Numerical Investigations on the Transition Within Separated Shear Layers Over Highly Loaded Compressor Blades With Heat Transfer
WANG Mingyang1,2, YANG Chengwu1,2, ZHAO Shengfeng1,2, ZHANG Yanfeng1,2, LU Xingen1,2
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1. Key Laboratory of Light-Duty Gas-Turbine, Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China;
2. University of Chinese Academy of Sciences, Beijing 100049, China
Large eddy simulations (LESs) were conducted to investigate the effects of wall heat transfer on the transition process within separated shear layers over two highly loaded compressor blades (adiabatic and isothermal cooled wall conditions) at a Reynolds number (Re) of 1.5×105. Results showed that wall cooling reduced the flow kinematic viscosity of the near-wall flow, which weakened the relative role of turbulent energy dissipation in suppressing the rapid amplification of amplifications. For the compressor blade IET-ULF1, the separated shear layers were more prone to being destabilized, and the transition process was accelerated. However, for the compressor blade IET-ULF2 with a higher loading level, the positive effect of wall cooling on promoting the transition process was much weaker. It was found that the reverse flow mixing, breakdown of large-scale threedimensional hairpin vortices, and the ejection-sweeping process of the near-wall flow determined the generation of turbulent fluctuations and the resulting loss. Compared with the adiabatic wall, the vortex dynamics on the cooled wall were weakened, and the generation rate of turbulent fluctuations declined. Thus, the growth rate of boundary layers was decreased, and the profile losses of the IET-ULF1 and IET-ULF2 were reduced by 18.2% and 22.1%, respectively.
WANG Mingyang, YANG Chengwu, ZHAO Shengfeng, ZHANG Yanfeng, LU Xingen.
Numerical Investigations on the Transition Within Separated Shear Layers Over Highly Loaded Compressor Blades With Heat Transfer[J]. Journal of Engineering Thermophysics, 2023, 44(9): 2376-2389