thermal engineering lab - i manual r 2013

DEPARTMENT OF MECHANICAL ENGINEERING

THERMAL ENGINEERING LABORATORY I

MANUAL

R 2013

II YEAR IV SEMESTER

Prepared by

S.SATHEESH KUMAR.S, M.B.A., M.E., Ph.D.,

Assistant Professor in Mechanical Engineering

PROFESSIONAL GROUP OF INSTITUTIONS

PALLADAM 641 662

PROFESSIONAL GROUP OF INSTITUTIONS, PALLADAM

I

ANNA UNIVERSITY CHENNAI

CURRICULAM&SYLLABI REGULATION 2013

ME 6412 THERMAL ENGINEERING LABORATORY - I

LIST OF EXPERIMENTS

I.C.ENGINE LAB

1. Valve Timing and Port Timing Diagrams.

2. Performance Test on 4-stroke Diesel Engine.

3. Heat Balance Test on 4-stroke Diesel Engine.

4. Morse Test on Multi-cylinder Petrol Engine.

5. Retardation Test on a Diesel Engine.

6. Actual p-v diagrams of IC Engines.

7. Determination of Flash Point and Fire Point of various fuels/lubricants.

STEAM LAB

1. Study on Steam Generators and Turbines.

2. Performance and Energy Balance Test on a Steam Generator.

3. Performance and Energy Balance Test on Steam Turbine.


II

THERMAL ENGINEERING LABORATORY

TABLE OF CONTENTS

S.No Name of the Experiment Page No

1. Determination of flash point and fire point using open cup apparatus. 1

2. Valve timing diagram of a four stroke diesel engine. 3

3. Port timing diagram of a two stroke petrol engine. 6

4. Performance test on 4 - stroke diesel engine. 9

5. Heat balance test on four stroke diesel engine. 14

6. Retardation test to find Frictional Power of a diesel engine. 19

7. Determination of Mechanical efficiency of multi cylinder petrol engine

using Morse test. 22

8. Study of Boiler and Steam Turbine. 26

Model Calculations


1

Ex.No. :

DATE :

DETERMINATION OF FLASH POINT AND FIRE POINT USING OPEN CUP APPARATUS

AIM:

To find the flash point and fire point of given oil sample using open cup apparatus.

APPARATUS REQUIRED:

1. Open cup tester.

2. Heating coil.

3. Thermometer.

4. Splinter sticks.

5. Sample oil.

PROCEDURE:

1. First of all, oil cups cleared well.

2. The given lubricating oil, sample is poured inside the oil cup up to the mark level.

3. Thermometer is placed inside the oil cup such that the bulb of the thermometer doesnt

touch the surface of the oil cup.

4. The oil is heated continuously using heater. The fire is ignited on the surface of the oil by

using a stick or candle.

5. Fire is ignited inside the cup for every temperature rises. The temperature is noted at

which the surface of the layer (oil) catches fire suddenly and fire off. This temperature is

called flash point of the lubricating oil.

6. When the oil cup is continuously heated after the flash point the oil catches fire

and burns continuously, the temperature at this point is called fire point of the lubricating

oil.

7. The procedure is repeated for various lubricating oil and readings were noted.


2

TABULATION:

S.No Sample oil Flash Point

(Temperature in 0C)

Fire Point

(Temperature in 0C)

1

RESULT:

Thus the flash point and fire point of the given sample oils were found by open cup apparatus.

Flash point of = ______C

Fire point of = ______C


3

Ex.No. :

DATE :

VALVE TIMING DIAGRAM OF A FOUR STROKE DIESEL ENGINE

AIM:

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

APPARATUS REQUIRED:

1. Chalk

2. Paper

3. String.

FORMULA:

1. To calculate the angle with respect to nearest dead center:

Angle =

360, degrees

Where X = Distance from the nearest dead center, cm

C = Circumference of the flywheel = D

D = Diameter of the flywheel

2. To calculate the valve timing:

Valve timing at particular speed = 60

360 , sec

Where N = Speed of the engine = 1500 rpm

VALVE TIMING DIAGRAM:

We consider theoretically that, the valve open and close at the dead centers of the

piston. But, in actual practice they do not open and close instantaneously at dead centers.

They operate some degree before or after the dead centers. The ignition is timed to occur a


4

little before top dead center. The timings of these sequences of events such as inlet valve

opening, inlet valve closing, ignition, exhaust valve opening, exhaust valve closing can be

shown graphically in terms of crank angles from dead center positions. These diagrams are

known as valve timing diagrams.

The inlet valve is opened 10 to 25 in advance of top dead center position. The fresh

air is admitted into the cylinder till the inlet valve closes. The inlet valve is closed 25 to 50

after the bottom dead center. The compression of the air takes place. The fuel injection starts

5 to 10 before the top dead center, in the compression stroke. Fuel injection closes 15 to 25

after the top dead center in the working stroke. The pressure and temperature increases.

The exhaust valve is opened 30 to 50 before bottom dead center. The exhaust gases

are forced out of the engine cylinder till the exhaust valve closes. The exhaust valve is closed

10 to 15 after the top dead center. Even before exhaust valve closes, again the inlet valve is

opened 10 to 25 before the top dead center. The period between the inlet valve opening and

exhaust valve closing (the period at which both valves are in open position) is known as valve

overlap period. The angle between these two events is known as angle of overlap.

PROCEDURE:

Find the engine running condition, by rotating the camshaft in clockwise

direction handle.

Rotate the flywheel, in the engine running direction and keep the piston at the

top most position of the cylinder. A reference needle has been fitted near the

flywheel, at the engine body. Mark the top dead center (T.D.C) on the

circumference of the flywheel towards the reference needle.

Measure the circumference of the flywheel using measuring tape. Take half

measurement of the circumference, from T.D.C and mark bottom dead center

(B.D.C)

Keep the engine in exhaust valve closed position and just before open position

of inlet valve by rotating the flywheel in its direction.

Take a piece of paper and insert it into the gap between rocker arm and inlet

valve head. Now we can shake the paper in between rocker arm and valve

head.


5

Rotate the flywheel slowly, shaking the paper. We cannot shake the paper at

the particular point. Stop the rotation of flywheel in that position. Mark the

inlet valve opening (I.V.O) position on the flywheel towards reference needle.

Rotate the flywheel in its direction, slightly pulling the paper. Paper comes out

at a particular point. Stop the rotation of the flywheel in that position and mark

inlet valve close (I.V.C) position, towards the reference needle.

Similarly, insert the paper in the gap of rocker arm and exhaust valve head,

after the compression stroke movement of the piston is completed.

The same procedures of I.V.O. & I.V.C. are flowed to mark exhaust valve

opening position (E.V.O) & closing position (E.V.C).

Take the measurements in cm of valve opening and closing points from the

nearest dead center.

Note the measurements and note the positions of valves opening and closing

either before the nearest dead center or after the nearest dead center.

Then, using the above readings, valve timings and timing diagram are worked.

TABULATION:

S.No Events Position with respect to the nearest

dead center

Observed Value

In cm

Angle in

degrees

1. IVO

2. IVC

3. EVO

4. EVC

IVO - Inlet Valve Open

IVC - Inlet Valve Close

EVO - Exhaust Valve Open

EVC - Exhaust Valve Close

RESULT:

Thus a valve timing diagram of the given four stroke diesel engine was drawn.


6

Ex.No. :

DATE :

PORT TIMING DIAGRAM OF A TWO STROKE PETROL ENGINE

AIM:

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

APPARATUS REQUIRED:

1. Chalk

2. Paper

3. String.

FORMULA:

1. To calculate the angle with respect to nearest dead center:

Angle =

360, degrees

Where X = Distance from the nearest dead center, cm

C = Circumference of the flywheel = D

D = Diameter of the flywheel

2. To calculate the valve timing:

Valve timing at particular speed = 60

360 , sec

Where N = Speed of the engine = 1500 rpm

PORT TIMING DIAGRAM:

Like valve timing diagram in four stroke diesel engines, the timing of the sequence are

represented graphically for two stroke petrol engine. The events such as opening and closing of inlet

port, transfer port, and exhaust port are shown graphically in terms of crank angles from dead center

positions. Theses diagram is known as port timing diagram.


7

The piston uncovers the inlet port 45 to 55 before the top dead center position. The induction of air

fuel mixture into the engine cylinder takes places, till the inlet port is covered. The inlet port is

covered 45 to55 after the top dead center position. The compression of the air fuel mixture takes

place till the spark occurs. The spark is produced at 30 to 40 before the top dead center position. This

is to give sufficient time to the fuel to burn. The pressure and temperature increases. The exhaust port

is uncovered by the piston 65 to 75 before the top dead center. The exhaust gases are forced of the

cylinder till the exhaust port is covered. The piston 65 to 75 covers the exhaust port after the bottom

dead center. The transfer is uncovered and covered55to 65 before and after bottom dead center.

Ignition occurs 15-25 before top dead center.

After the compression stroke (during expansion or working stroke) the charge from the

crankcase enters the cylinder at a pressure, which is above atmospheric. This forces the exhaust gases

to the atmosphere through exhaust port. There is a possibility of escaping out of charge with burnt

gases. However this is over come by designing the piston to have a deflected shape at its crown. Due

to this deflected shape of the piston crown the fresh charge is deflected upward in the engine cylinder.

Thus deflected shape also helps in forcing the exhaust gases to the atmosphere. This process is known

as scavenging.

PROCEDURE:

First find the running direction of the engine, using kicker.

Mark the T.D.C. & B.D.C points as the procedure stated in the four - stroke

diesel engine. (Circumference of the flywheel is 52 cm).

Mark a reference point near the flywheel, at the engine body.

Rotate the flywheel in its direction. Mark the inlet port opens position (I.P.O)

when the piston moves from the B.D.C, at which point the bottom edge of the

piston just uncovers the inlet port.

Continuously rotate the flywheel in the same direction. Now, piston

completely uncovers the inlet port and reaches the T.D.C and comes towards

B.D.C. Mark the inlet port close position (I.P.C) on the circumference of the

flywheel towards the reference mark when the bottom edge of the piston

closes the inlet port completely.

To mark the position of transfer port opening (T.P.O), piston movement

should be from T.D.C to B.D.C. Mark the T.P.O. point when the top edge of

the piston just uncovers the transfer port.


8

By rotating the flywheel in its direction continuously the motion of the piston

is continued. Now the transfer port is completely uncovered by the piston top

edge and the piston reaches the B.D.C, then closes the transfer port completely

during

its motion is towards T.D.C. stop rotation of the fly wheel at the particular

point and mark transfer port closing position (T.P.C) on the flywheel

Exhaust port opening & closing (E.P.O & E.P.C) points are marked as per the

same procedure adapted to the T.P.O & T.P.C.

Take the ports opening and closing points measurements in cm. From the

nearest dead center and note at which position the ports are opening or closing

either before or after with respect to nearest dead center.

Using the above datas port timing and timing diagram is worked.

TABULATION:

S.No Events Position with respect to the nearest

dead center

Observed Value

(cm)

Angle in

degrees

1. IPO

2. IPC

3. EPO

4. EPC

5. TPO

6. TPC

RESULT:

Thus a port timing diagram of a two stroke petrol engine was drawn. The angles of opening

and closing of ports were found.


9

Ex.No. :

DATE :

PERFORMANCE TEST ON 4 - STROKE DIESEL ENGINE

AIM:

To conduct a performance test on the four stroke diesel engine (Single cylinder) and to draw the

following graphs.

1. To find friction power (TFC Vs BP) 2. Brake power Vs Specific Fuel Consumption

3. Brake power Vs Brake Mean Effective Pressure

4. Brake power Vs Indicate Mean Effective Pressure

5. Brake power Vs Mechanical Efficiency

6. Brake power Vs Brake Thermal Efficiency

APPARATUS REQUIRED:

1. Digital rpm Indicator to measure the speed of the engine.

2. Differential manometer to measure quantity of air sucked into cylinder.

3. Burette to measure the rate of fuel consumed during test.

4. Stop watch

SPECIFICATION:

Engine : Four stroke single cylinder

BHP : 5HP (3.7 kW)

Speed : 1500 rpm

Fuel : diesel

Bore : 80 mm

Stroke length : 110 mm

Starting : cranking

Working cycle : four stroke

Method of cooling : water cooled

Method of ignition : compression ignition

Diameter of orifice : 35 mm


10

Specific gravity : 0.83

Calorific value : 44000 kJ/kg or 10,833 k.Cal/kg

THEORY:

The Test Ring consists of Four-Stroke Diesel Engine, to be tested for performance, is

connected to Rope Brake Drum with Spring Balace (Mechanical Dynamometer) with

Exhaust Gas Calorimeter. The arrangement is made for the following measurements of the

Set-up :

1) The Rate of Fuel Consumption is measured by using the pipette reading againt the

known time.

2) Air Flow is measured by Manometer connected to Air Box.

3) The different mechanical loading is achieved by operating the spring balance of

dynamometer in steps.

4) The different mechanical energy is measured by spring balance and radius of brake

drum.

5) The Engine Speed (RPM) is measured by electronic digital RPM Counter.

6) Temperature at different points is measured by electronic digital Temperature

Indicator.

The whole instrumentation is mounted on a self contained unit ready for table

operation.

PROCEDURE:

1. Check the diesel in the diesel tank.

2. Allow diesel, start the engine by using hand cranking.

3. The engine is set to the speed of 1500 RPM.

4. Apply load from the spring balance of dynamometer.

5. Allow some time so that the speed stabilizes.

6. Now take down spring balance readings.

7. Put tank valve in to pipette position and note down the time taken for particular quantity of fuel

consumed by the engine.


11

8. Note down the temperature readings at different points.

9. Note down the water readings.

10. Repeat the procedure (4) &(7) for different loads.

11. Tabulate the readings as shown in the enclosed list.

12. After the experiment is over, keep the diesel control valve at mains position.

TABULATION 1:

Sl.No

Weight

on

Hanger,

W1

Weight

in spring

balance,

W2

Net Weight

W=

(W1-W2) + W0

Speed

(N x 2)

Manometer Reading

(H)

Time for 10

cc of fuel

consumption

kg kg kg rpm h1 h2 H = h1-h2 t

TABULATION 2:

Sl.No

Brake

Power

Total fuel

Consumption

Specific fuel

consumption

Mechanical

Efficiency,

m

Brake

Thermal

Efficiency,

bth

Volumetric

Efficiency,

vol kW Kg/min Kg/min % % %

FORMULAE:

1. Brake Power, BP = 2

60 1000 kW

Where N = Speed in rpm

T = Torque in Nm

Torque, T = W x R

W = Net weight of the hanger, kg

R = effective radius of the fly wheel = 0.1575 m

2. Total Fuel consumption, TFC = .

1000 , kg/min

Where x = burette reading in cubic centi meter (cc)

Specific gravity of fuel = 0.83


12

t = time taken in seconds

3. Specific Fuel Consumption, SFC =

.. , kg/min

4. Indicated power, IP = B.P. + F.P., kW

Note: FP(Frictional power) can be arrived by drawing the graph between TFC and BP. The method

for obtaining the FP (frictional power) using graph is called Willans line method or Negative graph method.

5. Fuel Power, F.P. = TFC .

14.34 , kW

Where C.V = Calorific value = 10833 k.J/kg

6. Mechanical Efficiency, mech = ..

.. 100, %

7. Brake Thermal Efficiency = ..

.. 100, %

8. Actual air intake, = Va, kg/sec

Where Va = Actal volume of air intake

Va = cd a 2 , m3/sec

cd = coefficient of discharge = 0.62

a = 2

4 ; d = diameter of orifice = 0.03 m2

g = 9.81

Ha = 12

100 , m

Where 1 2 = manometer reading

= Density of water = 100 kg/m3

= density of air = 1.193 kg/m3

9. Theoretical air intake = 2( 60 )

4 , kg/sec

Where D = diameter of the piston = 0.0875 m

L = stroke length = 0.11 m


13

10. Volumetric Efficiency =

100 , %

11. Brake Mean Effective Pressure, BMEP or Pmb= .. 6

10 , bar

Where n = No of cylinders

L= Stroke length = 0.11 m

A = Area of the cylinder = 0.08 m2

N = Speed in rpm

k = 1

2 for 4-stroke cycle engine.

12. Indicated Mean Effective Pressure, IMEP or Pmi= .. 6

10 , bar

GRAPHS:

1. To find friction power (TFC Vs BP) 2. Brake power Vs Specific Fuel Consumption

3. Brake power Vs Brake Mean Effective Pressure

4. Brake power Vs Indicate Mean Effective Pressure

5. Brake power Vs Mechanical Efficiency

6. Brake power Vs Brake Thermal Efficiency

RESULT:

Thus the performance test on single cylinder diesel engine with mechanical brake loading was

conducted

Brake power (BP) =

Mechanical efficiency (mech) =

Brake thermal efficiency (bth) =

Volumetric efficiency (v) =

Total Fuel Consumption (TFC) =

Specific fuel consumption (SFC) =

Brake Mean Effective Pressure(BMEP) =


14

EX.NO:

DATE:

HEAT BALANCE TEST ON FOUR STROKE

DIESEL ENGINE

AIM:

To perform a heat balance test on the given single cylinder four stroke C.I engine and to prepare the

heat balance sheet at various loads.

APPARATUS REQUIRED:

1. C.I. Engine coupled to a three-phase alternator with lamp load.

2. Air tank with air flow meter

3. Burette for fuel flow measurement

4. Manometer

5. Stop watch.

SPECIFICATION:

Engine : Four stroke single cylinder

BHP : 5HP (3.7 kW)

Speed : 1500 rpm

Fuel : diesel

Bore : 80 mm

Stroke length : 110 mm

Starting : cranking

Working cycle : four stroke

Method of cooling : water cooled

Method of ignition : compression ignition

Diameter of orifice : 35 mm

Specific gravity : 0.833 kg/sec


15

Calorific value : 44000 kJ/kg

THEORY:

The Test Ring consists of Four-Stroke Diesel Engine, to be tested for performance, is

connected to Rope Brake Drum with Spring Balance (Mechanical Dynamometer) with

Exhaust Gas Calorimeter. The arrangement is made for the following measurements of the

Experimental Set-up:

1) The Rate of Fuel Consumption is measured by using the pipette reading against the

known time.

2) Air Flow is measured by Manometer connected to Air Box.

3) The different mechanical loading is achieved by operating the spring balance of

dynamometer in steps.

4) The different mechanical energy is measured by spring balance and radius of brake

drum.

5) The Engine Speed (RPM) is measured by electronic digital RPM Counter.

6) Temperature at different points is measured by electronic digital Temperature

Indicator.

7) Water Flow Rate through the engine & calorimeter is measured by Wattmeter.

PROCEDURE:

1. Check the diesel in the diesel tank.

2. Allow diesel, start the engine by using hand cranking.

3. The engine is set to the speed of 1500 RPM.

4. Apply load from the spring balance of dynamometer.

5. Allow some time so that the speed stabilizes.

6. Now take down spring balance readings.

7. Put tank valve in to pipette position and note down the time taken for particular quantity of

fuel consumed by the engine.


16

8. Note down the temperature readings at different points.

9. Note down the water readings.

10. Repeat the procedure (4) &(7) for different loads.

11. Tabulate the readings as shown in the enclosed list.

12. After the experiment is over, keep the diesel control valve at mains position.

TABULATION 1:

Sl.

No

Weight

on

Hanger,

W1

Weight

in spring

balance,

W2

Net

Weight W=

(W1-W2)

+ W0

Speed

(N x 2)

Manometer

Reading

(H)

Time for

10 cc of

fuel consumption,

t

Temperature

C

kg kg kg rpm h1 h2 H =

h1-h2 sec T1 T2 T3 T4 T5 T6

TABULATION 2:

Sl.

No

Load

Total Fuel

Consumption,

TFC

Heat

Supply,

Qs

Brake

Power,

B.P.

Frictio

nal

Power,

F.P.

Heat

Carried

away

by

Cooling

water,

Qw

Heat

Carried

away by

Exhaust

gases,

Qg

Unacco

unted

Heat

loss,

QU

Total

kg Kg/sec kW kW kW kW kW kW kW

HEAT BALANCE SHEET 3:

Sl.

No

Load

Total Fuel

Consumption,

TFC

Heat

Supply,

Qs

Brake

Power,

B.P.

Frictio

nal

Power,

F.P.

Heat

Carried

away

by

Cooling

water,

Qw

Heat

Carried

away by

Exhaust

gases,

Qg

Unacco

unted

Heat

loss,

QU

Total

kg Kg/sec % % % % % % %


17

FORMULAE:

1. Brake Power, BP = 2

60 1000 kW

Where N = Speed in rpm

T = Torque in Nm

Torque, T = W x R

W = Net weight of the hanger, kg

R = effective radius of the fly wheel = 0.1575 m

2. Total Fuel consumption, TFC = .

1000 , kg/min

Where x = burette reading in cubic centi meter (cc)

Specific gravity of fuel = 0.833 kg/sec

t = time taken in seconds

3. F.P. kW

Note: FP(Frictional power) can be arrived by drawing the graph between TFC and BP. The method

for obtaining the FP (frictional power) using graph is called Willans line method or Negative graph method.

4. Heat Supply, Q s = TFC C.V., kW

Where C.V. = calorific value = 44000k.cal/min

TFC = Total Fuel Consumption in kg/min

5. Heat Converted into useful work, QBP

QBP =

100, %

6. Heat Carried away by Cooling water, QW

QW = 1

100, %

Where QW1 = mw CW[T2-T1], kW

mw = Quantity of water (Say 2)

, kg/sec

CW = Specific heat capacity of water = 4.186 kJ/kg.K

T2&T1 = Inlet and Outlet conditions of water, K


18

7. Heat Carried away by Exhaust gases, Qg

Qg = 1

100, %

Where Qg1 = mg Cg[T2-T1], kW

mg = , kg/sec

Va = cd a 2 , m3/sec

cd = coefficient of discharge = 0.62

a = 2

4 ; d = diameter of orifice = 0.03 m2

g = 9.81

Ha = 12

100 , m

Where 1 2 = manometer reading

= Density of water = 100 kg/m3

= density of air = 1.193 kg/m3

8. Heat lost due to friction, QFP

QFP =

100 , %

Note: QFP = FP

9. Unaccounted Heat loss, QU

QU = 1

QU1 = QS [ Qg + QW + FP + BP ]

RESULT:

Thus the heat balance test on single cylinder diesel engine was conducted and the following

losses were found,

% of heat converted into useful work QBP =

% of heat carried away by cooling water QW =

% of heat lost due to friction QFP =

% of unaccounted heat loss QU =


19

EX.NO:

DATE:

RETARDATION TEST TO FIND FRICTIONAL POWER

OF A DIESEL ENGINE.

AIM:

To find Frictional power of a single cylinder slow speed Diesel Engine using Retardation test

method with mechanical dynamometer as loading device.

APPARATUS REQUIRED:

1. Single cylinder slow speed diesel engine with rope brake dynamometer setup.

2. Digital tachometer

3. Stop watch

SPECIFICATIONS:

Make - Kirloskar

Bore - 114.3 mm

Stroke - 139.7 mm

RPM - 700

B.H.P - 6 HP (4.4 kW)

Compression ratio - 16:1

Fuel - Diesel

Specific gravity - 0.833 kg/sec

Calorific value - 10,833 kCal/kg.

THEORY:

This test involves the method of retarding the engine by cutting the fuel supply. The engine is

made to run at no load and rated speed taking in to all usual precautions. When the engine is running

under steady operating conditions the supply of fuel is cut-off and simultaneously the time of fall in

speed by say 20%, 40%, 60%, 80% of the rated speed is recorded. The values are usually tabulated in

an appropriate table.

A graph connecting time for fall in speed (y-axis) at no load as well as 50% load conditions.

From the graph the time required to fall through the same range (say 100rpm) in both, no load and

load condition are found. Let t2 and t3 be the time of fall at no load and load conditions respectively.

The frictional torque and hence frictional power are calculated.


20

PRECAUTION:

Check the fuel level.

Check the lubricating oil level.

Open the three way cock valve, so that the fuel flows to the engine.

Supply the cooling water through inlet pipe of engine

Check the engine is in no load.

PROCEDURE:

Start the engine by rotating the handle.

Allow the engine to run for few minutes to attain rated speed.

Allow the cooling water in the brake drum and adjust it to avoid spilling.

Load the engine at the max.load note down the spring balance reading to calculate the

net load of the engine.

Measure the speed of the engine at no load condition.

The supply of fuel is cut-off using fuel cut-off lever and simultaneously the time of

fall in speed by say 20%, 40%, 60%, 80% of the rated speed is recorded.

Repeat the experiment at 50% load condition.

The values are tabulated and graph is plotted.

TABULATION:

S.No Engine speed

(rpm)

Drop in

speed

(rpm)

Time for

fall of

speed no

load(sec)

Time for

fall of

speed 50%

load (sec)

1 700 600 100

2 700 500 200

3 700 400 300

4 700 300 400

5 700 200 500


21

FORMULAE:

1. Frictional Power, F.P.,

F.P. = 2

601000 kW

Where = Frictional Torque, N-m

= T1 [2

32]

Where 2 = Time corresponding to No Load condition

3 = Time corresponding to 50% Load condition

In turn T1 = WR 9.81

Where R = Effective radius of brake drum = 0.207 m

W = Net load on brake drum

W = (W1-W2) +W0

Where W1 = Maximum dead weight, kg

W2 = Spring balance reading, kg

W0 = Weight of the Hanging unit = 1 kg

RESULT:

The frictional power of a single cylinder slow speed diesel engine is -------------------kW.


22

EX.NO:

DATE:

DETERMINATION OF MECHANICAL EFFICIENCY OF MULTI CYLINDER PETROL

ENGINE USING MORSE TEST

AIM:

To conduct a Morse test on a multi cylinder petrol engine using hydraulic dynamometer and to

determine Brake Power, Indicated power, Frictional power and Mechanical efficiency of the engine.

INSTRUMENTS REQUIRED

1. Tachometer

2. Stop watch

3. Orifice meter along with manometer

THEORY:

Morse test is one of the methods of finding indicated power of one cylinder of a multi

cylinder I.C.Engine without an indicator. This test is done for estimating the indicated power of multi

cylinder I.C. engines. The engine, which is to be tested, is coupled to a brake (hydraulic

dynamometer) and the brake power is determined. Let this be equal to Brake power (B.P). The first

cylinder is now cut off. This is done by shorting out the spark plug of the first cylinder in the case of

petrol engine. In the case of diesel engine the fuel supply to the first cylinder is cut off. Since, the first

cylinder is cut off, the engine speed drops. Load is removed from the brake to restore original speed.

Under this condition brake power is determined. Let this be B.P1

Then the operation of first cylinder is introduced again. Then the second cylinder is cut off.

The engine speed is restored to the original value and again brake power is determined. Let this be

B.P2

The same procedure is adopted for each cylinder in turn and in each case brake power is

determined like B.P3 and B.P4

Let us consider a four-cylinder engine:

Let, I.P1, I.P2, I.P3 & I.P4 are indicated powers of each cylinder.

F.P1, F.P2, F.P3 & F.P4 are frictional powers of each cylinder, if the all cylinders are working.


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Total brake power

B.P = I.P1+ I.P2+ I.P3 + I.P4 F.P1+ F.P2+ F.P3 + F.P4]

Now, when any one of the cylinders is cut out, the indicated power developed in the cylinder is cut

out. But, the friction and other losses of this particular cylinder still exist.

Hence, brake power with the first cylinder cut out,

B.P1 = I.P2+ I.P3 + I.P4 F.P1+ F.P2+ F.P3+ F.P4] 2

Subtracting 2 from 1,

B.P B.P1 = I.P1 = Indicated power of first cylinder.

Similarly, B.P B.P2 = I.P2 = Indicated power of second cylinder.

B.P B.P3 = I.P3 = Indicated power of third cylinder.

B.P B.P4 = I.P4 = Indicated power of fourth cylinder.

The total indicated power developed I.P = I.P1+ I.P2+ I.P3 + I.P4

PRECAUTIONS:

Checks fuel level and open the three-way cock valve (vertical) so that, fuel flows to

the engine directly from the tank.

Check the lubricating oil level.

Open the engine cooling water inlet, outlet valves and ensure that water flows

through the engine.

Open the hydraulic dynamometer water line inlet, outlet valves and keep the pressure

0.4 Kg / cm2 in pressure dial gauge by tightening the outlet valve. So that, loading

will be easy in dynamometer.

Keep the loading in dynamometer at minimum by operating loading / unloading

wheel.

Disengage the hydraulic dynamometer from the engine, using clutch.


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PROCEDURE:

Start the engine using ignition key and allow running the engine for few minutes.

Engage the hydraulic dynamometer with the engine, using clutch.

Load the engine to its maximum capacity of load, using both the hydraulic

dynamometer loading / unloading wheel and the accelerator screw.

The speed of the engine should be maintained at 1500 rpm and should not be raised.

Now the first cylinder is cut off using cylinder cut off lever.

Now the speed of the engine and the load in dynamometer dial gauge will be less than

the previous settings.

Maintain the speed of the engine in 1500 rpm by unloading the dynamometer loading

/ unloading wheel.

Do not use the accelerator screw of the engine to adjust the speed. This is to be used

only for initial maximum load settings.

Note the load in dynamometer dial gauge in Kg, using this reading B.P (2, 3, and 4) is

found out.

Engage the first cylinder and cut off the second cylinder, maintain the speed at1500

rpm, then take the dial gauge reading in Kg.

The same procedure is adopted for all the cylinders.

Finally, stop the engine using ignition key after completely unloading the

dynamometer, disengaging the dynamometer from the engine and keeping the

accelerator throttle in minimum position.

TABULATION:

Sl

No

Working

cylinders

Cut-off

cylinder

Speed

(N),

Rpm

Load,

Kg

Brake

Power,

kW

Indicate

Power,

kW

Friction

Power,

kW

Mechanical

Efficiency,

%

1 All Nil

2 2,3 &4 1

3 1,3 &4 2

4 1,2, &4 3

5 1,2, &3 4


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FORMULAE:

1. BRAKE POWER: (B.P in kW)

B.P =

2000 , HP

= X HP

= X

1.36 kW

Where, W = Load in hydraulic dynamometer dial gauge in kg.

N = Speed of the engine = 1500 rpm.

2. INDICATED POWER: (I.P in kW)

I.P = I.P1 + I.P2 + I.P3 + I.P4

Where I.P1 = B.P B.P1

Where, I.P1 = Indicated power of first cylinder (with first cylinder cut off)

B.P = Total brake power of the engine (with no cylinder cut off)

B.P1= Brake power of 2nd, 3rd & 4th cylinders (with 1st cylinder cut off)

Similarly, I.P2 = B.P B.P2

I.P3 = B.P B.P3

I.P4 = B.P B.P4

3. FRICTIONAL POWER OF THE ENGINE: (FP in k.W)

FP = I.P B.P

4. MECHANICAL EFFICIENCY OF THE ENGINE:

=

100 , %

RESULT:

Morse test was conducted in multi cylinder, four stroke petrol engines and the following were determined:

1. Brake power of the engine = K.W

2. Indicated power of the engine = K.W

3. Frictional power of the engine = K.W

4. Mechanical efficiency of the engine = %


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EX.NO:

DATE:

STUDY OF BOILER AND STEAM TURBINE

AIM:

To study the components and working principle of steam boiler and Steam turbine.

1. STEAM BOILER

1.1 INTRODUCTION

A boiler is an enclosed vessel that provides a means for combustion heat to be transferred to

water until it becomes heated water or steam. The hot water or steam under pressure is then usable for

transferring the heat to a process. Water is a useful and inexpensive medium for transferring heat to a

process. When water at atmospheric pressure is boiled into steam its volume increases about 1,600

times, producing a force that is almost as explosive as gunpowder. This causes the boiler to be

equipment that must be treated with utmost care.

The boiler system comprises of a feed water system, steam system and fuel system. The feed

water system provides water to the boiler and regulates it automatically to meet the steam demand.

Various valves provide access for maintenance and repair. The steam system collects and controls the

steam produced in the boiler. Steam is directed through a piping system to the point of use.

Throughout the system, steam pressure is regulated using valves and checked with steam pressure

gauges. The fuel system includes all equipment used to provide fuel to generate the necessary heat.

The equipment required in the fuel system depends on the type of fuel used in the system.

The water supplied to the boiler that is converted into steam is called feed water. The two

sources of feed water are:

(1) Condensate or condensed steam returned from the processes and

(2) Makeup water (treated raw water) which must come from outside the boiler room and plant

processes. For higher boiler efficiencies, an economizer preheats the feed water using the waste heat

in the flue gas.


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Schematic diagram of Boiler Room

1.2TYPE OF BOILERS

This section describes the various types of boilers: Fire tube boiler, Water tube boiler,

Packaged boiler, Fluidized bed combustion boiler, Stoker fired boiler, Pulverized fuel boiler, Waste

heat boiler and Thermic fluid heater.

1.2.1 .Fire Tube Boiler

In a fire tube boiler, hot gases pass through the tubes and boiler feed water in the shell side is

converted into steam. Fire tube boilers are generally used for relatively small steam capacities and low

to medium steam pressures. As a guideline, fire tube boilers are competitive for steam rates up to

12,000 kg/hour and pressures up to 18 kg/cm2. Fire tube boilers are available for operation with oil,

gas or solid fuels. For economic reasons, most fire tube boilers are of packaged construction (i.e.

manufacturer erected) for all fuels.

1.2.2 Water Tube Boiler

In a water tube boiler, boiler feed water flows through the tubes and enters the boiler drum. The

circulated water is heated by the combustion gases and converted into steam at the vapour space in the

drum. These boilers are selected when the steam demand as well as steam pressure requirements are


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high as in the case of process cum power boiler / power boilers. Most modern water boiler tube

designs are within the capacity range 4,500 120,000 kg/hour of steam, at very high pressures. Many

water tube boilers are of packaged construction if oil and /or gas are to be used as fuel. Solid fuel

fired water tube designs are available but packaged designs are less common. The features of water

tube boilers are:

Forced, induced and balanced draft provisions help to improve combustion efficiency.

Less tolerance for water quality calls for water treatment plant.

Higher thermal efficiency levels are possible.

1.2.3 Fluidized Bed Combustion (FBC) Boiler

Fluidized bed combustion (FBC) has emerged as a viable alternative and has significant

advantages over a conventional firing system and offers multiple benefits compact boiler design,

fuel flexibility, higher combustion efficiency and reduced emission of noxious pollutants such as SOx

and NOx. The fuels burnt in these boilers include coal, washery rejects, rice husk, bagasse & other

agricultural wastes. The fluidized bed boilers have a wide capacity range- 0.5 T/hr to over 100 T/hr.

When an evenly distributed air or gas is passed upward through a finely divided bed of solid particles

such as sand supported on a fine mesh, the particles are undisturbed at low velocity.

As air velocity is gradually increased, a stage is reached when the individual particles are suspended

in the air stream the bed is called fluidized. With further increase in air velocity, there is bubble

formation, vigorous turbulence, rapid mixing and formation of dense defined bed surface. The bed of

solid particles exhibits the properties of a boiling liquid and assumes the appearance of a fluid

bubbling fluidized bed. If sand particles in a fluidized state are heated to the ignition temperatures

of coal, and coal is injected continuously into the bed, the coal will burn rapidly and the bed attains a

uniform temperature. The fluidized bed combustion (FBC) takes place at about 840OC to 950OC.

Since this temperature is much below the ash fusion temperature, melting of ash and associated

problems are avoided. The lower combustion temperature is achieved because of high coefficient of

heat transfer due to rapid mixing in the fluidized bed and effective extraction of heat from the bed

through in-bed heat transfer tubes and walls of the bed. The gas velocity is maintained between

minimum fluidization velocity and particle entrainment velocity.

1.3 Boiler Mountings and Accessories:

Following are the boiler mountings and accessories frequently used:


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Boilers are equipped with two categories of components: boiler mountings and boiler

accessories. Boiler mountings are the machine components that are mounted over the body of the

boiler itself for the safety of the boiler and for complete control of the process of steam generation.

Boiler accessories are those components which are installed either inside or outside the boiler to

increase the efficiency of the plant and to help in the proper working of the plant.

2. STEAM TURBINE

2.1 INTRODUCTION

The motive power in a steam turbine is obtained by the rate of change in momentum of a high

velocity jet of steam impinging on a curved blade which is free to rotate. The steam from the boiler is

expanded in a nozzle, resulting in the emission of a high velocity jet. This jet of steam impinges on

the moving vanes or blades, mounted on a shaft. Here it undergoes a change of direction of motion

which gives rise to a change in momentum and therefore a force. Steam turbines are mostly 'axial


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flow' types; the steam flows over the blades in a direction parallel to the axis of the wheel. 'Radial

flow' types are rarely used.

2.2 CLASSIFICATION OF STEAM TURBINES

On the basis of operation, steam turbines can be classified as: (i) Impulse turbine and (ii)

Impulse-reaction turbine.

2.2.1 Impulse turbine

In impulse turbine, the drop in pressure of steam takes place only in nozzles and not in

moving blades. This is obtained by making the blade passage of constant cross-sectional area.

Simple impulse turbine

It primarily consists of: a nozzle or a set of nozzles, a rotor mounted on a shaft, one set of

moving blades attached to the rotor and a casing.

A simple impulse turbine can be diagrammatically represented below. The uppermost portion

of the diagram shows a longitudinal section through the upper half of the turbine, the middle

portion shows the actual shape of the nozzle and blading, and the bottom portion shows the

variation of absolute velocity and absolute pressure during the flow of steam through passage

of nozzles and blades. Example: de-Laval turbine


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Compounding of impulse turbine

This is done to reduce the rotational speed of the impulse turbine to practical limits. (A rotor

speed of 30,000 rpm is possible, which is pretty high for practical uses.)

Compounding is achieved by using more than one set of nozzles, blades, rotors, in a series,

keyed to a common shaft; so that either the steam pressure or the jet velocity is absorbed by

the turbine in stages. Three main types of compounded impulse turbines are: a) Pressure

compounded, b) velocity compounded and c) pressure and velocity compounded impulse

turbines.

Pressure compounded impulse turbine

This involves splitting up of the whole pressure drop from the steam chest pressure to the

condenser pressure into a series of smaller pressure drops across several stages of impulse

turbine.

The nozzles are fitted into a diaphragm locked in the casing. This diaphragm separates one

wheel chamber from another. All rotors are mounted on the same shaft and the blades are

attached on the rotor.

2.2.2 Impulse-Reaction turbine

In this type, the drop in pressure takes place in fixed nozzles as well as moving blades. The

pressure drop suffered by steam while passing through the moving blades causes a further generation

of kinetic energy within these blades, giving rise to reaction and adds to the propelling force, which is

applied through the rotor to the turbine shaft. The blade passage cross-sectional area is varied

(converging type).

2.3 COSTS:

Steam turbine plus boiler installation costs are between $800-$1000/kW. If a boiler is already

in place, the installation cost of just a steam turbine alone is $400-$800/kW. Maintenance costs for the

steam turbine are estimated to be $0.004/kWhr. Steam turbines have been known to last beyond 50

years with over 99% availability. Table 1 gives cost info for steam turbines only.


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2.4 EMISSIONS:

Steam turbines do not emit anything themselves. However, the steam generator emits

pollutants. Therefore, the emissions from a steam turbine system are highly variable and depend on

the type of fuel being used to create the steam and the method by which steam is created. Boilers will

emit NOx, SOx, PM, CO, and CO2. Typical boiler emissions are shown in the following table.

RESULTS:

Thus the study of Steam Boiler and Steam Turbine were made.

MODEL CALCULATIONS

PORT TIMING DIAGRAM OF A TWO STROKE PETROL ENGINE

thermal engineering lab - i manual r 2013

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