Effects of turbulence on secondary flow in compressor cascades at different Reynolds numbers

The effect of turbulence intensity on element flow separation in compressors has been well-established at different Reynolds numbers. However, the impact of turbulence intensity on the secondary flow is still not clearly understood and requires further investigation. Therefore, to explore the impact of turbulence intensity on the flow field structure and loss characteristics of the compressor cascade at different Reynolds numbers, this paper utilizes the RANS numerical simulation method to conduct steady-state calculations for the controlled diffusion stator cascade UKG030.3 under various Reynolds numbers and turbulence intensities. The results indicate that there is a different turbulence intensity corresponding to the minimum total pressure loss coefficient for each Reynolds number, which increases as the Reynolds number decreases. Under the high Reynolds number condition (Re=9.9×10⁵), the total pressure loss is insensitive to variations in incoming flow turbulence intensity, and the minimum total pressure loss coefficient occurs at a turbulence intensity of 2%. Under low Reynolds number condition (Re=2.2×10⁵), as the turbulence intensity increases and the laminar separation bubble disappears, there is a stronger momentum exchange on the suction surface boundary layer, resulting in intensified secondary flow. This leads to an increase in total pressure loss near the endwalls, with a turbulence intensity of 5% corresponding to the minimum total pressure loss.