Session: 12-02: End-wall and Tip Film Cooling

Paper Number: 152333

Effect of Suction Side Squealer Tip Height on Blade Tip Film Cooling in a Transonic Cascade 

Several studies have identified that using a suction side squealer on the blade tip is beneficial for reducing leakage flow while achieving a comparable film cooling effectiveness to a full squealer. The suction side squealer increases the local pressure on the tip, and leakage through the gap is reduced. This study investigates the effect of squealer height on tip leakage flow and film cooling effectiveness. At a given tip gap (1.6% of the 138 mm blade height), two different heights (1.84% and 3.68%) of a suction side squealer were tested with various coolant mass flow rates (MFR = 0.079%, 0.118%, and 0.157%) and density ratios (DR = 1.0, 1.5, and 2.0). The experiment was conducted in a 3-blade cascade wind tunnel under transonic conditions, controlling the outlet Mach number to 0.75. Pressure Sensitive Paint (PSP) was applied to the middle test blade to measure the film cooling effectiveness. Additionally, the local static pressure distribution at the tip surface, measured by the PSP, was used to estimate the tip leakage flow. The test results distinctly present the difference in the tip surface static pressure, resulting in variations in tip leakage flow for the two configurations of the suction side squealer. Moreover, compared to the previous study, the current configuration also demonstrates the positive effect of cooling hole location on the film cooling effectiveness at the tip surface.

Keywords: film cooling, blade tip leakage flow, squealer, blowing ratio, density ratio, transonic, PSP technique

Presenting Author: Ming-Feng Yeh Texas A&M University

Presenting Author Biography: Ming-Feng, Yeh received both his Bachelor’s and Master’s degrees in Mechanical Engineering from Taiwan. In 2021, he was honored with a full scholarship from the Taiwanese government to pursue his doctoral degree at Texas A&M University. Currently, he is researching in the turbine heat transfer laboratory, focusing on innovative cooling techniques for turbine blades. Upon obtaining his Ph.D., he plans to return to Taiwan to contribute to the academic field.

Authors:

Ming-Feng Yeh Texas A&M University
Lesley Wright Texas A&M University
Je-Chin Han Texas A&M University