Steam enters a turbine operating at steady state at 6 mpa, 600°c with a mass flow rate 125 kg/min and exits as a saturated vapor at 20 kpa. the turbine produces energy at a rate of 2 mw. kinetic and potential energy effects are negligible. the rate of heat loss from the turbine occurs to the air around the turbine at 27°c. a. what is the rate of entropy production for within the turbine? b. what is the isentropic efficiency of the turbine?

The rate of entropy production for within the turbine is 0.441 kJ/kgK

The Isentropic efficiency of the turbine is 80.76%

Explanation:

Given:

= 6MPa

=

= 3660kJ/kg

= 7.17Kj/kgK

= 20kPa

= 1

= 7.91kJ/kgK

= 2610kJ/kg

Isentrophic properties of stream

= 20kPa

=s_1

=7.17Kj/kgK

= 2360kJ/kg

Entropy generation of the stream:

=>

=>    

=>

=>

=>

=>

=> -0.299+(0.74)

=>0.441 kJ/kgK

Isentrophic efficeny of the turbine

=>

=>

=>

=>0.8076

=>80.76%

1.6 g

Explanation:

Use the formula: W =  m× g

       ∴ g =  W / m

Here, W = 128N

         m = 80 Kg

     ∴ g = 128 ÷ 80

           = 1.6 N (Ans)