具有密封结构的超临界二氧化碳离心压缩机特性研究  

Study on Characteristics of Supercritical Carbon Dioxide Centrifugal Compressor with Sealing Structure

作　　者：曹润 李志刚[1] 李军[1] 邓清华[1] 高铁瑜[1] CAO Run;LI Zhigang;LI Jun;DENG Qinghua;GAO Tieyu(Institute of Turbomachinery, Xi’an Jiaotong University, Xi’an 710049, China)

机构地区：[1]西安交通大学叶轮机械研究所,西安710049

出　　处：《西安交通大学学报》2022年第4期127-137,共11页Journal of Xi'an Jiaotong University

基　　金：国家重点研发计划资助项目(2017YFB0601804)。

摘　　要：为更全面了解超临界二氧化碳(SCO_(2))压缩机内部流场,针对150 kW级简单布雷顿循环的SCO_(2)离心压缩机,设计了盘腔和迷宫密封。采用数值求解三维RANS方程和k-ε湍流模型的方法,研究了考虑盘腔和密封结构的SCO_(2)离心压缩机的气动性能和轴向推力;采用有限元方法分析了考虑气动力和离心力综合作用下离心叶轮的应力和应变特性,同时计算了设计的迷宫密封的应变。结果表明:具有盘腔和密封结构的SCO_(2)离心压缩机在设计工况下气动效率为72.1%,压比为2.19;SCO_(2)离心压缩机的最大轴向推力为1635 kN;离心叶轮的表面等效应力最大值为109.95 MPa,满足设计材料304钢的强度需求;盘腔的泄漏流动会造成SCO_(2)离心压缩机气动效率的下降,但是在高流量工况下,盘腔泄漏可以缓解扩压器前缘的凝结现象。该研究可为具有盘腔和密封结构的SCO_(2)离心压缩机气动性能和强度特性分析以及密封结构设计提供参考。For a more comprehensive understanding of the internal flow field of a supercritical carbon dioxide(SCO_(2))compressor,the cavity and the labyrinth sealing structure are designed for a 150 kW simple Brayton cycle SCO_(2) centrifugal compressor in this paper.A numerical solution of the three-dimensional Reynolds-Averaged Navier-Stokes(RANS)equation and k-ε(Extended Wall Function)turbulence model was used to study the aerodynamic performance and axial thrust of the SCO_(2) centrifugal compressor considering the cavity and sealing structure.The finite element method is used to analyze the stress and the strain characteristics of the centrifugal impeller under the combined effect of aerodynamic force and centrifugal force,and the strain of the designed labyrinth seal is also calculated.The results show that the designed aerodynamic efficiency of the SCO_(2) centrifugal compressor with cavity and sealing structure is 72.1%and the pressure ratio is 2.19 at the design working condition.The maximum axial thrust of SCO_(2) centrifugal compressor is 1635 kN;The maximum surface equivalent stress of centrifugal impeller is 109.95 MPa,which meets the strength demand for 304 steel.The leakage flow of cavity will cause the reduction of aerodynamic efficiency of SCO_(2) centrifugal compressor,but under the high flow coefficient condition,the cavity leakage can alleviate the condensation phenomenon at the leading edge of the diffuser.The paper provides a reference for the analysis of the aerodynamic performance and strength characteristics of the SCO_(2) centrifugal compressor with cavity and sealing structure as well as the design of the sealing structure.

关 键 词：SCO_(2)离心压缩机 迷宫密封 气动性能 轴向推力 叶轮强度 

分 类 号：TH452[机械工程—机械制造及自动化]