百万吨级乙烯压缩机加气流动特性研究

Study on Sidestream Flows in Interstage Intake of a Million-ton Class Ethylene Compressor

级间加气是乙烯工业节能增产的重要手段,特别是百万吨乙烯压缩机加气量高达8倍于上游通流流量,对下游叶轮气动匹配及整机性能影响巨大。目前关于压缩机加气特性及与通流相互影响的研究鲜有报道。本文基于计算流体动力学方法,建立了通流部件与径向加气室内部流动的耦合模型,并以百万吨乙烯压缩机为研究对象,通过分析上一级通流特性、通流-加气侧流耦合特性、通流为射流的加气侧流特性,研究通流与侧流相互作用机理。结果表明:通流性能曲线的流动计算结果与压缩机选型程序结果吻合较好;侧流流量远高于通流流量时,通流为射流的加气侧流模型可替代复杂耗时的通流-侧流耦合模型。研究工作为压缩机级间加气的设计优化提供了快速准确的流动计算模型。

Interstage intake sidestream is an important way to save energy and increase production in ethylene industry,in particular for the million-ton class ethylene compressor where the mass flow of interstage intake is about eight times that of upstream stage,impacting greatly on the aerodynamic matching with the downstream stage and even the aerodynamic performance of the whole compressor.However there are few studies so far on the sidestream flow in interstage intake and the interaction with the mainstream flow.By applying computational fluid dynamics method,a coupling model is developed for the interaction between the mainstream and sidestream flow.The developed model is then used in a large scale ethylene compressor with an annual production of a million tone ethylene.The interaction between the mainstream and sidestream flow is analyzed with three coupling strategies,i.e.,the flow in the upstream stage,the coupling between the mainstream and sidestream,and the flow in the sidestream intake with a jet mainstream flow.The results show that the aerodynamic performance curve of the upstream stage predicted with the developed model fits well that with the compressor selection codes.As the sidestream flow rate is much higher than the upstream mainstream flow rate,the sidestream with a jet mainstream flow model can replace the time-consuming coupling model.The work provides a rapid and accurate flow calculation model for the design optimization of interstage intake of centrifugal compressor.