Mechanism of effects of adjustable stator clearances axial location on a high-load axial flow compressor performance

To investigate the influence of the partial clearance position of adjustable stator blades on the performance and flow field of an axial compressor, a numerical simulation was first conducted on an inlet-stage compressor with a loading coefficient of 0.5. The results indicate that the instability mechanism of the prototype compressor is attributed to the accumulation of low-energy fluid generated by tip leakage flow in the stator blade passage near-stall conditions. This fluid blocks the blade tip passage, subsequently triggering flow instability within the compressor. Then, based on the instability mechanism analysis of the prototype compressor, five different research schemes with varying partial clearance axial positions were designed by simultaneously shifting at both the blade root and tip. Results show that: Using the original platform positions (25 %∼60 % Ca at the root, 23 %∼48 % Ca at the tip) as the datum, forward-shifting the axial position of the platforms improves the compressor's total pressure ratio and efficiency across the entire operating range. Among these configurations, the scheme with platforms positioned closest to the leading edge (0 %∼35 % Ca at the root, 0 %∼25 % Ca at the tip) improved the compressor's pressure ratio and efficiency at peak efficiency condition by 0.64 % and 0.85 %, respectively. Additionally, the stall inception location shifted to the rotor tip region. When the platform axial position is shifted rearward, the compressor performance initially improved but subsequently deteriorated.