Process 1 - 2: Adiabatic compression from P1 = 50 psia, V1 = 3.0 ft3 to V2 = 1 ft3 along a path described by :
Process 2 - 3: Constant volume.
Process 3 - 1: Constant pressure with U1 - U3 = 46.7 Btu.
There are no significant changes in kinetic or potential energies in any of these processes.
a.) Sketch this cycle on a PV Diagram.
b.) Calculate the net work for the cycle in Btu.
c.) Calculate the heat transfer for process 2-3.
6 comments:
Am I correct to ignore the hat on PV^1.4 = C? I'm not sure if it would shift any pressures calculated from it by some factor, but I don't think the problem gives us any more info to speculate on a mass.
Parwiz,
Multiply through the eqn by the mass within the system. Because mass = constant, the resulting eqn is P V = constant ( a new constant, but still a constant) !
when we multiply pressure and volume we get the units of pound force*ft, how do we convert this to Btu?
SC:
Look up the unit conversion for ft-lbf to Btu in the back of the book.
For part c. did you want us to find Q23 or Q31? You gave us the data for delta U31, and the value I got for Q31 was around 65 Btu, which matches the answer you gave us in class.
George:
I gave you Q31 in class, but I want you to find Q23.
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