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A counter flowing heat exchanger cools air at 600 K, 400 kPa to 320 K using a supply. Find the water exit temperature and the power out of the heat engine(s).
Find the change in exergy of the disk and the energy depletion of the car's gas tank due to this process alone.
A compressor brings a hydrogen gas flow at 500 R, 1 atm up to a pressure of 10 atm. How hot is the exit flow, and what is the specific work input?
Find the final mass, the temperature T2, the final pressure P3, the heat transfer 1Q3, and the total entropy generation.
Helium gas enters a steady-flow expander at 120 lbf/in.2, 500 F and exits at 18 lbf/in.2. Calculate the power output of the expander.
Power input to the pump is 3 Btu/s. Assuming the pump process to be reversible, compute the pump exit pressure and temperature.
Compute the heat transfer to the tank and show that this process does not violate the second law.
The isentropic efficiency may be assumed to be 90%. What pressure and temperature are required in the line upstream of the nozzle?
The inlet temperature is 1800 R, and it exhausts to the atmosphere. Find the required inlet pressure and the exhaust temperature.
Air from a line at 1800 lbf/in.2, 60 F flows into a 20-ft3 rigid tank that initially contained air. What is the net entropy change for the overall process?
A nozzle involves no actual work; how should you then interpret the reversible work? Can entropy change in a control volume process that is reversible?
Analyze an example with respect to the power input and the air it can deliver to the engine and estimate its isentropic efficiency if enough data are found.
Study the turbine power output per unit initial mass, m1as a function of the pressure, P2.
Investigate the work input as a function of the pressure between the two stages, assuming the intercooler brings the air down to 50oC.
Also, find the time it will take to charge the system from startup and its continuous supply capacity.
In a turbine, what is the source of exergy? In a pump, what is the source of exergy? In a pump, what gains exergy?
How much entropy was generated in the throttling of the steam through the vent to 100 kPa when half of the original mass escaped?
Find the mass that escaped, the heat transfer, and the entropy generation, not including that made in the valve.
Assume the process is adiabatic and find the final mass, the final temperature, and the total entropy generation.
Find the two source mass flow rates and the total rate of entropy generation by this setup.
The inlet is at 200oC and the exit is at 40oC. Assume the heat transfer is to the ambient at 20oC and find the specific entropy generation.
Find the specific entropy generation in each of the two compressor stages. Find the flow rate of the water and the entropy generation in this intercooler.
Ammonia is brought from saturated vapor at 300 kPa to 1400 kPa. Find the compressor specific work, entropy generation, and its isentropic efficiency.
A gas turbine with air flowing in at 1200 kPa, 1200 K has an exit pressure of 200 kPa. Find the lowest possible exit temperature.
The heat exchanger is very long, so the two flows exit at the same temperature. Find the exit temperature by trial and error.