采用关联模型的离心压缩机喘振工况数值研究

摘要

为了研究管网系统特性对离心式压缩机喘振的影响,建立了包含温度项的关联模型,将管网效应耦合到压缩机出口的边界条件中,实现了压缩机系统从稳定工况到喘振工况的数值模拟.对一离心压缩机流道和无叶扩压器流场进行了非定常数值模拟,结合关联模型得到喘振时压缩机出口处压力及质量流量脉动随时间的变化情况,分析了管网容量、管网出口流量等管网参数对压缩机系统喘振的影响.模拟结果显示:所建模型能捕捉到喘振工况下压缩机出口的参数变化特征;随着管网容量的增大或管网出口质量流量的减小,压缩机出口流量、总压波动幅值增大,工况向喘振振荡特性转变;管网容量对失速频率影响较大,而管网出口流量的变化对压缩机的失速频率影响较小.该研究对进一步分析压缩机管网系统相互影响和喘振预测具有参考价值.%To reveal the influence of pipe network system characteristics on the surge of centrifugal compressor,a correlation model including temperature item is constructed.This correlation model couples the effect of plenum chamber to the boundary condition of the compressor outlet,thus the numerical simulation of the compressor system from steady state to surge state is realized.The flow fields in flow passage and vaneless diffuser of a centrifugal compressor are simulated in transient state,and the fluctuations of pressure and mass flow rate in the compressor outlet are obtained under surge condition over the simulation period.The effects of piping system characteristics including piping capacity and outlet mass flow rate on surge are analyzed.Simulation shows that the model is able to capture the changes of the parameters in compressor outlet under surge condition.With increasing pipe network capacity or decreasing outlet mass flow rate,the amplitudes of the mass flow rate and total pressure in compressor outlet increase,and working condition turns into surge.The influence of the pipe network capacity on the stall frequency is obvious,while the change of the mass flow rate in pipe network outlet slightly affects the stall frequency.