扩压器稠度对跨音速离心压气机性能影响及流动机理分析

Influence of Diffuser Solidity on the Performance of Transonic Centrifugal Compressorand Flow Field Analysis

以NASA某高压比离心压气机为研究对象,开展了不同稠度扩压器对跨音速离心压气机性能影响的数值模拟研究,通过对比离心压气机的数值模拟结果与实验数据,验证了本文采用的数值模拟方法的可靠性。通过调整扩压器叶片数目和改变扩压器叶片弦长(保持展弦比不变)来分析稠度变化对离心压气机整机性能的影响,并通过对三维流场分析找到影响离心压气机性能的主要因素。结果表明:对于改变叶片数及叶片弦长两种方式,对离心压气机整机效率影响最大的因素分别为由于叶顶间隙引起的泄漏损失和由于盘侧边界层分离引起的壁面回流,并分别得出在设计点效率最高的扩压器设计为80%叶片数扩压器及70%叶片弦长扩压器。

Based on the NASA's high-pressure ratio centrifugal compressor,this paper carried out the numerical study on the performance of a centrifugal compressor with different diffuser solidities.The numerical calculation method was verified by the centrifugal compressor experimental data.The diffuser solidities were changed by the different diffuser blade number and diffuser vane chord,and the influence of diffuser solidity on the compressor performance was analyzed.The numerical results show that the leakage loss caused by the blade tip clearance plays important role on the compressor performance when the diffuser vane number is changed,while the wall return caused by the separation of the boundary layer on the disc side is mainly responsible for the compressor performance when the diffuser vane chord length is changed.Numerical results indicate that the diffuser design with the highest efficiency at the design point is the 80%diffuser vane number or the 70%diffuser chord length.