A multistage high-pressure steam turbine is supplied with steam at a stagnation pressure of 7 MPa and a stagnation temperature of 500°C. The corresponding specific enthalpy is 3410 kJ/kg. The steam exhausts from the turbine at a stagnation pressure of 0.7 MPa, the steam having been in a superheated condition throughout the expansion. It can be assumed that the steam behaves like a perfect gas over the range of the expansion and that γ 5 1.3. Given that the turbine flow process has a small-stage efficiency of 0.82, determine
a. the temperature and specific volume at the end of the expansion;
b. the reheat factor.
The specific volume of superheated steam is represented by pv 5 0.231(h 2 1943), where p is in kPa, v is in m3 /kg, and h is in kJ/kg.