 3: Open Channel Flow Apparatus
5- Pitot tube
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Procedure:
1- The sluice gate is fixed in the channel at a convenient station upstream of the channel
outlet.
2- The aperture is set accurately to the desired value.
3- The depth gauge is now ready for a datum when the point touches the channel bed.
4- To obtain the discharge characteristic of the gate, a set of values of upstream head and
discharge is obtained with conditions of supercritical flow downstream.
5- The flow to the channel is gradually increased by opening the pump control until the water
level upstream of the gate settles to the highest value which may conveniently be read on
the depth gauge.
6- The flow is then measured along with the head upstream of the gate.
7- The flow is then reduced in stages and at each stage both the discharge and the head are
measured.
Results:
Time to Upstream Downstream
Test depth depth
collect 25 kg % Error
number of water (s) (m3/s) (m3/s)
(mm) (mm)

1
2
3
4
5
6

Analysis and Calculations

1- Calculate the actual flow rate. [Equation 3]
2- Calculate the upstream Froude number. [Equation 4]
3- Calculate experimental flow rate
4- Graph
5- Determine corresponding to maximum flow. Note that varies from 0 to 1.

Discussion
1- Comment on all calculations and plots
2- Are results agree with what expected theoretically.
3- Derive equation 3.
4. What is the significance of Froude number?
5. Where are sluice gates found?
6. What are they used for?

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Exp. # 9
Water Turbines
Part one: Francis Turbine
Objective:
a) To demonstrate the operation of Francis turbine and direct conversion of hydraulic
power into mechanical power.
b) To investigate the performance of the Francis turbine.
Theory:
Introduction
There are two categories of hydraulic machines, the impulse and the reaction turbines. In a
reaction turbine, the water flow is used to rotate a turbine wheel or runner through the action
of vanes or blades attached to the wheel. When the blades are oriented like a propeller, the
flow is axial and the machine is called Kaplan turbine. When the vanes are oriented an
impeller in a centrifugal pump, the flow is radial and the machine is called a Francis turbine.
In an impulse turbine, the water accelerates through a nozzle and impinges on vanes attached
to the rim of the wheel. This machine is called Pelton wheel.
Engineers and students of fluid mechanics need to know how pumps and turbines work and
how efficiently they work. This experiment helps them to pick the correct pump or turbine to
do the right job. The Francis turbine is a popular and efficient radial-flow reaction turbine. A
British-American engineer - James Francis developed it in 1848, by improving earlier designs
by other engineers. It is used in hydroelectric power stations to absorb the energy from falling
water in dams and turn electric generators. It is excellent for this purpose because it can also
work as a pump to return water to the reservoir if needed.
Useful Equations
 Torque (T)
This is the torque measured by the two spring balances.
The balances measure the turning force on the drum at
the back of the turbine (see Figure 1).

 Mechanical Power ( )
This is the power absorbed by the turbine, taken from the
water.[i.e. output power]

 Hydraulic Power ( )
This is the power in the water delivered to the
turbine. [i.e. input power]
Figure 1 Torque Measurement
 Hydraulic Efficiency ( )

Where: Pm: Mechanical Power [W]

-1
T: Torque [N.m] N: Rotational speed of the turbine [rev.min ]
A: Left spring balance reading [N] Ph: Hydraulic Power [W]
B: Right spring balance reading [N] P: Pressure of inlet water [Pa]

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3 -1
F: Force [N] Q: Volume Flow [m .s ]
R: Radius of drum [m] Hydraulic Efficiency [%]
Apparatus:
Francis Turbine is a cast metal body that surrounds a runner. Around the runner are adjustable
guide vanes that direct the water onto the runner and can also help to regulate the flow
through the runner.
The water flows around the metal body in a volute that gradually decreases in diameter and
helps to move the water centrifugally around the runner. The water passes through the guide
vanes onto the runner and changes from centrifugal flow to axial flow.
At the back of the runner is a drum that works with a cord and two spring balances to
measure the torque in the turbine. The drum [25 mm radius] has a reflector and a clear cover
to work with a tachometer to measure the speed of the turbine. To adjust the load, students
adjust the threaded thumb-nuts above the spring balances.
The control to the right of the turbine adjusts the guide vanes. The scale to the left of
the turbine shows how much the vanes are open (100% = fully open).
At the inlet of the turbine is a small mechanical pressure gauge to measure the inlet
water pressure.

Figure 2 The Francis Turbine

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Procedure:
1. Fully open the guide vanes (to the 100% position).
2. Adjust the spring balances to give no load and make sure that they show 0 (zero).
3. Set the H1D to give full flow and measure the initial flow for reference.
4. Use the optical tachometer to measure the maximum (no-load) speed of the turbine.
To do this, put the tachometer against the clear window at the back of the turbine
and use it to detect the reflective sticker on the drum.
-1
5. Slowly increase the load to decrease the speed in steps of 50 rev.min . At each step,
record the turbine speed and the reading of each spring balance. Stop when the
speed becomes unstable or the turbine stops rotating.
Results:

Test Speed Left Right Force Load Mechanical Hydraulic Hydraulic

Balance Balance (Torque) Power Power Efficiency
number (rev.min-1) (N)
(N) (N) (Nm) (W) (W) (%)

Analysis and Calculations

1. Volume flow rate of water:

2. Calculate torque (T), Mechanical Power ( ), Hydraulic Power ( ), and Hydraulic

Efficiency ( )
3. Plot performance curves of the turbine
 Torque [y-axis] versus rotational speed [x-axis]
 Mechanical Power [y-axis] versus rotational speed [x-axis]
 Hydraulic Efficiency [y-axis] versus rotational speed [x-axis]
Discussion and conclusions
1. Comment on your results and plots.
2. State the importance and applications related to this experiment.

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Part two: Pelton Wheel

Objective:
c) To demonstrate the operation of Pelton Wheel and direct conversion of hydraulic
power into mechanical power.
d) To investigate the performance of the Pelton turbine.

Theory:
Introduction
The Pelton wheel is a hydraulic turbine, in which one or more water jets impinge tangentially
onto buckets mounted around a wheel. The force produced by the jet impact generates a
torque that causes the wheel to rotate, thus producing power. The name ‘Pelton’ derives from
L.A. Pelton, an American engineer who performed notable research in order to determine the
best shape of the buckets.
Although the concept is very simple, some very large machines of high efficiency have been
developed with power outputs of more than 100 MW and efficiencies of around 95%. On a
small laboratory model, however, the output may be just a few watts. The efficiency will
therefore be very much smaller, because losses in bearings and by windage are proportionally
much higher than in a large, powerful turbine.

Figure 3 Pelton wheel layout

The Pelton wheel requires a source of water in order to run. If the head of water is known,
along with the flow rate, then it is possible to deduce the best size of wheel to use, how fast it
should rotate to obtain the maximum efficiency, and what power it is likely to develop.
The velocity in the jet can be estimated by using the known fixed head. The diameter of the
jet can then be found from the known flow rate. A suitable wheel diameter can be chosen in
relation to the jet size; typically the wheel would have a diameter of 10 times that of the jet.
The best speed of rotation may then be selected, such that the speed of the buckets is
approximately half that of the jet speed.
The power delivered in the jet can be calculated from the speed and cross-sectional area. The
power developed by the Pelton wheel will be less than this, in the ratio of the wheel’s

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efficiency, which may be estimated by reference to the known performance of existing

machines of comparable size and output.
Depending on the head and flow rate available, the size and speed of the Pelton wheel
obtained in this way may prove to be impracticable or uneconomic. Fortunately, other types of
water turbine are available to suit a wide variety of circumstances.
The Pelton wheel is usually chosen when the available head is high, but the flow rate is
comparatively low.

Force Exerted by a Jet

Figure 4(a) illustrates a water jet emerging at speed v from a nozzle, and striking one of the
buckets of the wheel, which itself is moving at speed u. The mass flow rate is and it is
assumed that all of the water emerging from the nozzle strikes one or other of the set of
buckets arranged around the periphery of the wheel, although, for simplicity, just one
bucket is shown in the diagram.

(a) Force exerted by a jet b) Momentum change diagram Figure 4 Water jet striking
bucket

The relative velocity at which the jet impacts on the bucket is k(v – u). The flow over the
bucket is decelerated slightly by frictional resistance at the surface. Suppose that the relative
velocity, as the water leaves the bucket, is k(v – u), where k is a velocity reduction factor
with a value somewhat less than unity.
The relative velocity is inclined at the bucket exit angle β to the jet’s direction. The
absolute velocity of the water at exit is the vector sum of the relative velocity and the
bucket velocity u, as shown.
momentum flow in the direction of motion of the bucket is ̇ , and the outgoing rate is: ̇[ ( ) ]
The force F generated on the bucket may be found by considering the momentum change, as shown in Figure 4(b). The incoming rate of

Note the positive sign before the relative velocity at exit, indicating addition of the relative
and bucket velocities. Note also that β is greater than 90°, therefore cosβ will be negative.

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Torque Exerted on the Wheel

The force F produced on the bucket by the difference between these rates of momentum flows is:
̇ ̇[ ( ) ] ̇( )( )

It is helpful to express the ratio of bucket speed u to jet speed v as λ: so that The torque
T exerted on the wheel is therefore:
( )( )

We see that for a particular wheel, supplied with water at some fixed flow rate (so that both ̇ and v are
(Where R = 0.046 m).
also fixed), torque T varies as (1 – λ). The torque therefore falls linearly from a maximum when λ = 0 (i.e.
when the wheel is stationary) to zero when λ = 1 (i.e. when the bucket moves at the same speed as the jet).
This is referred to as the runaway condition.

Figure 5 Variation of torque T with speed ratio λ

Power Developed
The power output P developed by the wheel is given by:
Pout = ωT
Where ω is the angular speed of rotation of the wheel, and noting that:

The power output may be written as:

̇ ( )( )

This varies as λ(1 – λ), so P is zero when λ = 0, or when λ = 1, i.e. when the wheel is either
stationary or when turning at runaway speed. Between these extremes, the power varies
parabolically, with a maximum when λ = ½. The maximum value of λ(1 – λ) is ¼, so the
maximum power output is:
̇( )

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Hydraulic Efficiency of the Wheel

The power input Pin, in the form of kinetic energy in the jet, is: ̇ so the hydraulic efficiency ηh, defined as the ratio of output power to input power is:
( )( )

With a maximum value: ηmax = ½(1 – kcosβ). In the absence of friction, the relative speed is
not reduced by passage over the bucket surface, so the value of k would then be unity.
Moreover, the lowest conceivable value of cosβ is –1, corresponding to β = 180°. So the factor
(1 – kcosβ) could ideally just reach the value 2. The maximum ideal efficiency, η max, would
then just reach 100%, all the kinetic energy in the jet being transformed into useful power
output, with the water falling from the buckets with zero absolute velocity. In practice,
however, surface friction over the bucket is always present, and β cannot reasonably exceed a
value of about 165°, so 100% efficiency can never be achieved.
It must be emphasized that the hydraulic efficiency used here gives the ratio of hydraulic
power generated by the wheel to the power in the jet. The overall efficiency of the turbine
will fall short of this hydraulic efficiency due to some loss of head in the nozzle, resistance
due to windage, and losses at the bearings.

Figure 6 Variation of efficiency η with speed ratio λ

Apparatus:
The experimental setup consists of Pelton wheel (figure 7) with
external optical tachometer to measure the rotational speed.
Hydraulic bench is also needed to supply water to the turbine
and to calculate the flow rate.
Procedure:
1. Close the spear valve and switch on the water supply.
2. Slowly open the spear valve, allowing the jet to drive the
Pelton wheel. Fully open the valve.
3. Increase the load on the wheel by adjusting the knob above
the spring balance(s) at desired intervals. At each interval
record the speed (using an optical tachometer), and both Figure 7 Pelton wheel

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spring balance forces.

4. Record the time needed to collect 15 L of water.

Results:
Test Speed Left Right Force Load Mechanical Hydraulic Hydraulic
Balance Balance (Torque) Power Power Efficiency
number (rev.min-1) (N)
(N) (N) (Nm) (W) (W) (%)

Analysis and Calculations

1.Volume and mass flow rate of water:
̇

2.Calculate torque (T), Output Power (mechanical Power) ( ), Input power (hydraulic
Power) ( ), and Hydraulic Efficiency ( )
3. Plot performance curves of the turbine
 Torque [y-axis] versus rotational speed [x-axis]
 Mechanical Power [y-axis] versus rotational speed [x-axis]
 Hydraulic Efficiency [y-axis] versus rotational speed [x-axis]
Discussion and conclusions
1. Comment on your results and plots.
2. State the importance and applications related to this experiment.

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Exp. # 10
Wind Tunnel
Lift and Drag of an Airfoil
Objective:
1. To determine the velocity distribution in a wind tunnel.
2. To obtain the lift and drag variation of an airfoil with angle of attack.
Theory:
Forces in Flight
The flight of an airplane, a bird, or any other object involves four forces that may be measured
and compared: lift, drag, thrust, and weight. As can be seen in the figure below for straight
and level flight, these four forces are distributed with the 1) lift force pointing upward; 2)
weight pushing downward; 3) thrust pointing forward in the direction of flight; 4) and the
drag force opposing the thrust. In order for the plane to fly, the lift force must be greater than
or equal to the weight. The thrust force must be greater than or equal to the drag force.

Figure1: Direction of Forces in Straight and Level Flight

Weight
The weight of the aircraft is a measure of a natural force that pulls the plane down towards the
earth (gravity). Therefore, the direction assigned to the weight is downward.
Lift
The force that pushes an object up against the weight is lift. On an airplane or a bird, the lift is
created by the movement of the air around the wings. Figure (2) shows two streamlines about
a typical airfoil (or wing); one travels over the top of the airfoil, the other moves underneath
it. If two particles were released from the same point at the same time, one on each streamline,
they would start out moving together. As they approach the front of the airfoil, however, their
velocity will start to change. Due to the shape of the airfoil, the air moves faster over the top
of the airfoil than it does on the lower surface. The faster air leads to a lower pressure (from
Bernoulli's Law) on the upper surface. A smaller force, on top, will be
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pointed downward, and a larger force (underneath) will be pointing upwards. When the two
forces are combined, the net force is lift, which is directed upwards.

Figure (2): Streamlines about airfoil

The shape of the airfoil (wing) is a very

important part of lift, and airplane designers
design these shapes very carefully. Most
airfoils today have camber, meaning they
have curved upper surfaces and flatter lower
surfaces (figure 3). These airfoils generate lift
even when the flow is horizontal (flat). The Figure 3: Camber airfoil
symmetric airfoils have similar upper and
lower surfaces, the particles on the
streamlines above and below the symmetric
airfoil move at same velocity.
The pressures on either surface (top or bottom) are exactly the same, so the net combined
force on the airfoil is zero! No lift is generated by a symmetric airfoil in horizontal flow (flat
wings moving straight ahead cannot fly).
In order to generate lift with a symmetric airfoil,
the airfoil must be turned (tilted) with respect to the
flow, so that the upper surface is "lengthened" and
the lower surface is "shortened". This "tilting
against the airflow" is called angle of attack. It can
be used for either cambered or symmetric wings
(figure 4). This is why an airplane rotates slightly
at takeoff; the pilot is increasing the angle of attack
to generate more lift. If the angle of attack is
doubled, the lift doubles. There is a limit to how
much lift can be generated, however. The angle of Figure 4: Tilting against the airflow
attack can be increased to a point where the net lift
force drops drastically.
Airflow deflection is another way to explain lift. To understand the deflection of air by an
airfoil let's apply Newton's Third Law of Motion. The airfoil deflects the air going over the
upper surface downward as it leaves the trailing edge of the wing. According to Newton's Third
Law, for every action there is an equal, but opposite reaction. Therefore, if the airfoil deflects
the air down, the resulting opposite reaction is an upward push. Deflection is an important
source of lift. Planes with flat wings, rather than cambered, or curved wings must tilt their
wings to get deflection. Another way to increase lift on a wing is to extend the flaps downward.
This again lengthens the upper surface and shortens the lower surface to generate more lift. The
velocity of the freestream air (actually of the airplane) is the most important element in
producing lift. If the velocity of the airplane is increased, the lift will increase dramatically. If

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the velocity is doubled, the lift will be four times as large. The generation of lift can be found
elsewhere. Race car designers use airfoil-like surfaces to generate negative lift, or downward-
directed force. This force, combined with the weight of the race car, helps the driver maintain
stability in the high-speed turns on the race track.

Thrust
Any force pushing an airplane (or bird) forward is called thrust. Thrust is generated by the
engines of the airplane (or by the flapping of a bird's wings). The engines push fast moving air
out behind the plane, by either propeller or jet. The fast moving air causes the plane to move
forward.
Drag
The drag is the fourth of the major forces for flight. It is a resistance force. This force works
to slow the forward motion of an object, including planes. There are four types of drag:
friction drag, form drag, induced drag and wave drag. These drag types develop around the
shape of the body, the smoothness of the surfaces, and the velocity of the plane. All four sum
together for the total drag force. The drag forces are the opposite of thrust. If the thrust force
is greater than the drag force, the plane goes forward, but if the drag force exceeds the thrust,
the plane will slow down and stop.
The friction drag is sometimes also called the skin friction drag. It is the friction force at the
surfaces of the plane caused by the movement of air over the whole plane. If a person were to
look at the furface of a wing, for example, he or she would see that all the sheets of metal join
smoothly, and even the rivets are rounded over and are as flush with the surface as possible.
This helps keep the friction drag at a minimum.
The form drag, or pressure drag as it is sometimes called, is directly related to the shape of the
body of the airplane. A smooth, streamlined shape will generate less form drag than a blunted
or flat body.
Any object that moves through a fluid (water/air) can get a decrease in form drag by
streamlining. Automobiles are streamlined, which translates (allows) better gas mileage; there
is less drag so less fuel is required to "push" the car forward. Buses, vans, and large trucks are
less streamline, and this one reason why they use more fuel than smaller, streamlined cars
(weight is another reason).
Form drag is easy to demonstrate using a hand out the window of a moving car. If the hand is
held flat, like a wing, it is a streamlined object. The person only feels a small tug or drag. If he
or she turns the hand so that the palm is facing forward, the drag force is greatly increased,
and the hand is pulled backwards! It is no longer streamlined. There are two additional drag
forces, the induced drag and wave drag.
Induced drag is sometimes called the drag due to lift. As the lift force is generated along a
wing, a small amount of excess (lift) force can be generated in the opposite direction. This
force acts like drag and slows the forward motion of the airplane. Aircraft designers try to
design wings that lower induced drag.
The last of the four types of drag is the wave drag. This generally only happens when the
airplane is flying faster than the speed of sound. Wave drag is caused by the interactions of
the shock waves over the surfaces and the pressure losses due to the shocks. Wave drag can
also occur at transonic speeds, where the velocity of the air is already supersonic, locally.
Since most commercial jets today fly at transonic speeds, wave drag is an important part of
the total drag.
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Lift and Drag for airfoil

Where: V is the average velocity in (m/s)

2
A is the area in (m )
c is the chord length
b is the span length

Figure 5: Airfoil Terminology

Velocity Distribution in wind tunnel
The upstream velocity in the tunnel at any point can be found using Pitot – Static tube.(Figure
6)
Apply Bernoulli equation between points 1 and 2

Point 1 is stagnation point, and Z1=Z2, Bernoulli equation reduces to:

√ √

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Figure 6: Velocity distribution using Pitot-Static tube

Apparatus:
The Experimental setup consists of the following components:
1- Subsonic wind tunnel (Figure 7)

Figure 7: Subsonic wind tunnel

2- Airfoil (Figure 8)

Figure 8: Airfoil used in the experiment

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3- Lift and Drag Balance

(Figure 9)

Figure 9: Lift and Drag Balance

Procedure:

Velocity distribution
1. Start the wind tunnel, and operate the fan at a certain speed.
2. Keep this speed constant for the whole experiment, even in lift and drag part.
3. Adjust the Pitot tube to zero distance from the test section bottom side.
4. Read the manometer height.
5. Readjust the Pitot tube to a 20 mm distance from bottom, read the manometer.
6. Continue with steps of 20 mm to cover the whole section height.
Lift and Drag
7. Install the airfoil and all the accessories in the test section.
8. Adjust Angle of attack to zero.
9. Switch on the power and operate fan at same speed.
10. Read the values of lift and drag.
11. Repeat the same steps for different angle of attacks as shown in table 2.

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Results:
Table 1: Velocity distribution
y (mm) 0 20 40 60 80 100 120 140 160

h (mmH2O)

V (m/s)

Average fan speed =

Table 2: Lift and Drag

 (degree) Drag, FD, (N) Lift, FL, (N) CD CL

-5
0
5
10
15
20
25
Analysis and Calculations
1- Calculate the velocity in wind tunnel at each point.
2- Plot the velocity Distribution in the tunnel test section.
3- Find the average velocity.
4- Calculate the Lift and Drag coefficients (CL , CD ).

5- Calculate the ratio

6- Plot the angle of attack on the x-axis and the lift and Drag coefficients on the y-axis.
7- Plot the angle of attack on the x-axis and the ratio on the y axis.
Discussion:
1. Comment on how the forces coefficients of lift and drag vary with angle of attack.
2. What is the relationship between stall, lift and drag?
3. If you were choosing this airfoil for use on an aircraft, what incidence angle would
give the best performance and why?
4. From your results, how can you tell that the airfoil have a symmetrical section?
5. State the importance of this experiment and its applications in real life.
6. Why Test in Wind Tunnels?
7. comment on the velocity distribution in the test section of the wind tunnel

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 References

1- Engineering Fluid Mechanics

Clayton T. Crowe
Donald F. Elger
Barbara C. Williams
John A. Roberson
th
9 Edition SI VERSION

2- Fluid Mechanics
Frank M. White
Fourth Edition
University of Rhode Island
Mc-Graw-Hill

3- Basics of Fluid Mechanics

Genick Bar–Meir, Ph. D.
Version (0.3.1.1 December 21, 2011)
Chicago, 7449 North Washtenaw Ave
Copyright © 2011, 2010, 2009, 2008, 2007, and 2006

4- Operation manuals and catalogues of all equipment and apparatus supplied

by the manufacturer.

5- CWR 3201L Fluid Mechanics Laboratory Manual

Spring 2008
Department of Civil and Environmental Engineering
Florida International University

6- Chemical Engineering Laboratory-I Laboratory Manual

Edited by S. U. Rahman
Second Edition (2001)
Department of Chemical Engineering
King Fahd University of Petroleum & Minerals
Dhahran-31261, Saudi Arabia

7- A Manual for the MECHANICS of FLUIDS LABORATORY

William S. Janna
Department of Mechanical Engineering
Memphis State University
Copyright ©1997

8- FLUID MECHANICS AND MACHINERY LABORATORY

STUDENTS REFERENCE MANUAL
DEPARTMENT OF MECHANICAL ENGINEERING
AWH ENGINEERING COLLEGE KOZHIKODE

65
9- CEE 341 Fluid Mechanics for Civil Engineers Lab Manual
Salt River Project Hydraulic Engineering Laboratory
Department of Civil and Environmental Engineering College
of Engineering and Applied Sciences
Arizona State University
by Paul F. Ruff1
Julia C. Muccino2
Scot L. Thompson3

10- FLUID MECHANICS LAB MANUAL

Syed Noh Syed Abu Bakar/ Sanisah Saharin
January 2008
DEPARTMENT OF MECHANICAL ENGINEERING
KULLIYYAH OF ENGINEERING
INTERNATIONAL ISLAMIC UNIVERSITY
MALAYSIA

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