1

BHARATHIDASAN ENGINEERING COLLEGE

NATTRAMPALLI – 635 854

DEPARTMENT OF MECHANICAL ENGINEERING

LABORATORY MANUAL

ME6412 THERMAL ENGINEERING LABORATORY - I YEAR / SEMESTER : II / IV

DEPARTMENT : Mechanical

REGULATION : 2013

Name : ………………………………………

Reg. No : ………………………………………

Branch : ………………………………………

Year & Semester : ………………………………………

PREPARED BY

Mr.N.RAJESH.M.E.,

AP/MECHANICAL

2

TABLE OF CONTENTS

Ex.No

Date

Name of the Experiment

Mark

Signature

1

PORT TIMING DIAGRAM OF TWO

STROKE PETROL ENGINE

PE

TR

OL

EN

GI

NE

2

VALVE TIMING DIAGRAM OF FOUR

STROKE DIESEL ENGINE

3

REDWOOD VISCOMETER

4

DETERMINATION OF FLASH POINT AND

FIRE POINT OF VARIOUS FUELS /

LUBRICANTS

5

PERFORMANCE TEST ON FOUR STROKE

DIESEL ENGINE BY MECHANICAL LOAD

6

PERFORMANCE TEST ON FOUR STROKE

DIESEL ENGINE BY ELECTRICAL LOAD

7

MORSE TEST ON MULTI CYLINDER

PETROL ENGINE

8

HEAT BALANCE TEST ON FOUR STROKE

DIESEL ENGINE

9

RETARDATION TEST ON A DIESEL

ENGINE

10

STUDY OF STEAM GENERATORS &

STEAM TURBINE

11

PERFORMANCE AND ENERGY BALANCE

TEST ON A STEAM GENERATOR

3

1. PORT TIMING DIAGRAM OF TWO STROKE

PETROL ENGINE Ex.NO: Date:

Aim:

To draw the port timing diagram of given two stroke cycle petrol engine.

Apparatus Required:

1. Two stroke petrol engine

2. Measuring tape

3. Chalk

Theory and Description:

In the case of two stroke cycle engines the inlet and exhaust valves are not present.

Instead, the slots are cut on the cylinder itself at different elevation and they are called ports.

There are three ports are present in the two stroke cycle engine.

1. Inlet port

2. Transfer port 3. Exhaust port

The diagram which shows the position of crank at which the above ports are open and

close are called as port timing diagram.

The extreme position of the piston at the bottom of the cylinder is called “Bottom

Dead centre “[BDC]. The extreme position of the piston at the top of the cylinder is called

“TOP dead centre “[TDC]

In two stroke petrol engine the inlet port open when the piston moves from BDC to

TDC and is closed when the piston moves from TDC to BDC.

The transfer port is opened when the piston is moved from TDC to BDC and the fuel

enters into the cylinder through this transport from the crank case of the engine. The transfer

port is closed when piston moves from BDC to TDC. The transfer port opening and closing

are measured with respect to the BDC.

The exhaust port is opened, when the piston moves from TDC to BDC and is closed

when piston moves from BDC to TDC. The exhaust port opening and closing are measured

with respect to the BD

4

Tabulation:

Sl.

No.

Event Position of

crank w.r to

TDC or BDC

Distance in cm Angle in Degree

1 IPO Before TDC

2 IPC After TDC

3 EPO Before BDC

4 EPC After BDC

5 TPO Before BDC

6 TPC After BDC

Port Timing Diagram:

5

Formula:

Required angle = Distance x 360 Circumference of the flywheel

Where, Distance = Distance of the valve opening or closing position marked on flywheel

with respect to their dead centre

Procedure:

1. Remove the ports cover and identify the three ports.

2. Mark the TDC and BDC position of the fly wheel. To mark this position follow the

Same procedure as followed in valve timing diagram.

3. Rotate the flywheel s l o w l y in usual direction (usually clockwise) a n d observe the

movement of the piston

4. When the piston moves from BDC to TDC observe when the bottom edge of the

piston. Just uncover the bottom end of the inlet port. This is the inlet port opening (IPO)

condition, make the mark on the flywheel and measure the distance from TDC

5. When piston moves from TDC to BDC observe when the bottom edge of the piston

Completely covers the inlet port. This is the inlet port closing (IPC) condition. Make

the mark on the flywheel and measure the distance from TDC.

6. When the piston moves from TDC to BDC, observe, when the top edge of the piston

just uncover the exhaust port . This is the exhaust port opening [EPO] condition.

Make the mark on the flywheel and measure the distance from BDC.

7. When the piston moves from BDC to TDC, observe, when the piston completely

cover the exhaust port. This is the exhaust port closing condition [EPC]. Make the mark

on the flywheel and measure the distance from BDC.

8. When the piston moves from TDC to BDC observe, when the top edge of the piston

just uncover the transfer port. This is the transfer port opening [TPO] condition.

Make the mark on the flywheel and measure the distance from BDC

9. When the piston moves from BDC to TDC, observe, when the piston completely

covers the transfer port. This is the transfer port closing [TPC] condition. Make the

mark on the flywheel and measure the distance from BDC.

6

Result:

Thus the port time for the given two stroke engine is found out and the port timing diagram

is drawn.

Inlet port opens =

Inlet port closes =

Transfer port opens =

Transfer port closes =

Exhaust Port opens =

Exhaust port closes =

7

2. VALVE TIMING DIAGRAM OF FOUR STROKE

DIESEL ENGINE Ex.NO: Date:

Aim:

To draw the valve timing diagram of the given four stroke cycle diesel engine.

Apparatus Required:

1. Four stroke cycle diesel engine

2. Measuring tape

3. Chalk

4. Piece of paper

Theory and Description:

The diagram which shows the position of crank of four stroke cycle engine at the

beginning and at the end of suction, compression, expansion, and exhaust of the engine are

called as Valve Timing Diagram.

The extreme position of the bottom of the cylinder is called “Bottom Dead Centre”

[BDC].IN the case of horizontal engine, this is known as “Outer Dead Centre” [ODC]. The

position of the piston at the top of the cylinder is called “Top Dead Centre” [TDC].In case of

horizontal engine this is known as “Inner Dead Centre” [TDC].In case of horizontal

engine this is known as “inner dead centre “ [IDC]

Inlet Valve opening and closing:

In an actual engine, the inlet valve begins to open 5°C to 20 °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 the 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 the exhaust valve is opens at 35° to 45° before BDC and

closes at 10° to 20° after the TCC. 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.

8

Tabulation: Sl. No. Event Position of crank w.r to

TDC or BDC

Distance in cm Angle in Degree

IVO Before TDC

IVC After BDC

EVO Before BDC

EVC After TDC

Valve Timing Diagram:

9

Formula:

Required angle = Distance x 360 Circumference of the flywheel

Where,

Distance = Distance of the valve opening or closing position marked on flywheel

with respect to their dead centre

Procedure:

1. Remove the cylinder head cover and identify the inlet valve, exhaust valve and piston of

particular cylinder.

2. Mark the BDC and TDC position of flywheel

This is done by rotating the crank in usual direction of rotation and observe the position of

the fly wheel, when the piston is moving downwards at which the piston begins to move

in opposite direction. i.e from down to upward direction . Make the mark on the flywheel

with reference to fixed point on the body of the engine. That point is the BDC for that

cylinder .Measure the circumference. That point is TDC and is diametrically opposite to the

BDC.

3. Insert the paper in the tappet clearance of both inlet and exhaust valves

4. Slowly rotate the crank until the paper in the tappet clearance of inlet valve is gripped

.make the mark on fly wheel against fixed reference. This position represent the inlet valve

open (IVO) . Measure the distance from TDC and tabulate the distance.

5. Rotate the crank further, till the paper is just free to move. Make the marking on the flywheel

against the fixed reference. This position represent the inlet valve close (IVC). Measure

the distance from BDC and tabulate the distance.

6. Rotate the crank further, till the paper in the tappet clearance of exhaust valve is gripped.

Make the marking on the flywheel against fixed reference. This position represents the

exhaust valve open (EVO). Measure the distance from BDC and tabulate.

7. Then convert the measured distances into angle in degrees

Result:

Thus the valve timing for the given four stroke engine is found out and is drawn.

Inlet valve opens = Inlet valve closes =

Exhaust valve opens =

Exhaust valve closes =

10

3. REDWOOD VISCOMETER

Ex.NO: Date:

Aim:

To determine the kinematic viscosity and absolute viscosity of the given lubricating

oil at different temperatures using Redwood Viscometer

Apparatus required:

1) Redwood Viscometer

2) Thermometer 0-100°c

3) Stop watch

4) 50 ml standard narrow necked

5) Flask Given Sample of oil Description:

The redwood viscometer consist of vertical cylindrical oil cup with an orifice in the

centre of its base. The orifice can be closed by a ball. A hook pointing upward serve as a

guide mark for filling the oil. The cylindrical cup is surrounded by the water bath. The water

bath maintain the temperature of the oil to be tested at constant temperature. The oil is heated

by heating the water bath by means of an immersed electric heater in the water bath, the

provision is made for stirring the water, to maintain the uniform temperature in the water

bath and to place the thermometer ti record the temperature of oil and water bath. The cylinder

is 47.625mm in diameter and 88.90mm deep. The orifice is 1.70mm in diameter and

12mm in length, this viscometer is used to determine the kinematic viscosity of the oil.

From the kinematic viscosity the dynamic viscosity is determined.

Theory and Definition:

Viscosity is the property of fluid. It is defined as “The internal resistance offered by

the fluid to the movement of one layer of fluid over an adjacent layer. It is due to the

Cohesion between the molecules of the fluid. The fluid which obey the Newton law of

Viscosity are called as Newtonian fluid.

The dynamic viscosity of fluid is defined as the shear required to produce unit rate of

angular deformation.

11

Tabulation:

S.no

Temperature of

oil

Time taken for

collecting 50cc oil

in flask

Kinematic viscosity

in m2/s

Dynamic viscosity

in NS/m2

1

2

3

4

5

12

Formula used:

1. Density (ρ) = ρ15 [1-α (T-15)] kg/m3

Where,

ρ15 = Density of the given oil = α = 0.00036 T =Temperature of oil

2. Kinematic Viscosity (ν ) = A t – B/t x 10-6 m2/s

t = t i m e t a k e n t o c o l l e c t 5 0 m l i n s e c o n d

3. Dynamic Viscosity (μ)

μ = ρ x ν in NS/m2

Procedure:

(1) Clean the cylindrical oil cup and ensure the orifice tube is free from dirt.

(2) Close the orifice with ball valve.

(3) Place the 50 ml flask below the opening of the Orifice.

(4) Fill the oil in the cylindrical oil cup upto the mark in the cup.

(5) Fill the water in the water bath.

(6) Insert the thermometers in their respective places to measure the oil and water bath

temperatures.

(7) Heat the by heating the water bath, Stirred the water bath and maintain the uniform

temperature.

(8) At particular temperature lift the bal valve and collect the oil in the 50 ml flask and

note the time taken in seconds for the collecting 50 ml of oil. A stop watch is used

measure the time taken. This time is called Redwood seconds.

(9) Increase the temperature and repeat the procedure ‘8’ and note down the Redwood

Seconds for different temperatures.

Graph:

The following graph has to be drawn

(1)Temperature Vs Kinematic Viscosity

(2)Temperature Vs Dynamic Viscosity

Result:

The kinematic and dynamic viscosity of given oil at different temperatures were

determined and graphs were drawn.

13

4. DETERMINATION OF FLASH POINT AND FIRE POINT OF VARIOUS FUELS / LUBRICANTS.

Ex.NO: Date:

Aim:

To determine the flash and power point temperatures of the given sample of

Lubricating oil using Cleveland open cup apparatus.

Apparatus Required:

1. Cleveland open cup apparatus

2. Thermometer

3. Splinter sticks

4. Sample of oil

Theory and Definition:

The flash point of the lubricating oil is defined as the lowest temperature at which it

forms vapours and produces combustible mixture with air. The higher flash point temperature

is always desirable for any lubricating oil. If the oil has the lower value of f l a s h p o i n t

temperatures, it will burn easily and forms the carbon deposits on the moving parts. The

minimum flash temperature of the oil used in IC engines varies from 200°C to 250°C. When

the oil is tested using the open cup apparatus, the temperature is slightly more than the above

temperatures. The flash and fire point temperatures may differs by 20°C to 60°C when it is

tested by open cup apparatus. However, a greater difference may be obtained if some

additives are mixed with oil. The flash and fire power point temperatures depends upon the

volatility of the oil.

Description:

The Cleveland open cup apparatus consists of a cylindrical cup of standard size. It is

held in position in the metallic holder which is placed on a wire gauge. It is heated by means

of an electric heater housed inside the metallic holder. A provision is made on the top of the

cup to hold the thermometer. A standing filling mark is done on the inner side of the cup and

the sample of oil is filled up to the mark. This apparatus will give more accurate results than

the pensky martens closed cup apparatus.

14

Tabulation:

S. No. Name of the oil sample Temperature ( 0C) Observations

1

2

3

4

5

6

Cleaveland open cup Apparatus

15

Procedure:

1. Clean the cup and fill it with the given sample of oil up to the filling mark.

2. Insert the thermometer in the holder. Make sure that the thermometer should not

touch the metallic cup.

3. Heat the oil by the means of electric heater so that the sample of oil

gives out vapour at the rate of 10°C per minute.

4. When the oil gives out vapour, introduce the test flame above the oil,

without touching the surface of the oil and watch for flash with flickering

sound.

5. Introducing the test flame should not continued at regular intervals until the

flash is observed with peak flickering sound. The temperature corresponding to

this flickering sound is noticed and it is the flash point temperature of the given

sample of oil.

6. Continue the process of heating and introducing the test flame until the

oil will begins to burn continuously and observe the temperature. This is

the fire pint temperature of the given sample of oil.

7. Repeat the test twice or thrice with fresh sample of oil and observe the

results.

8. The observations are tabulated.

Result:

The flash and fire point temperatures of the given sample of oil

were determined using Cleveland open cup apparatus.

1) The flash point temperature of the given sample of oil is °C

2) The fire point temperature is of the given sample of oil is °C

16

5. PERFORMANCE TEST ON FOUR STROKE DIESEL ENGINE BY

MECHANICAL LOAD

Ex.NO: Date:

Aim:

To conduct Performance test on a Single cylinder 4-stroke diesel engine by

mechanical loading with different loads at constant speed and draw the characteristics curve.

Apparatus Required:

1. Diesel engine with loading arrangement 2. Thread and scale (or) measuring tape 3. Stop watch 4. Tachometer

Procedure:

1. Calculate maximum load to be applied for a selected engine

2. Check the fuel supply, water circulation in the water system and

lubricating oil in the oil sump.

3. Ensure no load condition

4. The engine is started and allowed to run on idle speed for a few minutes.

5. Gradually the engine is loaded by mechanical brake method and

the speed is maintained constant.

6. Make sure the cooling water is supplied to the brake drum.

7. Load the engine in steps of 0%, 25%, 50%, 75% & 100% of maximum

load to be applied.

8. Note the corresponding readings of spring balance, fuel consumption,

manometer reading.

9. After taking the readings, unload the engine, allow it to run for few

minutes and then stop the engine.

17

Tabulation:

18

Formula:

1. Break power:

BP = 2 π N T KW

60 x 1000

2. Total Fuel consumption

TFC =Sp.Gravity x Volume of fuel consumed (cc) x 3 6 0 0 kg / hr.

t x 1000

Sp.Gravity of diesel = 0.83

Vol.of fuel consumed = 10 ml

Time for 10cc of fuel consumption= t

3. Specific Fuel Consumption:

SFC = TFC Kg / KW – hr B.P

4. Indicated Power

I.P = B.P + F.P

Where F. P = Frictional Power from William’s line diagram

5. Mechanical Efficiency:

mech = ___B.P x 100

I.P

6. Brake thermal efficiency or overall efficiency:

It is defined as the ratio of brake power to heat supplied by the combustion of fuel.

B.T or overall = B.P x 100

TFC X CV

Calorific value of the diesel 44631.96 KJ / Kg 7. Indicated thermal efficiency or Thermal efficiency

I.T = IP IPx 3600 x 100

TFC x C.V

19

Graph:

The following graphs has to be drawn

1. B.P Vs SFC

2. B.P Vs B.T

3. B.P Vs I.T

Result:

The performance test is conducted for a Single cylinder four stroke diesel

engine by mechanical loading with different loads and the characteristics graphs are draw.

20

6. PERFORMANCE TEST ON FOUR STROKE DIESEL ENGINE BY

ELECTRICAL LOAD

Ex.NO: Date:

Aim: To conduct Performance test on a Single cylinder 4-stroke diesel engine by Electrical

loading with different loads at constant speed and draw the characteristics curve.

Apparatus required:

Tachometer

Stopwatch

Thermometer

Measuring setup

Procedure:

1. Calculate maximum load to be applied for a selected engine

2. Check the fuel supply, water circulation in the water system and

lubricating oil in the oil sump.

3. Ensure no load condition

4. The engine is started and allowed to run on idle speed for a few minutes.

5. Gradually the engine is loaded by mechanical brake method and

the speed is maintained constant.

6. Make sure the cooling water is supplied to the brake drum.

7. Load the engine in steps of 0%, 25%, 50%, 75% & 100% of maximum

load to be applied.

8. Note the corresponding readings of voltmeter, ammeter, Fuel

consumption fuel consumption, manometer reading.

9. After taking the readings, unload the engine, allow it to run for few

minutes and then stop the engine.

21

Observation:

Specific gravity of the fuel =

Calorific value of the fuel =

Efficiency of alternator(a) =

Input voltage (Vi) =

Maximum load to be applied Amax=BP x a x 1000 Am/s

Vi

Where,

BP=Engine standard BP mention in engine Name plate

BP= HP x 736 Watts

Formula used:

1. Brake Power

B.P = V X I KW

ɳ x 1000 V=Voltmeter reading in volts

I=Ammeter reading in amps

ɳ =Generator efficiency= 0.85

2. Total Fuel consumption

TFC =Sp.Gravity x Volume of fuel consumed (cc) x 3 6 0 0 kg / hr.

t x 1000

Sp.Gravity of diesel = 0.83

Vol.of fuel consumed = 10 ml

Time for 10cc of fuel consumption= t

3. Specific Fuel Consumption:

SFC = TFC Kg / KW – hr B.P

22

4. Indicated Power

I.P = B.P + F.P

Where F. P = Frictional Power from William’s line graphical method

5. Mechanical Efficiency:

mech = ___B.P x 100

I.P

6. Brake thermal efficiency or overall efficiency:

It is defined as the ratio of brake power to heat supplied by the combustion of fuel.

B.T or overall = B.P x 100

TFC X CV

Calorific value of the diesel 44631.96 KJ / Kg 7. Indicated thermal efficiency or Thermal efficiency

I.T = IP IPx 3600 x 100

TFC x C.V

23

Tabulation:

24

Graph:

The following graphs has to be drawn

1. B.P Vs SFC

2. B.P Vs B.T

3. B.P Vs I.T

Result:

The performance test is conducted for a Single cylinder four stroke diesel engine by Electrical loading with different loads and the characteristics graphs are draw.

25

7. MORSE TEST ON MULTI CYLINDER PETROL ENGINE Ex.NO: Date:

Aim:

To conduct morse test on given multi cylinder petrol engine in order to determine the

indicated power developed in the each cylinder of the engine and to determine the mechanical

efficiency.

Apparatus Required:

1. Multi cylinder petrol engine with ignition cut off arrangement 2. Loading arrangements 3. Tachometer

Theory and Description:

For slow speed engine the indicated power is directly calculated from the indicator diagram. But in modern high speed engines, it is difficult to obtain accurate indicator diagram due to inertia forces, and therefore, this method cannot be applied. In such cases the morse test can be used to measure the indicated power and mechanical efficiency of multi cylinder engines. The engines test is carried out as follows. The engine is run at maximum load at certain speed. The B.P is then measured when all cylinders are working. Then one cylinder is made in operative by cutting off the ignition to that cylinder. As a result

of this the speed of the engine will decrease. Therefore, the load on the engine is reduced so

that the engine speed is restored to its initial value. The assumption made on the test is that

frictional power is depends on the speed and not upon the load on the engine.

Procedure:

1. Check the engine for fuel availability, lubricant and cooling water connections.

2 Release the load completely on the engine and start the engine in no load conditions

and allow the engine to run for few minutes to attain the rated speed.

3. Apply the load and increase the load upto maximum load. (All four cylinders should

be in working). Now note the load on the engine and speed of the engine say the

speed is ‘N’ rpm

4. Cut-off the ignition of first cylinder, now the speed of engine decreased. Reduce the

load on the engine and bring the speed of the engine to ‘N’ rpm. Now note the load

on the engine.

5.Bring the all four cylinders are in working conditions and cut off the 2nd

, 3rd

and 4th

cylinder in turn and adjust the load to maintain same ‘N’ rpm and note the load .

26

Observation and Tabulation:

(1) Brake power B.P =........... KW

(2) Rated Speed N =...........Rpm

(3) Type of loading : =...........

(4) Radius of brake drum : R =........... ‘m’

(5) Radius of Rope r = =........... ‘m’

(6) Number of cylinders = 4

S No Conditions Loading Speed BP ‘KW’

W1 kg W2 W1 – W2 Net load Rpm

kg kg W in ‘N’

1 All cylinders are

working

2 First cylinder

was cut off and

remaining are in

working

3 Second cylinder

was cut off and

remaining are in

working

4 Third cylinder

was cut off and

remaining are in

working

5 Fourth cylinder

was cut off and

remaining are in

working

Note: The speed should be same for all readings

27

Formula:

Break power: (BP)

The useful power available at the crank shaft of the engine is called brake power of the engine. The brake power of the engine are determined by

1. Rope brake dynamometer.

T = WRe

W = net load Re = effective radius of the brake drum

2. Prony brake dynamometer

T = WL

W = Load L = Distance at which the load is applied

3. Hydraulic dynamometer B.P = WN

C W = Load N = Speed in RPM C = Dynamometer constant

4. Electrical dynamometer

Indicated power: (IP)

The power actually developed inside the engine cylinder due to the

combustion of the fuel are called indicated power.

IP = FP + BP; FP = Frictional power

Frictional power (FP):

The power loss due to friction between the moving parts are called as frictional power.

Mechanical efficiency: (mech )

It is defined as the ratio of Brake power to indicated power.

mech=B.P x 100

I.P

28

From the name plate details, determine the maximum load that can be given to the Engine For example: B.P = 12.5 kw , N = 2000 rpm

B.P = __2πNT__

60 x 1000

T = 60 x 1000 x 12.5 = 59.68 N-m

2 π x 2000

T = W.Re Say Re = 0.4m

... W = T__ = 59.68 = 149.2N

Re 0.4

~ 150 N

Result:

Morse test was conducted on given petrol engine and indicated power developed in each cylinder are determined and mechanical efficiency are also determined

29

8. HEAT BALANCE TEST ON FOUR STROKE DIESEL ENGINE Ex.NO: Date:

Aim:

To conduct the test on the given IC engine and to prepare the heat balance sheet.

Apparatus Required:

4. Given IC engine with loading arrangement 5. measuring tape or Thread and scale 6. Tachometer 7. Stop watch 8. Bucket 9. Spring balance 10. Thermometer (3 Nos)

Theory and Description:

A heat balance sheet is an account of heat supplied and heat utilised in various ways in the

system. Necessary information concerning the performance of the engine is obtained from the heat balance sheet. The heat balance sheet is generally done on second basis or minute basis or hour basis.

The engine should equipped with suitable loading arrangement to measure the brake power

of the engine. Provisions are also made to measure the amount of air intake. Amount of fuel consumed, temperature of cooling water at inlet and outlet of the engine amount of cooling water circulated and temperature of exhaust gases.

The heat supplied to the engine is only in the form of fuel – heat and is equal to.

Qs = mf x C.V

Where,

mf = mass of fuel used in kg/min C.V = Calorific value of fuel in KJ /kg

The various way in which the heat is utilized are

1. Heat equivalent to brake power of the engine. 2. Heat carried away by the cooling water 3. Heat carried away by the exhaust gases 4. Unaccounted heat losses.

Procedure: 1. From the name plate details, calculate the maximum load that can be applied on the given

engine. 2. Check the engine for fuel availability , lubricant and cooling water connection

3. Release the load on engine completely and start the engine with no load condition. Allow

the engine to run for few minute to attain the rated speed 4. Adjust the cooling water flow and maintain steady flow of water.

5. Apply the load, from no load to required load slowly. At required load slowly. At required

load note the following.

30

i) Load on the engine ii) Speed of the engine in Rpm iii) Time taken for 10 cc of fuel consumption iv) Manometer readings v) Temperature of cooling water at engine inlet and engine outlet in °C vi) Time taken for collection of 5 lit or 10 lit of cooling water vii) Room temperature and temperature of exhaust gases

Tabulation:

Sl.No Load(W)

in Kg

Time for 10 cc

fuel

consumption

Temperature(°C)

T.F.C

Kg/hr

T1 T2 T3 T4 T5

Heat Balance Sheet:

Sl.No Load

input

Heat Input B.P P water P exhaust P unacc

Kg KW KW % KW % KW % KW %

31

Formulae:

1. Total Fuel consumption TFC = ( Kg/hr)

Where,

q = Fuel consumption (10cc) t = Time taken for 10cc of fuel consumption (sec)

ρ = Density of diesel =0.83 kg/m3

2. Specific Fuel consumption SFC

SFC = TFC/BP (Kg/Kwhr)

3. Heat input, HI = TFC x calorific value / 3600 ( Kw)

Where CV= 43000 Kj/Kg

4. Brake power, BP =

Where,

T = Torque = RS N-m

R= Torque arm length = 0.3 m

S = spring balance reading (kg)

5. Heat carried by cooling water, Qw = mwCpw(Tw2-Tw1) kW

Where,

Tw1 = Inlet temperature of engine cooling water (0C)

Tw2 = Outlet temperature of engine cooling water (0C)

Cpw = Specific heat of water = 4.187 kJ/kg0K

mw = Mass flow rate of cooling water = kg/sec

tw = Time taken for flow of 1 litres of water

6. Heat carried by exhaust gas Qg = mgCpg(Tag-Ta) kW

Where, Tag = Exhaust gas temperature (0C)

Ta = Atmospheric temperature (0C)

Cpg = Specific heat of exhaust gas = 1.1 kJ/kg0K

mg = Mass flow rate of exhaust gas = TFC+ma

ma = Mass flow rate of air = CdA ×ρa (kg/sec)

Cd = Co-efficient of discharge of orifice meter = 0.62

A = Area of orifice = m2

d = Diameter of orifice = 20mm

Ha = Head of air column = Hw× m

Hw = Head of water column (m)

ρw = Density of water = 1000kg/m3

ρa = Density of air = kg/m3

pa = Atmospheric pressure = 1.01325×105

N/m2

R = Characteristic gas constant of air = 287 J/kg K

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7. Percentage of brake power, %BP =

8. Percentage of heat carried by cooling water, %Qw =

9. Percentage of heat carried by exhaust gas, %Qg =

10. Percentage of unaccounted loss = 100-(%BP + %Qw + %Qg)

Result:

The test was conducted on the given IC engine and the heat balance sheet was prepared for the particular load.

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9. RETARDATION TEST ON A DIESEL ENGINE Ex.NO: Date:

Aim:

To conduct a retardation test on engine and determine the frictional power loss and hence determine the mechanical efficiency. .

Apparatus required: 1. Stop watch 2. Tachometer

Technical details of the engine: Four stroke diesel water-cooled brake drum loading:

1. Brea k power. : 2. Lubrication. oil: 3. Rated speed. :

Procedure: 1. Start the engine by hand cracking with the decompression lever pressing down the exhaust value.

2. Tack out the hand crank release the decompression lever to run at no load for about 5-10 mines to

warm up and attain steady state condition at rated speed. 3. Adjust the rate of cooling water flow.

4. By pulling the control rod cut off the diesel supply to the engine and simultaneously start the

stop watch. 5. Record the time for crankshaft speed to reduce 560, 460, 360, rpm by running the stopwatch.

Model calculation:

Effective radius, Re = Brake drum radius + Radius of rope

1. Brake torque B.T = W x 9.81 x Re in N-m

2. Frictional Torque T.F = Tf1 + Tf2 + Tf3 in N-m

Tf1 = BT – (T1/ (Tm-T1) in N-m

t1=time taken for fall of speed at no load condition

t2=time taken for fall of speed at no load condition 3. Break Power B.P = (2π x W x Re x g) / (60x1000) in KW

. 4. Frictional Power Loss FP = (x N x Tf ) / 60000 inKW 5. Mechanical Efficiency mech = (B.P /(BP + FP) x 100 i%

Where, g = Acceleration due to gravity = 9.81 m / sec

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Graph:

Thgraph drawn by B.P Vs mech

Tabulation:

Average

Time taken to reach

Break Friction Break Friction mech

LOAD(kg) Torque Torque Power Power

from 660 rpm to (sec)

N-m N-m KW KW

S.NO

%

W1 W2 W 560 460 360

W1-W2 rpm rpm rpm

1.

2.

3.

4.

Result:

Thus the Retardation test on engine in conducted and the. Frictional power loss mechanical efficiency at about three loads are found out.

35

10(a). STUDY OF STEAM GENERATORS Ex.NO: Date:

Aim:

To study the working of various types of steam generator (steam boilers)

Study of steam generators: Introduction:

A steam boiler is a closed vessel which boiler generator steam by transferring heat produced by burning of fuel to water. The steam boiler produced is used for power generation or process heating.

Selection of steam generators: The selection of type & size of a steam generator depends on the following factors.

11. The power required & working pressure. 12. The geographical position of power house. 13. The fuel & water available. 14. The probable load factor.

Classification of Boilers:

The steam boilers are classified according to the following basic:

1. Flow of water & heat gases Fire tube boiler Water Tube boiler

2. Method of firing Internally fired Externally fired

3. Method of water circulation Natural circulation Forced circulation

4. Pressure developed Low pressure boiler High pressure boiler

6. Nature of service a. Stationary boiler b. Mobile boiler

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7. Design of gas passage a. Single phase b. Multi-phase

8. Nature of service a. Stationary boiler b. Mobile boiler

9. Design of gas passage a. Single phase b. Multi-phase

10. Nature of service a. Stationary boiler b. Mobile boiler

11. Design of gas passage a. Single phase b. Multi-phase

High Pressure Boilers: Modern high pressure boilers generate steam at a pressure more than 75 bar.

Example: Babcock & Wilcox boiler, Lamont boiler, BHEL boiler.

Lamont Boiler: A forced circulating boiler was first introduced in 1725 by Camont . The arrangement

is shown in the figure. The most of sensible heat is supplied to the feed water passing through

the Economizer. A centrifugal pump circulates the water equal to 8 to 10 times the weight of

steam evaporated tubes and the part of water supplied drum. The large quantity of water

circulated prevents the tubes from being overheated.

To secure the uniform flow of feed water through each of parallel boilers circuits a

choke is fitted all the enhance to each circuits.

Bhell boilers: It consists of feed pump, a economizer a boiler drum, radiant & connective super

heaters, FD fan, air pre heaters 1 & 2 .Electro static precipitator 1D fan & chimney. The feed water from the hot well is pumped with the help of a feed pump to boiler from

the through economy .In boiler drawn the fed water is circulated to number of valves in the

furnaces with fuel is burnt. The feed water is evaporated into wet steam and the wet steam

flows back to boiler drawn. In this it’s supplied to prime mover through steam outlet.

The hot blue gases from the furnace pars over radiant & connective super heaters to super heat the steam. Then it passes through the pre heaters economizer and pre heater .Then the blue gases passes through the electrostatic precipitator.

Result:

Thus the working of various types of steam generator was studied.

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10(b). STUDY OF STEAM TURBINE Ex.NO: Date:

Aim:

To study the working of various types of steam turbines.

Study of steam turbines: Introduction:

A steam turbine is rotary machine which is designed to covert the energy of high temperature steam into mechanical power. In this the steam is first expanded in a set of nozzles or passages upto exit pressure where in the pressure energy of steam is converted into kinetic energy.

Classification of Steam Turbine: Steam turbines are classified according to:

1. Priciple of action of steam

Impulse turbine Reaction turbine

2. Direction of steam flow Axial Radial Tangential

3. Number of pressure stages Single stage Multi stage

4. Method of governing Throttle Nozzle By-pass Combination of throttle , nozzle by pass

Impulse Turbine: Velocity compound impulse turbine:

Arrangement of velocity compounded impulse turbine is shown in fig. In this type of

turbine steam expands in a set of nozzle from the boiler pressure up to the condenser pressure

which converts its pressure energy into kinetic energy. This high velocity steam is passed over

the rings of moving blades, each ring of moving blades being separated by a ring of

38

fixedblades. A part of high velocity steam is absorbed in the first ring of moving blades and

remaining in the first ring of moving blades is passed to next ring of fixed blades. The function

of fixed blades is to change the direction of flow of steam so that it can guide over the second

ring of moving blades. The velocity of steam while passing over the fix blades is particularly

constant except last for overcoming the friction losses. Again a part of steam velocity is

absorbed in the second ring of moving blades & the process of absorbing the steam velocity

continues till it finally wasted in exhaust.

Pressure compounded Impulse Turbine Arrangement of velocity compounds impulse turbine is steam is shown in fig. In this

type of turbine the total pressure drop does not take place in a single ring of nozzle, but it is

divided up in between the set of nozzle ring steam from the boiler is partially expanded in the

first ring of nozzle and then it is passed over the ring of moving blades till its velocity is

absorbed . Exhaust from blades till its velocity is absorbed.

Pressure – Velocity compounded Impulse Turbine:

Arrangement of velocity compounded impulse turbine is shown in figure. In this

arrangement both the previous method velocity & pressure compounding are utilized. The

total pressure drop of steam is due to expansion in each stage is also compounded. Reaction Turbine:

Arrangement of velocity compounded impulse turbine is shown in figure. Unlike

impulse turbine nozzle are not provided in this turbine and also there is a continous pressure

drop in the rings of fixed and moving blades. The function of fixed blades, which also get

nozzles is to change the direction of steam. So that it can enter into the ring of moving blades

without shock the term reaction is used because the steam expands over the ring of moving

blades giving a reaction on moving blades.

Result:

Thus the working of various types of steam generator (steam boilers) & steam turbine are studied.

39

11. PERFORMANCE AND ENERGY BALANCE TEST ON A STEAM

GENERATOR

Ex.NO: Date: Aim:

To conduct the Performance and energy balance test on a steam Generator

Apparatus required:

Stop watch

Beaker

Procedure:

1. Keep the main steam control valve and the valves of the calorimeter (as described above)

fully closed initially.

2. Supply the power to the main control panel to the digital voltmeter, ammeter, tachometer and

temperature indicator.

3. Start the condenser cooling water pump and circulate cooling water through the condenser.

Ensure that cooling water flows freely through the turbine casing bearing cooling water

jacket – the braided hoses.

4. Open the steam main valves and crack open the steam nozzle control valve to observe the

turbine start spinning.

5. Apply some initial load (switch on a few load bulbs) first. Continuously monitoring the

turbine speed, open the nozzle valve such that the turbine speed reaches about 2800rpm.

Note: Do not exceed 3000rpm under any circumstances as the alternator is rated only for

3000rpm and any overs peed will damage the coil windings.

6. Observe the operating parameters – rpm, pressure, alternator output voltage, current.

7. The turbine can be loaded further by switching on more bulbs and opening the second nozzle

valve also. Alternatively, both nozzles can be opened partially. If the turbine speed tends to

increase beyond the permissible speed, more bulbs are to be switched on.

8. Initially some steam may come out of the condenser along with condensate. After a few

minutes, it will stop and only water will flow. If steam continues to come out, it indicates

that either the cooling water flow rate is not sufficient or the cooling water temperature is too

hot for the condenser to be effective.

9. The condensate is to be measured directly to determine the exact steam flow rate through

the condenser and turbine.

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10. Monitor the coolant water inlet and exit temperatures. Once steady state is reached, note

down the temperatures and the orificemeter pressure gauge readings (to determine the flow

rate)

11. Steam quality measurement: Open the needle valve V1 and outlet valve V3 and let the steam

purge any air present inside the two chambers. Allow cooling water through the calorimeter

condenser. Now, adjust the valve V1 such that a small quantity of steam flows through the

separating calorimeter at first and then through the throttling calorimeter and finally is

condensed. If steam pressure is increasing in the separating chamber, it implies that the

condenser cooling is insufficient. So, increase the cooling water flow rate and/or close the

valve V0 slightly. Once steady conditions are reached, note the pressure and temperature at

the throttling calorimeter chamber. After a certain period of time (say 5 minutes), close V1

and measure the water collected in the separating chamber by opening valve V2 at its bottom.

Also measure the water condensed in the condenser.

12. Repeat the experiment for other loads.

Caution: Never run the turbine without any load. This may cause overspeed and damage the alternator

which is rated for 3000rpm.

Measured and observed data:

Inlet steam line pressure P0 -

Turbine rpm N -

Voltmeter reading V -

Ammeter reading A -

Separating calorimeter pressure P1 -

Throttling calorimeter pressure P2 -

Throttling calorimeter temperature T3 -

Moisture collected in separating calorimeter mS -

Moisture collected in throttling calorimeter mT -

Condenser cooling water inlet temperature TC1 -

Condenser cooling water outlet temperature TC2 -

Condenser orificemeter pressure PCO1 -

Condenser orificemeter pressure PCO2 -

Steam flow Rate (From Condenser) M -

41

Calorimeter calculations:

m be the total mass flow rate of steam sampled by the calorimeter

We have the following relations

m = mt + ms .... 1

h2 = h1 =hf1 + X1hfg1 .... 2

X1 = (h2 - hf1)/hfg1 .... 3

h1 is the enthalpy at P1 and h2 is the enthalpy at P2 and T2 .

X1 is the steam quality in separating chamber

(Note: Steam condition 1 is normally wet and 2 is superheated due to the throttling - hf1 and hfg1

are obtained from saturated steam tables and h2 from superheated steam tables)

For P1 = kg/ cm2 hf1 = and hfg1 = (saturated steam)

For P2 = and T3 = h2 = (super heat steam)

X1 = (h2-hf1)/hfg1

= ( – ) /

X1 =

mw be total moisture in steam sample

mw= [ms + (1-X1) mt] .... 4

= [ + ( – ) ]

mw =

Line Steam Quality X = [1 - mw/(ms+mt)]x100 % .... 5

= [1 – / ( + )] x 100%

X =

X =

42

Calculation of Isentropic work:

P0, X are inlet steam pressure and quality. Corresponding enthalpy and entropy h0 and s0 are

determined form steam tables.

For P0 = kg / cm2 , hf0 = and hfg0 = sf0 = and sfg0 =

h0 = hf0

+ X.hfg0

= + ( x )

h0 =

s0 = sf0 + X.sfg0

= + ( x )

s0 =

Exit pressure PE is atmospheric. Saturated steam properties for this condition are:

For PE =1bar hfE = and hfgE = sfE= and sfgE =

For isentropic expansion to exit pressure PE, s

E = s0 .Hence, exit steam quality X

E is determined

from the relation:

XE = (s0 -sfE)/sfgE .... 6

= ( – ) /

XE =

Enthalpy at exit conditions (for isentropic expansion) are

hE = hfE + XE.hfgE

= + ( x )

hE =

isentropic enthalpy drop: is

h s=const = ( h0- hE) ....7

= ( - )

h s=const = KJ/kg

Isentropic work W = M.( hs=const) .... 8

= x KJ / hour

= x / 3600 kw

= kw

43

Calculation of Output Power:

Voltmeter reading V = Volts

Ammeter reading A = amps

Alternator Output Power = V x A/1000 KW

= ( x /1000) KW

= KW

Steam turbine output = Alternator output/0.7 KW

(0.7 is the assumed alternator efficiency)

= V x A/(1000 x 0.7) KW

= KW

Calculation of isentropic efficiency of turbine:

Isentropic efficiency = Turbine Power/Isentropic work

= /

=

Calculation of condenser effectiveness:

Coolant water flow rate-

Pressure drop in condenser orificemeter OP = (Pco1 – Pco2) x 10 m of water

= ( - x 10) m

= m of water

Coolant water flow rate Q = 0.00204 √OP m3/sec

= 0.00204 √ m3/sec

= x x 6000

=

Heat exchanger effectiveness of condenser = (Tc2-Tc1)/(TE-Tc1)

(TE is the saturation temperature of exhaust steam at atmospheric pressure)

= ( – ) / ( – )

= ٪

44

Result:

Thus the Performance and energy balance test on a steam Generator was studied.

45