Aerodynamic Design and Analysis of a Two-Stage High-Load Low-Reaction Transonic Aspirated Counter-Rotating Compressor

Abstract

The design and numerical analysis of a two-stage, highly-loaded aspirated counter-rotating compressor is presented in the current paper. Compared with the conventional counter-rotating compressor (CRC), the CRC designed in this study included the stator downstream of each rotor. The stator in the counter-rotating compressor was used for enabling static pressure rise and turning the flow towards the axial direction which would decrease inlet relative velocity and inlet flow angle respectively in the following stage. With the low-reaction design concept in combination with boundary layer suction, the two-stage counter-rotating compressor produced a total pressure ratio of 5.99 at an adiabatic efficiency of 88.15%(η1), 85.35%(η2) by aspiration only implemented on the stators. The primary intent of this unconventional design was to mitigate the complexity of the bleed system design, eliminate the adverse effects of aspiration on the blade strength in the rotating parts and finally improve the structural stability of the compressor under the premise of achieving a high-load design. The tip speed of the two rotors was 370m/s and 377.5m/s, respectively at the design rotational speeds. The design aspiration requirement for the configuration reached 22.25% of the inlet mass flow. Detail design parameters, flow characteristics and aerodynamic performance were presented and discussed. The results show that the low-reaction design methodology based on an increase in rotor exit axial velocity was feasible and the integration between low-reaction design method, aspiration and counter-rotating technology could substantially improve the stage loading coefficient meanwhile a high efficiency could be achieved.