尾水管壁面加鳍对混流式水轮机压力脉动的影响  

Effects of fin installation on pressure fluctuationin a Francis turbine draft tube

作　　者：张锐志 西道弘[3] 罗先武[1,2] ZHANG Ruizhi;NISHI Michihiro;LUO Xianwu(Beijing Key Laboratory of CO 2 Utilization and Reduction Technology,Tsinghua University,Beijing 100084,China;State Key Laboratory of Hydroscience and Engineering,Tsinghua University,Beijing 100084,China;Senior Academy,Kyushu Institute of Technology,Kitakyushu 804-8550,Japan)

机构地区：[1]清华大学二氧化碳减排与资源化利用技术北京市重点实验室,北京100084 [2]清华大学水沙科学与水利水电工程国家重点实验室,北京100084 [3]九州工业大学,北九州市804-8550,日本

出　　处：《空气动力学学报》2020年第4期788-795,I0003,共9页Acta Aerodynamica Sinica

基　　金：国家自然科学基金(91852103、51776102)。

摘　　要：为了抑制混流式水轮机在部分负荷工况下的压力脉动,在尾水管直锥段设置鳍片是一种可取的工程措施。本文基于数值模拟方法细致考察了设置鳍片对混流式水轮机尾水管内部流动及压力脉动的影响。结果表明:鳍通过改变鳍周围的速度和压力分布,并作用于涡的演变过程,进而影响尾水管中的涡带运动和压力脉动。在非空化工况下,鳍表面产生的附鳍小涡带起到稳定压力场的作用,降低了尾水管直锥段的压力脉动;而附鳍小涡带与主流区涡带的相互作用则恶化了尾水管弯肘段的流动,反而使得弯肘段压力脉动略微回升;在空化工况下,尾水管壁面加鳍显著降低涡带规模和空泡体积,使得尾水管的压力脉动得到明显削弱。To alleviate pressure fluctuation inside a Francis turbine draft tube working under part-load operation,a fin installed on the wall of the conical part is one effective method in engineering application.This paper investigates the effects of fin installation on the internal flow and pressure fluctuation inside the draft tube based on numerical calculation.Results show that a fin can change the velocity and pressure distribution around the fin.Further,the fin affects the vortex evolution in draft tube and consequently changes vortex rope and pressure fluctuation.Under non-cavitation condition,an extra small vortex rope occurs near the fin,which plays the role of pressure stabilizer and decreases the pressure fluctuation amplitude in the conical part.It is the interaction of the extra small vortex rope with the vortex rope in mainstream results in the complicated flow in the elbow part of the draft tube.As a result,in the elbow,there is a slight increase of pressure fluctuation amplitude.Under cavitation condition,the fin reduces the size of both vortex rope and cavity,and suppresses the pressure fluctuation in the whole draft tube.

关 键 词：尾水管 压力脉动 鳍 涡带 空化 

分 类 号：TK73[交通运输工程—轮机工程]