Question

Steam enters with negligible velocity a well-insulated turbine operating at 

steady state at 4 MPa, 320°C. The steam expands to an exit pressure of 0.07 

MPa, a quality (dryness fraction) of 0.95 and a velocity of 90 m/s. The diameter 

of the exit is 0.6 m. Neglecting potential energy effects, find the power 

developed by the turbine in kW

Answer 1

Gives

$$P_1=4MPa,T_1=320°c,P_2=0.07Mpa, v=90m/sec$$

r=0.3m

$T_2=27°c$

Quality=0.95

$\dot{m}=Av$

$$A=\pi r^2=3.14\times0.3^2=0.2826m^2$$

$\dot{m}=0.2826\times90=25.434kg/sec$

Power

$P=\frac{dQ}{dt}$

We know that

$\dot{Q}=\dot{m}c_p∆T$

$$\frac{dQ}{dt}=25.43\times4.18(320-27)=31145.13J/sec$$

Now

$P=31.145KJ/sec$