A simple open cycle gas turbine has a compressor turbine and a free power turbine. It develops electrical power output of 250 MW. The cycle takes in air at 1 bar and 288 K. The total compressor pressure ratio is 14. The turbine inlet temperature is 1500 K. The total isentropic efficiency of compressor and turbine at 0.86 and 0.89, respectively. The mechanical efficiency of each shaft is 0.98. Combustion efficiency is 0.98 while combustor pressure loss is 3% of compressor delivery pressure. The exhaust pressure loss is 0.03 bar. Alternator efficiency is 0.98. Take calorific value of fuel equal to 42000 kJ/kg, cpa = 1.005 kJ/kgK and cpg = 1.15 kJ/kgK
Calculate the following :
(i) air-fuel ratio
(ii) specific work output
(iii) specific fuel consumption
(iv) mass flow rate of air
(v) cycle thermal efficiency