Problem 9.011 si consider a modification of the air-standard otto cycle in which the isentropic compression and expansion processes are each replaced with polytropic processes having n = 1.3. the compression ratio is 8 for the modified cycle. at the beginning of compression, p1 = 1 bar and t1 = 310 k. the maximum temperature during the cycle is 2200 k. determine: (a) the heat transfer and work in kj, for each process in the modified cycle. (b) the thermal efficiency. (c) the mean effective pressure, in bar.

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.