Answer
a) $\dot{m}=16.17\ kg/s$
b) $\mathcal{V}_2=680.6\ m/s$
c) $\dot{W}_s=14,560\ kW$
Work Step by Step
From tables A-4 to A-6:
Inlet ($P_1=7\ MPa, T_1=600°C$): $v_1=0.05567\ m³/kg,\ h_1=3650.6\ kJ/kg$
Outlet ($P_2=25\ kPa, x_2=0.95$): $v_2=5.8933\ m³/kg,\ h_2=2500.2\ kJ/kg$
$\dot{m}=\frac{A_1\mathcal{V}_1}{v_1}$
$A_1=0.015\ m^2,\ \mathcal{V}_1=60\ m/s$
$\dot{m}=16.17\ kg/s$
$\dot{m}=\frac{A_2\mathcal{V}_2}{v_2},\ A_2=0.14\ m^2$
$\mathcal{V}_2=680.6\ m/s$
$\dot{m}(h_1+\mathcal{V}_1^2/2)=\dot{m}(h_2+\mathcal{V}_2^2/2)+\dot{Q}+\dot{W}_s$
$\dot{Q}=20\ kJ/kg\times\dot{m}=323.4\ kJ/s$
$\dot{W}_s=14,560\ kW$
