A dissipative Joule-Brayton cycle model

In this paper we present an irreversible model of the Joule-Brayton cycle. As is well known, the gas-turbines follow approximately this thermal cycle. Our model reproduces several characteristics of a real gas-turbine such as convex curves of power versus pressure ratio and efficiency versus pressure ratio. Typical loop-shaped curves of power versus efficiency for real heat engines are also recovered. Our model is based in a lumped friction-like term and in a parameter arising from the Clausius inequality. We also suggest a procedure for improving the power and the efficiency of the cycle.