Experiment 1 PDF

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EXPERIMENT NO . 1 Drawing Of Heat Balance Sheet of Ruston Diesel Engine 1.1

OBJECTIVE: To draw the heat balance sheet of Ruston Diesel Engine.

1.2 i.

APPARATUS: Ruston Diesel Engine.

Figure 1 Ruston Vertical Cylinder type Diesel Engine ii.

Tachometer.

iii.

Dynamometer.

iv.

Stopwatch.

v.

Diesel Fuel.

1.3

ENGINE SPECIFICATIONS:

i.

Number of stokes = 4

ii.

Number of cylinders = 4

iii.

Engine Configuration = Vertical

iv.

Maximum Brake Horse Power = 40 hp

v.

Maximum Speed = 2000 RPM

vi.

Stroke Length = 15 cm

vii.

Dikameter of Bore = 8 cm

1.4 i.

PROCEDURE: Start the engine by manually rotating the crankshaft.

ii.

Verify that air and water circuits are running.

iii.

Use a Tachometer for determining the engine speed.

iv.

Now use a stopwatch for measuring time for 50 ml fuel filling in a metering system

v.

Take time for 2.25 liters of water in seconds in a gallon.

1.5

THEORY:

A Heat Balance Sheet is a record of heat provided and heat used in different courses in the framework or system. Vital / Important data concerning the execution of the motor is acquired from the warmth balance. The Heat Balance is commonly done on second premise or moment premise or hour premise. It is commonly a training to represent the warmth conveyance or transfer as level or percentage of heat provided. Such an appropriation or distribution is known as heat balance sheet . The primary parts of warmth balance are; i. ii.

Heat comparable or equivalent to compelling or effective work on the motor. Heat rejected to the cooling medium.kk

iii.

Heat carried away from the engine with the exhaust gases.

iv.

Unaccounted losses. The Unaccounted losses can be calculated as; Un accounted loses = Heat Supplied – (Brake Power+ Heat loss in cooling the engine + Heat loss in exhaust).

1.5.1 Diesel Engine : Diesel Engine was invented by a German Inventor and Mechanical Engineer named Rudolf Diesel. Diesel engine is also known as CI – Engine ( Compression Ignition - Engine ). Basically in a Diesel Engine, Fuel is ignited due to increase of temperature in the engine cylinder by adiabatic compression. A diesel Engine works by just compressing the air inside the cylinder so that the temperature of the air inside the cylinder will increased to such an extent due to which atomized Diesel fuel ignites spontaneously. This feature differentiate CI - Engines from SI – Engine (Spark Ignition – Engine). which uses spark plug for the fuel ignition. In Diesel Engines Glow Plugs used for starting the diesel engine in the cold weather or at low compression ratios. A Normal Diesel Engine operates at constant pressure cycle of smooth combustion and produces no audible knock. Diesel Engine has high thermal efficiency of 35% to 40% as compared to petrol engine which has 25% to 30% thermal efficiency.

1.5.2 Ruston Diesel Engine : Ruston diesel is basically a CI – Engine ( Compression Ignition Engine ) having four strokes, four cylinders , and vertical cylinder configuration.[1]

1.5.3 Important Engine Components : • Bore: The Diameter of the piston is called as Bore.

• Flywheel: Flywheel is one of the essential component in the engine, it is connected to the crankshaft and the power from the crankshaft and provides to keep the crankshaft turning when no power is being applied.[2]

• Crankshaft: Crankshaft is also an essential engine component, crankshaft is basically a shaft having one or more cranks that are coupled or connected with connecting rods to the engine’s piston. Crankshaft and the connecting together converts piston’s reciprocating motion into rotatory motion.

• Piston: A Piston is a hollow cylinder that is closed at one end and connected to the crankshaft through connecting rod, piston moves up and down and transmit power created by fuel explotion to the crankshaft through connecting rod.

• Carburetor: A carburetor is a fuel system component, which mixes air and fuel in the correct mixer and directs it into intake manifold through atomizer through which it is distributed in each combustion chamber.

• Timing Belt: Timing Belt, an engine component, is a cogged belt, usually of reinforced rubber. The purpose of a timing belt component is to provide a quiet, flexible connection between the camshaft and crankshaft to keep the engine valves opening and closing in phase with the movement of the engine pistons.[3]

• Spark Plug: A Spark Plug is an engine component which ignites the air fuel mixture and removes heat from the combustion chamber.

1.5.4 Four Stroke Diesel Engine: There are following Four strokes in a Four Stroke Diesel Engine:

• Intake Stroke: Also known as induction or suction. This stroke of the piston begins at top dead center (T.D.C.) and ends at bottom dead center (B.D.C.). In this stroke the intake valve must be in the open

position while the piston pulls an air-fuel mixture into the cylinder by producing vacuum pressure into the cylinder through its downward motion. The piston is moving down as air is being sucked in by the downward motion against the piston.[4]

• Compression Stroke: This stroke begins at B.D.C, or just at the end of the suction stroke, and ends at T.D.C. In this stroke the piston compresses the air-fuel mixture in preparation for ignition during the power stroke (below). Both the intake and exhaust valves are closed during this stage.

•

Exhaust Stroke: Also known as outlet. During the exhaust stroke, the piston, once again, returns from B.D.C. to T.D.C. while the exhaust valve is open. This action expels the spent air-fuel mixture through the exhaust valve.

Figure 2 A Four Stroke Diesel Engine https://www.google.com/imgres

1.6

OBSERVATIONS AND CALCULATIONS: At 900 RPM Heat Supplied Lower calorific value of fuel = Qnet, v = 44200 kJ / kg

Vf = 25ml = 25 x 10-6 m3 Vf = Vf / t ṁf = V f x ρf (ρf = 778 kg/m3) H.S = ṁf x L.C.V = 21.75 kW Brake Power V = Voltage I = Current B.P = VI/Efficiency = 1.37 kW Heat Supplied to the cooling Water Qw = ṁw x Cw x ∆T Cw = Specific heat capacity of water = 4.2 kJ/kg.K ∆T = Temperature of the coolant leaving the engine – Temperature of the coolant of the entering the engine. Qw = 0.497 kW Heat Energy in Exhaust gases QEG = ṁEG x CEG x ∆TEG Mass flow rate of exhaust gases = mass flow rate of fuel + mass flow rate of air ṁEG = ṁf + ṁa Mass flow rate of air = ṁa = V a x ρa

(ρa = 1.2 kg/m3)

𝑁×𝐴×𝐿×𝑛 Volume flow rate of air = Va = 120 𝜋

A = Area of piston = d2 4 L = Length of stroke N = Speed n = no. of cylinders CEG = 0.88 kJ/kg.K QEG = 1.995 kW Unaccounted Losses QUN = 17.88 kW

At 950 RPM Heat Supplied H.S = 26.43 kW Brake Power B.P = 3.61 kW Heat Supplied to the cooling water Qw = 1.823 kW Heat Energy in the Exhaust gases QEG = 2.588 kW Unaccounted losses

QUN = 18.409 kW

At 1000 RPM Heat Supplied H.S = 32.79 kW Brake Power B.P = 7.7 kW Heat Suppied to the cooling water QW = 2.465 kW Heat Energy in the Exhaust gases QEG = 3.741 kW Unaccounted losses QUN = 18.864 kW

At 1050 RPM Heat Supplied H.S = 38.9 kW Brake Power B.P = 10.65 kW Heat Supplied to the cooling water

No.

N

V

of

(rpm) (V)

I

𝒎󰇗𝒇 ×

Time

𝒎󰇗 𝒘 ×

Cooling 𝒎󰇗𝒂 ×

(A) for

𝟏𝟎−𝟒

for

𝟏𝟎−𝟐

water

50

(kg/s)

2.25L (kg/s)

outlet

ml

water

temp

Fuel

(s)

(℃ ℃)

obs.

Time

Exhaust HS

BP

QW

QEG

QUH

𝟏𝟎−𝟐

gases

kW

Kw

kW

kW

kW

(kg/s)

Tavg (℃)

(s) 1.

900

110

10

79

4.92

56.86

3.945

18

2.714

97.0

21.75

1.37

0.497 1.995

17.88

2.

950

170

17

65

5.98

56.86

3.945

26

2.865

115.5

26.43

3.61

1.823 2.588

18.409

3.

1000

280

22

52.39

7.42

56.86

3.945

30

3.016

152.6

32.79

7.7

2.485 3.741

18.864

4.

1050

355

24

44.15

8.8

56.86

3.945

40

3.166

188.7

38.9

10.65

4.143 4.974

19.133

QW = 4.143 kW Heat Energy in the Exhaust gases QEG = 4.974 kW Unaccounted losses QUN = 19.133 kW

For 900 RPM

Brake Power Heat Energy in exhaust gases Heat Energy to cooling water Unaacounted Losses Heat Supplied

50.01%

3.15% 4.59% 1.14%

41.11%

For 950 RPM

Brake Power Heat Energy in exhaust gases Heat Energy to cooling water Unaacounted Losses Heat Supplied

50%

34.83% 6.83% 3.45%4.9%

For 1000 RPM

Brake Power Heat Energy in exhaust gases Heat Energy to cooling water Unaacounted Losses Heat Supplied

50%

28.76% 3.79% 5.7%

11.74%

For 1050 RPM

Brake Power Heat Energy in exhaust gases Heat Energy to cooling water Unaacounted Losses Heat Supplied

50%

24.59%

5.33% 6.39%

13.69%

1.7 DISCUSSION: •

It is noticed that as the RPM of engine goes on increasing the heat losses start to increase because as the speed of the piston increase or the revolution per minute of the cranks shaft increases it will generate

more power, friction between the piston and the walls of the cylinder increases which will generate more heat. •

Also With the increase of RPM brake power also increases ( the maximum power available at the crankshaft ).

•

It is also observed that the mass flow rate of water remains constant.

•

With increase of RPM increase in the voltage and current was also observed.

•

Heat Supplied was different at different RPM’s.

1.8 REFERENCES: 1. www.quora.com 2. https://en.wikipedia.org/wiki/Flywheels. 3. https://en.wikipedia.org/wiki/Timingbelt 4. https://www.quora.com/Intake...