冲击式水轮机喷射机构结构参数对泥沙磨损特性的影响机制  

Effects of structural parameters of the injector on sediment erosion characteristics in a Pelton turbine

作　　者：李琛玺 李方 郭鹏程[1,2] 孙帅辉[1] 沈佩荣 LI Chenxi;LI Fang;GUO Pengcheng;SUN Shuaihui;SHEN Peirong(Institute of Water Resources and Hydroelectric Engineering,Xi’an University of Technology,Xi’an 710048,China;State Key Laboratory of Eco-hydraulics in Northwest Arid Region,Xi’an University of Technology,Xi’an 710048,China)

机构地区：[1]西安理工大学水利水电学院,陕西西安710048 [2]西安理工大学西北旱区生态水利国家重点实验室,陕西西安710048

出　　处：《水利学报》2025年第1期93-105,共13页Journal of Hydraulic Engineering

基　　金：国家自然科学基金青年项目(52306051);国家自然科学基金面上项目(52479087);中国博士后科学基金面上项目(2022M722560);陕西省自然科学基础研究计划(2023-JC-QN-0412)。

摘　　要：泥沙磨损是冲击式水轮机面临的核心问题之一,特别是喷射机构直面高速含沙水流冲击极易磨损破坏,威胁机组安全运行。为深究喷射机构的磨损特性及影响机制,本文基于VOF模型、欧拉-拉格朗日方法及Oka磨损模型,构建了喷射机构的磨损分析模型。结合流动与颗粒运动轨迹分析可知,磨损最严重的位置在喷嘴喉部及喷针尖部,喷嘴喉部呈片状磨损且受迪恩涡对的影响在内侧的磨损范围更大,而喷针尖部主要呈点状磨损。本文选取喷针过渡段直径、喷针角度和喷嘴角度三个喷射机构的关键结构参数开展磨损特性影响机制的研究。结果表明,三个参数对喷嘴和喷针不同区域的磨损特性影响机制不同。其中喷针角度的影响最为显著,且其对磨损特性与水力性能的影响存在互抑性。一定范围内,随喷针过渡段直径的增大,喷针的磨损程度加剧,当过渡段直径增大至接近喷针直径时,针尖的平均磨损率急剧恶化为小直径时的9倍;随喷针角度增大,喷嘴喉部和喷针尖部的磨损程度改善,喷针尖部的平均磨损率最大可降低94.17%,但喷针角度对磨损特性与水力性能的影响存在互抑性;随喷嘴角度增大,可有效抑制喷针过渡段的磨损程度。因此,设计较大的喷针角度,配合较大的喷嘴角度与较小的喷针过渡段直径,可改善喷针的高磨损区与减小整体的磨损范围,并兼顾考虑水力性能的要求,进而可保障机组的高效安全运行。Sediment erosion is one of the core problems faced by Pelton turbines,especially when the injector is exposed to high-speed sediment-laden water flow,leading to erosion damage that threatens the safe operation of the turbine.To investigate the erosion characteristics and influence mechanisms of the injector,based on the VOF(Volume of Fluid)model,the Euler-Lagrange method,and the Oka erosion model,an erosion analysis model for the injector is established.Firstly,combining the analysis of internal flow and the trajectory of sediment particles,this paper indicated that the most serious erosion regions are located at the throat of the nozzle and the needle tip.The throat of the nozzle shows flake wear and is affected by the Dean vortex,resulting in a larger inner erosion area.The needle tip shows serious scattered erosion.Then,the nozzle angle,the needle angle,and the diameter of the needle transition section are selected as three key structural parameters of the injector to study the influence mechanism of erosion characteristics.The results show that these three parameters have different effects on the erosion performance of different regions of the injector.Within a certain range,the erosion degree of the tip increases with the increase in the diameter of the needle transition section.When the transition section diameter increases too close to the needle diameter,the average erosion rate of the tip deteriorates to 9 times the small diameter.With the increase of the needle angle,the erosion degree of the nozzle throat and the needle tip is improved,and the average erosion rate of the needle tip can be reduced by 94.17%,but the effects of the needle angle on erosion performance and hydraulic performance are mutually inhibitory.With the increase of the nozzle angle,the erosion degree of the needle transition section can be effectively inhibited.Therefore,the design with a larger needle angle,a larger nozzle angle,and a smaller diameter of the spray needle transition section can enhance the erosion resistance at the h

关 键 词：冲击式水轮机 喷射机构 水气沙三相流动 泥沙磨损特性 影响机制 

分 类 号：TK735[交通运输工程—轮机工程]