Consider two types of steady-state expansion/throttling devices for ammonia: (1) a rigid valve & (2) a turbine that is used for power recovery (isentropic efficiency of turbine is 70%). In both cases, ammonia enters a device (valve/turbine) as a saturated liquid at 7 bar with a mass flow rate of 0.06 kg/min, and leaves a device at 1 bar. Also, both devices (valve/turbine) are perfectly thermally insulated. Find the following:
1. State your assumptions/observations
2. Draw the actual process for valve & turbine on T-s diagram
3. Enthalpy at the exit of the valve (in kJ/kg) h_2?
4. Rate of entropy production (in kW/K) for valve sigma_v?
5. Maximum possible power output of turbine (in kW) W_T,max
6. Actual power output of turbine (in kW) W_T,actual