A Strategy for Predicting Transonic Compressor Performance at Low Reynolds Number

A low Reynolds number (Re) environment leads to severe deterioration in compressor performance, and it is necessary and challenging to accurately predict performance at a low Re during the design phase of a compressor. This study first reveals the mechanism of typical flow characteristics in transonic compressor at a low Re via simulations. When comparing the cases with different Re, the equivalent blade profile variation due to the growth of the boundary-layer thickness is found to be the main reason for changing the flow field. On the basis of boundary-layer theory, a prediction model of the equivalent profile is developed for the viscous effect on the boundary layer, and a multiline strategy is applied to calculate the blade-load radial redistribution. The equivalent blade prediction error at different Re is up to 7.8% compared to the CFD results. Ultimately, this strategy improves the radial spatial resolution compared to the original method and is able to predict the compressor performance at a low Re with pressure ratio and efficiency errors of 0.23% and 1.8%, respectively.