with the help of the indicator diagram, briefly explain the four operations of a
Carnot cycle.
Answers
The Carnot cycle consists of the following four processes:
A reversible isothermal gas expansion process. In this process, the ideal gas in the system absorbs qin amount heat from a heat source at a high temperature Th, expands and does work on surroundings.
A reversible adiabatic gas expansion process. In this process, the system is thermally insulated. The gas continues to expand and do work on surroundings, which causes the system to cool to a lower temperature, Tl.
A reversible isothermal gas compression process. In this process, surroundings do work to the gas at Tl, and causes a loss of heat, qout.
A reversible adiabatic gas compression process. In this process, the system is thermally insulated. Surroundings continue to do work to the gas, which causes the temperature to rise back to Th.
Figure 1: An ideal gas-piston model of the Carnot cycle.
Figure 1 : An ideal gas-piston model of the Carnot cycle.
P-V Diagram
The P-V diagram of the Carnot cycle is shown in Figure 2 . In isothermal processes I and III, ∆U=0 because ∆T=0. In adiabatic processes II and IV, q=0. Work, heat, ∆U, and ∆H of each process in the Carnot cycle are summarized in Table 1 .
Figure 2: A P-V diagram of the Carnot Cycle.