Air is contained in a piston cylinder arrangement as shown in Fig.(Refer attachment). The piston can be assumed to be massless, frictionless, and perfectly insulated. 10 kg of dry ice (solid CO2) is placed on top of the piston. The initial conditions for air inside the cylinder are P1=121 kPa, T1= 300 K. Dry ice sublimates gradually, and its mass reduces to 5 kg. Ambient air is always at room temperature (27oC) and atmospheric pressure. (Given: R=287 J/kg ·K, g = 9.8 m/s2, CP/CV for air = 1.4; Neglect all heat transfer to the dry ice block.) a)Assuming the cylinder to be perfectly insulated, calculate the specific work done for the process. b)Assuming the cylinder to be perfectly conducting, what is the heat required per unit mass of air to complete the process? c) Plot the processes described in (a) and (b) together on a P-V diagram. From this plot, which process appears to have more work? Explain.
Air is contained in a piston cylinder arrangement as shown in Fig.(Refer attachment). The piston can be assumed to be massless, frictionless, and perfectly insulated. 10 kg of dry ice (solid CO2) is placed on top of the piston. The initial conditions for air inside the cylinder are P1=121 kPa, T1= 300 K. Dry ice sublimates gradually, and its mass reduces to 5 kg. Ambient air is always at room temperature (27oC) and atmospheric pressure. (Given: R=287 J/kg ·K, g = 9.8 m/s2, CP/CV for air = 1.4; Neglect all heat transfer to the dry ice block.)
a)Assuming the cylinder to be perfectly insulated, calculate the specific work done for the process.
b)Assuming the cylinder to be perfectly conducting, what is the heat required per unit mass of air to complete the process?
c) Plot the processes described in (a) and (b) together on a P-V diagram. From this plot, which process appears to have more work? Explain.
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