Isentropic efficiency

[danieldecko]

In gas turbine catalogues, performance characteristics of gas turbine at ISO conditions are given; such as: heat rate, exhaust temperature, exhaust pressure, pressure ratio, work output. Is there a way to calculate isentropic efficiencies of air compresor and gas turbine from these data? Or, Is there any source that states the isentropic efficincies of air compressor and gas turbine of commercially available gas turbine systems.
Thanks
DD

 

[davefitz]

Yes, the standard methods are in most Mechanical Engineer handbooks. For compressers, one useually uss the polytropic efficiency, and not the isentropic efficiency.

Another difficulty is determining what is the true value of the TiT ( turbine inlet temperature), considering the the vendors have different ways of defining this critical value. The straightforward method based on a heat and mass balance around the combustor is not correct for modern turbines that use various cooling methods for the first row of blades.