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Abstract The design of rotor tips is facing increasing challenges due to higher turbine inlet temperatures and blade loads. To tackle these issues, this study proposes a novel solution that integrates a circumferential casing groove (CG) configuration with a squealer tip. The CG is parameterized and integrated with an efficient global optimization algorithm, establishing an aerothermal optimization framework for the turbine rotor tip. Taking the stage efficiency and tip heat transfer coefficient as the optimization objectives, multiple representative optimized solutions for the CG configuration are obtained. The results demonstrate that the optimal solution aimed at maximizing stage efficiency achieves a superior trade-off in aerothermal improvement. Quantitatively, it increases the stage efficiency by 0.41% and decreases the tip and casing heat transfer coefficients by 7.06% and 7.75% respectively, while only slightly increasing the blade heat transfer coefficient. This improvement in aerothermal performance can be attributed to the CG’s ability to control tip leakage flow and regulate the topology of the tip vortex system. Besides, a global sensitivity analysis is employed to identify the key geometric parameters of CG. The starting point of the CG is found to be the most crucial parameter and its influence laws are investigated through a variable-controlling methodology. In summary, the proposed CG configuration and optimization strategy offer a promising solution to diminish tip leakage losses and enhance the thermal performance of turbine rotor tips.
Li et al. (Mon,) studied this question.