Chapter 8, Problem 8.15CU

) An open type heat exchanger (feed water heater) operates at 7 bar pressure. Compressed liquid water and superheated steam at 35°C enter heat exchanger and exits as saturated liquid. As the ratio of mass flow rates of compressed liquid and superheated steam flows is 4.5/1, determine a) The temperature of superheated steam b) Entropy generation during this process in kJ/kg.pthund stam K KARIŞIM ODASI 7 bar T35°C Pe7 bar su Kızgın buhar P-7 bar su P7 bar ve x0 su n, = m, + ih, -0.222 c)

Please draw the H-S diagram.

In a gas turbine plant, the pressure ratio, through which air at 15°C is compressed, is 6. The same air is then heated to a maximum permissible temperature of 750°C first in a heat exchanger which is 75% efficient and then in the combustion chamber. The same air at 750 C is expanded in two stages such that expansion work is maximum. The air is reheated to 750°C after the first state. Determine the cycle thermal efficiency, the work ratio and the net shaft work per kg of air. The efficiencies may be assumed to be 80% and 85% for the compressor and turbine respectively.e) Air enters the compressor of a gas turbine

3. In a gas turbine power plant, the air is preheated by the exhaust gases in a heat exchanger called a regenerator. Air enters at 1 MPa, 550 K, and the mass flow rate of 900 kg / min. Heat is transferred to the air with a rate of 3500 kJ / s. While the exhaust gas enters the regenerator at 150 kPa, 800 K and leaves at 130 kPa and 600 K. Assuming the air and the exhaust gases are ignoring kinetic and potential energy effects, determine the a) the air temperature at the outlet b) the exhaust gas flow rate [Assuming that air and exhaust gas has the same Cp = 1.005 kJ/kg.K]

REFRIGERATION ENGINEERING ACTUAL VCRS

Steamenters the turbine of a vapor power plant at 600 lbf/in., 1000°F and exits as a two-phase liquid-vapor mixture at 100°F. Condensate exits the condenser at 95°F and is pumped to 600 Ibf/in.? The turbine and pump isentropic efficiencies are 90 and 80%, respectively. The net power developed is 1 MW. Determine: (a) the percent steam quality at the turbine exit. (b) the percent thermal efficiency. (c) the steam mass flowrate, in Ib/h.

Problem 1 In a Rankine Thermodynamic cycle, steam leaves the boiler and enters the turbine at 600 psia, 800 °F. The condenser pressure is 1 psia. After presenting a schematic of the problem in addition to clearly labeled and explained T-s and h-s diagrams, you are asked to determine the following: (a) Pump work required per Ibm of working fluid. Quality of fluid at turbine inlet. Work output of turbine per lbm of working fluid. Energy input to the boiler per lbm of working fluid. Heat rejection by the condenser per Ibm of working fluid. Determine the cycle thermal efficiency. (d) (e) (f)

Suppose that the regenerative heat exchanger is only 80% efficient, i.e., only 80% of theheat exhausted in step (B) is absorbed in step (D). For an ideal gas working fluid (Cv = 5/2 R, R = 8.3145 J/mol K) operating with the heat reservoirs at Th = 400 K and Tc = 300 K, determine how much work per mol of working fluid is needed to supplement the regenerative heat exchanger in step (D) and ensure that the cycle is completed. What is the new ηcycle in light of this additional work requirement? (the answer does not need to be numeric)

A power plant using a Rankine power generation cycle and steam operates at a temperature of 81.25°C in the condenser, a pressure of 5 MPa in the boiler and a maximum boiler temp of 775°C. The cycle operates at steady state with a mass flow rate of 2.5kg/s. Use the steam tables in the appendix of Sandler (p. 917 to 925). a.) Draw out the cycle, calculate the work required for the pump, the work output by the turbine, the heat into the boiler, and the heat out of the condenser. b.) What is the efficiency of this power plant? c.) If the turbine was only 89% efficient but still adiabatic (only generates 89% of the calculated work from part b), what is the overall efficiency of the cycle?