L2 slide 5: Compressor, enthalpy change and work (ENGR5003)

L2 slide 5: Compressor, enthalpy change and workFrom lectureCurrent specThird2 marks3 min

ENGR5003 Lecture 2, slide 5 (First law of thermodynamics)

Steady-flow air enters a compressor with an enthalpy of 300 kJ/kg and leaves with an enthalpy of 500 kJ/kg. Neglect changes in kinetic and potential energy. If there is no heat transfer, what is the enthalpy change in the control volume in the compressor? What is the specific work input to the compressor?

Formulas you may need

First law for steady flow (technical work): $q = \Delta h + w_t$ , with $w_t > 0$ when work is done BY the fluid (on the formula sheet)
Steady flow: nothing stored in the control volume changes with time, $dE_{CV}/dt = 0$ (learn this)

A200 kJ/kg, 200 kJ/kgB200 kJ/kg, -200 kJ/kgC0, -200 kJ/kgD0, 200 kJ/kg