The high pressure (HP) turbine stages of a steam power plant is designed with impulse blading and have a constant, axial leaving velocity and a rotational speed of 3.000 RPM. Superheated vapor enters the turbine at 500°C. The total pressure drop in the HP turbine is from 100 bar to 40 bar and the stage efficiency is 87%. If the mean blade radius is 50 cm and the stator leaving angle is 75°, Calculate
a) The number of HP turbine stages
b) Axial velocity
c) Relative flow angle at exit.