Performance and optimization of gas turbines with real gas effects

The influence of various levels of mathematical modelling on gas turbine pe rformance is systematically analysed. It is shown that internal combustion with real gas effects gives rise to an optimum turbine entry temperature wh ich does not arise in a perfect gas analysis and has not been described pre viously in the literature. At any pressure ratio, the maximum possible effi ciency with real gas effects is significantly lower (15-20 per cent) than t he maximum possible value predicted by a perfect gas analysis. An explicit equation has been derived for determining the optimum pressure ratio as a f unction of turbine entry temperature and component efficiencies. It is show n that the optimum design depends very strongly on turbine and compressor e fficiencies. It is demonstrated that the optimum relation between pressure ratio and turbine entry temperature depends strongly on whether the optimiz ation is carried out at fixed pressure ratios or at fixed temperatures. All previous references seem to have considered only the latter method.