1 A vapor power plant operates with water as the working fluid, passing through the cycle at a flow rate of 12 kg/s. In the condenser, at constant pressure of 7 kPa, the water goes from a quality of 90% to saturated liquid state. The condenser uses a flow of cooling water to remove the heat from the working fluid water - the cooling water enters at 20°C and leaves the condenser at 35°C. What is the flow rate of the cooling water in the condenser? You may assume that the cooling water is incompressible, and is at atmospheric pressure = 100 kPa.
2. Answer the following as True or False, with a brief explanation:
(a) The change of entropy of a closed system is the same for every process between two specified states.
(b) The entropy of a fixed amount of an ideal gas increases in every isothermal compression process where V2 < V1.
(c) Wmint. rev.=-iev*dp is valid all the time, not just in certain situations.
3. A vapor power cycle is developed based on the Carnot cycle - not the Rankine cycle. Water is the working fluid, and the cycle operates at steady state. Saturated liquid enters the boiler at 16 MPa, and saturated vapor enters the turbine. The pressure in the condenser is 8 kPa. The mass flow rate of steam entering the turbine is 120 kg/s.
find:
(a) the thermal efficiency
(b) the back work ratio (bwr)
(c) the net power developed
4. Air at 300 K and 100 kPa enters a compressor, operating at steady state, and is compressed adiabatically to 150 kPa. The power input per mass flow rate (Wm) is 42 kJ/kg. For this analysis, assume that the ideal gas law applies, and that the specific heat ratio k is 1.4. Determine:
(a) the rate of entropy production per mass flow rate in kJ/kg*K
(b) the isentropic efficiency of the compressor
5. What was the big deal about the tsunami in Japan in 2012 and its effect on the Fukushima Nuclear Power Plant?