Question

Steam goes through an adiabatic turbine at 2kg/s. The power created by the turbine is 1523.5 kW.Determine the isentropic efficiency of the turbine.

Entrance conditions: 3 MPa and 400°C

Exit conditions: 30 kPa

Answer 1

Using Table A-6 (Superheated water);

• at P₁ = 3 MPa and T₁ = 400^oC

h₁ = 3231.7 kJ/kg

s₁ = 6.9235 kJ/kg.K

For an isentropic process;

s₂ = s₁ = 6.9235 kJ/kg.K

Using Table A-5 (Saturated water - Pressure table);

• at P₂ = 30 kPa and s₂ = 6.9235 kJ/kg.K;

Maximum possible work is;

Isentropic efficiency of the turbine is given as;

...(Answer)