An oil engine, working on the dual combustion cycle, has a compression ratio of 13:1. The heat supplied per kg of air is 2000KJ, half of which is supplied at constant volume and the other half at constant pressure. If the temperature and pressure at the beginning of compression are 100°C and 1 bar respectively, find (i) the maximum pressure in the cycle and (ii) the percentage of stroke when cut-off occurs. Assume y-1.4, R=0.287 kJ/kg.K and CV = 0.709 + 0.000028T kJ/kg.K.

Two ideal Brayton cycles (see Figure below) have the same inlet temperature and the same maximum temperature of the turbine inlet. Brayton Cycle A has a higher compression ratio than Cycle B. Which of the following statements is true about the cycles? Cycle A has a higher thermal efficiency and Cycle B has a higher work net for a given mass flow rate.   Cycle B has a higher thermal efficiency and a higher work net for a given mass flow rate.   Since the temperatures are the same the efficiencies and work net are also the same.   Cycle A has a higher work net for a given mass flow rate and Cycle B has a higher thermal efficiency.   Cycle A has a higher thermal efficiency and a higher work net for a given mass flow rate.

In a constant volume cycle, the pressure at the end of compression is 10 times that at the start, the temperature limits are 20 ° C and 1900 ° C. Determine i. Compression ratio, ii. Thermal efficiency and iii. Work done. Take R = 287 J/kg K, y = 1.4