Session: 12-03 Experimental techniques and scaling

Paper Number: 127088

127088 - Experimental Investigation of the Film Cooling Effectiveness Deviation Using Pressure Sensitive Paint Measurement for Different Hole Structures 

Film cooling is a crucial cooling method to ensure the operation of turbine blades under high-temperature conditions. Turbine blades operate under high-speed and complex flow conditions. During the evaluation of adiabatic film cooling effectiveness using Pressure Sensitive Paint, the substitution of the pressure field of the air-case with that of the foreign gas-case has introduced measurement deviation, when the density of two cases is different. The use of a specific ternary oxygen mixture during the test processes enables the correction of the deviation. The shaped holes widely used in turbine blade alter the mainstream-jet mixing process. Therefore, the deviation distribution generated during the PSP measurement of shaped holes is also different. The deviation of film cooling effectiveness was investigated for five kinds of film holes, including a circular hole, a hole with a 45-degree compound angle, double jet ejection, a fan-shaped hole, and a laid-back fan-shaped hole on a flat plate operating at a mainstream Mach number of 0.5. The results reveal that various hole structures broadly exhibit measurement deviation, which generally increases with an increase in the blowing ratio. The deviation originates from difference in momentum between air and foreign gas. Notably, significant negative deviation is observed near the holes under high blowing ratios, while pronounced positive deviation occurs downstream. The distributions of deviation are varied for different structures. The compound angle leads to increased and asymmetrical deviation. The deviation distribution of the double jet ejection is not simply a combination of the deviation distributions of two holes with a compound angle. Furthermore, the fan-shaped hole and the laid-back fan-shaped hole prevent coolant jet lift-off from the wall, reducing measurement deviation. However, under high blowing ratio conditions, the measurement deviation remains significant and should not be neglected.

Presenting Author: Yuzhu Lou School of Energy and Power Engineering, Beihang University

Presenting Author Biography: Yuzhu Lou received his B.E. degree in Aircraft Power Engineering from Beihang University, Beijing, China, in 2021. Currently, he is pursuing his Ph.D. degree in Engineering Thermophysics from the School of Energy and Power Engineering at Beihang University, Beijing, China. His research focuses on film cooling, Pressure Sensitive Paint, and correction method.

Authors:

Yuzhu Lou School of Energy and Power Engineering, Beihang University
Zhi Tao National Key Laboratory of Science and Technology on Aero Engines Aero-Thermodynamics, Beihang University
Haiwang Li Research Institute of Aero-Engine, Beihang University
Zhiyu Zhou Research Institute of Aero-Engine, Beihang University
Jinghan Zhang National Key Laboratory of Science and Technology on Aero Engines Aero-Thermodynamics, Beihang University
Gang Xie National Key Laboratory of Science and Technology on Aero Engines Aero-Thermodynamics, Beihang University