氢燃料电池空压机叶片扩压器迎角对气动性能影响研究

Effect of Vaned Diffuser Angle of Attack on Aerodynamic Performance of Hydrogen Fuel Cell Air Compressor

氢燃料电池所用的空压机主要为高速离心式空压机,其气动性能主要由叶轮和扩压器决定,两者的匹配性能与叶片扩压器的迎角有关。为探究迎角对空压机气动性能的影响,对设计工况下9组不同迎角的叶片扩压器进行研究。利用商业CFD软件Numeca对叶轮转速为95000r/min的空压机进行模拟计算,获得各个迎角下空压机的气动性能曲线,对流道子午面的马赫数和流场云图进行分析。结果表明:扩压器迎角对离心式空压机的气动性能有重要影响,在一定范围内,迎角越大,空压机的工作范围越宽,峰值效率越高,高效率区越广;在额定转速下,迎角在0°~2°之间存在最优值,使叶轮与扩压器的匹配性最优,空压机具有更好的气动性能。

The air compressors used for hydrogen fuel cell are mainly high-speed centrifugal air compressor,whose aerodynamic performance is primarily determined by impeller and diffuser,and their matching is related to the vaned diffuser angle of attack(AoA).In order to investigate the influence of AoA on aerodynamic performance of air compressors,nine groups of vaned diffusers with different AoA were studied under design conditions.Numeca,the commercial CFD software,was used to simulate and calculate the air compressors with the impeller at the speed of 95000r/min,and the aerodynamic performance curves of air compressors with different AoA were obtained.The Mach number and cloud image of flow field in meridional plane of flow passage are analyzed.The results show that the AoA of the diffuser has an huge influence on the aerodynamic performance of the centrifugal air compressor.In a certain range,the larger the AoA,the wider the working range of the air compressor,the higher the peak efficiency and the wider the high efficiency area.At the rated speed,the angle of attack has an optimal value between 0°~2°,which makes the matching between impeller and diffuser optimal,and the air compressor has better aerodynamic performance.