离心压缩机喘振动态特性的数值研究

Numerical Investigation of Dynamic Characteristic of Surge in a Centrifugal Compressor

为了阐述深度喘振发展的流动机理,本文以低转速带叶片扩压器的离心压缩机为研究对象,采用整周CFD数值计算方法研究了离心压缩机深度喘振过程中的系统动态特性以及流场细节。首先,结合系统参数化模型与非定常数值模拟结果分析了深度喘振循环中各个过程的系统波动特性,指出喘振循环中压缩机依次经历了正向减速、反向回流、正向恢复、容腔恢复四个阶段;然后,通过对比分别处于流动减速区、流动加速区的相同小流量工况,发现扩压器流场特性存在明显的差别,分析指出喘振的流动振荡特性会促进或抑制扩压器失速扰动的发展。全通道数值计算能够帮助进一步认识深度喘振过程中的流场特性,然后为精确化喘振模型的发展以及评估喘振对下游部件的影响给予一定的指导。

In order to elucidate the mechanism of the development of deep surge,a low-speed centrifugal compressor with a vaned diffuser is chosen to conduct whole-passage numerical investigation of the system dynamic characteristic and detailed flow field by technique of CFD.First,the system model of lumped parameter and the unsteady simulation results are combined together to analyze the system characteristic of the stage at different process of the deep surge cycle,which consists of positive deceleration,flow reverse,positive acceleration and plenum recovery.Second,after the comparison of detailed flow field at the same low mass flow rate of positive deceleration and positive acceleration region,there exists obviously difference about the characteristic of the diffuser flow field and the pulsation of the mass flow rate can promote or suppress the development of the difluser stall.The whole-passage simulation can help advance the understanding of the flow characteristic in the process of deep surge,which can be used to develop the surge model with more accuracy and determine the effect of surge on downstream component.