1. At steady state, a valve and steam turbine operate in series. The steam flowing through the valve undergoes a throttling process. At the valve  inlet,  the  conditions are 600 lbf/in.2, 8008F. At the valve exit, corresponding to the turbine inlet, the pressure is 300 lbf/in.2 At the turbine exit, the pressure is 5 lbf/in.2 The power developed by the turbine is 350 Btu per lb of steam flowing. Stray heat transfer and kinetic and potential energy effects can be ignored. Fix the state at the turbine exit: If the state is superheated vapor, determine the temperature, in 8F. If the state is a two-phase liquid-vapor mixture, determine the quality.

2. Steam at 500 lbf/in.2, 5008F enters a well-insulated valve operating at steady state with a mass flow rate of 0.11 lb/s area in which the velocity of a gas or liquid increases in the direction of flow.

(ii) The human body is an example of an integrated system.

(iii) When a substance undergoes a throttling process through a valve, the specific enthalpies of the substance at the valve inlet and valve exit are equal.

(iv) The hot and cold streams of cross-flow heat exchangers flow in the same direction.

(v) The thermodynamic performance of a device such as a turbine through which mass flows is best analyzed by studying the flowing mass alone.

(c) Answer the following true or false. Explain.

(i) For every control volume at steady state, the total of the entering rates of mass flow equals the total of the exiting rates of mass flow.

(ii) An open feedwater heater is a special type of a counterflow heat exchanger.

(iii) A key step in thermodynamic analysis is the careful listing of modeling assumptions.

(iv) An automobile's radiator is an example of a cross- flow heat exchanger.

(v) At steady state, identical  electric  fans  discharging air at the same temperature in New  York  City  and  Denver will deliver the same volumetric flow rate of air.