Evaluation of Aerodynamic Coefficients of High Temperature Gas Turbine Cascade of Cooled Blade


The aerodynamic force coefficients of five linear cascade of existing film coolingturbine blades are evaluated numerically. The blade is geometrically identical to thefirst rotor blades of the high pressure (HP) turbine of the F-100-PW-220 militaryturbofan. Cascade turbine blade test rig has been designed, constructed, and calibratedto introduce experimental work for the same flow conditions of the numerical solutionto validate correctness of the numerical results. The numerical simulation showsacceptable agreement with experimental. Also it was found experimentally that bothlift and drag coefficients are increased slightly with add of film cooling.The local Mach number distributions outside the boundary layer on both bladesides of the cascade blade are evaluated numerically and compared with the results ofwell known CFD code (Fine/Turbo) for existing gas turbine rotor stage of identicalblade. The computational results obtained for both cases show that the Mach numberdistributions trend along both blade sides for rotor stage and cascade are approximatelythe same, and the values of Mach number of rotor stage are higher than that for thecorresponded cascade. Also it was found that the Mach number distributions on bothblade sides are reduced in values by the addition of air cooling, and the local Machnumbers for the cascade case is reduced in values among the rotor stage for the twocases with and without film cooling on both blade sides.