离心泵叶轮全寿命周期泥沙磨损机理

Sediment erosion is inevitably faced by hydraulic machinery operated in silt laden river, and it is also a bottleneck problem of safe and high-efficient operation of the unit. Erosion position and erosion rate are always paid close attention in previous research, but the erosion mechanism is seldom mentioned. In this research, a centrifugal pump, which is the most widely used in the Yellow River Diversion Project, is taken as the object of study. By means of on-site data collection, model test and numerical simulation, sediment erosion mechanism of the pump impeller from its initial use to final wear failure is to be revealed. This research includes the following parts: Investigate the typical pumping station of the Yellow River to establish the corresponding relationship between impeller erosion morphology and running time, operating conditions and sediment properties; fabricate the experimental impellers of different erosion morphology and conduct experiments on the typical sediment concentration, particle size and operating conditions to observe the variation of erosion position and erosion intensity of the impeller; make observations to the surface morphology of the blade and the hub using scanning electron microscopy to determine the erosion type on each region of the impeller; develop an erosion prediction model suitable for the characteristics of sediment in the Yellow River, based on the Finnie’s erosion model and Oka’s erosion model; analyze the trajectories and erosion manners of sediment particles at different erosion stages to clarify the erosion law of the impeller in its whole life-cycle; propose the optimal shape parameters of anti-erosion centrifugal pump impeller and a long-life operation scheme. This study is of great significance for the research and development of anti-erosion hydraulic machinery.

泥沙磨损是多泥沙河流上运行的水力机械面临的普遍问题，也是制约机组高效、稳定运行的瓶颈问题。相关研究对磨损位置、磨损率等宏观特性关注较多，对细观层面的磨损机理研究较少。本研究以引黄工程中广泛应用的离心泵为对象，采用现场数据采集、模型试验和数值模拟方法，揭示离心泵叶轮从投入使用到磨损失效全过程的泥沙磨损机理。研究内容包括：对黄河典型泵站进行数据采集，分析泥沙物性、测量不同磨损阶段的叶轮形貌；制作不同磨损阶段的试验叶轮，对典型泥沙浓度、粒径和运行条件进行试验，观测叶轮磨损位置和磨损强度的动态变化；采用扫描电子显微镜观测叶片和轮毂面的磨损形态，分析叶轮各区域对应的磨损类型；基于Finnie切削磨损模型和Oka变形磨损模型，构建适合黄河泥沙的水泵磨损预测方法；分析不同磨损阶段的颗粒运动轨迹和磨损机理；探索抗磨损离心泵叶轮的优化结构参数和优化运行方案。对于多泥沙河流水力机械的研发具有重要的指导意义。

泥沙磨损是多沙河流上运行的水力机械面临的普遍问题，也是制约机组高效、稳定运行的瓶颈问题。本研究以引黄工程中广泛应用的离心泵为对象，采用现场数据采集、模型试验和数值模拟方法，研究了离心泵叶轮的泥沙磨损破坏机理、磨损预测方法及仿生抗磨损技术。研究结果表明：叶片表面磨损面积随运行时间的变化趋势符合双曲正切函数变化规律；泥沙粒径对离心泵叶片表面的泥沙磨损强度和磨损位置均产生影响，而泥沙浓度主要影响磨损强度，随着泥沙浓度增大，叶片表面磨损加重；流道涡的存在会显著改变颗粒在叶轮流道内的运动轨迹，颗粒会跟随漩涡加速运动后被甩出漩涡、撞击叶轮造成严重的磨损破坏；颗粒绕漩涡的运动过程与颗粒受到的离心力与向心力的平衡密切相关，颗粒速度较小时，颗粒受到的向心力大于离心力，颗粒在曳力作用下绕漩涡加速运动，颗粒速度增大后，向心力无法平衡离心力，颗粒被甩出漩涡撞击壁面；Qian磨损模型在Oka模型的基础上增加了考虑小角度磨损的滑擦磨损项，能够准确预测水泵叶片表面的颗粒磨损，适用于沿黄工程中水力机械的磨损预测；采用仿生抗磨技术，叶片表面的磨损强度和磨损面积均显著降低；仿生凸包体表面形成的漩涡结构能够改变叶片表面水流相对速度的分布并降低与叶片表面发生碰撞的颗粒数量，使仿生叶片具有更好的抗磨损特性。本项目提出的Qian磨损模型已应用于水轮机的泥沙磨损预测，离心泵仿生抗磨技术已在多个引黄工程中示范应用，取得了很好的抗磨效果。研究成果对于多沙河流抗磨水力机械的研发具有重要的指导意义。

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