Aerodynamic design of a radially-segmented 2-DOF VIGV for suppressing swirl distortion

Abstract

To address the challenges of leading-edge angle of attack mismatch  in axial flow compressors under high swirl distortion conditions, this paper proposes a design method for a two-degree-of-freedom (2-DOF) variable-camber inlet guide vane (VIGV) with anti-swirl distortion capabilities. The design features a movable front vane and a fixed rear vane, incorporating a radially segmented independent adjustment mechanism for the front vane to actively match radially non-uniform flow fields. First, based on parametric sweeps using 2D numerical simulations, a geometric design criterion correlating front vane deflection angle with blade chord length was established to determine the critical threshold for suppressing suction-side separation on the rear vane. Subsequently, the three-dimensional aerodynamic performance of the proposed 2-DOF VIGV was compared with a single-DOF design under typical radial swirl distortion inlet conditions. The results demonstrate that, by differentially adjusting the front vane angles at the hub and tip segments, the 2-DOF design reduces the outlet swirl distortion index (SC(60)) by 47.1% and the total pressure loss coefficient by 3.5% compared to the single-DOF baseline, while achieving an outlet flow angle closer to the axial design target. This design effectively mitigates flow separation at large turning angles and significantly enhances the aerodynamic stability and flow uniformity of the compressor under complex inlet distortion conditions.