SCO_(2)离心压缩机近失速工况流场特性研究  

Study on Flow Field Characteristics Near Stall Condition of SCO_(2) Centrifugal Compressor

作　　者：张磊 郑全泽 郎进花 安光耀 ZHANG Lei;ZHENG Quanze;LANG Jinhua;AN Guangyao(Department of Power Engineering,North China Electric Power University,Baoding 071003,China;Hebei Key Laboratory of Low Carbon and High Efficiency Power Generation Technology,Baoding 071003,China)

机构地区：[1]华北电力大学动力工程系,保定071003 [2]河北省低碳高效发电技术重点实验室,保定071003

出　　处：《工程热物理学报》2025年第4期1110-1119,共10页Journal of Engineering Thermophysics

基　　金：国家自然科学基金面上项目(No.52076079),河北省自然基金青年项目(No.E2024502038,No.E2022502048);中央高校基本科研业务费专项资金资助(No.2023MS121,No.2024MS143,No.2024MS149)。

摘　　要：为研究超临界二氧化碳(SCO_(2))离心压缩机近失速工况的流场特性,利用CFX软件对Sandia实验室模型进行三维数值研究,并对近失速工况的流场特性进行分析。结果表明,“尺寸效应”的影响下使得叶轮的相对叶顶间隙较大,从而使得叶顶处泄漏增强并形成大范围的低速区;由于通道中下的高逆压梯度使主叶片吸力面侧低能流体发生分离流动并开始形成回流区,回流区向上游叶顶处发展与叶顶处回流区结合,导致叶轮入口处形成阻塞,影响压缩机的正常通流能力;由于叶片吸力面侧回流区与主流相互作用形成的旋涡向下游低叶高发展、相邻通道马蹄涡的压力面分支、下游轮毂的边界层分离形成以及回流区的存在几者共同作使通道内部形成低速区和回流区,最终导致失速发生。SCO_(2)离心压缩机运行时在其叶片前缘和尾缘会出现凝结现象,这是主要是由于在叶片前缘和尾缘处产生的流动损失较大,使得CO_(2)的温度和压力低于临界点从而形成凝结。随着流量的减小,其在叶片前缘和尾缘处的损失减小,其凝结现象也逐渐减弱直至消失。To investigate the flow field characteristics near stall conditions of the supercritical carbon dioxide(SCO_(2))centrifugal compressor,three-dimensional numerical simulations of the Sandia National Laboratory(SNL)model were conducted using CFX software.The results indicate that the influence of“size effect”leads to a relatively large blade tip clearance,resulting in enhanced leakage at the blade tip and the formation of a large area of low-speed region.The high adverse pressure gradient in the lower part of the passage causes separation of low-energy fluid on the suction side of the main blade,initiating the formation of a reverse flow zone.This reverse flow zone extends to the upstream blade tip and combines with the reverse flow zone at the blade tip,resulting in blockage at the inlet of the impeller and affecting the normal flow capacity of the compressor.Interaction between the reverse flow zone on the suction side of the blade and the mainstream forms vortices that develop downstream to low span,along with pressure side branches of horseshoe vortex in adjacent passages,boundary layer separation at the downstream hub,and the presence of reverse flow zones.These collectively create low-speed and reverse flow zones within the passage,ultimately leading to stall.During the operation of SCO_(2) centrifugal compressor,condensation occurs at the leading and tailing edges of its blades.This is mainly attributed to significant flow losses at the leading and trailing edges of the blades,causing the temperature and pressure of CO_(2) to drop below the critical point,resulting in condensation.As the flow rate decreases,the losses at the leading and trailing edges of the blades decrease,leading to a gradual weakening and eventual disappearance of the condensation phenomenon.

关 键 词：超临界CO_(2)离心压缩机 流场特性 失速机理 凝结特性 

分 类 号：TH452[机械工程—机械制造及自动化]