Multi-objective aero-thermal coupled optimization and decoupling analyses of turbine squealer tip configuration and cooling layout

To enhance the aerothermal performance of squealer tips, a high-dimensional automatic optimization framework with efficient evolutionary algorithms was implemented, which simultaneously addressed the rim and cooling layout. The approach involved a novel methodology for parameterizing the pressure and suction side tip rim, as well as introducing oval holes with compound inclination angles. The decoupled analysis of the optimized configurations demonstrates that the inwardly inclined pressure-side shoulder with an acute edge concurrently reduces the cavity bottom thermal load and leakage flow. The outwardly inclined suction-side shoulder further develops the scraping vortex scale and achieves a 12.37% reduction in leakage flow. The loss associated with the passage vortex is also attenuated; however, the variation of the leakage vortex results in an increase in leakage loss and heat exchange. The optimal cooling layout features condensed front cavity hole spacing with positive axial inclination for improved bottom cooling, while negative inclination on the rear cavity enhances film coverage at the expense of intensified jet vortex. The cooling layout optimization yields 58.44% and 4.78% enhancements in adiabatic and conjugate cooling effectiveness respectively, while maintaining baseline aerodynamic performance. Furthermore, the coupled optimization of the rim and cooling layout demonstrates an enhanced aerodynamic efficiency of 0.48%.