Study of the flow and cooling performance for a high-load rotor blade tip with converging slot holes

The cavity tip is considered an efficient and reliable geometric design for blade tips, capable of reducing leakage loss and thermal load on heavy-duty gas turbine blades. After verifying the accuracy of the numerical method, this study focuses on several key aspects. Firstly, the cooling characteristics of the mid-arc nine-converging slot hole configuration under different blowing ratios are investigated. Then, based on the flow characteristics in the blade tip region, five schemes with varying converging slot hole outlet angles are proposed, and the cooling performance of each structure is analyzed. Finally, the most effective variable-angle converging slot hole configuration is combined with the optimal hole layout to achieve the best possible cooling performance in the blade tip area. The results show that, compared with cylindrical holes, converging slot holes can significantly improve the film formation capability and expand the area of high cooling effectiveness under the same blowing ratio (BR). When the angle is set to 45°, the cooling effectiveness increases by 13.54% compared to the 0° angle. Compared to the conventional mid-arc nine-hole cylindrical hole configuration, the improved layout (Case X) at BR = 1.0 increases by 34.78%.