The numerical simulation of three-dimensional viscous flow was carried out to investigate the effects of different diffuser stagger angle on flow field and performance of a high-speed centrifugal compressor. The numerical results indicated that the influence of different stagger angles on flow filed and performance of the centrifugal compressor is great. Too small stagger angle will cause flow channel blockage and Laval nozzle effect which greatly reduce the compressor efficiency. As the stagger angle which is in a appropriate range increases, the compressor's total pressure ratio and isentropic efficiency increased, but its surge margin is gradually reduced. In short, the stagger angle of vaned diffuser should be determined by efficiency, pressure ratio and surge margin.%以某高负荷离心压气机为研究对象,运用三维粘性数值模拟方法考察了不同叶片扩压器进口安装角对离心压气机流动及性能的影响.分析结果显示,叶片扩压器进口安装角对离心压气机流动及性能影响很大,过小的安装角会造成流道堵塞,产生拉瓦尔喷管效应,使整级效率急剧降低.叶片扩压器在合适的安装角范围内,随着进口安装角的增大,压气机等熵效率变大,总压比升高,但工作裕度却逐渐减小.由此可知,叶片扩压器具体安装角的确定要根据效率、压比和工作裕度的综合考虑所定.
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