Aerothermal optimization of a turbine rotor tip configuration based on free-form deformation approach

• Published in: The International journal of heat and fluid flow Vol. 110; p. 109644
• Main Authors: Tao, Zhi, Li, Weiqi, Guo, Zhendong, Chen, Yun, Song, Liming, Li, Jun
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.12.2024
• Subjects: Aerothermal optimization; Flow control; Free-form deformation; High pressure turbine; Rotor squealer tip; Free-form deformation; Flow control; Aerothermal optimization; High pressure turbine; Rotor squealer tip
• ISSN: 0142-727X
• DOI: 10.1016/j.ijheatfluidflow.2024.109644

•A novel turbine tip design approach based on the free-form deformation was proposed.•An automatic optimization flowchart for the turbine tip was established coupled with an efficient optimization algorithm.•The optimized tip design substantially enhances the turbine stage efficiency by 0.42%.•The optimized tip design demonstrates minimal impact on both tip and casing heat transfer performance. With increasing turbine inlet temperatures and blade loading, the demand for advanced flow control and thermal management for turbine tips becomes increasingly critical. This article proposes a novel squealer tip design approach based on the free-form deformation technique (FFD). Compared with the traditional winglet tip configurations, FFD-based blade tip design has high freedom and superior smoothness. Driven by an advanced large-variable optimization algorithm, an automatic aerothermal optimization framework for turbine tips is established. During the optimization, turbine stage efficiency serves as the primary objective, while tip heat transfer acts as a constraint. The results reveal that the optimized squealer tip incorporating the FFD significantly enhances the stage efficiency by 0.42% and slightly reduces the tip heat transfer level. Detailed flow and thermal analyses underscore that the aerodynamic enhancements primarily arise from the alterations of the scraping vortex, tip leakage vortex, and upper passage vortex, along with their interactions. In addition, the reduction of leakage flow from the suction side decreases the tip heat transfer level in the forward region, whereas the complete reattachment of leakage flow leads to an increase in the tip heat transfer level in the center-rear region. Overall, the FFD-based blade tip design approach and optimization strategy can provide valuable guidelines for the advancement of gas turbine rotors.