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Air is contained in a piston-cylinder device at 600 kPa
Chapter 4, Problem 77P(choose chapter or problem)
Problem 77P
Air is contained in a piston-cylinder device at 600 kPa and 927°C, and occupies a volume of 0.8 m3. The air undergoes an isothermal (constant temperature) process until the pressure is reduced to 300 kPa. The piston is now fixed in place and not allowed to move while a heat transfer process takes place until the air reaches 27°C.
(a) Sketch the system showing the energies crossing the boundary and the P-J diagram for the combined processes.
(b) For the combined processes determine the net amount of heat transfer, in kJ, and its direction.
Assume air has constant specific heats evaluated at 300 K.
Questions & Answers
QUESTION:
Problem 77P
Air is contained in a piston-cylinder device at 600 kPa and 927°C, and occupies a volume of 0.8 m3. The air undergoes an isothermal (constant temperature) process until the pressure is reduced to 300 kPa. The piston is now fixed in place and not allowed to move while a heat transfer process takes place until the air reaches 27°C.
(a) Sketch the system showing the energies crossing the boundary and the P-J diagram for the combined processes.
(b) For the combined processes determine the net amount of heat transfer, in kJ, and its direction.
Assume air has constant specific heats evaluated at 300 K.
ANSWER:
Step 1 of 4
Part (a)
The system showing the energies crossing the boundary is shown as:
The processes 1-2 (isothermal) and 2-3 (constant volume) are represented on the P-V diagram as shown below:
