There is a loss of 10% of calorific value in the combustion chamber.

Question

Find the required air- fuel ratio in a gas turbine whose turbine and compressor efficiencies are 85% respectively. Maximum cycle temperature is 875⁰C. The working fluid can be taken as air (C_p=1.00 kJ/kg K, g= 1.4) which enters the compressor at 1 atm and 27⁰C. The pressure ratio is 4. The fuel used has calorific value of 42000 kJ/kg. There is a loss of 10% of calorific value in the combustion chamber.