基于熵产理论的多级液力透平能量耗散机理分析  

Analysis of Energy Dissipation Mechanism of Multistage Hydraulic Turbine Based on Entropy Production Theory

作　　者：王晓晖[1,2] 蒋虎忠 苗森春 白小榜 祁炳 WANG Xiaohui;JIANG Huzhong;BAI Xiaobang;MIAO Senchun;QI Bing(School of Energy and Power Engineering,Lanzhou University of Technology,Lanzhou 730050,China;Key Laboratory of Fluid Machinery and System of Gansu Province,Lanzhou University of Technology,Lanzhou 730050,China;Chongqing Pump Industry Co.,Ltd.,Chongqing 404100,China)

机构地区：[1]兰州理工大学能源与动力工程学院,兰州730050 [2]兰州理工大学甘肃省流体机械及系统重点实验室,兰州730050 [3]重庆水泵厂有限责任公司,重庆404100

出　　处：《农业机械学报》2024年第3期162-172,共11页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金项目(52169019);甘肃省杰出青年基金项目(20JR10RA203);中国博士后科学基金项目(2022M712676)。

摘　　要：液力透平作为一种液体余压能回收装置,在小水电建设和能量回收领域得到广泛应用,但其内部能量损失特性不清。以两级径流式液力透平为研究对象,基于熵产理论和Omega涡识别准则分析了各过流部件内能量耗散机理。结果表明:速度脉动和壁面效应是能量损失的主要来源,设计工况下二者总占比为98.03%。叶轮和导叶是透平内能量耗散的主要区域;小流量工况,叶轮损失占比较高;大流量工况下,导叶损失占比较高。叶轮内的能量损失源于叶片前缘分离涡、吸力面回流涡以及叶片尾缘涡等不稳定流动现象,而相对液流角与叶片进口安放角的不匹配是导致叶轮内产生不稳定流动的根本原因;在导叶和导叶Ⅱ-反导叶中,不同流量下导致其能量耗散的因素基本保持一致,叶片前缘失速涡和流动分离等劣态流动引起的动量交换是导致能量损失的主要原因。环形吸水室内流动的非对称性导致导叶Ⅰ各流道内熵产率分布不均匀,而导叶Ⅱ-反导叶通过正导叶的整流减小了冲击效应,各流道内熵产率分布均匀且高熵区较小。As a liquid residual pressure energy recovery device,hydraulic turbine is widely used in the field of small hydropower construction and energy recovery,but its internal energy loss characteristics are unclear.The two-stage radial hydraulic turbine was taken as the research object.Based on the entropy production theory,the energy loss in each flow component was quantitatively analyzed,and the energy dissipation mechanism in the turbine was further revealed by combining the Omega vortex identification criterion and flow field distribution.The results showed that velocity pulsation and wall effect were the primary sources of energy dissipation.The total proportion of the two was 98.03%under the design condition.The impeller and the guide vane were the main areas of energy dissipation in the turbine;the impeller loss accounted for a higher percentage in the small flow condition,while the guide vane loss accounted for a higher percentage in the large flow condition.The energy loss in the impeller originated from the unstable flow phenomena such as vortex separation at the leading edge of the blade,return vortex at the suction surface,and vortex at the trailing edge of the blade,and the matching of the relative liquid flow angle and the angle of placement of the inlet of the blade was the fundamental reason for the unstable flow in the impeller;in the guide vaneⅠand the guide vaneⅡ-anti-guide vane,the factors leading to the dissipation of their energy at different flow rates were basically the same,and the poor flow such as the stagnation vortex at the leading edge of the blade and the flow separation.The momentum exchange caused by the blade leading edge stall vortex and flow separation was the main cause of energy loss.Due to the asymmetry of the flow inside the annular suction chamber,the entropy yield distribution in each channel of the guide vaneⅠwas not uniform,while the guide vaneⅡ-anti-guide vane reduced the shock effect through the rectification of the positive guide vane,and the entropy yield distribu

关 键 词：多级液力透平 熵产理论 Omega涡识别准则 能量耗散 熵产率 

分 类 号：TK734[交通运输工程—轮机工程]