A new analysis of recuperative gas turbine cycles

Abstract

It is shown that the classical recuperator effectiveness is not an appropriate evaluation criterion for the gas turbine recuperator or a suitable independent thermodynamic parameter of the recuperative gas turbine cycle. Another parameter—the average heat transfer temperature difference in the recuperator—is recommended as the new criterion instead of the recuperator effectiveness. Therefore, the original classical analysis results of the recuperative gas turbine cycle are also inappropriate and it is necessary to give a new analysis. In this paper, the analytical expressions of the simple recuperative cycle efficiency and the optimum pressure ratio based on the new criterion are derived from general simplified assumptions. Some typical calculation results are also presented. With this new criterion, the optimum pressure ratio values for efficiency of a simple recuperative gas turbine cycle do not vary very much with the temperature ratio and are approximately equal to 3, much lower than the figures generally recognized before. A similar analysis for the recuperative gas turbine cycle with intercooler and reheater and an analysis ensuring approximately constant recuperator heat transfer area per unit power output are given also.