1000 MW水轮机多工况运行水力损失及熵产特性分析  

Analysis of hydraulic loss and entropy production characteristics of 1000 MW Francis turbine under multi-operating conditions

作　　者：张泽泉 卢永刚[1,2] 朱荣生 王正伟[2] 李贤梁[1] ZHANG Zequan;LU Yonggang;ZHU Rongsheng;WANG Zhengwei;LI Xianliang(National Research Center of Pumps,Jiangsu University,Zhenjiang,Jiangsu 212013,China;Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]江苏大学国家水泵及系统工程技术研究中心,江苏镇江212013 [2]清华大学能源与动力工程系,北京100084

出　　处：《排灌机械工程学报》2024年第11期1142-1149,共8页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(52371322);江苏省自然科学基金资助项目(BK20210771);中国博士后科学基金资助项目(2021M701847)。

摘　　要：为研究1000 MW混流式水轮机组多工况运行时产生的水力损失,使用SST k-ω湍流模型进行数值模拟计算.根据热力学第二定律,基于熵产理论对3种常见出力工况下的水轮机进行水力损失研究,主要是对流动过程中的熵产分布和流场进行分析,从而得到水力损失的具体空间分布情况.研究结果表明:湍流熵产和壁面熵产占水轮机系统总熵产的99%以上,时均速度引起的直接熵产几乎可以忽略不计.熵产主要集中在导叶、转轮和尾水管3个部件,导叶无叶区的高速流动造成较大速度梯度,使得高局部熵产(LEPR)出现在无叶区.转轮内的回流、流动分离等不稳定流动,使得高LEPR区出现在转轮叶片的前缘和尾缘处.尾水管在额定出力下流态最好,偏额定出力工况会在直锥段出现螺旋状涡带或直柱状涡带,且在靠近入口的直锥段中心出现局部回流,导致高LEPR区出现在此处.导叶和转轮在超出力工况产生较大的水力损失,尾水管则在低出力工况下的水力损失较大.To study the hydraulic loss of 1000 MW Francis turbine under multi-operating conditions,the SST k-ωturbulence model was selected for numerical simulation.In accordance with the second law of thermodynamics,the hydraulic loss in Francis turbine under three typical output conditions through the lens of entropy production theory was analyzed.The primary objective was to analyze the distribution of entropy production and the characteristics of the flow field during the flow process,with the aim of determining the precise spatial distribution of hydraulic losses.The research findings demonstrate that the turbulent entropy production and wall entropy production account for more than 99%of the total entropy production within the turbine system,rendering the direct entropy production attribu-table to time-averaged velocity nearly negligible.The entropy generation is predominantly loca-lized within the three components of the stay/guide vane,runner and draft tube.The high-velocity flow in the bladeless area of the guide vane causes a significant velocity gradient,which consequently leads to the high local entropy production rate(LEPR)appearing in the bladeless area.Unstable flow pheno-mena,including backflow and flow separation within the impeller,leads to the formation of regions with elevated LEPR at both the leading and trailing edges of the impeller blades.The flow dynamics within the draft tube has the best flow pattern under the rated output.However,under the partial rated output condition,a spiral vortex band or a straight column vortex band will appear in the straight cone section.Additionally,local back-flow will appear in the center of the straight cone section near the inlet,resulting in a high LEPR area.Under conditions of excessive output,the guide vanes and impeller incur substantial hydraulic losses,while the draft tube exhibits increased hydraulic losses under conditions of reduced output.

关 键 词：1000 MW混流式水轮机 熵产理论 不稳定流动 水力损失 

分 类 号：S277.9[农业科学—农业水土工程]