Effect of Microchannel on the Composite Cooling Performance of a Simulated Turbine Blade Leading Edge

As the turbine blade leading edge becomes one of the hottest regions in the engine, a microchannel structure was applied to further improve the cooling performance. Adiabatic and conjugate heat transfer analyses were conducted to compare the heat transfer and cooling performance of the leading edge with or without microchannels, while the influence of mass flowrate of coolant was also included. Based on the investigations on the effect of geometrical designs, the flow and composite cooling performance of the microchannels were further optimized. The results indicate that the internal heat transfer intensity was greatly enhanced with the arrangement of microchannels, while the adiabatic film coolant coverage was slightly deteriorated. On this basis, the composite cooling performance of the leading edge was effectively improved by at least 7.54%. However, the flow resistance of film cooling holes was obviously increased due to the obstruction of microchannels, and a larger thickness of microchannels would alleviate this feature. In addition, the composite cooling performance of the leading edge was further optimized by increasing the radius of microchannels, and the same effect was achieved by reducing the spanwise distance between the film cooling holes and the microjet holes. Compared with the leading edge model without microchannels, the former design increased the area-averaged overall cooling effectiveness of the leading edge by at least 11.17% under all the mass flow rates of coolant studied in this paper, while the latter design improved the composite cooling performance by at least 12.76%.