Experimental study on three-dimensional blade designs in an aggressive compressor transition duct

Abstract

The increasing performance requirements for aero-engines necessitate the integrated design of compressor transition ducts with upstream components to reduce the axial length of the engine. This paper presents an experimental investigation of three-dimensional (3D) blade designs within an aggressive compressor transition duct integrated with the upstream stator. The aim is to reduce the total pressure loss and decrease the radial distortion of the flow field at the outlet of the transition duct, thus providing better inflow conditions for the high-pressure compressor. Detailed measurements of the internal flow field were conducted under both near stall (NS) and design (DE) conditions for three 3D blades. The results showed that in the downward path, adopting the 3D blades with positive dihedral and forward sweep contributed to mitigating the stator hub corner stall under the NS condition. Under the same operating conditions, enhanced kinetic energy at the stator root improved the spanwise uniformity of the transition duct outlet profile, while also increasing the anti-separation capability of the downstream hub boundary layer. The corner vortex at the stator root could enhance momentum mixing between the downstream hub boundary layer and the mainstream, thereby providing stronger separation resistance for the hub boundary layer under the NS condition. Compared to the baseline stators, the optimized 3D stators reduced system total pressure loss by 24% under the NS condition, while maintaining essentially unchanged total pressure loss under the DE condition.