The efficiency of an irreversible combined cycle at maximum specific power output

An irreversible combined cycle is used to analyse the performance of a two-stage combined heat engine system. The specific power output of the system is adopted as an objective function for optimization. The maximum specific power output and the corresponding efficiency are derived. The optimally combined conditions of two irreversible cycles are determined. Several special cases are discussed. The results obtained are compared with those of a single-stage irreversible heat engine. Moreover, it is expounded that the performance of a two-stage irreversible combined cycle may be described by an equivalent simplified cycle system and the optimal performance of an n-stage irreversible combined heat engine system is given. The aim of this research is to provide some new significant conclusions and redress some errors existing in a related investigation.