In the analysis of gas-turbine cycles, it is becoming more important to include the impact of turbine cooling on the expansion path and on cycle performance, as the turbine inlet temperatures are raised. Different approaches have been taken to include the effect of turbine cooling on the cycle performance in various studies. In the present work, a thermodynamic model was developed for turbine cooling, based on the work by El-Masri. Validation of the model and suitable selection of a few technology description parameters were done using the data for some commercially available gas-turbine engines. These parameters were then used on performance evaluation of gas-turbine engine by systematically varying the compressor pressure ratio and turbine inlet temperature. Results obtained using the model show that development in cooling technology is an important factor in obtaining higher efficiencies and specific work outputs. The overall performance evaluation of cooled turbine also confirmed the diminishing effect of turbine cooling on cycle efficiency beyond a certain value of turbine-inlet temperature.
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