PROBLEMS ON AIRSTANDARD CYCLES

1. An ideal Otto cycle has a compression ratio of 8. At the beginning of the compression process, air is at 100 kPa and 17°C, and 800 kJ/kg of heat is transferred to air during the constant-volume heat-addition process. Accounting for the variation of specific heats of air with temperature, determine(a) The maximum temperature and pressure that occur during the cycle,(b) The net work output, (c) the thermal efficiency, and (d) The mean effective pressure for the cycle.

2. An engine of 250 mm bore and 375 mm stroke works on otto cycle. The clearance volume is 0.00263 m3. The initial pressure and temperature are 1 bar and 50ºC. If the maximum pressure is limited to 25 bar. Find(1) The air standard efficiency of the cycle.(2) The mean effective pressure for the cycle.

3.) Air enters at 1bar and 230ºC in an engine running on diesel cycle whose compression ratio is 18. Maximum temperature of cycle is limited to 1500ºC. Compute(1) Cut off ratio(2) Heat supplied per kg of air(3) Cycle efficiency.

4. An air-standard Diesel cycle with a compression ratio of 16 and a cutoff ratio of 2 is considered. The temperature after the heat addition process, the thermal efficiency, and the mean effective pressure are to be determined.Assumptions 1 The air-standard assumptions are applicable. 2 Kinetic and potential energy changes are negligible. 3 Air is an ideal gas with constant specific heats.Properties The properties of air at room temperature are cp = 1.005 kJ/kg·K, cv = 0.718 kJ/kg·K, R = 0.287kJ/kg·K, and k = 1.4

5. A gas turbine works on air standard Bration cycle. The initial of the air is 250C and 100kPa.The maximum pressure and temperature are limited to 300kPa and 6500C Determine the following:1) The air standard efficiency of the cycle.2) Heat supplied and Heat rejected per kg of air.3) Exhaust Temperature

6. A hot air engine works on stirling cycle. The temperature and pressure limits are 300k and 600k and 1 kgf/cm2 and 10kg/cm2.Determine the thermal efficiency and mean effective pressure of cycle.

PROBLEMS ON AIRSTANDARD CYCLES

4.ANSWER