Effects of transverse divider wall within the squealer cavity on the performance of a novel squealer tip with rail crown holes for the gas turbine blade

Abstract

The squealer tip with rail crown holes is a novel design that offers superior overall performance, effectively enhancing tip cooling and controlling leakage flow in turbine blades. In this study, the transverse divider wall is added to the squealer cavity further to explore the potential advantages of this novel blade tip structure. This study aims to investigate the influence of the position and number of the divider walls on the blade tip performance. Numerical results show that the hindrance effect of the divider wall significantly enlarges the range of the cavity coolant, which enhances the coolant reattachment on the cavity floor and reduces the leading-edge high heat transfer coefficient (h). After cavity flow strides over the divider wall, it inclinedly impacts the rear cavity floor, forming a reattachment line (RL), which increases both the film cooling efficiency (η) and h behind the divider wall. As the divider wall shifts backward, the h near the leading-edge RL gradually increases, and the low-η region of the suction-side corner is expanded. As the divider wall number increases, the second utilization of the coolant within the cavity is improved, compared with Baseline, the $\bar{\eta }$ in case with three divider walls is improved by about 59.13 %. The flow structure near each divider wall is similar, simultaneously, the downstream divider wall can promote coolant attachment near the adjacent upstream divider wall. In aerodynamic aspect, the position and number of the divider walls minimally influence the total leakage flow rate (LFR), but they exert a notable effect on the LFR distribution along streamwise. In general, upstream of the divider wall, the LFR is significantly diminished, but the reduced leakage is compensated downstream of the divider wall, resulting in an overall constant total leakage.