Experiment: 01

CO-1 Draw and explain valve timing diagrams of petrol and diesel engines
AIM: To draw valve timing diagram of 4 stroke petrol engine and examine its impact on the
performance of an IC engine.
OBJECTIVE: To draw valve timing diagram of 4 stroke petrol engine.
Input/Apparatus Used:
Table 1: List of Equipment
S.N. EQUIPMENT QUANTITY
1. 4 Stroke Petrol Engine (Demo) 1

THEORY:
➢ Valve timing diagram for 4 stroke system
Theoretically it may be assumed that the valves open and close and the spark (or injection
of fuel) occurs at the engine dead centers. However, in actual operation, the valves do
not operate at dead center positions but operate some degree on either side of the dead
centers. The opening occurs earlier and the exhaust continues even at later crank angles.
The ignition is also timed to occur in advance of the completion of compression stroke.
The timing of these events, referred in terms of crank angles from dead center positions,
is represented on a valve timing diagram. The correct timings are of fundamental
importance for the efficient and successful running of the I.C. engine.
1. Inlet valve: Due to inertia effect and the time required in attaining full opening, the inlet
valve is made to open somewhat earlier than TDC so that by the time the piston reaches
TDC, the valve is fully open. For an engine running at low speed and with throttle
opening, there is vacuum in the cylinder throughout the intake strike and on the
completion of the strike the cylinder is almost filled with charge at atmospheric pressure.
However, majority of I.C. engines run at tremendous speeds. Consequently, during
suction stroke the piston will reach the BDC Before the charge could get enough time to
enter the cylinder through the inlet valve passages. Moreover, there is considerable
resistance to the flow of charge through the air cleaner. Inlet valve is closed at BDC the
cylinder by each cycle would receive charge less than its capacity and the pressure inside
the cylinder would remain somewhat less than the atmosphere.
Consequently, in actual operation, inlet valve is kept open the cylinder pressure equals
the atmospheric pressure. The inlet valve is open even during compression, some of the
charge may be sent back to the induction pipe. On the contrary, the kinetic energy of the
air fuel mixture (or air) produces the ramming effect which enables more charge to enter
the cylinder. Theoretically it may be possible to induce charge more than volume
capacity of the combustion space.
The greater charge sucked in by opening the inlet valve before TDC and closing it 40-
450 after BDC increases the potential output of the engine.
2. Ignition (or injection): The TDC would be proper time to produce spark if the charge

19
 could burn instantaneously. However, there is lag between the timing of spark and
that of actual ignition. For best result with regard to power and economy, and to avoid
explosion knock, the ignition of charge is timed to occur as early as the engine permits.
At higher speeds the ignition timing is called ignition advance.
With too early ignition, the complete ignition may occur before the piston reaches the
TDC and this may cause back explosion. The back explosion will cause the engine to run
in the reversed direction of rotation.
3. Exhaust valve: The scavenging period (period available for discharge of burnt gases) is
increased by opening the exhaust valve in advance i.e. before BDC and closing it with
delay, i.e. after TDC Earlier opening makes it possible for the exhaust gases to leave by
virtue of their pressure being higher than the atmosphere. During late closure, the kinetic
energy of fresh charge is utilized to assist in the maximum exhausting cylinder. Thus
scavenging is being obtained is being obtained at the cost of power from the expansion
stroke. All the same a greater portion of the burnt gases is exhausted and this reduces the
among of the work to be done by the piston on the return stroke.
It may be seen that for some part of the cycle near TDC both the valves are open and
this period is called overlap.
PROCEDURE:
• Observe the various parts of 4-stroke petrol engine and various strokes of engine. After
this set the pointer at flywheel at zero
• Now position at BDC on moving slowly the flywheel inlet valve opens before the
position reaching to TDC.
• Inlet valve opens before TDC and after slowly moved flywheel in the same
direction. The position reaches TDC and then BDC
• After BDC the inlet valve closes note the position of the inlet valve closes 200 after BDC
• Slowly move the flywheel in same direction after closing of inlet valve suction
stroke is completed.
• Exhaust valve is opens at 250 before BDC exhaust valve closes 50 after TDC.
Same time exhaust stroke completes and cycle is completed.

20
PRECAUTIONS:
1. Readings should be taking without parallax error.
2. Observe carefully the valves are closed or in open position.

DISCUSSION:
1. Discuss the types of IC Engine.
2. Discuss the petrol Engine.
3. Discuss working principle of Petrol Engine
4. Discuss the 4 stroke Petrol Engine.

VIVA QUESTIONS:
Q.1.: What do you mean by stroke?
Ans: A phase of the engine's cycle (e.g. compression stroke, exhaust stroke), during which
the piston travels from top to bottom or vice versa.
Q.2: What is TDC and BDC?
Ans.: TDC is the top most position of the piston whereas BDC is Bottom Death Center of the
Piston.
Q.3: What is Inertia effect?
Ans.: property of a body by virtue of which it opposes any agency that attempts to put it in
motion or, if it is moving, to change the magnitude or direction of its velocity.
Q.4: Does the valves open before TDC or BDC point not later?
Ans.: The Valves open before TDC or BDC points.
Q.5: Why the valves close after the TDC or BDC not before?
Ans.: Because of the inertia effect the valves close after TDC or BDC points.

21
 EXPERMENT NO.2
CO1: Draw and explain valve timing diagrams of petrol and diesel engines

AIM: To draw valve timing diagram of 4 stroke diesel engine and examine its impact on the
performance of an IC engine.

OBJECTIVE: To draw valve timing diagram of 4 stroke diesel engine and examine its impact
on the performance of an IC engine.

Input/Apparatus Used:
Table 1: List of Equipment
S.N. EQUIPMENT QUANTITY
1. 4 Stroke Diesel Engine (Demo) 1

THEORY

In four stroke cycle engines the four events namely suction, compression, power and
exhaust take place inside the engine cylinder. The four events are completed in four strokes
of the piston (two revolutions of the crank shaft). This engine has got valves for controlling
the inlet of charge and outlet of exhaust gases. The opening and closing of the valve is
controlled by cams, fitted on camshaft. The camshaft is driven by crankshaft with the help
of suitable gears or chains. The camshaft runs at half the speed of the crankshaft. The
events taking place in I.C. engine are as follows: 1. Suction stroke 2. Compression stroke
3. Power stroke 4. Exhaust stroke.

1. Suction stroke: During suction stroke inlet valve opens and the piston moves
downward. Only air or a mixture of air and fuel are drawn inside the cylinder. The exhaust
valve remains in closed position during this stroke. The pressure in the engine cylinder is
less than atmospheric pressure during this stroke.

2. Compression stroke : During this stroke the piston moves upward. Both valves are in
closed position. The charge taken in the cylinder is compressed by the upward movement
of piston. If only air is compressed, as in case of diesel engine, diesel is injected at the end
of the compression stroke and ignition of fuel takes place due to high pressure and
temperature of the compressed air.

3. Power stroke: After ignition of fuel, tremendous amount of heat is generated, causing
very high pressure in the cylinder which pushes the piston downward. The downward
movement of the piston at this instant is called power stroke. The connecting rod transmits

22
 the power from piston to the crank shaft and crank shaft rotates. Mechanical work can be
taped at the rotating crank shaft. Both valves remain closed during power stroke.

4. Exhaust stroke: During this stroke piston moves upward. Exhaust valve opens and
exhaust gases go out through exhaust valves opening. All the burnt gases go out of the
engine and the cylinder becomes ready to receive the fresh charge. During this stroke inlet
valve remains closed. Thus it is found that out of four strokes, there is only one power
stroke and three idle strokes in four stroke cycle engine. The power stroke supplies
necessary momentum for useful work.

➢ Inlet Valve opening and closing

In an actual engine , the inlet valve begins to open 5°C to 25 °C before the piston reaches
the TDC during the end of exhaust stroke. This is necessary to ensure that the valve will
be fully open when the piston reaches the TDC. If the inlet valve is allowed to close at
BDC , the cylinder would receive less amount of air than its capacity and the pressure at
the end of suction will be below the atmospheric pressure . To avoid this inlet valve is kept
open for 25° to 40°after BDC.
➢ Exhaust valve opening and closing
Complete clearing of the burned gases from the cylinder is necessary to take in more air
into the cylinder . To achieve this exhaust valve is opens at 35° to 45° before BDC and
closes at 10° to 20° after the TDC. It is clear from the diagram , for certain period both
inlet valve and exhaust valve remains in open condition. The crank angles for which the
both valves are open are called as overlapping period . This overlapping is more than the
petrol engine.
➢ Fuel valve opening and closing
The fuel valve opens at 10° to 15 °before TDC and closes at 15° to 20 ° after TDC . This
is because better evaporation and mixing fuel.

23
 The valve timing diagram for actual engine is shown in figure for a typical diesel
engine.

PROCEDURE:
• Observe the various parts of 4-stroke diesel engine and various strokes of engine. After
this set the pointer at flywheel at zero
• Now position at BDC on moving slowly the flywheel inlet valve opens before the
position reaching to TDC.
• Inlet valve opens before TDC and after slowly moved flywheel in the same direction.
The position reaches TDC and then BDC
• After BDC the inlet valve closes note the position of the inlet valve closes 300 after BDC
• Slowly move the flywheel in same direction after closing of inlet valve suction stroke
is completed.
• Exhaust valve is opens at 450 before BDC exhaust valve closes 150 after TDC. Same
time exhaust stroke completes and cycle is completed.

PRECAUTIONS:
1. Readings should be taking without parallax error.
2. Observe carefully the valves are closed or in open position.

DISCUSSION:
1. Discuss Diesel Engine.
2. Discuss how Diesel engine is different from Petrol engine.
3. Discuss advantages and disadvantages of Diesel engine over petrol engine.

VIVA QUESTION:
Q.1: What is Overlapping?
Ans: Valve overlap is the short period of time in which both the inlet and the exhaust valve is
open. It happened at the end of exhaust stroke and at the beginning of intake. The intake valve

24
opens before piston reaches the TDC and exhaust didn't close until piston passes the TDC.
Q.2: How petrol engine is different from Diesel engine?
Ans: The primary difference between Petrol and Diesel engines is that the Petrol engine
works on the Otto cycle whereas the Diesel engine works on the Diesel cycle.
Q.3: Why Diesel engine don’t need Spark plug?
Ans: Air heats up as it is compressed. Squeeze enough of it quickly enough within an engine
cylinder and the temperature and environment will be just right for it to ignite fuel without
the need of a spark. This is what happens in a diesel engine.
Q.4: What is the purpose of valve overlap?
Ans: Without valve overlap, some portion of exhaust gases remains in the cylinder. During the
suction stroke, these gases mix with the intake charge and dilute the fresh mixture. As the valve
overlap helps to expel out the maximum amount of exhaust gases thus it helps to avoid the
dilution of the air-fuel mixture.
Q.5: Which engine generates more power (Petrol or Diesel engine)?
Ans: Diesel Engine.

25
 EXPERMENT NO.3

CO2: Measure the performance parameters of petrol and diesel engines

AIM: Determination of brake power, indicated power, friction power and mechanical
efficiency of a multi-cylinder petrol engine running at constant speed (Morse Test) and to
draw the heat balance sheet of multi-cylinder petrol engine.
OBJECTIVES: To measure the performance parameter of petrol engine.
Input/Apparatus Used:
Table 1: List of Equipment
S.N. Equipment Quantity
1. Petrol and diesel engine apparatus 1

INTRODUCTION

26
27
DESCRIPTION

28
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30
31
32
33
34
35
36
DISCUSSION:
Q1: Discuss what is performance parameter.
Q2: Discuss the difference between performance and Efficiency.
Q3: Discuss the importance of Performance Parameter in design.

Viva Question:
1. What is performance parameter?
Ans: A Key Performance Parameter is a characteristic, function, requirement or design basis
that if changed would have a major impact on the system or facility performance, schedule,
cost and/or risk.
2. What is Frictional Power?
Ans: The friction power is defined as the difference. between the power delivered to the piston
while. the working fluid is contained within the cylinder, and the usable work delivered to the
drive shaft.
3. What is relation between Brake power & Indicated Power?
Ans.: By indicated power we mean GROSS indicated power, the total work done by gas on
piston during compression and power strokes. The brake power is the power available at the
dynamometer. The difference is called friction power.
4. What is Mechanical Efficiency:
Ans: measure of the effectiveness with which a mechanical system performs
5. SFC is the measure of ……………………?
Ans: Quantity of fuel burned in unit time required.

37
 EXPERMENT NO. 4
CO2: Measure the performance parameters of petrol and diesel engines.

AIM: Performance of a diesel engine from no load to full load (at constant speed) for a single
cylinder engine in terms of brake power indicated power, mechanical efficiency and calculate
the SFC (Specific fuel consumption) and further obtain power consumption curves and draw
the heat balance sheet of single cylinder Diesel engine.

OBJECTIVE: To measure the performance parameters of diesel engines

Input/Apparatus Used:
Table 1: List of Equipment
S.N. Equipment Quantity
1. Diesel engine setup 1

38
39
40
41
42
43
44
45
46
47
 DISCUSSION:
1. Discuss performance of a Petrol Engine.
2. Discuss how Multi Cylinder Petrol Engine Work.
3. Discuss bout Morse Test.

VIVA QUESTION:
1. What is performance parameter?
Ans: A characteristic, function, requirement or design basis that if changed would have a
major impact on the system
2. What is Brake Power?
Ans: The usable power output of the engine, not including power required to fuel, lubricate,
or heat the engine, circulate coolant to the engine, or to operate after treatment devices.
3. What is Indicated Power?
Ans: The total power of engine which is graphically represented by area of cycle on P-V
chart
4. What is Efficiency:
Ans: The ratio of the useful work performed by a machine or in a process to the total energy
expended or heat taken in.
5. What is Specific Fuel Consumption?
Ans: The amount of fuel consumed by a vehicle for each unit of power output

48
 Experiment No. 5

CO3: Evaluate and explain various performance parameters of reciprocating compressor

Aim: To calculate actual volume of air intake by measuring pressure difference by manometer
of Double stage reciprocating compressor.
OBJECTIVE: To evaluate the performance of reciprocating compressor
Input/Apparatus Used:
Table 1: List of Equipment
S.N. Equipment Quantity
1. Reciprocating compressor 1

Introduction:

Air Compressor is a device, which sucks the air from atmosphere and compresses it and
delivers in reservoir tank. It compresses the air by means of a reciprocating piston, which
reciprocates in a stationary cylinder. It can be single stage or multistage. It can be single acting
or double acting.

Theory:

In two-stage compression, air is partially compressed in low-pressure cylinder. This air is

passed through cooler between first stage and second stage so that air at inlet of second stage
is at lower temperature than the first stage outlet. This is done to reduce the work of
compression in second stage. Final compression is completed in second stage i.e. in high
pressure cylinder. Also, the compressors are provided with clearance volume, two stage
compressors can achieve higher volumetric efficiency than single stage compressors, because
of lower compression per stage.
As the compressed air is used in a wide range in industrial, domestic, aeronautics fields etc. so
compressors are applied in wide range. Compressors are used where the air is required at high
pressure.

Description:

Double stage air compressor test rig consists of two cylinders and pistons, a reservoir tank,
driven by AC motor. Temperature sensors are provided at inlet and outlet. To find out the
inlet volume of air, an orifice meter is provided. To stream line the intake, a diaphragm base
manifold is provided. Pressure gauge is provided at reservoir tank. Safety valve and auto
power out switch is provided for the safety factor.

49
Utilities Required:

1. Electricity supply: single phase, 220 V AC, 50 Hz, 5-15 Amp combined socket with
earth connection.
2. Water supply: continuous @2 LPM at 1 bar.
3. Floor Area required: 2.5m × 1.25 m

Experimental Procedure:

Starting Procedure:
• Close the valve V1 of the tank and start the compressor.
• Let the receiver pressure rise up to around 1 kg/cm2. Now open the valve V1 so that
constant delivery pressure is achieved.
• Connect cooling water supply to condenser and outlet of condenser cooling water to
drain.
• Open valve V2 and start cooling water supply.
• Wait for some time and see that delivery pressure remain constant. Now note down
the pressure.
• Record the manometer reading.
• Record the temperature of air at inlet, before second stage and after second stage.
• Record the RPM of compressor by RPM indicator.
• Record the weight balance reading.
• Repeat the same procedure for different delivery pressure by closing valve V1.

Closing Procedure:
• When experiment is over open valve V1.
• Switch OFF compressor.
• Switch OFF the main supply.
• Stop cold water supply by valve V2.
• Drain the condenser by valve V3.

Observation and Calculation:

Data
Atmospheric pressure Pa = 103327 N/m2 Length of Stroke L = 0.078 m
Co-efficient of discharge of orifice meter Bore diameter d=0.0935m
Cd= 0.64
Density of Air 𝜌𝑎 = 1.21 𝑘𝑔/𝑚3 Diameter of orifice do= 0.011 m
3
Density of water , 𝜌𝑚 = 1000𝑘𝑔/ 𝑚 Diameter of pipe dp= 0.022 m
RPM of Motor Nm= 1440 RPM
Radius of swinging field Dynamometer R = 0.16 m

50
Observation Table
S.NO N Pd h1 (cm) h2 (cm) W (kg) T1 (°C) T2 (°C) T3 (°C) T4 (°C)
(RPM) (kg/cm2)
1
2
3
4

NOMENCLATURE:
Nom Column Heading Units Type
𝑎𝑜 Cross-sectional area of orifice m2 Calculated
𝑎𝑝 Cross-sectional area of pipe m2 Calculated
𝐶𝑑 Co-efficient of discharge of orifice Given
d Bore diameter m Given
do Diameter of orifice m Given
dp Diameter of pipe m Given
𝐸𝑖𝑠𝑜 Isothermal power kW Calculated
𝐸𝑆 Shaft Power kW Calculated
g Acceleration due to Gravity m/sec2 Given
h Manometer pressure difference m Calculated
h1, h2 Manometer reading at both points Cm Measured
L Length of stroke m Given
N RPM of Compressor RPM Measured
Nm RPM of Motor RPM Given
𝑃𝑎 Atmospheric Pressure N/m2 Given
Pd Guage Pressure Kg/cm2 Measured
𝑄𝑎 Actual Volume of air m3/sec Calculated
𝑄𝑡 Swept Volume of compressor m3/sec Calculated
R Radius of swinging field m Calculated
Dynamometer
r Compression ratio Calculated
T Torque Nm Calculated
T1 Temp. of air inlet to 1st stage of °C Measured
compressor
T2 Temp. of air outlet to 1st stage of °C Measured
Compressor

51
 T3 Temp. of air inlet to 2nd stage of °C Measured
Compressor
T4 Temp. of air outlet to 2nd stage of °C Measured
compressor
W Weight Balance Reading kg Measured
𝜌𝑎 Density of air 𝑘𝑔/𝑚3 Given
𝜌𝑚 Density of water 𝑘𝑔/𝑚3 Given
∆𝐻 Total Head m of air Calculated
𝜂𝑖𝑠𝑜 Isothermal efficiency % Calculated
𝜂𝑣 Volumetric efficiency % Calculated

Precaution & Maintenance Instructions:

1. Never run the apparatus if power supply is less than 200 volts and above 230 volts.
2. Check the oil before starting the Air compressor.
3. Close the delivery valve of tank before starting the experiment.
4. Always keep the apparatus free from dust.

Troubleshooting:

1. If control panel does not show input, check main supply.

2. If pressure gauge is not showing the pressure, there may be a leakage of air.
3. Check the suction line and valves provided on delivery line.

Discussion:
1. Discuss Reciprocating Compression.
2. Discuss Stage of a reciprocating engine.
3. Discuss why performance parameter of reciprocating compressor is important

Viva Questions:
1. What is Compressor?
Ans: A mechanical device that increases the pressure of a gas by reducing its volume.
2. What do you mean by reciprocating Compressor?
Ans: A positive-displacement compressor that uses pistons driven by a crankshaft to
deliver gases at high pressure.
3. What do you understand by Double stage reciprocating stage?
Ans: The process within a two-stage compressor — alternately referred to as a dual-stage
compressor — is similar to that of a single-stage, but with one variation: the compressed
air isn't sent to a storage tank; it's instead sent to a smaller piston for a second stroke, this

52
time at roughly 175 psi.
4. Explain the word intake in reciprocating engine?
Ans: To begin the cycle, a fuel mixture is introduced inside the cylinder through the
intake port, expanding the piston to the bottom of the cylinder.
5. What happen when air intake take place?
Ans. The function of the air intake system is to allow air to reach engine.

53
 EXPERIMENT NO. 06

CO3: Evaluate and explain various performance parameters of reciprocating compressor

AIM: To determine swept volume of compressor, volumetric efficiency, compression ratio

and isothermal efficiency of Double stage reciprocating compressor.

OBJECTIVE: To evaluate and explain various performance parameters of reciprocating

compressor

Input/Apparatus Used:
Table 1: List of Equipment
S.N. Equipment Quantity
1. Reciprocating compressor setup 1

INTRODUCTION:
Air compressor is a device, which sucks the air from the atmosphere and Compresses it and
delivers in reservoir tank. It compresses the air by means of a reciprocating piston, which
reciprocates in a stationary cylinder. It can be single stage or multi stage.
In single stage compression, air from the atmospheric pressure is compressed to the desired
discharge in a single operation.
In two-stage compression, air is partially compressed in low-pressure cylinder. This air is
passed through cooler between first stage and second stage so that air inlet of second stage so
that air at inlet of second stage is at lowers temperature than the first stage outlet. This is done
to reduce the work of compression in second stage. Final compression is completed in second
stage i.e. in high- pressure cylinder. Also, the compressors are provided with clearance volume,
two stage compressors can achieve higher volumetric efficiency than single stage compressors,
because of lower compression per stage.
As the compressed air is used in a wide range in industrial, domestic, aeronautics fields etc. so
compressors are applied in wide range. Compressors are used where the air is required at high
pressure.

DESCRIPTION:
Single and double stage air compressor test rig consists of a reservoir tank, two cylinders and
pistons driven by AC motor. Thermometers are provided at inlet of low-pressure cylinder and
outlet of high-pressure cylinder. Two more thermometers are provided before and after the
intercooler. To find out the inlet volume of air, an orifice meter is provided. To stream line the
intake, a diaphragm base manifold is provided. Pressure gauge is provided at reservoir tank.
Safety valve and auto power cut-off switch is provided for the safety factor.

54
Experimental Procedure (Single Stage):
• Close the outlet valve of tank and also close the valves 1, 2, 3 and 6.
• Now open the valves 7, 4 and 5 and start the compressor. The air will be compressed in
single cylinder i.e. low-pressure cylinder.
• Let the receiver pressure rise up to around 2 kg/cm2. Now open the delivery valve so
that constant delivery pressure is achieved.
• Wait for some time and see that delivery pressure remain constant. Now note down the
pressure.
• Record the energy meter pulses/time to find out the input H.P.
• Record the manometer reading to find out the volume of air input.
• Record the temperature of air at inlet of cylinder.
• Find out the RPM of compressor with the help of RPM indicator.
• Find out the volumetric efficiency and isothermal efficiency by given formulae.
• Repeat the same procedure for different delivery pressure.
• After completing the experiment stop the compressor by pressing the red button
provided at the control panel.

Experimental Procedure (Double stage):

• Close the outlet and also close the valves 2,4,5 and 7.
• Now open the valves 1,3 and 6 and connect the continuous water supply to the
intercooler for cooling the compressed air and then start the compressor.
• Let the receiver pressure rise up to around 2 kg/cm2. Now open the delivery valve so
that constant delivery pressure is achieved.
• Wait for some time and see that delivery pressure remain constant. Now note down the
pressure.
• Record the energy meter pulses/time to find out the input H.P.
• Record the manometer reading to find out the volume of air input.
• Record the temperature of air at inlet, outlet, before and after intercooler.
• Find out the RPM of compressor with the help of RPM indicator.
• Repeat the same procedure for different delivery pressure.
• After completing the experiment stop the compressor by pressing the red button
provided at the control panel.

Precautions:
1. Check the oil before starting the air compressor.
2. Check the proper voltage while conducting experiments.
3. Be careful while measuring the RPM.
4. Close the delivery valve of tank before starting the experiment.

55
Specifications:

Motor : 2 H.P. AC Single Phase, 1440 RPM

Compressor : Single and double stage, Single acting
Cylinder 1 : Dia 70 mm, Stroke = 70 mm
Cylinder 2 : Dia 52 mm, Stroke=70 mm Energy meter constant (EMC) : 3200 Pulses/
kWh

Standard Data:

Low pressure cylinder 1:

d = Bore Diameter = 70 mm
L = Length of stroke = 70 mm
do = Diameter of orifice = 8 mm
ao = Cross-sectional area of orifice = 5.026 × 10−5𝑚2
dp = Diameter of pipe = 16 mm
ap = Cross-sectional area of pipe = 2.011×10-4 m2
𝜌𝑚 =Density of water = 1000 kg/m3
𝜌𝑎 = Density of air at 0°C i.e. 273 k = 1.293 kg/m3
Cd = Co efficient of discharge = 0.64
EMC = Energy Meter Constant = 3200 pulses/ kWh
Pa = Atmospheric pressure = 1.013×105 N/m2
R = Radius of swinging field dynamometer = 265 cm
T1 = Inlet air temperature
T2 = Temperature of air before the intercooler and outlet of first stage
T3 = Temperature of air after the intercooler and inlet of second stage
T4 = Temperature of air at outlet of second stage
P = No. of pulses of energy meter
Cp = 1.005 kJ/kg k

For Single Stage Compressor:

Observation Table:

S. No Delivery Differential Manometer RPM Inlet Energy meter 20 Force,

2
Pressurekg/cm Reading (cm) Temp T1 pulses/time (Sec) F (kg)
1
2
3
4
5

56
Calculation Table:

S. No. ∆𝑝 𝑚 𝑜𝑓 𝑎𝑖𝑟 𝑄𝑅𝑇𝑃 m3/sec Swept Volume Volumetric

𝑄𝑡 𝑚3/𝑠𝑒𝑐 Efficiency 𝜂 (%)
1
2
3
4
5

S. No. H.P. Elec. Torque, T H.P. Shaft Compression Isothermal Isothermal

ratio, r H.P. 𝜂 (%)
1
2
3
4
5

For Double stage compressor:

Observation Table:

Differential Energy
Delivery Manometer Inlet Temp meter 20
S. No Pressure Reading RPM T1 pulses/time Force, F (kg)
kg/cm2 (cm) (Sec)
1
2
3
4
5

Calculation Table:

S. No. ∆𝑝 𝑚 𝑜𝑓 𝑎𝑖𝑟 𝑄𝑅𝑇𝑃 m3/sec Swept Volume Volumetric

𝑄𝑡 𝑚3/𝑠𝑒𝑐 Efficiency 𝜂 (%)
1
2
3
4
5

57
S. No. H.P. Elec. Torque, T H.P. Shaft Compression Isothermal Isothermal
ratio, r H.P. 𝜂 (%)
1
2
3
4
5

DISCUSSION:
1. Discuss Swept Volume of Compressor.
2. Discuss Volumetric Efficiency & Isothermal Efficiency.
3. Discuss Compression Ratio.
Viva Question:
1. What is swept volume of compressor?
Ans: Swept volume is the displacement of one cylinder. It is the volume between top dead
center (TDC) and bottom dead center (BDC). As the piston travels from top to bottom, it
"sweeps" its total volume. This measurement can be listed in cubic inches or cubic
centimeters.
2. What is volumetric efficiency?
Ans: The volumetric efficiency represents the efficiency of a compressor cylinder to
compress gas. It may be defined as the ratio of the volume of gas actually delivered to the
piston displacement, corrected to suction temperature and pressure.
3. What is compression ratio?
Ans: The compression ratio (CR) is defined as the ratio of the volume of the cylinder and
its head space (including the pre-combustion chamber, if present) when the piston is at
the bottom of its stroke to the volume of the head space when the piston is at the top of its
travel ('top dead centre', tdc).
4. What is isothermal efficiency?
Ans: The isothermal efficiency compares the power requirement for an isothermal
compression with the actually required power input. The isothermal power is the product
of mass flow and the mass specific work required at ideal isothermal conditions.
5. What do you mean by efficiency?
Ans: The ratio of the useful work performed by a machine or in a process to the total
energy expended or heat taken in.

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 EXPERMENT NO. 07

CO4: Determine dryness fraction of wet steam by separating and throttling calorimeter.

AIM: Determination of dryness fraction of steam by using separating and throttling calorimeter.
OBJECTIVE: To determine the dryness fraction of stream.
INPUT/APPARATUS USED:
Table 1: List of Equipment
S.N. Equipment Quantity
1 Throttling calorimeter setup 1

THEORY:

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Discussion:
Q.1: Discuss Calorimeter?
Q.2: Discuss Throttling Calorimeter?
Q.3: Discuss Dryness Fraction?

Viva Questions:
1. What do you mean by dry ness fraction?
Ans: the ratio of mass of dry steam (vapour) to combined mass of dry steam (vapour) &
mass of liquid in mixture.
2. What is the percentage of dryness for saturated stream?
Ans: 100%
3. What is the percentage of dryness for saturated water?
Ans: 0%
4. How can you explain the word throttling calorimeter?
Ans: It is a vessel with a needle valve fitted on the inlet side.
5. Why we determine the dryness fraction of Wet Stream?
Ans: Steam dryness is important because it has a direct effect on the total amount of
transferable energy contained within the steam (usually just latent heat), which affects
heating efficiency and quality. For example, saturated steam (100% dry) contains 100% of
the latent heat available at that pressure.

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 EXPERIMENT NO-8

CO4- Determine dryness fraction of wet steam by separating and throttling calorimeter.

AIM: To determine the heat extraction efficiency of vertical cooling tower.

OBJECTIVE: To study mass transfer operation in water cooling tower for different flow &
thermodynamic conditions.

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DISCUSSION:
1. Discuss the purpose of cooling tower?
2. Discuss why heat extraction is important in thermodynamics cycle?
3. Discuss the purpose of the experiment?

Viva Question:
1. What is the purpose of vertical cooling tower?
Ans: Cooling tower is used to cool the hot water coming from condenser. This water is
cooled by evaporating cooling by the flowing air.
2. What do we perform this experiment?
Ans: A cooling tower is a device that rejects waste heat to the atmosphere through the cooling
of a coolant stream, usually a water stream to a lower temperature.
3. What do you mean by heat extraction?
Ans: It is the energy in transit that moves from one thing to another and is measured in terms
of calories or joules.
4. What is the density of water?
Ans: 1000kg/m3
5. What is the density of air?
Ans: 1.225 Kg/m3

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 EXPERIMENT NO.: 09

CO5: Determine the efficiency of vertical/horizontal condenser

AIM: To determine the efficiency of vertical/Horizontal condenser.

OBJECTIVE: To determine the overall Heat Transfer Co-efficient and film co-efficient for
vertical and horizontal condenser.

Input/Apparatus Used:
Table 1: List of Equipment
S.N. Equipment Quantity
1. Condenser apparatus 1

INTRODUCTION:
When a saturated vapor is brought in contact with a cooler surface, condensation occurs.
Condensation occurs at different rate of heat transfer by either of the two distinct physical
mechanism, drop and film wise condensation. The occurrence of drop or film wise
condensation depends largely on the characteristics of the condensing vapor and the surface
available for condensation. The condensing film coefficient is influenced by the texture of the
surface on which the condensation occurs and also by whether the condensing surface is
mounted vertically or horizontally. The heat transfer coefficients obtained during film wise.
Condensation are 1/5th to1/6th of that in drop wise condensation. Most practical cases
correspond to mixed condensation. However, due to lack of control in drop wise condensation,
calculations are mostly based on film condensation heat transfer coefficients.

THEORY
FOR VERTICAL CONDENSER
In case of condensation on the surface of a vapor tube, as in vertical condensers, the condensate
film flows downwards under the influence of gravity, but is retarded by the viscosity of the
condensate film. The flow is normally streamlined and heat flows through the film by
conduction only. In vertical tube, about 60% of the vapor condenses in the upper half of the
tube. Nusselt has derived a theoretical relation for the determination of film heat transfer
coefficient in terms of physical properties of condensate film, characteristic dimension and the
temperature driving force. The film coefficient for condensation over a vertical plate of height,
L, is given by:

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FOR HORIZONTAL CONDENSER:

DISCRIPTION:

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OBSERVATION & CALCULATION:

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Discussion:
1. Discuss the role of vertical condenser.
2. Discuss the role of horizontal condenser.
3. Discuss the importance of the experiment in industry.
Viva Questions:
1. Where is vertical condenser used?
Ans: Although horizontal condensers are widely equipped, vertical condensers are used in
distillation columns, especially in continuous rectification towers where the top product is
condensed and is withdrawn at the bottom of the condenser.
2. What is the role of horizontal condenser?
Ans: the horizontal condenser installation method is a horizontal installation, which is
characterized by more than the cooling water flow pipe inside the vertical condenser. The
equipment is a Compact Condenser, and the condenser volume of the same scale is smaller
than that of the vertical condenser.
3. Why is a condenser placed vertically?
Ans: The reason is related to the layer of condensate film formed on the tube surface. The
condensate film is thin only near the top of the tube. For a horizontal tube, the thin film
area is larger, therefore easier condensing.
4. What is the purpose of the condenser?
Ans: The purpose of the condenser is to receive the high-pressure gas from the compressor
and convert this gas to a liquid. It does it by heat transfer, or the principle that heat will
always move from a warmer to a cooler substance.
5. Why are condenser tubes horizontal?
Ans: In case of horizontal position the effective heat transfer coefficient will be
comparatively higher. Thus the tubes are placed in horizontal position for faster
condensation.

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 EXPERIMENT NO-10
CO5: Measure the performance parameters of petrol and diesel engines.

Aim: Calibration of Thermometers and pressure gauges.

OBJECTIVE: To study Calibration of Thermometers and pressure gauges.

Input/Apparatus Used:
Table 1: List of Equipment
S.N. Equipment Quantity
1. Temperature Measurement device (Thermistor) 1

CALIBRATION OF THERMISTOR FOR TEMPERATURE MEASUREMENT

Fig: Temperature measurement by THERMISTOR

THEORY
THERMISTORS.
Temperature – measuring sensor based on the fact that the resistance of a material may change
with temperature is known as a THERMISTOR. Thermostats differ from resistance
temperature detectors in that they are fabricated from semi conducting materials instead of
metals. The semi – conducting materials, which include oxides of copper, cobalt, manganese,
nickel and titanium, exhibit very large change in resistance with temperature. Resistance with
temperature can be expressed by an equation of the form
Inp = A0 + A1 / T + A2 / T2 + + An / Tn
Where P is the specific resistance of the material.
A1, A2, An are material constants.
T is the absolute temperature.

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Thermistor have many advantage over other temperature sensors and are widely used in
industry. They can be small and consequently, permit point sensing and rapid response to
temperature change. Their high resistance minimizes lead
– wire problems. Their out put is more than 10 times that of a resistance temperature detector.
The disadvantages of thermistor includes non linear out put with temperature and limited range.
Since the instrumentation tutors are not instrument as a whole the accuracy of the measurement
cannot be claimed. It is very clear that the instrumentation tutor are only for demonstration
purpose and cannot be used for any external measurement other than conducting experiments.

CIRCUIT EXPLANATION
The circuit comprises of three parts.
1. POWER SUPPLY
2. SIGNAL CONDITIONING AND AMPLIFYING
3. ANALOG TO DIGITAL CONVERTER.

POWER SUPPLY.
Inbuilt power supply use power to all electronic devices inside the circuitry. High stable
regulated Power supply is used for better performance.
There are three different power supply inside the unit.

+12-0 012 V 500mA to drive digital integrated circuitry.

+5-0—5V 250mA to drive A to D converter.

SIGNAL CONDITIONING AND AMPLIFYING

The circuitry comprises of signal conditioner and amplifier. The output of the sensor is
amplified to required level. The Thermocouple gives out directly which is amplified.
Thermistor and RTD are connected to the ground through a resister, and the voltage is applied
to the other end of the sensor. The resistance change in the sensor will gives the mV out put
which is amplified and controlled. Analog out put is fad to the ADC.

ANALOG TO DIGITAL CONVERTER.

The output from the amplifier is a linearized analog DC voltage. This analog output is
converted into digital output with the help of IC 7107 3.5 digit 200mA. A to D converter. Then
it is displayed through seven segmented LEDs.

PANEL DETAILS

DISPLAY : 3 ½ Digit LED Display of 200 mV FSD.

INITIAL SET : Single turn potentiometer to set Initial Temperature
(Room Temperature)

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FINAL TEST : Single turn potentiometer to Calibrate the instrument
(Max. Temperature)
SELECT : 3 Way rotary switch to select Thermistor.
POWER ON : Rocker switch to control power supply to the instrument.

CONNECTION DETAILS

POWER : 3 pin mains cable is provided with the instrument.

Connect the 3 pin socket to the instrument at the rear panel and to the AC mains 230v supply.
NOTE : Before connecting ensure the voltage is 230 V and the Power switch is in off
position)
SENSORS : Connect Thermistor to the connector on the rear panel.

OPERATING PROCEDURE

Check connection made and Switch ON the instrument by rocker switch at the front panel. The
display glows to indicate the instrument is ON. Allow the instrument in ON Position for 10
minutes for initial warm-up. Pore around 3/4th full of water to the kettle and place sensors and
thermometer inside the kettle. Note down the Initial water temperature from the thermometer.
Select the sensor on which the experiment to be conducted through selection switch on the
front panel. Adjust the Initial set Potentiometer in the front panel till the display reads initial
water temperature. Switch on the kept and wait till the water boils note down the reading inn
the thermometer and set Final set potentiometer till the display reads boiling water temperature.
Remove the sensor from the boiling water immerse it I the cold water. Set the cold water
temperature using initial set potentiometer. Repeat the process till the display reads exact
boiling water and cold water temperature. Change the water in the kettle with and re heat the
water. Now the display starts showing exact temperature raise in the kettle.Experiment can be
repeated for all the three sensors. Temperature in the thermometer and the indicator readings
in steps of 100 C can be tabulated.

EXPERIMENTS AND TABULAR COLUMN-1

EXPERIMENT TO MEASURE TEMPERATURE USING THERMISTOR:

Experiment can be conducted on the instrument as per the operating instruction given above
for Thermistor and various parameters like Linearity. Accuracy, Hysteresis etc, can be
calculated. The readings can be tabulated and graphs can be plotted to calculated the above
parameters.

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 TABULAR COLUMN-1

Sr. No. THERMOMETER REARING 0C THERMISTER (˚C)

(Actual Temperature)

Graphs: Actual reading V/s indicator Reading

EXPERIMENTS AND TABULAR COLUMN – 2

EXPERIMENT TO STUDY THE CHARACTERISTICS OF THERMISTER.
• Remove the YELLOW & GREEN terminals of the sensors from the instrument
• Connect Thermistor to Ohm-meter to measure ohms.
• Tabulate the readings in the tabular column given below. Plot the graphs for
Temperature change in the thermometer V/s Change in the millivolt/Resistance

TABULAR COLUMN-1
EXPERIMENT-2
Sr. No. THERMOMETER REARING 0C THERMISTER (˚C)
(Actual Temperature)

CALIBRATION OF PRESSURE GAUGES

Pressure measurement using Pressure cell

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THE INSTRUMENT
UNIQUE Digital pressure measuring setup comprises of pressure indicator and pressure cell
with loading system. Pressure indicator is a strain gauge signal conditioner and amplifier used
to measure pressure due to load applied on the pressure cell. The strain gauge are bonded on
the diaphragm and are connected in the form of whetstones bridge. A foot pump of capacity
7Kg/cm2 is provided to load the Pressure cell UNIQUES Pressure measuring setup in a
complete system which can be used to conduct measurement of pressure applied on the
Pressure cell. The pressure indicator is provided with zero balancing facility through adjustable
potentiometer. Digital display will enable to take error free readings.
The digital indicator comprises of four parts.
1. Power supply
2. Signal conditioning
3. Amplifier
4. Analog and digital converter.
The inbuilt regulated power supply used will provide sufficient power to electronic parts and
also excitation voltage to the strain gauge bridge transducers. The signal conditioner Buffers
the output signals of the transducers. Amplifier will amplifies the buffered output signal to the
required level where it is calibrated to required unit. Analog to digital converter will convert
the calibrated analog out put to digital signals and display through LED’s.

THEORY:
Transducers that measure force, torque or pressure usually contains an elastic member that
converts the quantity to be measured to a deflection or strain. A deflection sensor or,
alternatively, a set of strain gauges can be used to measure the quantity of interest (force, torque
or pressure) indirectly. Characteristics of transducers, such as range, linearity and sensitivity
are determined by the size and shape of the elastic member, the material used in its fabrication.
A wide variety of transducers are commercially available for measuring force. Torque and
pressure the different elastic member employed in the design of these transducer include link,
columns, rings, beams, cylinders, tubes, washers, diaphragms, shear webs and numerous other
shapes of special purpose applications. Strain gauges are usually used as sensors; however
linear variable differential transformers (LVDT) and linear potentiometers are some time used
for static or quasistatic measurement.

PRESSURE MEASUREMENT (PRESSURE CELL).

Pressure cells are divisors that convert pressure into electrical signal through a measurement
of either displacement strain or Piezoelectric response. Diaphragm type pressure transducers
with strain gauges as sensor is used here for measurement of pressure.
This type of pressure transducers uses diaphragm as the elastic element. Diaphragms are used
for low and middle pressure ranges. Strain gauges are bonded on the diaphragm and the
pressure force is applied to the specimen the material gets elongated or compressed due to the
force applied i.e., the material get strained. The strain incurred by the specimen depends on the
material used and its elastic module. This strain is transferred to the strain gauges bonded on
the material resulting in change in the resistance of the gauge. Since the strain gauges are

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connected in the form of whetstones bridge any change in the resistance will imbalance the
bridge. The imbalance in the bridge will intern gives out the output in mV proportional to the
change in the resistance of the strain gauge.

CIRCUIT EXPLANATION
The circuit comprises of three parts.
1. Power Supply
2. Signal Conditioning And Amplifying
3. Analog To Digital Converter.

1. POWER SUPPLY:
Inbuilt power supply use power to all electronic devices inside the circuitry. High stable
regulated Power supply is used for better performance There are two different power supply
inside the unit
+12 – 0 -12V 500mA to drive digital integrated circuitry. +5 – 0 - -5V 250mA to drive A to D
converter.
2. SIGNAL CONDITIONING AND AMPLIFYING
Signal conditioner will process the output of transducer and presents a linear DC voltage to the
amplifier. This circuit will also buffers the inputs signal given to the differential amplifier. The
operations amplifier is used as a differential amplifier where the signal gets amplified to
required level. The amplifier gives out the analog output.
This output is controlled and calibrated to get the linear to micro strain. This analog output is
sed to the A to D converter.
3. ANALOG TO DIGITAL CONVERTED.
The output from the amplifier is a linearised analog DC voltage. This analog output is converted
into digital output with the help of IC 7107 3.5 digit 200mV A to D converter. Then it is
displayed through seven segmented LED’s.

SPECIFICATIONS MEASUREMENT OF PRESSURE

PRESSURE CELL :
SENSOR : strain gauges bonded on steel diaphragm for pressure
measurement.
TYPE : Diaphragm
RANGE : 10 Kg/cm2
CONNECTION : Through four cure shielded cable with the connector Attached
EXCITATION : 10V DC
ACCURACY : 1%
LINEARITY : 1%
MAX OVER LOAD : 150% MECHANICAL
CONNECTION : 1/4 INCH BSP thread.
INDICATOR :
DISPLAY : 3 ½ digit seven segment LED display is used for the indicator
of 200mV full scale deflection to read +/- 1999’

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EXCITATION : 10 V DC
ACCURACY : 1%
TARE : Front panel zero adjustment through Potentiometer
POWER SUPPLY : 230 V +/- 10% 50 Hz
CONNECTION DETAILS

POWER: 3 pin mains cable is provided with the instrument. Connect the 3 pin socket to the
instrument at the rear panel and to the AC mains 230v supply.

NOTE: Before connecting ensure the voltage is 230 V and the Power switch is in off
position.

SENSOR: Connect one end of the cable attached with connector to the sensor and the other
end to the instrument. While connecting match the colors of the wires with the connectors.

PERATING PROCEDURE
• Check connection made and switch ON the instrument by rocker switch at the front
panel. The display glows to indicate the instrument is ON.
• Allow the instrument in ON Position for 10 minutes for initial warm-up.
• Adjust the Potentiometer in the front panel till the display reads “000”
• Apply pressure on the sensor using the loading arrangement provided.
• The instrument reads the pressure coming on the sensor and display through LED.
Readings can be tabulated and % error of the instrument, linearity can be calculated.

EXPERIMENTS AND TABULAR COLUMN

Experiments can be conducted on the instrument as per the Operating Instruction given and
various parameters like Linearity. Accuracy, Hysteresis etc of the Pressure indicator can be
calculated. The readings can be tabulated and graphs can be plotted to calculate the above
parameters.

TABULAR COLUMN
SL.NO. ACTUAL INDICATOR 3-2 ERROR % ERROR
PRESSURE (N/m2) READING (kg/cm2)

Error =
𝐶𝑜𝑙𝑢𝑚𝑛 𝑁𝑜 #4
𝑥100%
𝑀𝑎𝑥 𝐿𝑜𝑎𝑑

Graphs: Actual reading V/s indicator Reading

SPECIMEN READINGS

Sr. No. ACTUAL INDICATOR 3-2 %

PRESSURE READING ERROR ERROR
Kg/cm2 Kg/cm2
1 1.0 0.9 -0.1

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2 2.0 2.0 0
3 3.0 3.0 0
4 4.0 4.0 0
5 5.0 5.1 0.1
6 6.0 6.1 0.1
7 7.0 7.1 0.1

DISCUSSION:
1. Discuss the Calibration of Pressure gauge.
2. Discuss the calibration of thermometer.
3. Discuss the importance of this exiperment.

Viva Question:
1. Why is calibration important?
Ans: The primary significance of calibration is that it maintains accuracy, standardization
and repeatability in measurements, assuring reliable benchmarks and results. Without
regular calibration, equipment can fall out of spec, provide inaccurate measurements and
threaten quality, safety and equipment longevity.
2. Why is it important to calibrate thermometer?
Ans: It is necessary to calibrate a thermometer to assure accurate readings, as the
accuracy of a thermometer can drift over time. Thermometers can drift over time for
various reasons. One reason a thermometer can drift is mechanical shock.

3. What is accuracy in calibration?

Ans: Accuracy is precision with calibration. This means that you not only repeat time and
again within prescribed error limits but also that you hit what you are aiming for.

4. What is the process of calibration?

Ans: Calibration is the process of configuring an instrument to provide a result for a sample
within an acceptable range. Eliminating or minimizing factors that cause inaccurate
measurements is a fundamental aspect of instrumentation design.
5. What is error in calibration?
Ans: The difference between values indicated by an instrument and those that are actual.
Normally, a correction card is placed next to the instrument indicating the instrument error.
Also called calibration error.

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