Heat Balance Test On Diesel Engine 3e5d2e

E2

HEAT BALANCE TEST ON SINGLE CYLINDER 4 STROKE DIESEL ENGINE (KIRLOSKAR) AIM

To conduct heat balance test on Diesel Engine to prepare a heat balance sheet.

SPECIFICATIONS: Engine make: Kirloskar AV1 B.H.P = 5H.P R.P.M = 1500 Diameter of brake drum =300mm Orifice Diameter =20 mm

PRECAUTIONS 1. Fuel and lubricating oil are checked and if needed they are to be supplied. 2. Cooling water inlet and outlet for engine jacket and brake drum should be opened. 3. Engine should be started and stopped with no load. 4. De-compression liver should be engaged before cranking.

THEORY: To balance the energy input and output what is done usually is to add all the known forms of energy output in heat units and, the difference between this and the given energy input is termed as uned losses ( lost by radiation etc). Thus law of conversion of energy is kept unaltered.

1. The work input of engine can be calculated using TFC and calorific value. 2.

The heat carried away by cooling water can be calculated from its rate of

flow, specific heat and temperature difference between inlet and outlet. 3.

The heat carried away by exhaust gases can be calculated from the exhaust

calorimeter

(1) Time for 10cc fuel consumption =

(sec)

Total fuel consumption ,

Heat Input to the engine ,

Calorific value (

) of diesel = 46057kJ/kg.

(2) Output Power or Brake Power

Torque, (

)

Where =

Speed of the engine in rpm,

=

Weight in kg,

=

spring balance reading (kg)

=

(Radius of the brake drum +1/2 the dia of rope) in meters.

̇

(3)

(

)

Where

̇

=

mass flow rate of water ( Kg/sec)

=

specific heat of water ((4.186 KJ/KgK)

=

inlet temperature of water to the engine K

=

outlet temperature of cooling water from engine K

̇

4.

(

Where

̇

=

mass of exhaust gas kg/sec

=

Specific heat of exhaust gases ( KJ/KgK)

=

Temperature of exhaust gases at engine exit

)

= ̇

Room temperature

is obtained from the exhaust gas calorimeter relation as given below

For calorimeter : Heat lost by exhaust gas = heat gained by water

̇

(

) ̇

(

)

Where

̇

=

mass flow rate of water ( Kg/sec)

=

Specific heat of water (4.186 KJ/KgK)

=

inlet temperature of water the calorimeter

=

outlet temperature of water from the calorimeter

=

Temperature of exhaust gases at the exit of calorimeter

̇ ̇

̇

(

)

kJ/sec

PROCEDURE

The maximum load on the engine is calculated and range of loading is selected. The necessary precautions are taken. The lubricating oil and fuel in the tank is checked.

The supply of fuel and cooling water is opened.

The

decompression lever is engaged and engine is started by cranking. The desired load is applied and time for 10 c.c of fuel consumption is noted. The temperature of cooling water at outlet and the temperature of exhaust gas are observed. From the flow meter the rate of cooling water supply is noted. The atmospheric temperature and temperature of cooling water inlet are also noted.

The

observations are also tabulated as shown. From the observations the heat balance is done and balance sheet is plotted.

E3

LOAD TEST ON TWO CYLINDER 4 STROKE DIESEL ENGINE (USHA) AIM: To conduct load test (Constant speed characteristics) on Single cylinder 4S Diesel Engine with rope brake dynamometer and to plot the following Characteristic Curves. 1. Brake power (B.P) Vs T.F.C (total fuel consumption) 2. B.P Vs S.F.C (Specific fuel consumption) 3. B.P Vs M.E (Mechanical efficiency) 4. B.P Vs B.T.E (brake thermal efficiency) 5. B.P Vs I.T.E (indicated thermal efficiency) 6. B.P. vs. volumetric efficiency SPECIFICATIONS: Engine make: USHA B.H.P = 10H.P R.P.M = 1500 No. of cylinders = 2 Compression ratio = 17.5:1 Bore =87.5mm Stroke = 110mm Arm length of hydraulic dynamometer = 320 mm Orifice Diameter =20 mm

PRECAUTIONS 1. Fuel and lubricating oil are checked and if needed they are to be supplied. 2. Cooling water inlet and outlet for engine jacket and brake drum should be opened. 3. Engine should be started and stopped with no load. 4. De-compression liver should be engaged before cranking.

THEORY: (1) Output Power or Brake Power

Torque,

Where =

Speed of the engine in rpm,

=

Hydraulic Dynamometer reading

=

spring balance reading (kg)

=

Arm length of hydraulic dynamometer = 320 mm

Time for 10cc fuel consumption

=

(sec)

(2) Total fuel consumption

(3) Specific fuel consumption

(4) Indicated Power,

I.P

=

B.P + F.P

Where F.P is the Frictional Power obtained from the characteristic plot (TFC Vs B.P). (5) Mechanical efficiency,

(5) Input Power (Heat energy Input),

Calorific value (

) of diesel = 46057kJ/kg.

(6) Brake thermal efficiency,

(7) Indicated thermal efficiency,

(8) Volumetric efficiency

Hw

=

Manometer reading (h1-h2)

(a)

Actual volume of air taken in, √

(b)

( where a= area of orifice)

Theoretical volume (

)

k= ½ for 4 stroke engine, 1 for 2 stroke engine n = no of cylinders

Volumetric efficiency,

(

),

PROCEDURE Before starting the engine maximum load that can be applied on the engine is calculated using the formula

Torque, T

( ) Start the engine at no load condition. Fuel supply is switched on and the decompression lever is engaged. The engine is started by manual cranking. Then the time taken for 10c.c of fuel consumption is noted at no load. And level difference in the water manometer is noted. Initial load is applied at the end of the hook in the rope. Note the spring dial reading. Repeat the experiment up to maximum load. Then the engine is stopped by cutting the fuel supply.

CALCULATIONS:

CHARACTERISTIC CURVES RESULT: INFERENCE: