Design, modification and optimization of an ultra-high-load transonic low-reaction aspirated compressor

Low-reaction (LR) aspirated compressor is a promising design methodology to enhance the work capacity substantially. However, for the high-load transonic compressor, to achieve LR design, the effect of different combinations of inlet pre-swirl and meridian contraction on performance has not been investigated. In addition, the quantitative advantage of LR design over convention-reaction (CR) design is also not available. This paper presents a series of aerodynamic designs of the high-load transonic compressor stage, including a CR stage and three LR stages with a comprehensive application of the LR design method and the aspiration technology. 3D calculation reveals that under the same tip speed and rotational speed and a total bleed flow fraction of 2.84% of the stage inlet mass flow, the preliminary LR design achieves a total pressure ratio of 2.34 and a throughflow adiabatic efficiency of 88.11%, which is respectively 30% and 0.19% higher over CR design. The corresponding loading coefficient rises from 0.45 to 0.66. Through the modified design of introducing non-uniform counter-swirl along the span and increasing the meridian contraction, the loading coefficient is further increased to 0.69. Due to the insufficient stall margin induced by ultra-high-load LR design, a further casing contraction of the optimized design relative to the modified one is conducted to decrease the loading and thus the stall margin is increased by 1%.