Experimental investigation of film cooling from compound angle holes supplemented by secondary holes

摘要

Gas turbine performance largely depends on the inlet temperature. Higher the inlet temperature better is the performance of the turbine which in turn may adversely affect the turbine blades. Film cooling techniques are used to protect the turbine from hot gases. In this study, secondary holes were added to the compound angle holes to improve the turbine performance by enhancing the film cooling. Four blowing ratios were considered in this study. A Baseline case with zero orientation angle and 30 degrees inclination angle was used as a reference. To analyze the film cooling effectiveness with reference to the Baseline case, four different cases (cases with 30 degrees and 60 degrees orientation angles with and without secondary holes) were studied. Thermocouples and infrared camera were used to study the effectiveness of the film cooling. Infrared camera shows its ability to capture the temperature variation in a finite area due to its high resolution. The results show that the cases with compound angle have higher effectiveness compared to the Baseline case. Also, providing secondary holes helps keep the main hole jet to move beside the test surface and results in higher effectiveness especially at high blowing ratios. (C) 2019 Elsevier Ltd. All rights reserved.