Highly Resolved Simulations of a CDA Compressor Cascade: Effect of Reynolds Number on Losses

The Reynolds number effects on performance of a Controlled Diffusion Airfoil (CDA) geometry in a linear compressor cascade setup are presented. A set of highly-resolved Large Eddy Simulations at Reynolds numbers from 300,000 to 1,000,000 at a Mach number of 0.7 are performed, with one of the simulations including incident wakes at engine relevant reduced frequency of 1.56. The focus of this work is to investigate loss variation of a modern blade geometry by applying both the novel entropy analysis introduced by (Zhao & Sandberg, GT2019-90126) and the mechanical work potential analysis by Miller (GT2013-95488) in the form presented by Leggett et al. (GT2019-91253). The loss analysis, applied both to the whole blade, and to carefully selected subvolumes, including suction and pressure surface boundary layers, highlights regions of increased loss production and the effects of Reynolds number on the location and strength of different flow processes, such as transition and separation. The results are further broken down to show the contribution to loss of individual terms of the analyses and the changes that occur due to changes in Reynolds number. The effects of incident wakes are also captured using this analysis technique and detailed in the paper.