Effect of Jet Pulsation on Film cooling Effectiveness at the Leading Edge of a Symmetrical Turbine Blade Model

This paper investigates the effect of the pulsating film cooling at the leading edge of a symmetrical turbine blade model. Numerical finite volume method is used to resolve the Unsteady Reynolds Averaged Navier Stokes Equations coupled at turbulence model. Detailed numerical film cooling effectiveness have been made for both steady and pulsating flows. The test case blade model is symmetric and has one injection row of discrete cylindrical holes on each side near the leading edge. Jet pulsing frequencies of 5 Hz, 10 Hz, and 20 Hz have been studied. The computational domain is discretized using a highly refined multi-bloc structured grid including the plenum area. The turbulence field is resolved by use of the SST turbulence Model. The numerical simulations are conducted for three different blowing ratios of 0.3, 0.5, and 0.7; film cooling effectiveness contours on the blade surface and lateral averaged adiabatic film cooling effectiveness are presented and the continuous jet results compared with available measurements. In addition to validation data, several longitudinal and transversal contours and vector planes are reproduced. It was found mainly that pulsating for low blowing ratios, cold jet decreases the film cooling effectiveness with no effect of frequency levels.