Ex. No.

1 CALIBRATION OF FLOW METERS (VENTURIMETER)

Date:

Aim: To calibrate the given venture meter for flow measurements

Apparatus requirement
Experimental setup with venturimeter, stopwatch, measuring scale & others
Theory
BASIC INTRODUCTION TO FLOW METERS
The most common principals for fluid flow metering are:
1. Differential Pressure Flow meters - eg. Venturi, orifice as also Variable area meters like rota
meter
2. Velocity Flow meters - eg. Pitot tube
3. Positive Displacement Flowmeters - Reciprocating piston, Nutating disk, Rotary vane
4. Mass Flowmeters – e.g. Coriolis mass flow meter
5. Open Channel Flowmeters – e.g. Vnotch, Weir
No flow meter or measuring technique is fool proof & hence the calibration of instrument is highly

necessary. Calibration of venturimeter means that determination of coefficient of discharge (i.e., Cd)

which truly indicates the discrepancy between actual and real or theoretical discharge.

WORKING PRINCIPLE AND CONSTRUCTION OF A VENTURIMETER

Schematic of a venturimeter

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In the venturi meter the fluid is accelerated through a converging cone of angle 15-20o and the

pressure difference between the upstream side of the cone and the throat is measured and provides the

signal for the rate of flow. The pressure difference between 1 and 2 is measured by the differential

mercury manometer. The fluid slows down in a cone with smaller angle (5-7o) where most of the

kinetic energy is converted back to pressure energy. Because of the cone and the gradual reduction in

the area there is no vena contracta. The flow area is at minimum at the throat. The attraction of this

meter lies in its high energy recovery so that it may be used where only a small pressure head is

available, though its construction is expensive. Venturimeters are highly applicable for the

computation of flow rates in the closed Pipes, including the measurement of gas flow rates. A

discharge coefficient - Cd - of 0.975 may be taken as standard, but the value varies noticeably at low

values of the Reynold‟s number. The pressure recovery is much better for the venturi meter than for

the orifice plate. However, because of their constructional aspects and no suitability in congested

spaces, other flow meters are used.

The standard dimensions for the meter are:

Entrance cone angle (2a1) = 21+ 2o

Exit cone angle (2a2) = 5 to 15o

Throat length = one throat diameter

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PROCEDURE
1. Before switching on the pump, ensure the priming of pump & closure of all valves (i.e. gate
valves & others).
2. Select the given venturimeter for which calibration is to be done and appropriately de-air the
manometer limbs, using the respective valves.
3. Open the main valve fully (i.e., w.r.t. the selected venturimeter) and observe the maximum
pressure difference between the limbs of manometer.
4. With this initial position, note down the time required to collect volume of water for the 10cm
height of water in the tank.
5. Following a similar procedure, vary the flow rate and get the other data pertaining to pressure
difference and time for collection of water. Take at least 6 readings.
6. Calculate the actual rate of discharge (Qact) and determine the theoretical rate of discharge
(Qth)
7. Determine the Co-efficient of discharge (Cd) by computation. Also determine Cd graphically
by plotting Qact vs Qth.

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Specification

Length of collecting tank = L = m, breadth of collecting tank = B = m,

a) Experimental data pertaining to venturimeter 1 (i.e., attached to Pipe 1)

Inlet diameter of Venturimeter 1 = Pipe 1 dia = d1 = m.
Throat diameter of venturimeter 1 = d2 = m
Cross sectional area of inlet = a1 = m2
Cross sectional area of throat = a2 = m2

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Tabulation:
Differential Time Head
Manometric Actual Theoretical Coefficient
S. manometer taken for loss,
head, discharge discharge of discharge
No. reading(m) 10cm hf
hm, (m) Qa (m3/s) Qthe, (m3/s) Cd
Ll Rl rise, (s), (m)

1
2

Calculations (i.e., for any one set of data) :-

Data :- Ll = m, Rl = m, & t = s
Manometric head = hm = L l ~Rl = m
Head loss through the meter = hl = hm x (13.6 – 1) = = m of H2o.
Actual discharge through the Venturimeter = Volume of water collected in tank for 10cm rise

Time taken, t secs

= = m3/s
Theoretical discharge through the Venturimeter = a1a2 (a1 – a22)
2

(2gh)

= = m3/s
Computed coefficient of discharge = Cd = Qa /Qth =

Coefficient of discharge from the graph of Qa v/s Qth:

Slope = Cd = Constant.
Qa
Coefficient of discharge from the graph = Cd =
Qth

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RESULT

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Ex. No. 2 CALIBRATION OF FLOW METERS (ORIFICE METER)
Date:

Aim:
To calibrate the given orificemeter for flow measurements in the Pipe

Apparatus requirement:

Experimental set up with orificemeter, stop watch, measuring scale, & others.

WORKING PRINCIPLE AND CONSTRUCTION OF AN ORIFICEMETER

The following sketches depict the orifice and also its principle of construction.

Schematic of streamlines in an orificemeter during fluid flow

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The orifice meter consists of a flat orifice plate with a circular hole drilled in it. There is a pressure

tap upstream from the orifice plate and another just downstream. There are in general three methods

of placing the taps. The coefficient of the meter depends upon the position of taps.

Distance of upstream tap Distance of downstream tap

Type of tap
from face of orifice from downstream face

Flange 1 inch 1 inch

1 pipe diameter (actual 0.3 to 0.8 pipe diameter,

Vena contracta
inside) depending on b

2.5 times nominal pipe

Pipe 8 times nominal pipe diameter
diameter

The principle of the orifice meter is identical with that of the venturi meter. The reduction

of the cross section of the flowing stream in passing through the orifice increases the velocity head at

the expense of the pressure head, and the reduction in pressure between the taps is measured by a

manometer. The pressure recovery is limited for an orifice plate and the permanent pressure loss

depends primarily on the area ratio. For an area ratio of 0.5, the head loss is about 70 - 75% of the

orifice differential.

Orifices serves many purposes in engineering practice other than the metering of fluid flow,
but the study of the orifice as a metering device will allow the application of principles to other
problems. Orifices may be used in closed conduits or fitted to the containers for discharging the
fluids. They are highly preferred over venturimeters because of its simplicity in construction and
utility in space congestions, in spite of this lower Cd values.

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PROCEDURE
1. Before switching on the pump, ensure its priming and proper closure of all valves (i.e., gate
valves & others).
2. Select the given orificemeter for which calibration is to be done and appropriately de-air the
manometer limbs, using the respective valve.
3. Open the main value fully (i.e., with respect to the selected orificemeter) and observe the
maximum pressure difference between the limbs of manometer.
4. With this initial position, note down the time required to collect volume of water for 10 cm
height of water in the tank.
5. Following a similar procedure, vary the flow rate and get the other data pertaining to pressure
difference and time for collection of water. Take at least 6 readings.
6. Calculate the actual rate of discharge (Qact) and determine the theoretical rate of discharge
(Qth)
7. Determine the Co-efficient of discharge (Cd) by computation. Also determine Cd graphically
by plotting Qact vs Qth.

POINTS TO BE NOTED
 Formation of Vena-contracta- Fluid stream separates from the downstream side of the orifice

plate and forms a free-flowing jet in the downstream side.

 Orifice coefficients are more empirical than those for the Venturi meter.

 Orifice coefficient, generally, is 0.61 in case of flange taps and vena-contracta taps for NRe<

30,000.

In the process of calculating fluid velocity with a orifice meter, the velocity of approach is not
included

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Specifications
Length of collecting tank = L = m,
breadth of collecting tank = B m,
Plan area of tank = A = L x B = m2 .

Tabulations
a) Experimental data pertaining to orificemeter 1 (i.e., attached to Pipe 1)
Diameter of Pipe 1 = d1 = m, Diameter of orifice 1 = d2 = m

Differential Time Head

Manometric Actual Theoretical Coefficient
S. manometer taken for loss,
head, discharge discharge of discharge
No. reading(m) 10cm hf
hm, (m) Qa (m3/s) Qthe, (m3/s) Cd
Ll Rl rise, (s), (m)

1
2

Calculations (i.e., for any one set of data)

Data, Ll = m, Rl = m, & t = s
Manometric head = Hm = Ll – Rl = m
Head loss through orifice = hl = hm (13.6 – 1) = m of water
Actual discharge through the orificemeter = Volume of water collected in tank for 10cm rise

Time taken , t secs

= = m3/s
Theoretical discharge through the Venturimeter = a1a2 (a12 – a22)

(2gh)

= = m3/s

Computed coefficient of discharge = Cd = Qa /Qth =

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Coefficient of discharge from the graph of Qa v/s Qth:

Slope = Cd = Constant.
Qa
Coefficient of discharge from the graph = Cd =

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RESULT

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Ex. No. 3
Date: CALIBRATION OF A ROTAMETER

Aim:
To calibrate the given Rota meter for flow measurements in the Pipe

Apparatus requirement
Experimental set up with rotameter, stop watch, measuring scale, & others.

WORKING PRINCIPLE AND CONSTRUCTION OF A ROTAMETER

Rotameter belongs to the category of variable area flowmeters. In the variable area meter, the

drop in pressure is constant and the flow rate is a function of the area of constriction.A rotameter

consists of a tapered glass tube with the smallest diameter at the bottom. The tube contains a freely

moving float which rests on a stop at the base of the tube. When the fluid is flowing the float rises

until its weight is balanced by the upthrust of the fluid, the float reaches a position of equilibrium, its

position then indicating the rate of flow. The flow rate can be read from the adjacent scale, which is

often etched on the glass tube. The float is often stabilized by helical grooves incised into it, which

introduce rotation - hence the name. Other shapes of the floats - including spheres in the smaller

instruments may be employed. The pressure drop across the float is equal to its weight divided by its

maximum cross-sectional area in the horizontal plane. The area for flow is the annulus formed

between the float and the wall of the tube. This meter may thus be considered as an orifice meter with

a variable aperture, and the formula derived for orifice meter / venturi meter are applicable with only

minor changes. Both in the orifice-type meter and in the rotameter the pressure drop arises from the

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conversion of pressure energy to kinetic energy (recall Bernoulli's equation) and from frictional

losses which are accounted for in the coefficient of discharge.

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The coefficient CD depends on the shape of the float and the Reynolds number (based on the velocity

in the annulus and the mean hydraulic diameter of the annulus) for the annular space of area A2.

In general, floats which give the most nearly constant coefficient are of such a shape that they set up

eddy currents and give low values of CD. The constant coefficient for the float C arises from

turbulence promotion, and for this reason the coefficient is also substantially independent of the fluid

viscosity. The meter can be made relatively insensitive to changes in the density of the fluid by the

selection of the density of float, rf. If the density of the float is twice that of the fluid, then the

position of the float for a given float is independent of the fluid density.

Because of variable-area flowmeter relies on gravity, it must be installed vertically (with the flowtube

perpendicular to the floor). The range of a meter can be increased by the use of floats of different

densities. For high pressure work the glass tube is replaced by a metal tube. When a metal tube is

used or when the liquid is very dark or dirty an external indicator is required.

The advantage of rotameters is direct visual readings, wide range, nearly linear scale, and constant

(and small) head loss. It requires no straight pipe runs before and after the meter.

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PROCEDURE
1. Before switching on the pump, ensure its priming and proper closure of all valves (i.e., gate
valves & others).
2. Select the given rotameter for which calibration is to be done and appropriately de-air the
manometer limbs, using the respective valve.
3. Open the main value fully (i.e., with respect to the selected rotameter) and note the reading on
the scale (Qth).
4. With this initial position, note down the time required to collect volume of water for 10 cm
height of water in the tank.
5. Following a similar procedure, vary the flow rate (noting the reading of the rotameter scale)
and get the other data pertaining to time for collection of water. Take at least 6 readings.
6. Calculate the actual rate of discharge (Qact).
7. Determine the Co-efficient of discharge (Cd) by computation. Also determine Cd graphically
by plotting Qact vs Qth.

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TABULATION

Rotameter Time taken

Sl. Rotameter reading Actual discharge Coefficient of
reading (m3 / s) for 10cm rise,
No. (l/min.) Qa (m3/s) discharge Cd
(Qth) (s)

1
2

Calculations

Actual discharge through the rotameter = Volume of water collected in tank for 10cm rise

Time taken , t secs

= m3/sec

Computed coefficient of discharge = Cd = Qa /Qth =

Coefficient of discharge from the graph of Qa v/s Qth:

Slope = Cd = Constant.
Qa
Coefficient of discharge from the graph = Cd =

Qth

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RESULT

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Ex. No. 4 DETERMINATION OF DARCY’S FRICTION FACTOR
Date :

Aim
To determine the Darcy‟s friction factor for the given pipe material

Apparatus requirement

Experimental set up related to the given experiment, stop watch, Measuring scale and others.

PRINCIPLE
In steady incompressible flow in a pipe irreversibilities are expressed in terms of a head loss,
or drop in grade line. Losses, or irreversibilities, cause this line to drop in the direction of flow.
Experiments on the flow of water in long, straight, cylindrical pipes indicated head loss varied
directly with velocity head and pipe length, and inversely with pipe diameter (as shown in figure)

Schematic of Pipe Friction

The Darcy–Weisbach equation is probably more rationally based than other empirical

formulations and has received wide applications & acceptance. The equation is given by hf =

flv2/2gd, where, hf is loss due to friction in m; f is dimensionless friction factor; V is the average

velocity across the C/S in m/s; d is pipe diameter in m. The friction factor f also depends upon fluid

properties (such as density and viscosity) and also on material roughness.

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Friction factor under different flow conditions

a) Laminar flow

According to the Hagen-Poiseuille equation for fluid flow under laminar conditions, the friction

factor is proportional to viscosity and inversely proportional to the velocity, pipe diameter, and fluid

density under laminar flow conditions. The friction factor is independent of pipe roughness in laminar

flow because the disturbances caused by surface roughness are quickly damped by viscosity.

b) Turbulent flow

Under turbulent conditions of flow, the relationship becomes more complex and is best shown

by means of a graph since the friction factor is a function of both Reynolds number and roughness.

Nikuradse showed the dependence on roughness by using pipes artificially roughened by fixing a

coating of uniform sand grains to the pipe walls. The degree of roughness was designated as the ratio

of the sand grain diameter to the pipe diameter (/D).

The main significance of friction factor is to assess the extent of energy loss in pipe flow,
while designing a pipe, pump to pressurize the fluid in pipes and other similar situations.

Applications
To evaluate the capacity of a pump for conveying fluids including media, jams, powders
etc. Process engineering, Design of pumps

PROCEDURE

1. Before switching on the Pump, ensure the priming of pump & closure of all valves (i.e., gate
valves & others).
2. Select the given Pipe for which the friction factor of the materials is to be determined and
appropriately de-air the manometer limbs, using the respective values.
3. Open the main valve fully and observe the maximum pressure difference between the limbs of
manometer.
4. With this initial position, note down the time required to collect volume of water for 10 cm
height of water in the tank.
20 | P a g e
5. Following a similar procedure, vary the flow rate and get the other data pertaining to pressure
difference and time for collection of water. Take at least 6 readings.
6. Calculate the head loss (hf). Determine the theoretical head loss (hth).
7. Determine the friction factor graphically by plotting hf Vs hth.

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 Observations:

Length of collecting tank = L = m,

Breath of collecting tank = B = m,
Plan area of tank = A = L x B = m2.
Diameter of Pipe 1 = d1 = m,
Cross section area = a1 = m2
Diameter of Pipe 2 = d2 = m,
Cross section area = a2 = m2
Length of Pipe under consideration = l m

Tabulations

(a) Experimental data pertaining to Pipe 1

Diameter of Pipe 1 (or Pipe 2) = d1 (or d2) = m. and a1 (or a2) = m2 .

Differential Time Head

Manometric Actual Actural Computed
Sl. manometer taken for loss, Velocity
head, discharge velocity friction
No. readings (m) 10cm hf head (m)
hm, (m) (m3/s) Va, (m/s) factor f
Ll Rl rise, t(s) (m)
1

Calculations (i.e., for any one set of data)

Data :- Ll = m, Rl = m, & t = s
Manometric head = hm = Ll – Rl = m,
Head loss (due to friction) = hf = hm x (13.6 – 1) = m of H2O.

Actual discharge through the pipe = Qa = Volume of water collected in tank for 10cm rise

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 (Volumetric flow rate) Time taken , t secs

= m3/s

Actual velocity through the pipe = va = Qa/a = m/s

Computed friction factor = f = hf2gd

----------- = =
lv2

Friction factor from the graph of hf v/s V2/2g

Slope = hf/(Va2/2g) = Const.

or Slope = fl/d
f = slope * d/l
hf

Friction factor from graph =

Va2/2g

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RESULT

24 | P a g e
EX. No: 5 DETERMINATIONS OF MINOR LOSSES IN PIPES

Date: (SUDDEN EXPANSION AND CONTRACTION)

Aim
To determine the various minor losses in Pipes subjected to sudden expansion and
contraction arrangements. (i.e., determination of appropriate loss coefficients)
Apparatus requirement
Experimental setup containing sudden expansion and contraction arrangements, stopwatch,
measuring scale & others.

Theory

Into the category of minor losses in Pipelines fall those losses incurred by change of section,
bends, elbows, valves and fitting of all types. Although in long pipelines these are distinctly “minor”
losses and can often be neglected without serious error, in shorter Pipelines an accurate knowledge of
their effects must be known for correct engineering calculations,. Early experiments with water (at
high Reynolds No.) indicated that minor losses vary approximately with the square of velocity and
led to the proposal of the basic equation, hl = Kl (V22/2g), in which kl is loss coefficient when an
abrupt enlargement of section occurs in a Pipeline, a rapid deceleration takes place, accomplished by
characteristic large – scale turbulence, which may persist in the larger pipes for a distance of 50
diameters or more before the normal turbulence pattern of established flow is restored. (refer the
following Fig.). Whereas, flow through an abrupt contraction is featured by the formation of Vena –
contracta and subsequent deceleration and re-expansion of the live-stream of flowing fluid. (Refer the
following sketch.) Various contraction patterns are also shown below along with their loss
coefficients.

25 | P a g e
 Pipe with Abrupt Enlargement Section Pipe with Contraction of section

PROCEDURE

1. Ensure Proper priming, before turning on the Pump.

2. Fully open the valve and allow the flow through the selected arrangement (i.e., abrupt
enlargement or contraction).
3. Appropriately de-air the limbs of manometer by using or operating suitable valves.
4. Observe the maximum pressure difference & for this note down the time required to collect
water for 10cm rise in the collecting tank for sudden expansion.
5. Following a similar procedure, vary the flow rate and get the other data pertaining to pressure
difference and time for collection of water. Take at least 4 readings each for sudden
expansion.
6. Repeat the same procedure to determine the losses due to sudden contraction.

26 | P a g e
Observations
Length of collection tank = L = m,
breadth of collecting tank = B = m.
Plan area of tank = A = lxB = m2.

Tabulations

a) Experimental Data for Pipe with Abrupt or sudden enlargement

Pipe diameter = d1 = m, c/s area of Pipe = a1 = m2.
& Pipe enlarged diameter = d2 = m, c/s area of enlargment Pipe = a2 = m2 .

Time
Actual Loss
Differential taken Actual
Manometri Theoretica discharg Actual Coeff
Sl. manometer for Velocity
c head, l head loss e head icient
No. readings(m) 10cm V (m/s)
hm, (m) (m) Qa loss(m) Kl
Ll Rl rise, V1 V2
,(m3/s)
t(s)
1

b) Experimental Data for Pipe with abrupt or sudden contraction

Pipe contracted diameter = d2 = m, c/s area of contracted pipe = a2 = m2 .

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 Time
Actual Loss
Differential taken Theoretic
Manometric dischar Actual Actual Coeff
Sl. manometer for al head
head, ge Velocity head icient
No. readings(m) 10cm loss
hm, (m) Qa Va (m/s) loss(m) Kl
Ll Rl rise, (m) 3
,(m /s)
t(s)
1

Coefficient of head loss from the graph of (hl)a v/s (hl)th

Slope = Kl = Constant.
(hl)ac
Head loss Coefficient from the graph = Kl =

(hl)the
Calculations
For sudden Expansion

Ll = m, Rl = m, and t = secs.

Manometric head loss = hm = Ll ~ Rl = m

Actual head loss = (hl)ac = hm (13.6 – 1) = m of water

Actual Discharge = Qa = Volume of water collected for 10 cm rise

Time of collection

Theoretical head loss = (hl)th = (V1 – V2)2/2g = = m

Computed head loss coefficient = (hl)act

-------- = Kl =
(hl)th

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For sudden contraction,
Ll = m, Rl = m, and t = secs.

Manometric head loss = hm = Ll ~ Rl = m

Actual head loss = (hl)ac = hm (13.6 – 1) = m of water

Actual Discharge = Qa = Volume of water collected for 10 cm rise

Time of collection
= = m3/s

Velocity of flow in the contracted pipe = V2 = Qa/a2 = m/s

Theoretical head loss = (hl)th = 0.5 V22/2g = m

Computed head loss coefficient = (hl)act

-------- = Kl =
(hl)th

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Result:

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EX.No: 6
Date: PRESSURE DROP ACROSS PACKED COLUMN

AIM:
To verify relationship between the flow of the fluid and pressure drop per unit length of

packing.

THEORY:
Packed columns for gas- liquid contacting is used extensively for adsorption

occupations, distillation and extraction processes. Usually the columns are filled with randomly

oriented packing materials. The resistance to the flow of the liquid through the voids in a bed of

solids is the result of the total drag on all the particles on the bed. The total drag per unit area of the

channel is the sum of two kinds i.e. viscous drag forces and inertial forces.

1. Flow in a packed bed involves a complex pattern of solvent traveling in and around spaces in

thesupport materials, through channels or pores of various sizes and shapes.

2. The basic structure of a packed bed is made up of three regions

a) Flowing mobile phase: the solvent which is flowing freely through the column, located outside the

pores of the support material.

b) Stagnant mobile phase: the solvent which is near the surface of the support or in it pores and which

does not travel freely through the column (it is significant in liquid chromatography).

31 | P a g e
c) Support material and stationary phase

3) Measure of amount of space occupied by solvent or solid support in a packed bed: porosities.

There are three types of porosities used to describe a packed bed

a) Intraparticle porosity (εp): the fraction of the column volume occupied solvent inside the

pores of the support or directly in contact with its surface (i.e., the stagnant mobile phase)

εp = Pore volume of the column

Empty volume of the column

For most porous support materials, εp ~ 0.4

b) Interparticle porosity (εe): the fraction of the column volume occupied by solvent in the

column but excluded or outside of the support materials (i.e., the flowing mobile phase)

Volume outside of support

εe =
Empty column volume
For uniform spherical supports, εe ~ 0.4

c) Total porosity (εtot): the total fraction of the column volume occupied by solvent

Void volume of column

εtot =
Empty column volume
For most prous supports, εtot ~ 0.8 (I.e., 80% of the average column is ocupied by mobile phase and

20% by the solid support.

32 | P a g e
 4. Flow in packed beds, as in open tubes, can be characterized by Reynolds number (Re), where dp is

now set equal to the diameter of the particles in the packed bed. In order words, for a packed bed the

average width of each flow channel is assumed to be the same as the width of one support particles

Re = udp/

Where: ρ = solvent density (kg/m3)
u = solvent linear velocity (m/s)
dp = diameter of the particles in a packed-bed system(m)
η = solvent viscosity (Pa. s)
5. Due to the complex flow pattern in packed beds, the values of Re that characterize turbulent vs.

laminar flow are not as well as defined as they are in open tubes. However, the following guidelines

are general considered to be true.

Turbulent flow only: Re >100

Laminar + turbulent flow: Re = 1 to 100

Laminar flow only: Re < 1

6. The presence of a solid support in the packed bed creates resistance to solvent flow. The result is

that it is more difficult to move a solvent through a packed bed at a given flow-rate than it is to move

it through an open tube.

Open channel Packed bed

7. The degree of flow resistance in any medium is given by Bo the specific permeability coefficient.

Bo is usually given in units of cm2, or Darcy unit (where 1 Darcy = 10-8 cm2).
33 | P a g e
 8. For any packed bed containing solid support, the average linear velocity (uAvg) of solvent in the

bed in given by Darcy‟s equation.

uAvg = ΔP Bo /(εeηL)

Where: ΔP = pressure drop across the tube (i.e., P at inlet – P at the outlet)

η = solvent viscosity; L = tube length; εe= intra-particle porosity

At low Reynolds‟s number viscous forces are much more and inertial forces are negligible. At high

Reynolds‟s number inertial forces are more and viscous forces are negligible.

The pressure drop suffered by a single liquid in flowing through a bed is given by Ergun‟s

Equation.

For 1<NREP<1000

p 3 DP S =150(1-)  1.75
LV02(1-) S NREP
For NREP<1
P 3 DP2 S2 =150 , Koenzy Carmen Equation
L V0  (1-) 

For NREP >1000
 1.75

P  D 
3 2
P S=


LV02(1-)

PROCEDURE:

1. Slightly open the inlet valve and wait for steady state and note down manometer heads in both
the arms.
2. Note the time required for a 10 cm rise in the level of water in the collection tank.
3. Repeat step 1and 2 for various flow rates.
4. Tabulate the observation and calculate (P/L) theory and exp (pressure drop per unit length of
the column) and friction factor theoretical & experimental.

34 | P a g e
 FORMULAS:

For NRE between 1 and 1000

(P/L0)TH =1502  2V03 (1-)2 2

+ 1.75 V03 (1-)
D   D 
P S S P

For NREP<1

(P/L0)TH =150  V0 (1-)2

DP2 S2 3

For NREP>1000

(P/L0)TH = 1.75  V02 (1-)

S DP 3

NREP = DP V0 


Friction Factor (f) exp = P 3 DP s
 V02 L (1-)

(P/L)EXP = (g) HH2O , HH2O= (h1- h2)10-2

L

For NREP

Friction factor fth = 150(1-)

S DPV0 NREP

For 1<NREP<1000

Friction factor fTH = 150(1-) + 1.75 sNREP

For NREP >1000

Friction factor fth = 1.75

Spherical velocity = Q/A m/s
Volumetric flow rate = Volume of water collected m3/s
Time of collection

35 | P a g e
Area A = D2/4 m2

Where
p = Pressure drop
L = Bed height
 = Viscosity of water
V0 = Spherical velocity
 = Porosity
DP = Diameter of spherical particle
s = Sphericity
 = Density
D = Diameter of column

36 | P a g e
OBSERVATION:

Diameter of particles = 1.43110-2 m

Diameter of column = 7.210-2 m
Bed height = 1.175 m
Porosity = 0.3428

Specification

Packing used Raschig rings

Diameter of the tube (Dc) = 50 x 10-3 m
Effective length of the column = 1.0 m
Density of the manometric fluid (rm) = 13521.6 kg / m3
Density of the fluid used (water) r = 995.372 kg / m3
Viscosity of the fluid used = m = 9 x 10-4 Ns / m2

Dimensions of the packing

Outside diameter = 9mm
Inside diameter = 6 mm
Height = 10 mm
Total surface area of the packing (Sp) = pL (do+di) = 2 x (p/4 (do2 – di2) = 541.65 mm2
Volume of the packing (Vp) = 353.20 mm3
Volume of the sphere (Vp) = 353.2 mm3
Diameter of the sphere = 8.77 mm
Equivalent diameter of the packing (Dp) = 8.77 m
Surface area of the packing (As) = 241.6 mm2
Sphericity of the packing (ps) = as / Sp = 0.446
Modified Reynold‟s No. (Rem.) = s Dp Vo  / µ (1-) = 12723.261 Vo
Ergun‟s Friction factor (fr) = 150 / Rem
= 150 / Rem + 1.75 (Rem >1000)
Experimental Friction factor (fr) =P s Dp 3 / L Vo2  (1-)

37 | P a g e
TABULATION

S.NO MANOMETER (H)H2O Time Velocity Q=V/A (H/L)TH (H/L)EXP

READING h1- h2 taken (V0) NRE FTH FEXP
h1 h2 m for 10 m/s m/s
(m) (m) cm
rise (s)

1.
2.

3.

4.

5.

GRAPHS:

NREP Vs (Friction factor)EXPERIMENTAL

NREP Vs (Friction factor)THEORITICAL
NREP Vs (P/L)EXPERIMENTAL
NREP Vs (P/L)THEORETICAL

38 | P a g e
Result:

39 | P a g e
Ex. No. 7
Date: PRESSURE DROP IN A FLUIDISED BED COLUMN

AIM:

1. To observe and study the behaviour of bedding fluidisation

2. To determine the pressure drop per unit length as a function of superficial velocity of

fluidisation medium

3. To determine the minimal fluidisation velocity

4. To study the effect of the porosity .

THEORY:

When a gas or liquid is passed at very low velocity up through a bed of solid particles, the

particles do not move and the pressure drop is given by Ergun‟s equation.

If the fluid velocity is steadily increased, the pressure on the individual particles increase and

eventually the particles start to move and become suspended in the fluid. This form of fluidisation

and fluidized bed are used to describe the condition of fully suspended particles.

When a fluid passes through a bed of solids, there will be a certain pressure drop across the

bed required to maintain the fluid flow. Depending upon the bed geometry, fluid velocity and particle

characteristics, and the following phenomena occurs with gradual increase in fluid velocity.

At low velocities there is a pressure drop across the bed, but the particles are stationary and

the flow of fluid through a fixed bed. As the velocity is gradually increased assert. A value is reached

when the bed starts expanding. The point is known as fluidized bed.

40 | P a g e
PROCEDURE:

1. Note the initial bed height.

2. Open the valve slightly and allow the water to flow through the bed.

3.Note the bed height.

4. Note the right and left arm readings in the inverted manometer and also the time required for a

10 cm rise in the level of water in the collecting tank.

5. Gradually increase the flow of water by opening the valve and repeat steps 3 and 4.

6.Repeat the aforementioned steps until the maximum bed height is obtained.

41 | P a g e
 OBSERVATION:

Diameter of column D =0.044m

Diameter of particle dp =410-3
Initial bed height Lo =1.3310-2
Initial porosity o =0.2036
STANDARD DATA:

Fluidising medium is water

Column diameter (Dc) = 5.0 x 10-2 m
Packing material – Spherical glass beads
Diameter of the beads (Dp) = 3.0 x 10-3 m
Initial height of the packing, Zo = 1.2 x 10-1 m
Density of the fluid, (water)  = 998 kg / m3
Viscosity of the fluid (water) µ = 8.5 x 10-4 Ns/m2
Initial porosity of the packed bed = 3 x 10-1
FORMULA USED:

Minimal fluidisation velocity Vom = 0.005 g dp2(s-w)o3 m/s

(1-o)

Reynolds Number Nre= DV


Velocity Vo=Q/A m/s

Volumetric flow rate Q = Volume of water collected m3/s

Time of collection

Porosity  = 1-Lo [1-o]

L

Initial Porosity o = Void volume

Total volume

Cross sectional area of the column = d2 m2

4
Where,
D - Diameter of column m
42 | P a g e
 dp - Diameter of particle m
s - Density of particle kg/m3
w - Density of water kg/m3
 - Viscosity of water kg/ms
Lo - Initial bed height m
L - Bed height m

GRAPHS:
Velocity Vs Porosity
Velocity Vs (H/L)exp
Velocity Vs Bed height

Tabulations:

S.no Manometer H Time Q Bed Porosity V0=Q/A NRE H/L

Reading of taken height  (m/s)
water for L
h1 h2 10cm
(m) (m) (m) rise (s) (m3/s) (m)
1

2.

3.

4.

5.

6.

43 | P a g e
RESULT:

44 | P a g e
Ex No: 8
Date: HEAT TRASFER THROUGH COMPOSITE WALLS

Aim:

To determine the thermal conductivity of the composite wall.

Theory:

The apparatus consists of a central heater sandwiched between two sheets. Three types of
slabs are provided on both sides of heater which forms a composite structure. A small hand press
frame is provided to ensure the perfect contact between the slabs. A dimmerstat is provided for
varying the input to the heater and measurement of input is carried out by a voltmeter, ammeter.
Thermocouples are embedded between interfaces of the slabs, to read the temperature at the surface.
The experiment can be conducted at various values of input and calculation can be made accordingly.

Specifications:

1. Slab assembly arranged symmetrically on both sides of heater.

2. Heater: Nichrome heater wound on mica former and insulation with control unit capacity 300
watt maximum.
3. Heater Control Unit: 0-230 V , 0-2 Amps. Single phase dimmerstat ( 1 No.)
4. Voltmeter 0-100-200V. Ammeter 0-2 Amps.
5. Temperature indicator (digital type) 0-200 c. service required- A.C. single phase 230 V.
earthed electric supply.
6. Length of the slab = 253 mm
7. Width of the slab = 203 mm
8. Thickness of aluminium and alloy = 12 mm
9. Thickness of wood and hylum = 12.64
10. Test section efficiency = 58 %

Experiments to be carried out:

1. To determine total thermal resistance and thermal conductivity of composite wall.

2. To plot temperature gradient along composite wall structure.

45 | P a g e
Precautions:
1. Keep dimmerstat to zero before start.
2. Increase the voltage slowly.
3. Keep all the assembly undisturbed.
4. Remove the air gaps between the plates by removing the hand press gently.
5. While removing the plates do not disturb the thermocouples.
6. Operate the selector switch of temperature indicator gently.
Procedure:

Arrange the plates in proper fashion (symmetrical) on both sides of the heater plates.
1. See that plates are symmetrically arranged on both sides of the heater plates.
2. Operate the hand press properly to ensure perfect contact between the plates.
3. Close the box by cover sheet to achieve steady environmental conditions.
4. Start the supply of heater. By varying the dimmerstat, adjust the input at the desired value.
5. Take readings of all the thermocouples at an interval of 10 minutes until fairly steady
temperatures are achieved and rate of rise is negligible.
6. Note down the readings in observation table.

46 | P a g e
Mean Readings: Ti = (T1 + T6) / 2

To = (T5 + T10) / 2

T = Ti -- To

CALCULATIONS:

Read the heat supplied Q = V * I Watts ( In S.I. units) = 0.861 VI Kcal/hr ( In M.K.S units). For
calculating the thermal conductivity of complete walls, it is assumed that due to large diameter of the
plates, heat flowing through central portion is unidirectional i.e. axial flow. Thus for calculations,
central half diameter area where unidirectional flow is assumed is considered. Accordingly,
thermocouples are fixed at close to center of the plates.

Now q = Heat flux = Q/A = K T w / m2 (In S.I. units)

x
Tabulations:

S.No Volts Ampere T1 T2 T3 T4 T5 T6 T7 T8 T9 T10

(V) (A) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C)

47 | P a g e
Application:

1) Composite wall is used in cold storage units, where fresh fruits and vegetables are stored to
increase the shelf life.
2) Composite wall is also applied to any food industry.

Result:

48 | P a g e
Ex No: 9
Date: SHELL AND TUBE HEAT EXCHANGER

Aim:

To determine

ii) The overall heat transfer coefficient „u‟

iii) Distance coefficient hd of the given shell and tube heat exchanger

Theory:

When a saturated vapour is bright in contact with a cooled surface, heat is transferred from the
vapour to the surface and a film of condensate is produced. During the process one can obtain either
film wise or drop wise condensation.

a) If the surface is wettable, film wise condensation occurs

b) Otherwise dropwise condensation occurs. However one cannot completely eliminate mixed
condensation (i.e) combination of film wise and dropwise condensation.

The heat transfer coefficients obtained during film wise are one fifth to one sixth of drop wise
condensation. In industrial condensers, film wise condensation occurs unless promoters are added to
sustain drop wise condensation.

If one of the fluid is to be condensed or vapourized, its introduced to shell side. The tube side fluid
may take numerous passes of tube bundle because the design of passages. The shell side fluid may be
forced to follow a desirous path over outside surfaces of the tubes by cross and longitudinal baffles
inserted among the tubes. The baffles are provided are provided to increase the heat transferred
between the fluids.

By adjusting the baffle openings and baffle spacing it is possible to vary the heat transfer rates.

49 | P a g e
Specifications

Shell side:

i) Baffle space - 200mm

ii) Inside Diameter - 10mm
iii) Passes - 1
iv) No. of baffles - 2
v) Prantl number - 2.851
vi) Viscosity,µ - 0.0112
vii) Area - 741.14 x 10 -6
viii) Thermal conductivity - 0.6617 w/m2 C

Tube side
i) Number of tubes 37
ii) Inside diameter 160mm
iii) Outside diameter 13mm
iv) Thickness 1.5 mm
v) Pitch 20mm
vi) Passes 1
vii) Length of tube 600mm
viii) Prantl number 4.976
ix) Viscosity,µ 0.00491
x) Thermal conductivity 0.0623

Experimental procedures

i) The flow rate of hot water and cold water should be initially set in the rotameter.
ii) Then the heater is switched on
iii) When the constant desired temperature is attained the hot water at known flow rate is
pumped through the shell
iv) The cold water is allowed through the tubes at the known flow rate
v) When steady state is reached the flow rate inlet and outlet temperatures of cold and hot
water are noted down.
vi) The experiment is repeated for different cold water flow rates.

50 | P a g e
Observation

Sl Hot water Inlet temp. Outlet Cold water Inlet temp. Outlet
no flow rate of Hot temp. of flow rate of cold temp. of
Lpm water C Hot water Lpm water C cold water
C C

51 | P a g e
Application:

1) Shell and tube heat exchangers are used in Dairy plants, Soft drinks, and cane sugar industry
to heat food materials.
2) It is also used to liquefy the crystals especially in chemical industry

Result:

52 | P a g e
 Ex No: 10
Date: PARALLEL AND COUNTER FLOW HEAT EXCHANGER.

Aim:
To find the effectiveness and overall heat transfer coefficent in parallel flow and counter flow
heat exchanger.

Description:

The apparatus consist of a tube in tube type concentric heat exchanger. Hot fluid
flow through inner tube and cold water through the tubes. According to the instrument given on the
board, the direction of cold fluid flows to the counter flow arrangement. Thermometer is provided for
temperature measurement. Electrical geyser is used to heat the water flow rate of hot and cold water
are measured with help of measuring instrument (measuring flask and stopwatch) Outer tube of heat
exchanger is provided with adequate asbestos rope insulation to minimize heat losses.

Procedure:

Parallel Flow Heat Exchanger

1. Place the thermocouple in position

2. The values are adjusted to make the setup as a parallel flow heat exchanger.
3. Start the heater and allow the water to flow.
4. Adjust the flow rate on hot water side between the range of 1.5 to 4 lit./min.
5. Adjust the flow rate on cold water side between the range of 3 to 8 lit./min.
6. Keep the flow rate same until steady state condition are reached.
7. Record the temperature on hot water and cold water and also the rate.
8. Take down the time taken for 50 cc collection of both inlet hot and cold water.

Counter Flow Heat Exchanger

1. The valve positions are changed such that the apparatus is a counter flow heat exchanger.
2. The flow rate is adjusted.
3. Adjust the flow rate on hot water side between the range of 1.5 to 4 lit./min.

53 | P a g e
4. Adjust the flow rate on cold water side between the range of 3 to 8 lit./min.
5. Keep the flow rate same until steady state condition are reached.
6. The flow rate are calculated using the measuring flask at 50 cc.
7. Temperatures are recorded for hot water side and cold water side.

54 | P a g e
Formula:

I. Heat transfer rate from hot water Qh = mh Cph ( Thi - Tho ) watts.
II. Heat transfer rate from cold water Qc = mc Cpc ( Tci – Tco ) watts.
Cph = Cpc = 1 K cal / Kg = 4.187 KJ / Kg. K.
III. Heat transfer rate Q = ( Qh + Qc) / 2 .
IV. Logarithmic mean temperature difference
LMTD = (ΔTi – ΔTo )/ ln (Ti / To).
V. Overall heat transfer coefficient Q = U A Δ Tm.
U = ( Q / A ) Δ Tm.
VI. Effectiveness = [ mc Cpc ( Tco - Tci ) ] / [ mh Cph ( Tho –Thi) ]
(With mh < mc)
Observation

Type of Hot water Hot water Cold Cold water

flow flow rate temperature water temperature
l/s flow rate
l/s
T3 ( Thi) T1( Tho) T5 (Tci) T4 (Tco)
C C C C

Parallel
flow

Counter
flow

55 | P a g e
Applications:

1) In the design of heat exchange equipments like boilers, pasteurizers, jacketed pans, freezers,
air heaters, cookers and oven.
2) Heat exchangers are applied in Milk processing, sugar, Soft drinks, Fruit juices, and Chemical
Industry.

RESULT:

56 | P a g e
 Ex No: 11
THERMAL CONDUCTIVITY FOR INSULATING MEDIUM
Date:

Aim:

To conduct heat transfer test in the given apparatus and to find the thermal conductivity of an
insulating medium.

Apparatus used:

Thermal conductivity apparatus, stop watch.

Basics:

When heat transfer takes place through different medium or materials which are having different
thermal conductivity, the temperature used to drop across the medium and depends on the normal
resistance offered to heat transfer by the medium or material.
The resistance offered by the material depends on the thermal conductivity of the different materials
and the width or length of the materials. The theory or phenomena can be well demonstrated through
an apparatus and this apparatus is designed for demonstrating the principle of thermal conductivity to
indicating materials the ideal asbestos fiber powder. The apparatus is a modular and portable system
having good degree of insulating in the part of thermal and electrical shocks to the part of thermal
trainer. The apparatus is manufactured out of the best quality copper, plywood, stainless steel enamel
and other materials.

Specification:

The test section has a holding element surrounded by the insulating medium (asbestos powder)
and is covered by a cylindrical shell which has fitted thermocouple sensors. Load is brought out of
control panel.

Efficiency of the section = 76% + 4%

Length of section = 352mm

57 | P a g e
 Diameter of the shell = 133.6mm
Diameter of heating element = 31.8mm

PROCEDURE:

1) Energy provided through 230volts 50hd power supply.

2) Switch ON the digital multichannel temperature indicator
3) Switch On the system.
4) Load through variable diammersatic by 50V and 2A.
5) Constantly tabulate the reading of temperature against the steady power input ammemeter
and voltmeter.
6) Similarly by varying the amps and volts the other observations are made.

Application:

1) Insulating medium is used in food industry and food processing equipments to prevent the
heat loss.
2) Insulating medium is also used in chemical industries to reduce the heat dissipation at the
surroundings.

58 | P a g e
Observation:

SL V I T1 T2 T3 T4 T5 T6
NO. (VOLTS) (AMPS)

1
2
3
4
5

CALCULATION:

1) Actual heat transfer = Q = I * V *

2) Theoretical heat transfer
Ti = (T1 + T2 + T3)/3
To = (T4 + T5 + T6)/3

T = Ti – To

Q = (K2  L  T)/ln(r2/r1)

59 | P a g e
Result:

60 | P a g e