Chapter 7, Problem 7.3E

A heat exchanger enters a mass flow of 100 / b / s of water at 30psia and 100 ° F and exits at 200 ° F. The heat supplied to the water stream comes from a stream of hot air that enters at 1000R and 45psia and exits at 680R. Considering that the ambient temperature is 520R. Determine: Ans: a) The exergy variation of the water current. b) The exergy variation of the air stream. c) The total irreversibility of the heat exchange process d) The exergy efficiency of the heat exchanger

Define the exergy destruction, which is the wasted work potential during a process as a result of irreversibilities.

10. Carnot cycle thermal efficiency is increased by reducing lower(sink) temperature 11. A system with higher exergy has more capacity to do work than a system with lower exergy. 12. A diffuser has low pressure at inlet and high pressure at outlet 13. Carnot efficiency equation can also be used to find efficiency of conversion of electrical and/or magnetic energy to work. 14. Quality factor of 0.75 indicates supersaturated vapor 15. Law of conservation of Mass and energy applied to Nozzles and Diffusers indicates that under ideal conditions, the change in kinetic energy of the fluid results in a complimentary change in enthalpy of the fluid

The turbine section of a Brayton cycle gas turbine receives the hot compressed air at 150 psia and 2100 °R, expand it to 15 psia and develops a gross output of 15,000 hp. Air enters the compressor at 500 R. Determine a) mass of air required,  lb/s, b) compressor power required, c) net power output, and d) cycle efficiency. Show pV and Ts diagram. (THERMODYNAMICS 2)

As in mechanical systems, friction in the workplace is bound to generate entropy and reduce performance.

A closed system undergoes a cycle consisting of three process 1-2, 2-3 and 3-1.  Given that Q12 = 30kJ, Q23 = 10 kJ, 1w2 = 5 kJ, 3w2 = 5 kJ and DE31 = 15 kJ, Evaluate Q31, w23, DE12 and DE23.

Q1. Heat engines convert internal energy to mechanical energy. Describe the operation of this reversible engine on a PV diagram and show how to determine the efficiency of the cycle.

Air enters a diesel engine with a density of 1.0 kg/m³. The compression ratio is 21. At steady state, the air intake is 30 x 10-3kg/s and the net work output is 15 kW. The mean effective pressure (in kPa)

Show that the thermal efficiency of any internal combustion engine can besimplified as a ratio of temperature differences