Effect of pressure-side squealer shape and coolant supply on tip aerothermal characteristics in a turbine blade

Overtip leakage flow (OTL), caused by a pressure difference between the two sides of the turbine blade, leads to significant aerodynamic losses and high heat loads on the blade tip. This study first investigates the impact of pressure-side squealer tip structures (conventional and inclined-shelf) on the cooling performance. Furthermore, the combined pressure-side squealer tip structures and effect of pressure-side coolant injection on the cooling and aerothermal performance of the blade tip. Using the validated RNG k-ε turbulence model, tip leakage flow behavior, cooling effectiveness and heat transfer on the tip are analyzed for various squealer tip and coolant injection configurations. Key findings show that the inclined-shelf pressure-side squealer tip directs coolant flow over the trailing-edge rib, enhancing the cooling performance of the blade tip. The combination of this squealer tip with pressure-side coolant supply achieves the greatest reduction in tip leakage flow and optimal aerodynamic performance. Thus, coupling the inclined-shelf pressure-side squealer tip with pressure-side coolant supply is proposed to improve turbine performance.