Me6412 Thermal Engineering Laboratory manual – i

ME6412

THERMAL ENGINEERING LABORATORY – I I

2015

1. VALVE TIMING DIAGRAM OF FOUR STROKE CYCLE PETROL ENGINE Exp. No. :

Date:

Aim :

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

Apparatus Required :

1. Four stroke petrol engine 2. Measuring tape 3. Chalk 4. Piece of paper. 5. Polar Graph

Theory and Description :

The diagram which shows the position of crank of four stroke 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 piston at the bottom of of the cylinder is called “Bottom Dead Centre” [BDC]. In the case of horizontal engine, this is known as “Outer Dead Center”(ODC). The extreme position position of the piston at the top of the cylinder is called “Top Dead Centre” (TDC). In the case of horizontal engine this is known as “Inner Dead Centre” (IDC). Ideal Engine:

In an ideal engine, the inlet valve opens at TDC and close at BDC. The exhaust valve opens at BDC and close at TDC. The charge is ignited when the piston is at TDC at the end of compression stroke. But in actual practice it will differ.

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PREPARED BY C. BIBIN, AP/MECH, RMKCET

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Actual Engine: Inlet valve opening and closing :

In an actual engine, the inlet valve begins to open few degrees before the piston reaches the TDC during the exhaust stroke. This is necessary to ensure that the valve will be fully open to allow the more amount of air fuel mixtures into the cylinder as soon as the piston starts to move TDC during the suction su ction stoke. If the inlet valve is allowed to close at BDC, the cylinder would receive less amount of air-fuel mixture than its capacity and the pressure of the mixture at the end of suction stroke will be below, the atmosphere pressure. To avoid this, the inlet valve is 0

0

0

kept open for 40 to 50 rotation of the crank after the BDC for high speed engine and 20 0

to 25 for low speed engine. Exhaust valve opening and closing :

Complete clearing of the burned gases from the cylinder is necessary to take in more air-fuel mixtures into the cylinder and also to avoid the dilution of the fresh 0

0

mixture. To achieve this the exhaust valve is open at 25 to 45 before the piston reaches the BDC during the power stroke. In order to completely remove the burned products, the exhaust valve is remain 0

0

open for 5 to 10 after the TDC during the suction stroke. For certain period both inlet valve and exhaust valve remains in open condition. The crank angle for which the both the valves are open are called as over lapping. This overlap must not be excessive enough to allow the burned gases to be checked into the intake manifold or the fresh charge escape through the exhaust valve. Ignition:

There is always a time between the spark and ignition of mixture. The ignition starts some time after giving the spark, therefore it is necessary to produce the spark before piston reaches the TDC to obtain proper combustion without losses. The angle through which the spark is given earlier is known as “Ignition Advantage” or Angle of of 0

0

Advance. It may ranges from 35 to 40 before the piston reaches the TDC during the compression stroke.

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THERMAL ENGINEERING LABORATORY – I

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Observation

1. Circumference of flywheel = ................. cm Formula used:

1. Crank angle = Distance of flywheel 2. Time duration =

x 360 Circumference

of flywheel

Crank angle displacement 360 x Engine speed in sces

Tabulation

Sl. No

Event

Position of crank w.r.to Nearest Dead centre

1

IVO

Before TDC

2

IVC

After BDC

3

EVO

Before BDC

4

EVC

After TDC

5

IG

Before TDC

Model calculation:

4


Distance from their respective dead centres in „cm‟

Angle in degrees

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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 the 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 circumstance of the flywheel and mark the point from BDC at a distance of half of 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 represents the inlet valve close (IVC). Measure the distance from BDC and tabulate the distance. 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. 6. Then convert the measured distances into angle in degrees

Result: The valve timing diagram for the given four stroke Petrol engine was drawn.

6



Duration of suction stroke

= ....................



Duration of compression stroke

= ....................



Duration of expansion stroke

= ....................



Duration of exhaust stroke

= ....................


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2. VALVE TIMING DIAGRAM OF FOUR STROKE CYCLE diesel ENGINE Exp. No. :

Date:

Aim :

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


1. Four stroke diesel engine 2. Measuring tape 3. Chalk 4. Piece of paper. 5. Polar Graph


The diagram which shows the position of the crank of four stroke 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 piston at the bottom of the cylinder is called “Bottom Dead Centre” [BDC]. In the case of horizontal engine, this is known as “Outer Dead Center”(ODC). The extreme position of the piston at the top of the cylinder is called “Top Dead Centre” (TDC). In the case of horizontal engine this is known as “Inner Dead Centre” (IDC). Ideal Engine:

In an ideal engine, the inlet valve opens at TDC and close at BDC. The exhaust valve opens at BDC and close at TDC. The fuel is ignited when the piston is at TDC at the end of compression stroke. But in actual practice it will differ.

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Actual Engine: Inlet valve opening and closing : 0

0

In an actual engine, the inlet valve begins to open 5 to 20 before the piston reaches the TDC during the 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 atmosphere pressure. To avoid this, the inlet valve is 0

0

kept open for 40 to 50 after the BDC.

Exhaust valve opening and closing :

Complete clearing of the burned gases from the cylinder is necessary to take in 0

0

more air into the cylinder. To achieve this the exhaust valve is open at 25 to 45 before 0

0

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. 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 the 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 circumstance of the flywheel and mark the point from BDC at a distance of half of the circumference. That point is TDC and is diametrically opposite to the BDC.

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Observation

1. Circumference of flywheel (X ) = ................. cm

Formula used:


x 360 Circumferenc e of flywheel


Tabulation:

S.No

Event

Position of crank w.r.to TDC or BDC

1

IVO

Before TDC

2

IVC

After BDC

3

EVO

Before BDC

4

EVC

After TDC

5

FVO

Before TDC

6

FVC

After TDC

Model calculation:

10


Distance from their respective dead centres in „cm‟

Angle in degrees

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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 tabu late 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 it. 7. Rotate the crank further, till the paper in the tappet clearance of exhaust valve is just free to move. Making the marking on the flywheel against fixed reference. This position represents the exhaust valve close (EVC). Measure the distance from TDC and tabulate it. 8. Then convert the measured distances into angle in degrees.

Result:

The valve timing diagram for the given four stroke Diesel engine was drawn.

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

Duration of suction stroke

= ....................



Duration of compression stroke

= ....................



Duration of expansion stroke

= ....................



Duration of exhaust stroke

= ....................



Duration of valve overlap

= ....................


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3. port TIMING DIAGRAM OF two STROKE CYCLE petrol ENGINE Exp. No. :

Date:

Aim :

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


1. Two stroke petrol engine 2. Measuring tape 3. Chalk 4. Polar Graph


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 Center” [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.

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Observation

1. Circumference of flywheel (X ) = ................. cm

Formula used:


x 360 Circumference

of flywheel


Tabulation:

S.No

Event

1

IPO

Position of crank w.r.to TDC or BDC Before TDC

2

IPC

After TDC

3

EPO

Before BDC

4

EPC

After BDC

5

TPO

Before BDC

6

TPC

After BDC

Model calculation:

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Distance in „cm‟

Angle in degrees

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The transfer port is opened when the piston is moves 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 ad closing are measured with respect to the BDC. The transfer port is opened when the piston is moves 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 ad closing are measured with respect to the BDC.

Procedure :

1. Remove the ports cover and identify the three ports. 2. Make the TDC and BDC position on the fly wheel. To mark this position follow the same procedure as followed in valve timing diagram. 3. Rotate the flywheel slowly in usual direction (usually clockwise) and observe the movement of the position. 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 fly wheel and measure the distance from TDC. 5. When piston moves from TDC to BDC observe, when the bottom edge of 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 TBDC.

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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 of the flywheel and measure the distance from BDC. Note :

1. The inlet port opening distance and closing distance from TDC are equal. 2. The exhaust port opening distance and closing distance from BDC are equal. 3. The transfer port opening distance and closing distance from BDC are equal.

Result :

The port timing diagram for the given two stroke cycle petrol engine was drawn.

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4. ACTUAL INDICATOR DIAGRAM FOR A FOUR STROKE CYCLE PETROL ENGINE Exp. No. :

Date:

Aim :

To study the actual indicator diagram for a four stroke cycle petrol engine.

Actual indicator diagram for a four stroke cycle petrol engine:

The actual indicator diagram for a four stroke cycle petrol engine is shown. The suction stroke is shown by the line 1-2, which lies below the atmospheric pressure line. This pressure difference, which makes the fuel-air mixture to flow into the engine cylinder. The inlet valve offers some resistance to the incoming charge. That is why, the charge cannot enter suddenly into the engine cylinder. As a result of this, pressure inside the cylinder remains somewhat below the atmospheric pressure during the suction stroke. The compression stroke is shown by the line 2-3, which shows that the inlet valve closes (lVC) a little beyond 2 (i.e. BDC ). At the end of this stroke, there is an increase in the pressure inside the engine cylinder. Shortly before the end of compression stroke (i.e. TDC), the charge is ignited (lGN) with the help of spark plug as shown in the figure. The sparking suddenly increases pressure and temperature of the products of combustion. But the volume, practically, remains constant as shown by the line 3-4. The expansion stroke is shown by the line 4-5, in which the exit valve opens (EVO) a little before 5 (i.e. BDC). Now the burnt gases are exhausted into the atmosphere through the exit valve. The exhaust stroke is shown by the line 5-1, which lies above the atmospheric pressure line. It

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is this pressure difference, which makes the burnt gases to flow out of the engine cylinder. The exit valve offers some resistance to the outgoing burnt gases. That is why the burnt gases cannot escape suddenly from the engine cylinder. As a result of this, pressure inside the cylinder remains somewhat above the atmospheric pressure line during the exhaust stroke

Result:

Thus the actual indicator diagram for a four stroke cycle petrol engine was studied.

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5. ACTUAL INDICATOR DIAGRAM FOR A FOUR STROKE CYCLE diesel ENGINE Exp. No. :

Date:

Aim :

To study the actual indicator diagram for a four stroke cycle diesel engine. Actual indicator diagram for a four stroke cycle diesel engine:

The actual indicator diagram for a four-stroke cycle diesel engine is shown. The suction stroke is shown by the line 1-2 which lies below the atmospheric pressure line. This pressure difference, which makes the fresh air to flow into the engine cylinder. The inlet valve offers some resistance to the incoming air. That is why, the air cannot enter suddenly into the engine cylinder. As a result of this pressure inside the cylinder remains somewhat below the atmospheric pressure during the suction stroke. The compression stroke is shown by the line 2-3, which shows that the inlet valves closes (IVC) a little beyond 2 (i.e. BDC).At the end of this stroke, there is an increase of pressure inside the engine cylinder. Shortly before the end of compression stroke (i.e. TDC), fuel valve opens (FVO) and the fuel is injected into the engine cylinder. The fuel is ignited. Actual indicator diagram for a by high temperature of the compressed air. The ignition suddenly increases volume and temperature of the products of combustion. But the pressure, practically, remains constant as shown by the line 3-4. The expansion stroke is shown by the line 4-5, in which the exit valve opens a little before 5 (i.e. BDC). Now the burnt gases are exhausted into the atmosphere through the exhaust valve. The exhaust stroke is shown by the line 5-1, which lies above the atmospheric pressure line. It is this pressure difference, which makes the burnt gases to flow out of the engine cylinder. The exhaust valve offers some resistance to the outgoing burnt gases. That is why, the burnt gases cannot (escape suddenly from the engine cylinder). As a result of this, pressure inside the cylinder remains somewhat above the atmospheric pressure during the exhaust stroke.

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Result:

Thus the actual indicator diagram for a four stroke cycle diesel engine was studied.

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6. ACTUAL INDICATOR DIAGRAM FOR A two STROKE CYCLE petrol ENGINE Exp. No. :

Date:

Aim :

To study the actual indicator diagram for a two stroke cycle petrol engine. Actual Indicator Diagram For A Two Stroke Cycle Petrol Engine:

The actual indicator diagram for a two-stroke cycle petrol engine is shown in suction is shown by the line 1-2-3, i.e. from the instant transfer port opens (TPO) and transfer port closes (TPC). We know that during the suction stage, the exhaust port is also open. In the first half of suction stage, the volume of fuel-air mixture and burnt gases increases. This happens as the piston moves from I to 2 (i.e. BDC). In the second half of the suction stage, the volume of charge and burnt gases decreases. This happens as the piston moves upwards from 2 to 3. A little beyond 3, the exhaust port closes (EPC) at 4. Now the charge inside the engine cylinder is compressed which is shown by the line 4-5. At the end of the compression, there is an increase in the pressure inside the engine cylinder. Shortly before the end of compression (i.e. TDC) the charge is ignited (IGN) with the help of spark plug. The sparking suddenly increases pressure and temperature of the products of combustion. But the volume, practically, remains constant as shown by the line 5-6. The expansion is shown by the line 6-7. Now the exhaust port opens (EPO) at 7, and the burnt gases are exhausted into the atmosphere through the exhaust port. It reduces the pressure. As the piston is moving towards BDC, therefore volume of burnt gases increases from 7 to 1. At 1, the transfer port opens (TPO) and the suction starts.

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Result:

Thus the actual indicator diagram for a two stroke cycle petrol engine was studied.

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7. ACTUAL INDICATOR DIAGRAM FOR A two STROKE CYCLE diesel ENGINE Exp. No. :

Date:

Aim :

To study the actual indicator diagram for a two stroke cycle diesel engine. Actual Indicator Diagram For A Two Stroke Cycle Diesel Engine:

The actual indicator diagram for a two-stroke cycle diesel engine is shown. The suction is shown by the line: 1-2-3 i.e. from the instant transfer port opens (TPO) and transfer port closes (TPC). We know that during the suction stage, the exhaust port is also open. In the first half of suction stage, the volume: of air and burnt gases increases. This happens as :the piston moves from 1-2 (i.e. BDC). In the second half of the suction stage, the volume of air and burnt gases decreases. This happens as the piston moves upwards from 2-3. A little beyond 3, the exhaust port closes (EPC) at 4. Now the air inside the engine cylinder is compressed which is shown by the line 4-5. At the end of compression, there is an increase in the pressure inside the engine cylinder. Shortly before the end of compression (i. e. TDC), fuel valve opens (FVO) and the fuel is injected into the engine cylinder. The fuel is ignited by high temperature of the compressed air. The ignition suddenly increases volume and temperature of the products of combustion. But the pressure, practically, remains constant as shown by the line 5-6. The expansion IS shown by the line 6-7, Now the exhaust port opens (EPO) at 7 and the burnt gases are exhausted into the atmosphere through the exhaust port. It reduces the pressure. As the piston is moving towards BDC, therefore volume of burnt gases increases from 7 to 1. At 1, the transfer port opens (TPO) and the suction starts.

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Result:

Thus the actual indicator diagram for a two stroke cycle diesel engine was studied.

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8. PERFORMANCE TEST ON FOUR STROKE SINGLE CYLINDER AIR COOLED DIESEL ENGINE Exp. No. :

Date:

Aim :

The experiment is conducted to a. To study and understand the performance characteristics of the engine. b. To draw Performance curves. Apparatus Required:

1. Single cylinder Diesel Engine 2. Tachometers 3. Stop watch 4. Temperature indicators Theory:

A machine, which uses heat energy obtained from combustion of fuel and converts it into mechanical energy, is known as a Heat Engine. They are classified as External and Internal Combustion Engine. In an External Combustion Engine, combustion takes place outside the cylinder and the heat generated from the combustion of the fuel is transferred to the working fluid which is then expanded to develop the power. An Internal Combustion Engine is one where combustion of the fuel takes place inside the cylinder and converts heat energy into mechanical energy. IC engines may be classified based on the working cycle, thermodynamic cycle, speed, fuel, cooling, method of ignition, mounting of engine cylinder and application. Diesel Engine is an internal combustion engine, which uses heavy oil or diesel oil as a fuel and operates on two or four stroke. In a 4-stroke Diesel engine, the working cycle takes place in two revolutions of the crankshaft or 4 strokes of the piston. In this engine, pure air is sucked to the engine and the fuel is injected with the combustion taking place at the end of the compression stroke. The power developed and the performance of the engine depends on the condition of operation. So it is necessary to test an engine for different conditions based on the requirement.

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Specification: Engine:

Make

: Kirloskar

Number of cylinder

:1

Bore

: 87.5 mm

Stroke

: 80 mm

Cubic capacity

: 0.662 litres

Compression Ratio

: 17.5:1

Power

: 4.41 Kw

Cooling Type

: Air cooled

Fuel

: Diesel

Calorific Value of fuel

: 44800 KJ/Kg

Density of fuel

:………..Kg/m

Type

: Rope Brake

Diameter of brake drum

: 300 mm

Range

: 0-25 Kg

Load Indicator

: Dial gauge

Diameter of the Rope

: …….mm

3

Load:

CC Tube:

Range

: 0-100 CC

Material

: Glass

Air Drum:

Size

: 400 X 400 X 400 mm

Inlet Diameter

: 10 mm

Outlet Diameter

: 25.4 mm

Thermocouple:

29

Type

:K

Range

: Alumel / Chromal

Material

: 200 C

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Manometer:

Range

: 0 – 240 mm

Manometer Liquid

: Mercury

Temperature Indicator

Type

: Digital

Channel

:1

Thermocouple

:K

Input

: 230 V / 50 Hz

Formula Used:

1.Effective Brake Radius  R  =

D  d .............m 2

Where D- Brake wheel diameter in metres d - Rope diameter in metres 2.Torque T  = W  R.......N.m Where W - Effective Brake Load in Newtons R - Effective Brake Radius in metres 3.Brake Power  BP  =

2 NT ..............KW 60 X 1000

Where N - Engine Speed in rpm T - Torque in Nm

10 X 10 6 X  .......... Kg / s 4.Total fuel consumption TFC (m f ) = t 

Where  -

Density of fuel in Kg/m

3

t- Time taken for 10 cc of fuel consumption in seconds.

5.Indicated Power = BP+FP ...............Kw Where

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BP - Brake Power in Kilowatts. FP - Frictional Power in Kilowatts.(by Willan's line Method) 6.Mechanical Efficiency

ηmech  =

BP  100% IP

Where BP - Brake Power in Kilowatts. IP - Indicated Power in Kilowatts. 7.Heat Supplied Q s  =

m f 3600

CV..............Kw



Where mf - Mass of fuel consumed in Kg/s CV - Calorific Value of fuel in KJ/Kg = 44800 KJ/Kg 8.Indicated thermal Efficiency

η IT  =

IP  100% Q s

Where Qs - Heat Supplied in Kilowatts. IP - Indicated Power in Kilowatts.

9.Brake thermal Efficiency

η BT  =

BP  100% Q s

Where BP - Brake Power in Kilowatts. Qs - Heat Supplied in Kilowatts. 10.Brake Specific Fuel Consumption  BSFC  =

m f

X 3600.......... Kg / KW .hr BP

Where BP - Brake Power in Kilowatts. Qs - Heat Supplied in Kilowatts.

11.Indicated Specific Fuel Consumption  ISFC  = Where

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m f IP

X 3600.......... Kg / KW .hr

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IP - Indicated Power in Kilowatts. Qs - Heat Supplied in Kilowatts. Procedure:

1. Before starting the engine check the fuel supply and lubricating oil level. 2. Check the water supply 3. Crank the engine by hand lever and start 4. Allow the engine to reach steady state condition 5. Supply water to brake drum and adjust the flow 6. At no load condition note down the following readings 

Time taken for 10cc of fuel consumption



Load indicated on dial gauge



Speed of the engine using tachometer.

7. Apply the load, then note down the mentioned. 8. Repeat the procedure at different load conditions 9. Calculate the performance of an engine. 10. Repeat the experiment for different loads and note down the above readings. 11. After the completion release the load and then switch of the engine. 12. Allow the water to flow for few minutes and then turn it off.

Precautions:

1. Do not run the engine if supply voltage is less than 180V 2. Do not run the engine without the supply of water. 3. Supply water free from dust to prevent blockage in rotameters, engine head and calorimeter. 4. Note that the range for water supply provided is an approximate standard values, however the user may select the operating range to his convenience not less than 3 & 2 LPM for engine and calorimeter respectively. 5. Do not forget to give electrical earth and neutral connections correctly. 6. It is recommended to run the engine at 1500 rpm otherwise the rotating parts and bearing of engine may run out.

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Graph:

The following graphs are drawn by taking Brake power on X-axis and other variable parameters on Y-axis. Brake power Vs Total fuel consumption Brake power Vs Specific fuel consumption Brake power Vs Brake thermal efficiency Brake power Vs Indicated thermal efficiency Brake power Vs Mechanical efficiency

Result:

The performance of a given engine was tested and mechanical efficiency was found and graphs are drawn

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9. Heat balance test on SINGLE CYLINDER AIR COOLED DIESEL ENGINE Aim:-

To conduct a heat balance test and prepare heat balance sheet on Single-Cylinder Diesel Engine.

Apparatus Required:

1. 2. 3. 4. 5. 6. 7.

Given IC engine with loading arrangement Measuring tape or Thread and scale Tachometer Stop watch Bucket Spring balance Temperature indicator

Theory:-

The thermal energy produced by the combustion of fuel in an engine is not completely utilized for the production of the mechanical power. The thermal efficiency of I. C. Engines is about 33 %. Of the available heat energy in the fuel, about 1/3 is lost through the exhaust system, and 1/3 is absorbed and dissipated by the cooling system. It is the purpose of heat balance sheet to know the heat energy distribution, that is, how and where the input energy from the fuel is distributed. The heat balance sheet of an I. C. Engine includes the following heat distributions: a. Heat energy available from the fuel brunt. b. Heat energy equivalent to output brake power. c. Heat energy lost to engine cooling water. d. Heat energy carried away by the exhaust gases. e. Unaccounted heat energy loss.

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Formula Used:


D  d .............m 2


2 NT ..............KW 60 X 1000

Where N - Engine Speed in rpm T - Torque in Nm

10 X 10 6 X  .......... Kg / s 4.Total fuel consumption TFC (m f ) = t 

Where  -

Density of fuel in Kg/m

3

t- Time taken for 10 cc of fuel consumption in seconds.

5.Heat energy available from the fuel brunt, Q s  =

m f 3600

CV..............Kw



Where mf - Mass of fuel consumed in Kg/s CV - Calorific Value of fuel in KJ/Kg 6.Heat energy equivalent to output brake power, QBP = BP x 3600 7.Heat carried away by the exhaust gases (Qg )= mg CPg (Tg – TR )

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mg ma mf C pg Tg TR


= mass of the exhaust gases in kg/s = mass of air consumed in kg/s = mass of fuel consumed in kg/s = Specific heat of exhaust gases = 1.005 KJ/kgK = Temperature of exhaust gases in °C = Room temperature in °C

8.Mass of the exhaust gases (mg) = ma + mf ………. kg/s 9.Mass of air supplied ma  = Qa .  a .............. Kg / s Where Qa- Volume of air supplied in m3/s ρa – Density of air in kg/m3 10.Pressure Head  H a  =

H w

 a

X  m ..........m

Where Hw- Difference in manometer reading ρa – Density of air in kg/m3 = 1.164 Kg/m3 ρm – Density of water in kg/m3 = 13000 Kg/m3 11.Volume of air consumed Qa  = C d

a1 .a2 a1

2



a2

2

2gH a ........m3 / s

Where 2

a1 - Cross sectional area of pipe in m

a2 - Cross sectional area of Orifice in m

2

2

g – Acceleration due to gravity in m/s 12.

Cross sectional area of pipe a1 =



4

2

d 1 ...................... m2

Where d1 – Diameter of pipe in metres = 25.4 mm 13.

Cross sectional area of Orifice a2 =



4

2

d 2 ...................... m2

Where d2 – Diameter of Orifice in metres = 10 mm

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14.Heat energy carried away by the exhaust gases, QEG = mg x Cpg (tg – ta) ………Kw

15.Unaccounted heat energy loss, QUnaccounted = Qs – { QBP + QEG } KJ/hr ta = Ambient Temperature

o

C

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 stead y flow of water. 5. Apply the load, from no load to required load slowly. At required load slowly. At required load note the following. 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)

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Procedure:-

1.

Before starting the engine check the fuel supply, lubrication oil, and availability

of cooling water. 2.

Set the dynamometer to zero load and run the engine till it attain the working

temperature and steady state condition. 3.

Note down the fuel consumption rate, Engine cooling water flow rate, inlet and

outlet temperature of the engine cooling water, Exhaust gases cooling water flow rate, Air flow rate, and Air inlet temperature. 4.

Set the dynamometer to 20 % of the full load, till it attains the steady state

condition. Note down the fuel consumption rate, Exhaust gases flow rate, Air flow rate, and Air inlet temperature. 5.

Repeat the experiment at 40 %, 60 %, and 80 % of the full load at constant speed.

6.

Disengage the dynamometer and stop the engine.

7.

Do the necessary calculation and prepare the heat balance sheet.

Result:-

The heat balance test was completed and heat balance sheet was drawn.

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10. load test, performance test and Heat balance test on SINGLE CYLINDER AIR COOLED DIESEL ENGINE using data acquisition system Ex. No:

Date:

Aim:

To conduct load test, performance test and heat balance test on four stroke single cylinder air cooled diesel engine using data acquisition system.

Apparatus Required:

1. Engine with load 2. Computer with data acquisition 3. Data acquisition system cable

Specification:

Engine:

Make

: Kirloskar

Number of cylinder

:1

Bore

: 87.5 mm

Stroke

: 80 mm

Cubic capacity

: 0.662 litres

Compression Ratio

: 17.5:1

Power

: 4.41 Kw

Cooling Type

: Air cooled

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Fuel

: Diesel

Calorific Value of fuel

: 44800 KJ/Kg

Density of fuel

:………..Kg/m

Type

: Rope Brake

Diameter of brake drum

: 300 mm

Range

: 0-25 Kg

Load Indicator

: Dial gauge

Diameter of the Rope

: …….mm

3

Load:

CC Tube:

Range

: 0-100 CC

Material

: Glass

Air Drum:

Size

: 400 X 400 X 400 mm

Inlet Diameter

: 10 mm

Outlet Diameter

: 25.4 mm

Thermocouple:

Type

:K

Range

: Alumel / Chromal

Material

: 200 C

0

Manometer:

Range

: 0 – 240 mm

Manometer Liquid

: Mercury

Temperature Indicator

48

Type

: Digital

Channel

:1

Thermocouple

:K

Input

: 230 V / 50 Hz


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Procedure:

1. Before the start of the engine, check the fuel supply electrical supply and lubricating oil level 2. Crank the engine by hand lever and start. 3. Allow the engine to reach steady state condition 4. Switch on the data acquisition system. 5. Open data acquisition software on computer 6. Now click „connect‟ icon on the main window then click start icon. 7. Values will display on main window 8. Close the fuel tank value now engine take fuel from cc tube. 9. When fuel level decreases beyond high level sensor timer in the window starts. 10. When fuel level decreases beyond low level sensor time stops. 11. Each time when reading taken wait until the fuel consumption clock stops. 12. At no load condition after timer stopper takes the reading by clicking „ read‟ icon 13. After reading taken open the fuel tank value to fill the fuel in cc tube. 14. When fuel level reaches high level sensor timer in window reset. 15. Now click start icon to read the values in engine. 16. Apply load on engine. 17. Wait till fuel consumption clock stops. 18. Now read the values displayed on the computer by clicking „read‟. 19. Repeat the procedure at different load condition. 20. Now click the calculation icon. A new window will open in that window enter radius of arm and click ‟show‟. 21. Click graph icon a new window will appear

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Graph:


Result:

Thus load test, performance test and heat balance are done on four stroke single cylinder air cooled diesel engine using data acquisition system.

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12. load test, performance test and Heat balance test on three CYLINDER water cooled petrol ENGINE using data acquisition system Ex. No:

Date:

Aim:

To conduct load test, performance test and heat balance test on four stroke three cylinder water cooled petrol engine using data acquisition system. Apparatus Required:

1. Engine with load 2. Computer with data acquisition 3. Data acquisition system cable Procedure:

1. 1. Before the start of the engine, check the fuel supply electrical supply and lubricating oil level 2. Crank the engine by hand lever and start. 3. Allow the engine to reach steady state condition 4. Switch on the data acquisition system. 5. Open data acquisition software on computer 6. Now click „connect‟ icon on the main window then click start icon. 7. Values will display on main window 8. Close the fuel tank value now engine take fuel from cc tube. 9. When fuel level decreases beyond high level sensor timer in the window starts. 10. When fuel level decreases beyond low level sensor time stops. 11. Each time when reading taken wait until the fuel consumption clock stops.

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12. At no load condition after timer stopper takes the reading by clicking „ read‟ icon 13. After reading taken open the fuel tank value to fill the fuel in cc tube. 14. When fuel level reaches high level sensor timer in window reset. 15. Now click start icon to read the values in engine. 16. Apply load on engine. 17. Wait till fuel consumption clock stops. 18. Now read the values displayed on the computer by clicking „read‟. 19. Repeat the procedure at different load condition. 20. Now click the calculation icon. A new window will open in that window enter radius of arm and click ‟show‟. 21. Click graph icon a new window will appear Graph:


Result:

Thus load test, performance test and heat balance are done on three cylinder water cooled petrol engine using data acquisition system.

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13. load test, performance test and Heat balance test on single CYLINDER water cooled diesel ENGINE using data acquisition system Ex. No:

Date:

Aim:

To conduct load test, performance test and heat balance test on four stroke single cylinder water cooled diesel engine using data acquisition system. Apparatus Required:


1. 1. Before the start of the engine, check the fuel supply electrical supply and lubricating oil level 2. Crank the engine by hand lever and start. 3. Allow the engine to reach steady state condition 4. Switch on the data acquisition system. 5. Open data acquisition software on computer 6. Now click „connect‟ icon on the main window then click start icon. 7. Values will display on main window 8. Close the fuel tank value now engine take fuel from cc tube. 9. When fuel level decreases beyond high level sensor timer in the window starts. 10. When fuel level decreases beyond low level sensor time stops. 11. Each time when reading taken wait until the fuel consumption clock stops. 12. At no load condition after timer stopper takes the reading by clicking „ read‟ icon

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13. After reading taken open the fuel tank value to fill the fuel in cc tube. 14. When fuel level reaches high level sensor timer in window reset. 15. Now 15. Now click start icon to read the values in engine. 16. Apply load on engine. 17. Wait till fuel consumption clock stops. 18. Now 18. Now read the values displayed on the computer by clicking „read‟. 19. Repeat the procedure at different load condition. 20. Now 20. Now click the calculation icon. A new window will open in that window enter radius of arm and click ‟show‟. 21. Click graph icon a new window will appear Graph:


Result:

Thus load test, performance test and heat balance are done on four stroke single cylinder water cooled diesel engine using data acquisition system.

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12. load test, performance test and Heat balance test on single CYLINDER air cooled petrol ENGINE using data acquisition system Ex. No:

Date:

Aim:

To conduct load test, performance test and heat balance test on four stroke single cylinder air cooled petrol engine using data acquisition system. Apparatus Required:


1. 1. Before the start of the engine, check the fuel supply electrical supply and lubricating oil level 2. Crank the engine by hand lever and start. 3. Allow the engine to reach steady state condition 4. Switch on the data acquisition system. s ystem. 5. Open data acquisition software on computer 6. Now click „connect‟ icon on the main window then click start icon. 7. Values will display on main window 8. Close the fuel tank value now engine take fuel from cc tube. 9. When fuel level decreases beyond high hi gh level sensor timer in the window starts. 10. When fuel level decreases beyond low level sensor time stops. 11. Each time when reading taken wait until the fuel consumption clock stops. 12. At no load condition after timer stopper takes the reading by clicking „ read‟ icon

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13. After reading taken open the fuel tank value to fill the fuel in cc tube. 14. When fuel level reaches high level sensor timer in window reset. 15. Now click start icon to read the values in engine. 16. Apply load on engine. 17. Wait till fuel consumption clock stops. 18. Now read the values displayed on the computer by clicking „read‟. 19. Repeat the procedure at different load condition. 20. Now click the calculation icon. A new window will open in that window enter radius of arm and click ‟show‟. 21. Click graph icon a new window will appear Graph:


Result:

Thus load test, performance test and heat balance are done on four stroke single cylinder air cooled petrol engine using data acquisition system.

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10. MORSE TEST ON four stroke three CYLINDER PETROL ENGINE Ex. No:

Date:

Aim:

To conduct mores 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 mores 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.

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Formula used:


D  d .............m 2


2 NT ..............KW 60 X 1000

Where N - Engine Speed in rpm T - Torque in Nm 4. Indicated Power ( IP ) of each Cylinders: IP1 = ( BP – BP1)

KW

IP2 = ( BP – BP2)

KW

IP3 = ( BP – BP3)

KW

5.Total IP of the Engine, IP = ( IP1 + IP2 + IP3) KW 6.Mechanical Efficiency, ηmech = BP / IP 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 =

Note: The speed should be same for all readings

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Procedure:

1. From the name plate details, determine the maximum load that can be given to the engine 2. Check the engine for fuel availability, lubricant and cooling water connections. 3. 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. 4. Apply the load and increase the load up to 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 5. 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. nd

rd

6. Bring the all three cylinders are in working conditions and cut off the 2 and 3 cylinder in turn and adjust the load to maintain same „N‟ rpm and note the load .

Result:

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

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15. DETERMINATION OF FLASH AND FIRE POINT Exp. No. :

Date:

Aim :

To determine the flash and fire point temperatures of the given sample of lubricating oil using pensky – martens apparatus. Apparatus Required:

1. Pensky-martens apparatus 2. Electric heater 3. Thermometer 4. Bunsen Burner Principle:

Flash point is the lowest temperature at which the lubricating oil gives off enough vapors that ignite for a moment when tiny flame is brought near it. Fire point is the lowest temperature at which the vapors of the oil burn continuously for at least five seconds when a tiny flame is brought near it. Significance:

Flash and fire points are used to indicate 

Fire hazard of petroleum products and evaporation loses under high temperature loses



It gives us the idea about the maximum temperature below which the oil can be used



It is used as the means of identification of specific lubricating oil



For detection of contamination in the given lubricating oil

Description of Pensky Marten’s apparatus :

It is used to determine the flash point of the lubricating oils, fuel oils, solvents, solvent containing material and suspension of solids. It consists of three parts

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a) Oil Cup

Material- Brass Height – 5.5cm Diameter-5cm Lid of the cup is provided with four openings of standard sizes, first opening is for stirrer, second is for admission of air, third is for thermometer and fourth is for introducing test flame b) Shutter

At the top of the cup shutter is provided. By moving the shutter, opening in the lid opens and flame is dipped in to this opening, bringing the flame over the oil surface. As the test flame is introduced in the opening, it get extinguished, but when the test flame is returned to its original position, it is automatically lightened by the pilot burner c) Stove

It consists of 1. Air bath, 2. Top plate on which the flange of the cup rest

Procedure:

1. Clean and dry all parts of the apparatus with the help of suitable solvent e.g. CCl4, ether, petroleum spirit or benzene and dry it to remove any traces of solvent. 2. Fill the oil cup with the test oil up to the mark. 3. Fix the lids on the top through which are inserted a thermometer and a stirrer. Ensure that the flame exposure device is fixed on the top. 4. Light the test flame and adjust it to about 4 mm in diameter. 5. Heat apparatus as temp. of oil increases by 5 to 60 per min. as stirrer is continuously rotated. 6. At every 10 C rise of temp. Introduce test flame into the oil vapor. This is done by operating the shutter. On moving knob of shutter, test flame is lowered in oil vapors through opening.

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Tabulation:

S.No

95

Temperature of oil in 0C

Flash point temp


fire point temp

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7. When test flame causes a distinct flame in interior cup, note temp. which represent the flash point 8. Further heat the oil at the rate of 10C/ min. and continue applying the test flame as before. 9. The temperature at which the vapors of the oil give a clear and distinct blue flash for five seconds is recorded as the fire point of the oil. Precautions:

1. The apparatus should be thoroughly dried. There should be no trace of moisture inside the cup. 2. The thermometer bulb should dip into the oil. 3. While applying the test flame, stirring should be continued. 4. Fill the sample of the lubricating oil up to the mark. There should be no oil on the outer part of the cup. 5. Avoid breathing over the surface of the oil. Before starting the experiment

1. Ensure that the cup is clean from unwanted makes 2. Carbon deposits to be removed completely. After starting

1. Ensure that there is no air bubble in the cup. 2. Care should be taken that the operator does not breath near the cup. When stopping

1. Hot fuel should be carefully transferred from the cup to the breaker before stopping. 2. Ensure that the flame and Bunsen burner. 3. Ensure that the workplace and apparatus are clean.

Result:

The flash and fire point temperatures of the given sample of oil was determined by using pensky-martens apparatus. 0

The flash point temperature of the given sample of oil is …………… C 0

The fire point temperature of the given sample o f oil is …………… C

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16. SIMPLE VERTICAL BOILER Exp. No. :

Date:

Aim: -

To study about the construction, working and application of simple vertical boiler.

Construction : -

Figure shows the simplest form of an internally fired vertical fire-tube boiler. It does not require heavy foundation and requires very small floor area.

Cylindrical shell:

The shell is vertical and it attached to the bottom of the furnace. Greater portion of the shell is full of water which surrounds the furnace also. Remaining portion is steam space. The shell may be of about 1.25 meters diameter and 2.0 meters height. Cross-tubes:

One or more cross tubes are either riveted or flanged to the furnace to increase the heating surface and to improve the water circulation. Furnace (or fire box):

Combustion of coal takes place in the furnace (fire box). Grate:

It is placed at the bottom of fire box and coal is fed on it for burning. Fire door:

Coal is fed to the grate through the fire door. Chimney (or stack):

The chimney (stack) passes from the top of the firebox through the top of the shell. Manhole:

It is provided on the top of the shell to enable a man to enter into it and inspect and repair the boiler from inside it. It is also, meant for cleaning the interior of the boiler shell and exterior of the combustion chamber and stack (chimney).

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Hand holes:

These are provided in the shell opposite to the ends of each cross tube for cleaning the cross tube. Ash pit:

It is provide for collecting the ash deposit, which can be removed away at intervals.

Theory:

The fuel (coal) is fed into the grate through the fire hole and is burnt. The ash pit placed below the grate collect the ashes of the burning fuel. The combustion gas flows from the furnace, passes around the cross tubes and escapes to the atmosphere through the chimney. Water goes by natural circulation due to convection currents, from the lower end of the cross tube and comes out from the higher end. The working pressure of 2

the simple vertical boiler does not exceed 70 N/cm .

Working of simple vertical boiler:

In a simple vertical boiler fuel is added through the fire hake into the grate which burn there to produce the hot gases. Fuel when co nverted into ash is collected into the ash pit. Hot gases rise above and pass their heat to the water in the cross box and go out of the boiler through the chimney. Water heats up and steam production starts. Steam which produce as a result of water heating is collected at the steam space of the boiler. Steam is collected until a certain pressure is attained and then steam is passed out for use like running turbine or engine.

Application of simple vertical boiler:

Simple vertical boiler have may application is railway locomotives for example railway steam engine Simple vertical boiler are used in the road vehicles like steam wagon (steam lorry or steam wagon) Simple vertical boiler have a very famous application that steam tractor There are number of boats specially smaller one which uses the simple vertical boiler to power the engine In some parts of the world simple

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vertical boiler are used in steam donkeys Simple vertical boilers are also used in the steam cranes and steam shovels.

Advantages of simple vertical boiler:

•

low initial cost because of lesser parts

•

Low maintenance cost

•

Simple working

•

Easy to install and replace

•

Occupy small space on ground

•

Simple vertical boiler have water level tolerance

Disadvantages of simple vertical boiler:

Vertical design limits its working in many places Because of the limited grate area steam production is limited Impurities settle down at the bottom thus prevent water from heating Boiler tubes must be kept short to minimise height. As a result, much of the available heat is lost through the chimney, as it has too little time to heat the tubes.

Result:

Thus the construction, working and application of simple vertical boiler was studied.

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17. COCHRAN BOILER Exp. No. :

Date:

Aim: -

To study about the construction, working and application of cochran boiler.

Theory: -

Cochran boiler is a vertical, multitubular, internally fired, fired, fire tube boiler. It is a low pressure, medium capacity boiler. The maximum capacity of cochran boiler is about 4000 kg of steam per hour and the maximum pressure of steam produced is about 10 bat. It mainly consists of a cylindrical shell with hemispherical crown, fire box, grate, combustion chamber, smoke box and chimney for connecting pressure gauge, water gauge, safety valve, steam stop value, fusible plug. The boiler is filled with water to the specified level using a feed pump. The feed check valve permits the feed water to entire into the boiler, but does not allow water to flow back. Coal is fed into the grate through the fire hole and burnt. Ash formed is collected in the provided below the grate and is removed. The hot gases from the firebox pass through the flue pipe to the combustion chamber. From the combustion chamber the hot gases pass through the horizontal flue tubes to smoke box. The gases from the smoke box are discharged to the atmosphere through the chimney. Smoke box is provided with a door for cleaning the flue tubes and smoke box. The hot gases while passing through the flue tubes transfer heat to the water which is already heated by the fire box. The water gets converted into steam and accumulates in the steam space at the top of the shell. This steam is taken to the steam supply pipe through the steam stop valve. Working:

The fuel is burnt on the grate and ash is collected and disposed of from ash pit. The gases of combustion produced by burning of fuel enter the combustion chamber through the flue tube and strike against fire brick lining which directs them to pass through number of horizontal tubes, being surrounded by water. After which the gases escape to the atmosphere through smoke box and chimney.

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Construction :

Cochran boiler consists of a cylindrical shell with a dome shaped top where the space is provided for steam. The furnace is one piece construction and is seamless. Its crown has a hemispherical shape and thus provides maximum volume of space. Characteristics:

1.

Vertical Boiler

2.

Multi tube Boiler

3.

straight tube Boiler

4.

low pressure Boiler

5.

Coal fired Boiler

6.

Single tube Boiler

7.

Natural draft Boiler

8.

Natural circulation Boiler

9.

Stationary Boiler

10.

internally fired Boiler

11.

Water tube Boiler

Advantages: 

The minimum floor area is required.



Cost of construction is low.



It can be moved and stet up take it to different location.



Boiler has self contained furnace. No brick work s etting is necessary.



Any type of flue can be used.

Disadvantages: 

Steam raising capacity is less due to vertical design.



Difficult in cleaning and inspection due to v ertical design.



The capacity and pressure are limited.



The boiler requires high head room.

Result:

Thus the construction, working and application of Cochran boiler was studied.

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18. BABCOCK-WILCOX BOILER Exp. No. :

Date:

Aim:

To study about the construction, working and application of Babcock-Wilcox boiler Theory:

Evaporating the water at appropriate temperatures and pressures in boilers does the generation of steam. A boiler is defined as a set of units, combined together consisting of an apparatus for producing and recovering heat by igniting certain fuel, together with arrangement for transferring heat so as to make it available to water, which could be heated and vaporized to steam form. One of the important types of boilers is Babcock-Wilcox boiler. Observation:

In thermal powerhouses, Babcock Wilcox boilers do generation of steam in large quantities. The boiler consists essentially of three parts. 1. A number of inclined water tubes: They extend all over the furnace. Water circulates through them and is heated. 2. A horizontal stream and water drum: Here steam separate from the water which is kept circulating through the tubes and drum. 3. Combustion chambers: The whole of space where water tubes are laid is divided into three separate chambers, connected to each other so that hot gases pass from one to the other and give out heat in each chamber gradually. Thus the first chamber is the hottest and the last one is at the lowest temperature. The Water tubes 76.2 to 109 mm in diameter are connected with each other and with the drum by vertical passages at each end called headers. Tubes are inclined in such a way that they slope down towards the back. The rear header is called the down-take header and the front header is called the uptake header has been represented in the fig as DC and VH respectively.

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Whole of the assembly of tubes is hung along with the drum in a room made of masonry work, lined with fire bricks. This room is divided into three compartments A, B, and C as shown in fig, so that first of all, the hot gases rise in A and go down in B, again rises up in C, and then the led to the chimney through the smoke chamber C. A mud collector M is attached to the rear and lowest point of the boiler into which the sediment i.e. suspended impurities of water are collected due to gravity, during its passage through the down take header. Below the front uptake header is situated the grate of the furnace, either automatically or manually fired depending upon the size of the boiler. The direction of hot gases is maintained upwards by the baffles L. In the steam and water drum the steam is separated from the water and the remaining water travels to the back end of the drum and descends through the down take header where it is subjected to the action of fire of which the temperature goes on increasing towards the uptake header. Then it enters the drum where the separation occurs and similar process continuous further. For the purpose of super heating the stream addition sets of tubes of U-shape fixed horizontally, are fitted in the chamber between the water tubes and the drum. The steam passes from the steam face of the drum downwards into the super heater h eater entering at its upper part, and spreads towards the bottom .Finally the steam enters the water box W, at the bottom in a super heated condition from where it is taken out through the outlet pipes. The boiler is fitted with the usual mountings like main stop valve M, safety valve S, and feed valve F, and pressure gauge P. Main stop valve is used to regulate flow of steam from the boiler, to steam pipe or from one on e steam one steam pipe to other. ot her. The function of safety valve is used to safe guard the boiler from the hazard of pressures higher than the design value. They automatically discharge steam from the boiler if inside pressure exceeds design-specified limit. Feed check valve is used to control the supply of water to the boiler and to prevent the escaping of water from boiler due to high pressure inside. Pressure gauge is an instrument, which record the inside pressure of the boiler. When steam is raised from a cold boiler, an arrangement is provided for flooding the super heater. By this arrangement the super heater is filled with the water up to the

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level. Any steam is formed while the super heater is flooded is delivered to the drum ultimately when it is raised to the working pressure. Now the water is drained off from the super heater through the cock provided for this purpose, and then steam is let in for super heating purposes.

Result:

Thus the construction, working and application of Babcock – Babcock – Wilcox Wilcox boiler was studied.

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19. LANCASHIRE BOILER Exp. No. :

Date:

Aim:

To study about the construction, working and application of Lancashire boiler.

Theory:

Evaporating the water at appropriate temperatures and pressures in boilers does the generation of system. A boiler is defined as a set of units, combined together consisting of an apparatus for producing and recovering heat by igniting certain fuel, together with arrangement for transferring heat so as to make it available to water, which could be heated and vaporized to steam form. One of the important types of boilers is Lancashire boiler.

Observation:

Lancashire boiler has two large diameter tubes called flues, through which the hot gases pass. The water filled in the main shell is heated from within around the flues and also from bottom and sides of the shell, with the help of other masonry ducts constructed in the boiler as described below.

The main boiler shell is of about 1.85 to 2.75 m in diameter and about 8 m long. Two large tubes of 75 to 105 cm diameter pass from end to end through this shell. These are called flues. Each flue is proved with a fire door and a grate on the front end. The shell is placed in a placed in a masonry structure which forms the external flues through which, also, hot gases pass and thus the boiler shell also forms a part of the heating surface.

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SS is the boiler shell enclosing the main flue tubes. SF are the side flues running along the length of the shell and BF is the bottom flue. Side and bottom flues are the ducts, which are provided in masonry itself. The draught in this boiler is produced by chimney. The hot gases starting from the grate travel all along the flues tubes; and thus transmits heat through the surface of the flues. On reaching at the back end of the boiler they go down through a passage, they heat water through the lower portion of the main water shell. On reaching again at front end they bifurcate to the side flues and travel in the forward direction till finally they reach in the smoke chamber from where they pass onto chimney. During passage through the side flues also they provide heat to the water through a part of the main shell. Thus it will be seen that sufficient amount of area is provided as heating surface by the flue tubes and by a large portion of the shell operating the dampers L placed at the exit of the flues may regulate the flow of the gases. Suitable firebricks line the flues. The boiler is equipped with suitable firebricks line the flues. The boiler is equipped with suitable mountings and accessories. There is a special advantage possessed by such types of boilers. The products of combustion are carried through the bottom flues only after they have passed through the main flue tubes, hence the hottest portion does not lie in the bottom of the boiler, where the sediment contained in water as impurities is likely to fall. Therefore there are less chances of unduly heating the plates at the bottom due to these sediments.

Result:

Thus the construction, working and application o f Lancashire boiler was studied.

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20. La Mont boiler Exp. No. :

Date:

Aim: -

To study about the construction, working advantages and disadvantages of La Mont boiler

Construction: -

La Mont boiler is vertical boiler. It has two t ypes of evaporator namely convective evaporator and radiant evaporator. Radiant evaporator are mounted as near as possible to the combustion chamber. The economizer is also used in La Mont boiler to heat the feed water from flue gases. This heated water passed to evaporating drum. At the top of the boiler air preheater is installed to heat the air which is required for combustion in combustion chamber. Working: -

The feed water from hot well is supplied to a storage and separating drum through the economizer. The most of the 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. This water is circulated through the evaporator tubes and part of the water evaporated is separated in the separator drum. The large quantity of water circulated prevents the tubes from being overheated. The centrifugal pump delivers the feed water to the headers at pressure of 2.5 bars above the drum pressure. The distribution header distributes the water through the nozzle into the evaporator. The steam separated in the boiler is further passed through the superheater and then supplied to the turbine. The air drawn by the blower is preheated in the air preheater by the flue gases before these are discharged through the chimney. The heated air from air preheater is supplied to the combustion chamber and it improves the combustion efficiency.

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Advantages:-

1. The boiler can generate steam up to a pressure of 150 bars and the generation rate of steam ranges from 30000 to 45000 kg per hour. 2. Starting of Lamont boiler is quick.

Disadvantages:-

1. Bubbles are formed at the inner face of heating tube. Because of which it reduces the heat transfer rate.

Result:

Thus the construction, working advantages and disadvantages of La Mont boiler was studied.

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21. Benson boiler Exp. No. :

Date:

Aim: -

To study about the construction, working advantages and disadvantages of Benson boiler.

Construction: -

Benson boiler is also vertical boiler. It has two types of evaporators viz. Convective evaporator and radiant evaporator. Radiant evaporator are mounted as near as possible to the combustion chamber. The economizer is also used in Benson boiler to heat the feed water from flue gases. This heated water passed to evaporating drum. At the top of the boiler air preheater is installed to heat the air wh ich is required for combustion in combustion chamber.

Working: -

The main difficulty of Lamont boiler is the formation of bubbles at the inner side of heating tubes which reduces the heat flow and steam generation as it offers high thermal resistance than water film. Benson argued in 1922 that if the boiler pressure was raised to critical pressure (225 bars) the steam and water have the sane density and therefore the danger of bubble formation can be easily eliminated. The arrangement of boiler is as shown below. The water as passed through the economizer into the radiant evaporator where most of the water is converted into the steam. The remaining water is evaporated in the convective evaporator absorbing the heat from hot gases by convection. The saturated high pressure steam (at 225 bar) is further passed through the super heater as shown.

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Advantages:-

1. As the generation of steam is carried out in the evaporating tubes at pressure higher than critical pressure it doesn‟t require any evaporating drum. 2. The boiler can be started in short time in 10 to 15 minutes only. o nly. 3. Benson boiler is lighter in weight with high generation rate of steam. 4. Due to absence of the evaporating drum the total weight is 20% less than other boilers. 5. The superheater of the Benson boiler is the integral part of forced circulation system therefore no special starting arrangement for superheater is required. 6. The cost of the boiler is reduces as there is no evaporating drum. 7. Bubble formation is eliminated in Benson boiler which is critical problem in Lamont boiler.

Disadvantages:-

1. The evaporation process will leave small deposits during conversion of water into steam due to which it requires frequent cleaning. To obviate this problem, the water softening plant is require. 2. Tubes are likely to be overheated in case of water flow is insufficient.

Result:

Thus the construction, working advantages and disadvantages of Benson boiler was studied.

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22. Loeffler boiler Exp. No. :

Date:

Aim: -

To study about the construction, working and advantages of Loeffler boiler.

Construction: -

Components in Loeffler boiler are air pre heater, evaporating drum radiant and convective evaporator feed pump etc. in Loeffler boiler H.P. and L.P. boilers are added with steam circulating pump. The economizer is used to heat the incoming water from feed pump. Steam circulating pump draws superheated steam from evaporating drum.

Working: -

The major difficulty in Lamont boiler is the deposition of salt and sediment on the inner surface of the water tubes. This difficulty was solved in Loeffler boiler by preventing the flow of water into the boiler tubes. Most of the steam is generated outside from the feed water using part of the superheated steam coming out from the boiler. The arrangement is shown in the following diagram. The pressure feed pump draws the water through the economizer and delivers it into the evaporator drum as shown. About 35% f the steam coming out from the superheater is supplied to the H.P. steam turbine. The steam coming out from H.P. turbine is passed through reheater before supplying to L.P. turbine. The amount of heat generated in the evaporator drum is equal to the steam tapped (65%) from the superheater. The nozzles which distribute the superheated steam throughout the water into the evaporator drum are of special design and avoid priming and noise. This boiler can carry higher salts concentration than any other type.

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Advantages:-

1. Loeffler boiler can carry higher salt concentration than any other type of boiler. 2. Since evaporating tubes of Loeffler boiler carries only superheated steam there is no salt deposition so it is suitable for marine applications. 3. Boiler is compact in design.

Result:

Thus the construction, working and advantages of Loeffler boiler was studied.

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23. Schmidth-Hartmann boiler Exp. No. :

Date:

Aim: -

To study about the construction, working, disadvantages and advantages of Schmidth-Hartmann boiler. Construction: -

Schmidth-Hartmann boiler consists of air preheater to heat the surrounding air which is required for combustion chamber. It also consist steam drum, superheater, and feed pump. Feed water preheater, primary separator is also used in this boiler. In Schmidth-Hartmann boiler there are two circuits one uses distilled water and other uses impure water. Working: -

The Schmidth-Hartmann boiler is different from other boiler because in this boiler distilled water is used for generation of the high pressure steam which is recalculated without any wastage in the circuit. This high pressure steam is utilized for generation of low pressure steam from impure water. Distilled water from water drum enters into the primary evaporating tubes by natural circulation. Steam at 95-100 bar pressure is generated in the evaporating tubes with the help of hot flue gases circulated over the tubes from combustion chamber. This steam enters via primary separator into the tubes submerged in impure water of the evaporator or steam drum. The exchange of heat between high pressure steam and impure water allows the water to be converted into steam at a pressure of 55-60 bar which is further passed into superheater for superheating purposes. The superheated stem is finally supplied to the steam turbine. The condensate of high pressure steam collected from the drum passes through the feed water preheater where it heat the low pressure feed water up to its saturation temperature. The low pressure (L.P.) feed water is pumped into preheater with the help of feed pump.

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Advantages:-

1. It can use impure water for generation of steam. 2. As it can use impure water there is no requirement of water softening plant ultimately reduces cost. 3. Any deposits in the evaporator drum due to impure water can easily brushed off by removing the submerged tube from the drum or by blowing off the water. 4. Wide fluctuations of load are easily taken by this boiler without undue priming or abnormal increase in the primary pressure due to high thermal and water capacity of the boiler.

Disadvantages:-

1. Due to deposits in the evaporator drum because of impure water plant has to stop frequently for cleaning. 2. Evaporating drum is used which increase the bulkiness of plant with cost. Result:

Thus the construction, working, disadvantages and advantages of SchmidthHartmann boiler was studied.

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24.Velox boiler Exp. No. :

Date:

Aim: -

To study about the construction, working, disadvantages and advantages of Velox boiler. Construction: -

In Velox boiler pressurized combustion is used so axial flow compressor is used which is ran by gas turbine. The combustion chamber and evaporating tubes are arranged in such a way that the hot products from combustion chamber are directly passed to annulus of evaporating tubes. Steam separator is arranged tangential to evaporating tubes. Hot flue gases are used for running gas turbine, for economizer, and for superheater. Working: -

As we know heat transfer rate is much higher in sonic velocity than that of the subsonic velocity. Same concept is utilized in the design of Velox boiler in order to reduce the surface area hence the size of evaporating tubes. The salient feature of the Velox boiler is pressurized combustion. Air drawn from surroundings by axial flow compressor is compressed up to 2.5 to 3 bar pressure. Compressed air at above sonic velocity and the fuel are injected into the vertical combustion chamber. The hot products of combustion at high velocity are passed into the annulus of the concentric evaporating tubes. These hot gases transfer heat to feed water flowing inside the concentric evaporative tubes. Hot gases circulated about 10 to 20 times that of feed water circulation. The wet steam generated in the evaporative tubes is passed to a steam separator in tangential direction. It forms the vortex in the separator and due to centrifugal action moisture content of steam is separated. This separated water is pumped back into feed water line. The dry steam separated is passed through the superheater tubes where it is superheated with the help of hot flue gases collected from evaporating tubes.

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The hot gases discharged from the superheater are expanded in gas turbine. The power developed by the turbine is used to drive the compressor. The exhaust of the gas turbine is used to heat the feed water in the economizer before these are discharged to the surroundings through the chimney. Advantages:-

1. Velox boiler is compact. 2. Very high combustion rates are possible as 35 to 45 million kJ per cu. m. of combustion chamber volume. 3. Low excess air is required as the pressurized air is used and the problem of draught is simplified.

Disadvantages:-

1. It can only operate on liquid or gaseous fuels.

Result:

Thus the construction, working, disadvantages and advantages of Velox boiler was studied.

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25. Supercharged boiler Exp. No. :

Date:

Aim: -

To study about the construction, working, disadvantages and advantages of supercharged boiler.

Construction: -

In supercharged boiler there are two feed pumps one for feed water and one for boiler drum. Gas turbine supplied the used flue gases to economizer to heat the feed water. This gas turbine also run compressor. Compressor supplies compressed air to combustion chamber.

Working: -

Combustion in supercharged boiler carried by pressurized combustion process at 5-6 bars. The heated feed water from economizer and also from boiler drum are mixed and supplied to the evaporating tubes where it is converted into wet steam and further heating is carried out in evaporating tube and the steam is discharged in the boiler drum. Almost dry steam from the drum is superheated in the superheater before it is supplied to the steam turbine. The high pressure exhaust gases from the boiler are used to run a gas turbine. The power developed by gas turbine is used turbine is used to run the compressor and other auxiliaries. Turbine exhaust gases are used to heat the feed water in the economizer and finally these are exhausted to surrounding through the chimney.

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