冲击式水轮机喷射机构泥沙磨损特性的数值模拟  

Numerical simulation of silt erosion characteristics of an injector of Pelton turbine

作　　者：葛新峰[1] 孙洁[1] 李阳 吴丹 张雷[3] 化洪昌 GE Xinfeng;SUN Jie;LI Yang;WU Dan;ZHANG Lei;HUA Hongchang(College of Energy and Electric Engineering,Hohai University,Nanjing 210098,China;College of Materials Engineering,Jiangsu University of Technology,Changzhou 213001,China;Yellow River Institute of Hydraulic Research,Zhengzhou 450003,China)

机构地区：[1]河海大学能源与电气学院,江苏南京210098 [2]江苏理工学院,江苏常州213001 [3]黄河水利科学研究院,河南郑州450003

出　　处：《水利学报》2020年第12期1486-1494,共9页Journal of Hydraulic Engineering

基　　金：中央高校基本科研业务费(2015B02814);国家自然科学基金面上项目(51579080)。

摘　　要：为分析泥沙颗粒的直径及浓度对喷射机构磨损位置和磨损率的影响,基于Fluent平台对模型冲击式水轮机的喷射机构进行了三维建模,在水气两相流非定常计算稳定的基础之上,加入离散相,应用基于颗粒轨道的欧拉-拉格朗日法对水气沙三相进行了非定常数值模拟。在泥沙体积分数为1%的条件下,泥沙径粒分别取0.01、0.05、0.4和1 mm;在泥沙径粒为0.05 mm的条件下,泥沙体积分数分别取1%、2%、3%、4%和5%。结果表明,喷嘴出口处的压能大部分转化为了动能,且喷嘴出口处出现了负压;随着泥沙径粒的增加,泥沙的随流性会变差;泥沙径粒影响喷嘴的磨损范围,但喷嘴表面的磨损位置是相似的;喷针头部的针尖位置更容易受到细小颗粒的磨损,且喷针的过渡段磨损与径粒大小呈正相关;喷射机构受到的最大磨损率随泥沙浓度的增加而增大;在同一泥沙浓度下,喷嘴受到的磨损要大于喷针;泥沙浓度的增加会使喷嘴、喷针的磨损率增加,但泥沙颗粒的运动轨迹及喷针磨损的位置是相似的。In order to analyze the effect of the diameter and concentration of silt particles on the erosion location and erosion rate of the injector,the nozzle and needle of a Pelton turbine were modeled,and the unsteady calculation was carried out for the two-phase flow.After the flow field is stabilized,the discrete model was added.Then the Eulerian-Lagrangian method based on particle orbit was used to simulate the unsteady three phases of water,air,and sand.With a sediment volume fraction of 1%,the sediment diameters were set to 0.01,0.05,0.4 and 1 mm,respectively.With the sediment diameter of 0.05 mm,the volume fraction of silt was set to 1%,2%,3%,4%and 5%,respectively.The results show that most pressure energy of the nozzle is converted into kinetic energy.With the increase of sediment diameter,the fluidity of silt becomes worse.The diameter of the silt affects the erosion range of the nozzle,but the erosion position of the nozzle surface is similar.The needle tip is more likely to be erosion by fine particles,and the erosion of the nozzle tip is positively correlated with the size of the diameter particles.The maximum erosion rate of the injector increases with the increase of silt concentration.At the same silt concentration,the erosion of the nozzle is larger than that of the needle.The erosion rate of nozzle and needle increase with the increase of silt concentration,the movement track of silt particles,and the position of needle erosion are similar.

关 键 词：冲击式水轮机 喷射机构 磨损 离散相模型 非定常数值模拟 

分 类 号：TK735[交通运输工程—轮机工程]