The present paper discusses gas turbine operating ranges of values of controlling cycle parameters for maximum first law efficiency , second law efficiency II, and work output wnet. Three cycles have been studied: simple cycle, recuperative cycle and general open cycle. Correlation equations relating maximum values of I, II and wnet to controlling parameters (compressor and turbine efficiencies, maximum cycle temperature, isentropic temperature ratio, fuel/air ratio, heat exchanger effectiveness and pressure drops in combustion chamber and heat exchanger) have been determined and discussed.

The present paper reveals that cycle performance parameters I , II and wnet…. drastically depend on cycle controlling parameters. There is no narrow region of values of controlling parameters that produce concurrent maximum values of I , II and wnet . The maximum cycle temperature for the three cycles considered has a linear effect on I. , while other controlling parameters have nonlinear effects on I , II and wnet. For the general open cycle, the pressure drops Pcc and Pex have equal decreasing effects on I , II and wnet., while, both the fuel/air ratio f and heat exchanger effectiveness X have equal increasing effect on these performance parameters. The present correlation equations, augmented with other experimental and detailed design studies for each of the cycle units could provide good basis for the realistic design process of actual turbines.