Cooling layout optimization for a turbine blade squealer tip with the application of oval holes

Abstract

For the purpose to enhance the cooling performance of the squealer tip under stage conditions, an automatic optimization framework was constructed to optimize the cooling holes on a squealer tip, including the utilization of oval-shaped holes. The analysis of the optimization results indicates that the configuration of the cooling holes with positive axial inclination and the reduction in the arrangement interval of holes that are assembled in the front cavity can effectively enhance the film attachment, resulting in augmented film coverage and cooling effectiveness. The coefficient of heat transfer in the region between and downstream the holes is observed to decrease in accordance with the film coverage. Meanwhile, the positive axial inclination guides the jets to accumulate towards the rear of the cavity, enhancing the blocking effect to leakage flow. The film attachment is further improved as the jets outflow along the long axis edge of oval holes, which exhibit low curvature. In general, the implementation of round hole optimization has led to an increase in cooling effectiveness by 54.85 % in comparison to the benchmark. Furthermore, the use of oval holes has resulted in a greater improvement of 67.65 %. The aerodynamic performance has remained uncompromised throughout these modifications.