小流量工况下汽轮机低压缸内流动与鼓风加热特性数值研究  

Numerical Study on Flow and Windage Heating Characteristics in Low Pressure Cylinder of Steam Turbine Under Small Mass Flow Conditions

作　　者：谈晓辉 张奔 王耀文 穆祺伟 王宏武 翟鹏程 于龙文 王汀 马汀山 TAN Xiao-hui;ZHANG Ben;WANG Yao-wen;MU Qi-wei;WANG Hong-wu;ZHAI Peng-cheng;YU Long-wen;WANG Ting;MA Ting-shan(Shengli Oilfield,Dongying 257091,China;Xi'an Xire Saving&Emissions Control Technology Co.,Ltd.,Xi'an 710054,China;National Key Laboratory of Efficient Coal,Electricity and Carbon Capture,Utilization and Storage,Xi'an 710054,China)

机构地区：[1]中石化胜利石油管理局有限公司胜利发电厂,东营257091 [2]西安西热节能技术有限公司,西安710054 [3]高效灵活煤电及碳捕集利用封存全国重点实验室,西安710054

出　　处：《汽轮机技术》2022年第6期445-450,455,共7页Turbine Technology

基　　金：中国华能集团总部科技项目(HNKJ21-59)。

摘　　要：针对目前供热机组低压缸零出力改造导致汽轮机低压缸处于小流量工况的问题,以国内某电厂汽轮机低压缸为研究对象,建立了低压缸单边六级叶栅单通道流场计算模型,数值研究了变工况尤其是小流量工况下低压缸内部的流动结构和气动性能,重点分析了小流量工况下末级动叶的鼓风加热特性。结果表明:在小流量工况下,低压缸的末级叶栅内会出现汽流分离和回流现象,汽流分离首先出现在末级动叶叶根处,并随着入口流量的持续减小逐渐向上游叶栅及叶顶发展,同时,末级叶栅通道内会出现局部涡流并伴随有动叶入口的负攻角现象,严重阻碍蒸汽工质的流动;末级静叶的叶顶区域出汽边在入口流量降低至额定工况的10.0%时会出现局部高温区,表现为小流量下末级动叶的鼓风加热效应,同时,鼓风加热效应会随着入口流量的减小而持续加剧,包括局部高温区范围的扩大和最高温度的提升;鼓风加热效应对末级静叶表面最高温度的影响显著大于末级动叶,研究的最小入口流量工况下末级静叶与动叶表面最高温度相较于额定工况分别提高了70.22%和40.29%。Due to the face that the current heating steam turbine is retrofitted,the low-pressure cylinder of the steam turbine works in the condition of small mass flow.The low-pressure cylinder of a steam turbine in a domestic power plant is taken as the research object,a numerical model of the single-channel flow field of the single-side six-stage cascade of the low-pressure cylinder is established.The flow structure and aerodynamic performance inside the low-pressure cylinder under variable working conditions were numerically investigated,especially for the windage heating characteristics of the last stage cascade under the condition of small mass flow.The result shows that the outlet area began to reflux under the condition of small mass flow,while the flow separation occurred in the final stage cascade.In addition,the flow separation first appeared at the root of the last stage rotor,and gradually developed to the upstream cascade and the tip of the rotor with the continuous decrease of the inlet flow rate.Meanwhile,there are local vortices appeared in the last stage cascade,accompanied by the negative attack angle at the inlet of the rotor,which seriously hinders the flow of the steam.When the inlet flow rate is reduced to 10.0%of the rated condition,a local high temperature region is appeared on the outlet edge of the tip area of the last stage stator,which is manifested as the windage heating effect of the last stage rotor under the condition of small mass flow.Meanwhile,the windage heating effect is continue to intensify with the decrease of the inlet flow rate,including the expansion of high temperature region and the increase of the maximum temperature.The windage heating effect has a significantly greater impact on the maximum surface temperature on the last stage stator than the last stage rotor.Compared with the rated condition,the maximum surface temperature of the last stage stator and rotor under the minimum inlet flow condition studied in this paper is increased by 70.22%and 40.29%.

关 键 词：汽轮机 低压缸 变工况 鼓风加热 数值模拟 

分 类 号：TK263.1[动力工程及工程热物理—动力机械及工程]