Question

A simple twin-spool turbofan is designed for a business jet. The cruise design point for a Mach number of 0.75 ans altitude of 12,500m (Ta=216.7K, Pa=0.1793bar, a=295.1m/s) is as follows:

Airflow 9.6kg/s

Bypass ratio 3.8

Fan pressure ratio 1.7

Compressor pressure ratio 7.9

Turbine inlet temperature 1220K

Polytropic effciency (all) 0.90

Combustion pressure loss/compressor delivery pressure 5%

Mechanical efficiencies 0.99

Combustion efficiency 0.98

Intake efficiency 0.96

Nozzle efficiencies 1.00

Seperate exhaust are used. Calculate the thrust, fuel flow and SFC. answers [1881 N, 133.6 kg/h, 0.0711 kg/Nh]

Answer 1