Thermodynamic Modeling of Gas Turbine Blade Cooling

Gas turbines are widely used in various industries and the thermal modeling of this equipment is of primary interest to predict its operating condition. One of reasons for deviation of numerical values obtained for actual gas turbine performance and the results obtained from thermal modeling is the effects of blade cooling. In this paper, three blade-cooling models are studied. The first one is the El-Masri continuous model which later modified by Bolland and De Paepe. The Jordal stage-by-stage model and Walsh & Fletcher model are the second and third blade cooling models studied here. The amounts of cooling air mass flow rates estimated by three models are compared for various values of compressor pressure ratios and turbine inlet temperatures for gas turbines in various ranges of power outputs. Furthermore the deviation of key performance parameters predicted by using the above blade cooling models from the actual (reported) corresponding values, was analyzed. It was found that for all three above blade cooling models the deviation was less than three percent for various classes of gas turbines.