As a degree of freedom in three-dimensional blade design of axial compressors, the sweep technique significantly affects aerodynamic performance of axial compressors. In this paper, the influence of backward sweep rotor configurations on aerodynamic performance of a 1.5-stage highly loaded axial compressor is studied by numerical simulation. The aim of this work is to improve understanding of flow mechanism of backward sweep on aerodynamic performance of a highly loaded axial compressor. A commercial CFD package is employed for flow simulations and analysis. The aerodynamic performance of backward sweep of the zero sweep configuration are validated with experimental data. Results of the detailed numerical simulation with different backward sweep rotor configurations at transonic and subsonic conditions are presented. The study found that the backward sweep rotor configurations affect the passage shock wave, the blade loading, tip leakage flow, the boundary layer and blade row interactions, et al. At the design rotational speed, as the degree of backward sweep increases, backward sweep has little effect on peak efficiency of the 1.5-stage axial compressor. The stall margin of the 1.5-stage highly loaded axial compressor increases first and then decreases. Among different backward sweep rotor configurations, the 10% backward sweep rotor configuration has the stall margin of about 2.4% higher than that of zero sweep configuration. This is due to backward sweep rotor configuration reduces blade loading near the leading edge but slightly increases blade loading near the trailing edge in rotor hub region, which changes downstream stator incidence and improves the flow capacity near the hub region. However, when the degree of backward sweep is large, the intensity of passage shock wave near rotor tip region increases and the position of the passage shock wave moves upstream. The passage shock wave and tip leakage flow together results in severe flow blockage near the tip region, thus the stall margin deteriorates and should be avoided in the design process. At the 60% rotational design speed, the passage shock disappears. The blade passage is almost full of subsonic flow. As the degree of backward sweep increases, peak efficiency hardly not changed, but the total pressure ratio and adiabatic efficiency increases when flow rate is lower than that of peak efficiency condition. Due to the increase of rotor angle of attack, flow capacity deteriorates in the tip region, thus stall surge decreases. Therefore, it is necessary to consider flow field structure of axial compressors in the design process and use the design freedom of sweep to improve the aerodynamic performance  of axial compressors


Effect of Backward Sweep on Aerodynamic Performance of a 1.5-Stage Highly Loaded Axial Compressor

Division / Sponsor:
International Gas Turbine Institute (IGTI)

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2020/volume/84058

Turbo Expo - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.