Design and Optimization of Micro-Blade Passive Flow Control for Total Pressure Loss Reduction in an Axial Compressor Cascade

Abstract

The present paper investigates the aerodynamic influence of a micro-blade (MB) flow control in a low-speed axial compressor cascade, through a combined two-dimensional (2D) optimization and three-dimensional (3D) validation framework. The influence of the MB’s key geometric parameters, including chord length, camber angle, stagger angle, and maximum thickness, as well as spatial positioning, was systematically analyzed to identify the optimal configuration. Results reveal a size-wake trade-off; small elements fail to sustain meaningful momentum exchange, whereas large elements introduce excessive blockage and wake losses. An intermediate chord of 20% of the main blade, combined with a medium element maximum thickness (5% of the MB chord) and 50° camber, provides the most favorable compromise, achieving a 55.56% reduction in total pressure loss coefficient (TPL) under stall conditions. The optimized MB was subsequently evaluated in a 3D cascade configuration to examine its influence on corner separation and 3D flow structures across design and off-design inlet flow angles. The 3D results showed a clear reduction in the corner separation spanwise extent, especially at high incidences, though a TPL penalty is observed at the nominal design angle, where the baseline flow is already attached. Overall, the findings demonstrate that carefully optimized MB can effectively mitigate losses and enhance compressor operability when geometry and placement are properly designed.