Chapter 8, Problem 8.79P

Compute for the work steady flow.

Steam @ 500 C and 3500 kPa enters a nozzle at a velocity of 30 m/s and leaves as saturated vapor at 100 kPa, steam experiences a heat loss of 128 kg/ş to the surroundings which are at 25 C. What is the amount of entropy generation (kJ/kg.K)? Select one: A. 0.6291 B. 0.5473 C. 0.2299 D. 0.7424 E. 0.1996

Q3. 1000 kJ of heat are transferred irreversibly and isothermally at atemperature of 800 K. The temperature of surrounding is 300 K. a. What is the maximum work that can be obtained frome this isothermal heat transfer? b. What is the amount of heat that regected to the surrounding? c. What is the entropy change of the two reservoirs? d. What is the total entropy change? Ans: a. 625 kJ b. 375 kJ c.-1.2, 1.25KJ/k d. zero

7. If 10 kg/min of air are compressed isothermally from = 96 kPa and V, = 7.65 m/min to p, = 620 kPa, find the work, the change of entropy and the heat for (a) nonflow process and b) a steady flow process with v, = 15 m/s and v, = 60 m/s. Ans. (a)-1370KJ/min,-5.356 kJ/K.min; (b)-1386.9kJ, %3D min

Steam to a turbine at a mass flow rate of 1.4 kg/s, 700 kPa pressure and 400 °C enters the temperature. Steam at 100 kPa pressure and 1.4 m3/kg specific volume exits the turbine. Heat transfer from turbine to environment 50 kW, with turbine Since the boundary temperature between the environment is 70 °C, a) Find the power produced by the turbine, entropy produced in the turbine and isentropic efficiency of the turbine. Note: The changes in kinetic and potential energies will be neglected and T (K) = 273 + °C will be taken.

Given 0.603MW electrical power supplied to a boiler when the temperature of the entering water is 20 C and the exiting temperature is 89 C. The flow of.the pressured water is 2 Kg/s. There is a negligible pressure drop through this boiler and it operates at a constant pressure of 3 bars. The specific heat is c = 4,370 J/(Kg K).  a) Calculate the total rate of entropy production b) Calculate the total rate of exergy destruction (W). The dead state temperature is 293.2 K and pressure is 1 bar. c) Calculate the mass flowrate of fuel (natural gas, CH4) required to heat the water flow to the conditions of the problem if the electrical heating device is replaced with a gas fired boiler. The high heating value (HHV) of the fuel is 50.02 MJ/kg.

Helium at 660 K expands in a turbine to 420 K during which 77 kJ/kg of heat was lost to the surroundings which are at 27 °c. The pressure across the turbine was 6.0, What is the isentropic efficiency "%"?

I have been working on this problem for a while but I need to figure out how to get the specific enthalpy when the refridgerant exits the system to find the mass flow rate of when the refridgerant exits the system but I don't know how to do this

A 5 m3rigid tank has propane at 500 kPa, 700 K and connected by a valve to another tank of 0.7 m3with propane at 350 kPa, 600 K. The valve is opened and the two tanks come to a uniform state at 350 K. What is the final pressure?For propane R = 0.1886 kJ/kgK