Steam enters an adiabatic turbine at 10 MPa and 500°C and leaves at 10 kPa with a quality of 90 percent. Neglecting the changes in kinetic and potential energies, determinethe mass flow rate (kg/s) required for a power output of 5 MW.

The value of mass flow rate from the turbine = 5.224

Explanation:

Turbine entrance pressure = 10 M pa

Turbine entrance Temperature ( ) = 500 °c = 773 kelvin

Turbine outlet pressure = 10 k pa

Quality at exit = 0.9

Specific heat for the steam = 2.108

From the steam table the temperature at pressure = 10 k pa of saturated liquid vapour steam is calculated. it is the exit temperature  .

⇒ Turbine exit Temperature ( ) = 46  °c = 319 kelvin

Power output of turbine ( )= 5 MW = 5000 KW

We know that Power output of turbine is given by = m × × ( - )

Put all the values in the above formula we get,

⇒ 5000 = m × 2.108 × ( 773 - 319 )

⇒ m = 5.224

This is the value of mass flow rate from the turbine.