0.UNIT I
1Kg, of air is taken to a diesel cycle. Intially the air is at 25° C and 1 bar. Compassion ratio is 14 and the heat added is 1850 KJ. Calculate cycle efficiency.
A diesel engine working on gas std. cycle takes air at 1 bar and 25° C. Specific volume of air at inlet at 0.8m3 /Kg. Compression ratios is 14 and heat is added at constant pressure is equal to 840KJ/Kg. Find cut off ration and air std. efficiency.
A gas std. diesel cycle has a compression ratio of 12 and cut off takes place at 5.5% of stroke . Calculate air std. efficiency.
Estimate the loss in air std. efficiency for a diesel cycle engine of compression ratio 14 when the cut off changes from 6% to 13% of stroke.
Determine the air std efficiency of diesel cycle . If the compression ratio is 14. Heat is supplied upto 5% of stroke.
Compression ratio is increased from 14 to 18 cut off is adjusted to give the same air std. efficiency. Find the change in cut off?
In an ideal constant volume cycle, pressure, temperature and volume at the beginning of the cycle are 1.2bar, 35° C and 0.5 m3 . At the end of compression stroke, pressure is 12 bar and 315KJ/Kg. heat is added. Calculate pressure, temperature and volume at all points. Find air std. efficiency.
An engine working on an ideal air std. diesel engine has the compression ratio 15 and heat transfer 140KJ/Kg. Find pressure and temperature at the end of each process. if inlet conditions are 280K and 1.1 bar. Find air std. efficiency.
In an engine working on diesel cycle, the ratio of weights of air and fuel supplies is 50:1. The temperature of air at beginning of combustion is 333K and compression ratio used in 14:1 what is the ideal efficiency of the engine for calorific value of fuel used is 4200KJ/Kg. Assume Cp =1.004KJ/Kg°K and Cv =0.717KJ/Kg°K.
In the oil engine working on dual cycle heat supplied at constant pressure is twice that of heat supplied at constant volume Rc and Re are 8 and 5.3. Pressure and temperature at inlet are 0.93 bar and 27°C. Find efficiency of cycle. Take Cp =1.005KJ/Kg°K and Cv =0.718KJ/Kg°K.
A dual combustion air std. cycle has a compression ratio of 10. The constant pressure part of combustion takes place at 40 bar. The highest and lowest temperature of cycle are 1727° and 27°C. the pressure at the beginning of compression is 1 bar. calculate.
Pressure and temperature of all points.
Heat supplied at constant pressure
Heat supplied at constant volume
Heat rejected
An std. efficiency
UNIT II
The following details were noted in a test on a four cylinder 4 stroke engine
Dia meter – 100mm;
Stroke – 120mm;
Speed of engine – 1600rpm;
Fuel consumption – 0.2Kg./min;
Calorific value - 44000KJ/Kg;
Difference in fusion on either
side of the brake pulley - 40kgf;
Brake circumference - 300cm;
Calculate brake thermal efficiency
Mechanical efficiency - 80%;
Also find indicated thermal ŋ
Also find indicated mean effective pressure brake specific flow consumption
An 8 cylinder 4 stroke engine of 0.9m bore and stroke of 0.08m with compression ratio of 7 is tested at 4500rpm and dynamometer which has 0.54 arm. During a 10 minute test the dynamometer scale been reading was 42 kgf and engine consume 4.4kg of gasoline having a calorific value of 44000KJ/kg. Air at 300k and 1 bar was supplied to carburetor at the rate 6kg/min. Find
Brake power delivered
Brake mean effective pressure
Brake specific fuel consumption
Brake thermal efficiency
Volumetric efficiency
Air fuel ratio
During a test on single cylinder 4 stroke oil engine the following data were obtained
Stroke volume - 0.0227m3
Mean effective pressure - 5 bar
Engine speed - 4000 rpm
Brake torque - 67.6Nm.
Fuel used per hour - 37.3 Kg.
Calorific value of fuel - 43000Kj/Kg.
Calculated
indicated power,
brake power,
indicated thermal efficiency,
brake thermal efficiency
The following data relates to 4 cylinder, 4 stroke petrol engine oil, air fuel ratio by weight 16:1
Caloric value - 45.200KJ/Kg.
ŋ mech - 82%
Air std ŋ - 52%
ŋ relative - 70%
ŋ vol - 78%
Stroke by bore ratio - 1.25
Suction condition - 1 bar, 25°C
Speed - 2400 rpm
Power at brakes - 72KW
Calculate :
Rc
ŋ Ith
BSFC
Bore and stroke
4 Cylinder 4 stroke petrol engine 79mm bore, 132mm stroke develops 28.35KW brake power while running a 1450 rpm. The volume of air into the cylinder where measured at 15.5°C and 760 mm of mercury is 70% of swept volume. The air fuel ratio is 14.8. The heating value of Petrol used is 44000KJ/Kg. and the mechanical efficiency is 90%.
Find: ŋ Ith Take r = 0.287KJ/Kg°K
The following observations were taken during a test on single cylinder 4 stroke cycle engine having a bore of 300mm and stroke of 450mm.
Ambient air temperature - 22°C
Fuel consumption - 11Kg/hr
CV of fuel - 42000KJ/Kg.
Engine speed - 300rpm
Mean effective pressure - 6 bar
Net Brake load - 1KN
Brake drum diameter - 2m
Quantity of Jacket cooling water - 590 KJ/hr
Temperature of entering cooling water - 22°
Temperature of leaving cooling water - 70°C
Quantity of air as measured - 225Kg/hr
CP of exhaust gas - 1.005 KJ/kg°K
Exhaust gas temperature - 405°C
Rope radius - 2cm
Determine BP, IP, ŋmech and and draw a heat balance sheet on hour basis.
A test on a single cylinder 4 stroke oil engine having bore of 180mm and stroke of 360mm. It gave the following results.
Speed - 290rpm
Brake torque - 392 Nm
IMEP - 7.2 bar
Oil consumption - 3.5 kg/hr
Room Temperature - 21°C
Coolant flow - 270Kg/hr
Cooling water temperature raise - 36°C
Air fuel ratio - 25
Exhaust gas Temperature - 415°C
CVfuel - 45200KJ/Kg.
Take specific heat of exhaust gas as 1.005KJ/Kg°K.
Calculate:
ŋ Ith
Draw heat balance sheet in KJ/min basis.
UNIT III
A single stage reciprocating compresses taken 1m3 of air per minute at 1 bar and 15°C and delivers it at 7 bar. If the law of compression PV 1.3 - C.
Calculate the indicated power, Neglect clearance, The speed of compressor is 300rpm and stroke to bore ratio is 1.5. Calculate cylinder dimensions. Find the power required if ŋmech is 85% and ŋmotor 90%.
A single acting single stage compression is belt driver from an electric motor at 400 rpm. The cylinder diameter is 15cm and the stroke is 17.5cm. Air is compressed from 1 bar to 7 bar and law of compression is PV 1.3 - C. Find the motor power if the ŋtransmission is 97% and ŋmech is 90%. Neglect the clearance.
Free air delivery of single cylinder single stage reciprocating air compressor is 2.5m3 /min. The ambient air at STP conditions and delivery pressure is 7 bar. The clearance volume is 5% of stroke volume and law of compression is PV 1.25 - C. If L-1.2d and compressor runs at 150rpm. Determine the size of cylinder.
A single acting reciprocating air compressor has a piston dia of 200mm and stroke of 300mm and runs at 350rpm. Air is drawn at 1.1 bar and delivered at 8 bar. Law compression is PV 1.35 - C. and clearance volume is 6 % of stroke volume. Find mean effective pressure and power required to drive the compressor.
A single acting 14cm X 10cm reciprocating compressor is operating at P1 – 1bar, T1 - 20°C, P2 – 6bar, T2 - 180°C, The speed of the compressor is 1200 rpm and shaft power is 6.25 KW. Mass of air delivered is 1.7kg/min.
Calculate:
ŋvol
Isothermal work (power)
IP
ŋmech
ŋvol
A single stage reciprocating air compressor has clearance volume 5% of the stroke volume of 0.05m3 /s. The intake conditiens are 95KN/ m2 , 300K. The delivery pressure is 720KN/ m2 . Determine Volumetric efficiency referred to:
intake conditions
Atmospheric conditions of 100KN/ m2
Free air delivered
Power required to drive the compressor.
Power required to drive the compressor
The ratio of actual to indicated power is 1.5
A three stage reciprocating compressor compresses air from 1 bar and 17°C to 35 bar. The law of compression is PV 1.25 - C. and is same for all stages of compression. Find the minimum power required to compress 15m3 /min of free air . Also find intermediate pressure. Assume perfect intercooling and neglect clearance.
A two stage single acting reciprocating air compressor with perfect intercooling with suction pressure of 1 bar and 25°C. Find pressure is 5 bar. Compression and expansion follows the law PV 1.3 - C. Find per Kg of air
Work done
Mass of H2O required for cooling the air temperature raise is 30°C
What is the percentage saving is work by compressing air in 2 stages from 1 bar to 6 bar instead of in 1 stage. Assume compression index is 1.3 and intercooling restored air to its original temperature.
A two stage compressor with complete intercooling delivers 5 kg/min of air at 15bar. Assuming intake state are 1 bar and 15°C and ŋ value for compression and expansion is 1.3. Calculate the power required and ŋisothermal. The speed of compressor is 420rpm. Assuming C is 5% and 6% for low pressure and high pressure cylinder respectively. Find the swept and clearance volume for both the cylinders.
A two stage double acting air compressor operating at 200rpm takes air at 1.013 bar and 27°C the size of LP cylinder is 350 X 380mm. The stroke of HP is same as that of LP. Both the cylinders have clearance ratio of 4%. The LP cylinder discharge air at a pressure of 4.052 bar. The air passes through intercooler so that is enters HP cylinder at 27°C and 3.85 bar. Finally it is discharge at 15.4 bar, n=1.3. Find :
Heat rejected in intercooler
Dia of HP cylinder
IP of HP cylinder
A two stage air compressor delivers 2m3 of free air per minute. The temperature and pressure of air at suction is 27°C and 1bar. Pressure at delivery is 15 bar clearance us 5% if respective stroke both in LP and HP cylinder. Assuming perfect intercooling. Find the minimum power required to run the compressor at 200rpm. Also find dia and length assuming strokes of both cylinder are equal to dia of LP cylinder.
UNIT IV
Steam expands from 3 bar to 1 bar is a nozzle. The intial velocity and temperature are 90m/s and 150°C. The nozzle efficiency is 95% . Determine the exit velocity.
The inlet conditions of steam to a convergent divergent nozzle is 2.2 MN/ m3 and 260°C. The exit pressure is 0.4MN/ m3. Assuming frictionless flow upto throat and ŋnozzle is 85%. Determine
flow rate for throat are of 32c m2
exit area
The inlet conditions of a steam nozzle are 10 bar, 250°C. The exit pressure is 2 bar Mass flow rate is 0.2kg/s. Assuming isentropic expansion and negligible inlet velocity. Determine
throat area
Exit area
A day saturated steam at 2.8 bar is expanded through a convergent nozzle 1.7bar. Exit area is 3cm2 . Estimate the exit velocity and mass flow rate. Assuming
Isentropic expansion
Super saturated
Super saturated expansion is a nozzle is supplied with steam at 2MN/m2. for flow rate of 450kg/min. Determine.
throat and exit area
Degree of under cooling at exit
1Kg, of air is taken to a diesel cycle. Intially the air is at 25° C and 1 bar. Compassion ratio is 14 and the heat added is 1850 KJ. Calculate cycle efficiency.
A diesel engine working on gas std. cycle takes air at 1 bar and 25° C. Specific volume of air at inlet at 0.8m3 /Kg. Compression ratios is 14 and heat is added at constant pressure is equal to 840KJ/Kg. Find cut off ration and air std. efficiency.
A gas std. diesel cycle has a compression ratio of 12 and cut off takes place at 5.5% of stroke . Calculate air std. efficiency.
Estimate the loss in air std. efficiency for a diesel cycle engine of compression ratio 14 when the cut off changes from 6% to 13% of stroke.
Determine the air std efficiency of diesel cycle . If the compression ratio is 14. Heat is supplied upto 5% of stroke.
Compression ratio is increased from 14 to 18 cut off is adjusted to give the same air std. efficiency. Find the change in cut off?
In an ideal constant volume cycle, pressure, temperature and volume at the beginning of the cycle are 1.2bar, 35° C and 0.5 m3 . At the end of compression stroke, pressure is 12 bar and 315KJ/Kg. heat is added. Calculate pressure, temperature and volume at all points. Find air std. efficiency.
An engine working on an ideal air std. diesel engine has the compression ratio 15 and heat transfer 140KJ/Kg. Find pressure and temperature at the end of each process. if inlet conditions are 280K and 1.1 bar. Find air std. efficiency.
In an engine working on diesel cycle, the ratio of weights of air and fuel supplies is 50:1. The temperature of air at beginning of combustion is 333K and compression ratio used in 14:1 what is the ideal efficiency of the engine for calorific value of fuel used is 4200KJ/Kg. Assume Cp =1.004KJ/Kg°K and Cv =0.717KJ/Kg°K.
In the oil engine working on dual cycle heat supplied at constant pressure is twice that of heat supplied at constant volume Rc and Re are 8 and 5.3. Pressure and temperature at inlet are 0.93 bar and 27°C. Find efficiency of cycle. Take Cp =1.005KJ/Kg°K and Cv =0.718KJ/Kg°K.
A dual combustion air std. cycle has a compression ratio of 10. The constant pressure part of combustion takes place at 40 bar. The highest and lowest temperature of cycle are 1727° and 27°C. the pressure at the beginning of compression is 1 bar. calculate.
Pressure and temperature of all points.
Heat supplied at constant pressure
Heat supplied at constant volume
Heat rejected
An std. efficiency
UNIT II
The following details were noted in a test on a four cylinder 4 stroke engine
Dia meter – 100mm;
Stroke – 120mm;
Speed of engine – 1600rpm;
Fuel consumption – 0.2Kg./min;
Calorific value - 44000KJ/Kg;
Difference in fusion on either
side of the brake pulley - 40kgf;
Brake circumference - 300cm;
Calculate brake thermal efficiency
Mechanical efficiency - 80%;
Also find indicated thermal ŋ
Also find indicated mean effective pressure brake specific flow consumption
An 8 cylinder 4 stroke engine of 0.9m bore and stroke of 0.08m with compression ratio of 7 is tested at 4500rpm and dynamometer which has 0.54 arm. During a 10 minute test the dynamometer scale been reading was 42 kgf and engine consume 4.4kg of gasoline having a calorific value of 44000KJ/kg. Air at 300k and 1 bar was supplied to carburetor at the rate 6kg/min. Find
Brake power delivered
Brake mean effective pressure
Brake specific fuel consumption
Brake thermal efficiency
Volumetric efficiency
Air fuel ratio
During a test on single cylinder 4 stroke oil engine the following data were obtained
Stroke volume - 0.0227m3
Mean effective pressure - 5 bar
Engine speed - 4000 rpm
Brake torque - 67.6Nm.
Fuel used per hour - 37.3 Kg.
Calorific value of fuel - 43000Kj/Kg.
Calculated
indicated power,
brake power,
indicated thermal efficiency,
brake thermal efficiency
The following data relates to 4 cylinder, 4 stroke petrol engine oil, air fuel ratio by weight 16:1
Caloric value - 45.200KJ/Kg.
ŋ mech - 82%
Air std ŋ - 52%
ŋ relative - 70%
ŋ vol - 78%
Stroke by bore ratio - 1.25
Suction condition - 1 bar, 25°C
Speed - 2400 rpm
Power at brakes - 72KW
Calculate :
Rc
ŋ Ith
BSFC
Bore and stroke
4 Cylinder 4 stroke petrol engine 79mm bore, 132mm stroke develops 28.35KW brake power while running a 1450 rpm. The volume of air into the cylinder where measured at 15.5°C and 760 mm of mercury is 70% of swept volume. The air fuel ratio is 14.8. The heating value of Petrol used is 44000KJ/Kg. and the mechanical efficiency is 90%.
Find: ŋ Ith Take r = 0.287KJ/Kg°K
The following observations were taken during a test on single cylinder 4 stroke cycle engine having a bore of 300mm and stroke of 450mm.
Ambient air temperature - 22°C
Fuel consumption - 11Kg/hr
CV of fuel - 42000KJ/Kg.
Engine speed - 300rpm
Mean effective pressure - 6 bar
Net Brake load - 1KN
Brake drum diameter - 2m
Quantity of Jacket cooling water - 590 KJ/hr
Temperature of entering cooling water - 22°
Temperature of leaving cooling water - 70°C
Quantity of air as measured - 225Kg/hr
CP of exhaust gas - 1.005 KJ/kg°K
Exhaust gas temperature - 405°C
Rope radius - 2cm
Determine BP, IP, ŋmech and and draw a heat balance sheet on hour basis.
A test on a single cylinder 4 stroke oil engine having bore of 180mm and stroke of 360mm. It gave the following results.
Speed - 290rpm
Brake torque - 392 Nm
IMEP - 7.2 bar
Oil consumption - 3.5 kg/hr
Room Temperature - 21°C
Coolant flow - 270Kg/hr
Cooling water temperature raise - 36°C
Air fuel ratio - 25
Exhaust gas Temperature - 415°C
CVfuel - 45200KJ/Kg.
Take specific heat of exhaust gas as 1.005KJ/Kg°K.
Calculate:
ŋ Ith
Draw heat balance sheet in KJ/min basis.
UNIT III
A single stage reciprocating compresses taken 1m3 of air per minute at 1 bar and 15°C and delivers it at 7 bar. If the law of compression PV 1.3 - C.
Calculate the indicated power, Neglect clearance, The speed of compressor is 300rpm and stroke to bore ratio is 1.5. Calculate cylinder dimensions. Find the power required if ŋmech is 85% and ŋmotor 90%.
A single acting single stage compression is belt driver from an electric motor at 400 rpm. The cylinder diameter is 15cm and the stroke is 17.5cm. Air is compressed from 1 bar to 7 bar and law of compression is PV 1.3 - C. Find the motor power if the ŋtransmission is 97% and ŋmech is 90%. Neglect the clearance.
Free air delivery of single cylinder single stage reciprocating air compressor is 2.5m3 /min. The ambient air at STP conditions and delivery pressure is 7 bar. The clearance volume is 5% of stroke volume and law of compression is PV 1.25 - C. If L-1.2d and compressor runs at 150rpm. Determine the size of cylinder.
A single acting reciprocating air compressor has a piston dia of 200mm and stroke of 300mm and runs at 350rpm. Air is drawn at 1.1 bar and delivered at 8 bar. Law compression is PV 1.35 - C. and clearance volume is 6 % of stroke volume. Find mean effective pressure and power required to drive the compressor.
A single acting 14cm X 10cm reciprocating compressor is operating at P1 – 1bar, T1 - 20°C, P2 – 6bar, T2 - 180°C, The speed of the compressor is 1200 rpm and shaft power is 6.25 KW. Mass of air delivered is 1.7kg/min.
Calculate:
ŋvol
Isothermal work (power)
IP
ŋmech
ŋvol
A single stage reciprocating air compressor has clearance volume 5% of the stroke volume of 0.05m3 /s. The intake conditiens are 95KN/ m2 , 300K. The delivery pressure is 720KN/ m2 . Determine Volumetric efficiency referred to:
intake conditions
Atmospheric conditions of 100KN/ m2
Free air delivered
Power required to drive the compressor.
Power required to drive the compressor
The ratio of actual to indicated power is 1.5
A three stage reciprocating compressor compresses air from 1 bar and 17°C to 35 bar. The law of compression is PV 1.25 - C. and is same for all stages of compression. Find the minimum power required to compress 15m3 /min of free air . Also find intermediate pressure. Assume perfect intercooling and neglect clearance.
A two stage single acting reciprocating air compressor with perfect intercooling with suction pressure of 1 bar and 25°C. Find pressure is 5 bar. Compression and expansion follows the law PV 1.3 - C. Find per Kg of air
Work done
Mass of H2O required for cooling the air temperature raise is 30°C
What is the percentage saving is work by compressing air in 2 stages from 1 bar to 6 bar instead of in 1 stage. Assume compression index is 1.3 and intercooling restored air to its original temperature.
A two stage compressor with complete intercooling delivers 5 kg/min of air at 15bar. Assuming intake state are 1 bar and 15°C and ŋ value for compression and expansion is 1.3. Calculate the power required and ŋisothermal. The speed of compressor is 420rpm. Assuming C is 5% and 6% for low pressure and high pressure cylinder respectively. Find the swept and clearance volume for both the cylinders.
A two stage double acting air compressor operating at 200rpm takes air at 1.013 bar and 27°C the size of LP cylinder is 350 X 380mm. The stroke of HP is same as that of LP. Both the cylinders have clearance ratio of 4%. The LP cylinder discharge air at a pressure of 4.052 bar. The air passes through intercooler so that is enters HP cylinder at 27°C and 3.85 bar. Finally it is discharge at 15.4 bar, n=1.3. Find :
Heat rejected in intercooler
Dia of HP cylinder
IP of HP cylinder
A two stage air compressor delivers 2m3 of free air per minute. The temperature and pressure of air at suction is 27°C and 1bar. Pressure at delivery is 15 bar clearance us 5% if respective stroke both in LP and HP cylinder. Assuming perfect intercooling. Find the minimum power required to run the compressor at 200rpm. Also find dia and length assuming strokes of both cylinder are equal to dia of LP cylinder.
UNIT IV
Steam expands from 3 bar to 1 bar is a nozzle. The intial velocity and temperature are 90m/s and 150°C. The nozzle efficiency is 95% . Determine the exit velocity.
The inlet conditions of steam to a convergent divergent nozzle is 2.2 MN/ m3 and 260°C. The exit pressure is 0.4MN/ m3. Assuming frictionless flow upto throat and ŋnozzle is 85%. Determine
flow rate for throat are of 32c m2
exit area
The inlet conditions of a steam nozzle are 10 bar, 250°C. The exit pressure is 2 bar Mass flow rate is 0.2kg/s. Assuming isentropic expansion and negligible inlet velocity. Determine
throat area
Exit area
A day saturated steam at 2.8 bar is expanded through a convergent nozzle 1.7bar. Exit area is 3cm2 . Estimate the exit velocity and mass flow rate. Assuming
Isentropic expansion
Super saturated
Super saturated expansion is a nozzle is supplied with steam at 2MN/m2. for flow rate of 450kg/min. Determine.
throat and exit area
Degree of under cooling at exit
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