The power output versus efficiency characteristics of an irreversible turbine

SYNOPSIS On the basis of Bejan's model of an irreversible turbine, the dissipative losses resulting from friction are described by using two different methods. The power output and efficiency are maximised with respect to the flow rate. The characteristic curves of the system are presented for a set of given parameters. The optimal operating regions of some important parameters are determined. Analytical expressions of the main parameters are derived under some approximate conditions. The results obtained here may be used to analyse the performance of real turbines affected by different friction laws.