可变几何楔形扩压器设计与流动分析

Design and flow analysis of variable geometry wedge diffuser

为了兼顾离心压气机具有高压比的同时可以拥有更宽的稳定工作裕度,以匹配楔形扩压器的高压比离心压气机为研究对象,提出一种新的扩压器轴向滑移变几何设计方案。利用经过校核的数值模拟方法开展了扩压器叶片安装角和扩压器叶片前缘轴向滑移尺寸的参数化研究,详细讨论了叶片扩压器的变角度方案和轴向滑移剪切方案对离心压气机气动性能、稳定裕度的影响规律。研究结果表明,在扩压器叶片初始设计阶段通过增大扩压器叶片安装角使压气机在小流量工况范围内运行,再通过轴向滑移式变几何扩压器机构改变叶轮与扩压器间的转静间隙,有效地将堵塞流量增大2.9%,失速流量减小7%,拓宽了离心压气机稳定运行流量范围。

In order to ensure the centrifugal compressor has a high pressure ratio and a wide stable operating margin,a high pressure ratio centrifugal compressor matching wedge diffuser was studied and a new design scheme of axial slip variable geometry for diffuser was presented.Parameterized study on the stagger angle and axial slip dimension of the leading edge of the diffuser blade was carried out by using the verified numerical simulation method,and the influences of variable stagger angle and axial sliding shear schemes on the performance and stability margin of centrifugal compressor were discussed in detail.The results show that at the initial design phase of the diffuser blade,the stagger angle of the diffuser blade is increased to make the compressor operating condition within the small flow range,and then the rotor-stator clearance between the impeller and the diffuser is changed by the axial sliding variable geometry diffuser mechanism.The choked flow rate is increased by 2.9%,the stall flow rate is decreased by 7%,as a result,the stable operating range of centrifugal compressor is increased effectively.