Chapter 6, Problem 6.87P

Air within a piston–cylinder assembly, initially at 50 lbf/ in.2, 510°R, and a volume of 6 ft3, is compressed isentropically to a final volume of 0.5 ft3. Assuming the ideal gas model with k = 1.4 for the air, determine the: (a) mass, in lb. (b) final pressure, in lbf/in.2(c) final temperature, in °R.(d) work, in Btu.

C6 no.4

Refrigerant 134a at p1 = 30 lbe/in?, T1 = 40°F enters a compressor operating at steady state with a mass flow rate of 400 Ib/h and exits as saturated vapor at p2 = 160 Ib/in?. Heat transfer occurs from the compressor to its surroundings, which are at To = 40°F. Changes in kinetic and potential energy can be ignored. The power input to the compressor is 4 hp. Determine the heat transfer rate for the compressor, in Btu/hr, and the entropy production rate for the compressor, in Btu/hr.°R.

Refrigerant 134a at p1 = 30 lbf/in2, T1 = 40°F enters a compressor operating at steady state with a mass flow rate of 350 Ib/h and exits as saturated vapor at p2 = 16O Ib/in?. Heat transfer occurs from the compressor to its surroundings, which are at To = 40°F. Changes in kinetic and potential energy can be ignored. The power input to the compressor is 3.5 hp. Determine the heat transfer rate for the compressor, in Btu/hr, and the entropy production rate for the compressor, in Btu/hr.°R.

A divider separates 1 lb mass of carbon monoxide (CO) from a thermal reservoir at 150o F. the carbon monoxide, initially at 60o F  and 150 lbf/in2, expands isothermally to a final pressure of 10 lbf/in2 while receiving heat transfer through the divider from the reservoir. The carbon monoxide can be modeled as an ideal gas. (a) For the carbon monoxide as the system, evaluate the work and heat transfer, each in Btu and the amount of entropy produced, in Btu/oR. (b) Evaluate the entropy production, in Btu/oR, for an enlarged system that includesthe carbon monoxide and the divider, assuming the state of the divider remains unchanged. Compare with the entropy production of part (a) and comment on the difference.

One kg of an ideal gas (gas constant R = 287 J/kg.K) undergoes an irreversible process from state-1 (1 bar, 300 K) to state -2 (2 bar, 300 K). The change in specific entropy (52 - s1) of the gas (in J/kg. K) in the process is

2 kg of water vapor in a piston-cylinder assembly expands at a constant pressure of 300 kPa (3.0 Bar) from a saturated vapor state to a volume of 2.064 m³. a. Determine the initial temperature, in °C b. Determine the final temperature, in °C C. Determine the work for the process, in kJ. Water p= constant = 3.0 bar V22.064 m³ m = 2 kg State 1-2: Isochoric Process

Air within a piston-cylinder assembly, initially at 15 Ibf/in.?, 510°R, and a volume of 6 ft°, is compressed isentropically to a final volume of 1.75 ft³. Assuming the ideal gas model with k = 1.4 for the air, determine the: (a) mass, in Ib. (b) final pressure, in Ibf/in.2 (c) final temperature, in °R. (d) work, in Btu.

A piston–cylinder assembly fitted with a slowly rotating paddle wheel contains 0.17 kg of air, initially at 300 K. The air undergoes a constant-pressure process to a final temperature of 400 K. During the process, energy is gradually transferred to the air by heat transfer in the amount 12 kJ.Assuming the ideal gas model with k = 1.4 and negligible changes in kinetic and potential energy for the air, determine the work done by the paddle wheel on the air and by the air to displace the piston, each in kJ.