Experimental study on enhanced swirl-film composite cooling of turbine blade leading edge

To enhance the cooling performance of the turbine blade leading edge， a novel leading-edge swirling-flow film cooling scheme combining internal ridged surfaces and offset jets is proposed. Using steady-state infrared thermography， experimental studies investigate the heat transfer and pressure loss characteristics of impingement-film cooling， swirling-flow film cooling， and ridged swirling-flow film cooling， focusing on the influence of blowing ratio on cooling performance. The results show that， under the same blowing ratio， the ridged swirling-flow film cooling achieves the highest overall cooling efficiency. The ridged structure significantly enhances internal heat transfer and optimizes the distribution of coolant on the blade’s leading edge， thereby substantially improving the film cooling efficiency. Compared to impingement-film cooling， within the studied parameter range， the overall average cooling efficiency of the leading edge increases by 3.4%~3.9% and 6.5%~8.5% for smooth and ridged swirling-flow film cooling， respectively， while the coolant pressure loss for swirling-flow film cooling reduces by up to 2.2%.