Question

A modern jet engine has a temperature after combustion of about 1500 K at 3200 kPa as it enters the turbine setion, The compressor inlet is 80 kPa, 260 K state 1 and outlet state 2 is 3300 kPa, 780 K; the turbine outlet state 4 into the nozzle is 400 kPa, 900 K and nozzle exit state 5 at 80 kPa, 640 K. Neglect any heat transfer and neglect kinetic energy except out of the nozzle. Find the compressor and turbine specific work terms and the nozzle exit velocity.

Answer 1

The compressor, turbine and nozzle are all steady state single flow devices and they are adiabatic.

We will use air properties

h1 = 260.32, h2 = 800.28, h3 = 1635.80, h4 = 933.15, h5 = 649.53 kJ/kg

Energy equation for the compressor gives

wc in = h2 – h1 = 800.28 – 260.32 = 539.36 kJ/kg

Energy equation for the turbine gives

wT = h3 – h4 = 1635.80 – 933.15 = 702.65 kJ/kg

Energy equation for the nozzle give