Answer to Question #309450 in Mechanical Engineering for Jhonny

Question

10. A supercritical power generates steam at 25 Mpa and 560℃. The condenser pressure is 7 kpa. Determine

the exit quality of steam if it expands through a turbine in this power plant.

Answer 1

Solution;

From the steam table;

At 25MPa,560°C;

$s_1=7.4168kJ/kgK$

At 70kPa;

$s_f=1.192kJ/kgK$

$s_{fg}=6.286kJ/kgK$

Assuming isentropic expansion;

$s_1=s_2=s_f+xs_{fg}$

$7.4168=1.192+x(6.286)$

$x=\frac{7.4168-1.192}{6.286}=0.9903$