Effect of different bionic structures on clearance flow and aerodynamic performance in linear cascades

Three bio-inspired structures are proposed: the tip bionic chamber structure (TBC), the casing bionic chamber structure (CBC), and the pressure-side tip winglet structure (PSTW), drawing inspiration from the excellent airflow characteristics of dragonfly wing cavities and avian feather bifurcations. Numerical simulations are carried out to examine their influence on the interaction between corner flow and tip clearance leakage flow within compressor cascades. The results indicate that all three bionic cases can effectively suppress clearance leakage flow, attenuate vortex-induced losses, and diminish the total pressure loss. Overall, these bio-inspired designs optimize the clearance leakage flow characteristics. Among the three, PSTW exhibits superior performance, achieving a 16.8% reduction in tip leakage flow ratio (RQm) and a 0.64% decrease in total pressure loss coefficient (Cpt). Additionally, the mechanisms by which these structures control leakage flow behavior are systematically analyzed across various incidence angles and tip clearance heights to evaluate their potential for extending the stability margin. The findings demonstrate that all three designs effectively suppress leakage flow across a wide range of operating conditions. Notably, PSTW provides the most robust suppression of RQm across different clearance heights, despite causing a slight increase in Cpt at positive incidence angles. Generally, under various operating conditions, PSTW most significantly enhances the aerodynamic performance of the tip clearance region.