Determine the temperature and pressure of the steam in its intermediate state between the two turbines.

A steam power plant employs two adiabatic turbines in series. Steam enters the first

turbine at 650°C and 7000 kPa and discharges from the second turbine at 20 kPa. The

system is designed for equal power outputs from the two turbines, based on a turbine

efficiency of 78% for each turbine. Determine the temperature and pressure of the

steam in its intermediate state between the two turbines. What is the overall efficiency

of the two turbines together with respect to isentropic expansion of the steam from the

initial to the final state?