黄河泥沙对双吸式离心泵性能影响的机理研究

With the large flow rate and high pump head, double-suction centrifugal pumps are widely used in irrigation pumping stations along the Yellow River. However, the performance of these pumps is affected by the characteristics of sediment particles in water flow, which has been seldom studied. Therefore, this project aims to investigate the effects of the sediment concentration and sediment size on pump performance by model test and numerical simulation. The main work includes: the effects of different sediment concentrations and sediment sizes on the turbulence structure, flow velocity and performance parameters of the double-suction centrifugal pump are researched on the model test rig; the whole three-dimensional flow model is established and the numerical simulation of the typical experimental conditions is carried out to analyze the mechanism of turbulent flow, flow velocity and sediment distribution effecting on the pump performance; combined with model test and numerical simulation, the relationship between sediment parameters and pump performance parameters is established. This project would provide scientific guidance for the design and operation of the double-suction centrifugal pumps in irrigation pumping stations along the Yellow River, and the achievements have important academic value and broad engineering application prospects.

双吸式离心泵由于其流量大、扬程高的特点而广泛应用于黄河沿岸提灌泵站中。当前，沿黄提灌泵站双吸式离心泵设计生产多是基于清水考虑，黄河泥沙对水泵性能影响的研究还不够深入。本项目以模型试验和数值模拟为手段，以阐明不同黄河泥沙水流条件下双吸式离心泵性能变化规律及揭示其影响机理为目标，主要研究工作包括：在模型试验台上，研究不同泥沙浓度、不同泥沙粒径对泵内紊流结构、水流流速以及水泵性能参数的影响；建立全三维流道模型并进行典型实验工况的数值模拟，分析含沙水流下泵内紊流结构、水流流速以及泥沙分布对水泵性能的影响机理；结合模型试验和数值模拟，建立泥沙浓度、泥沙粒径等与水泵性能参数之间的关系。本项目可以为沿黄提灌泵站双吸式离心泵的设计、运行提供科学依据，具有重要的学术价值和工程应用前景。

本项目研究了黄河含沙水流条件下双吸式离心泵性能的变化规律，揭示了黄河含沙水流条件下双吸式离心泵性能变化的影响机理，主要开展了以下三个方面的研究工作：研究了黄河泥沙浓度和泥沙粒径对双吸式离心泵性能特性的影响，揭示了泥沙对双吸式离心泵扬程、轴功率等特性的影响机理，建立了适合于黄河含沙水流的双吸式离心泵性能预测模型；探讨了不同运行工况下双吸式离心泵的压力脉动特性；阐释了不同流量和泥沙对双吸式离心泵振动的影响机理。研究结果表明：双吸式离心泵的扬程随着泥沙浓度和泥沙粒径的增大而下降，是由于泥沙颗粒和水体离开叶轮出口的相对速度和相对流动角不同，导致圆周分速度减小；轴功率随着泥沙浓度和泥沙粒径的增大而降低，是由于含沙水流中泥沙的制紊作用，使得阻力损失降低。离心泵由额定转速降低转速，压力脉动能大幅度降低，但转速降低到一定程度，压力脉动反而升高；在小流量和设计流量下随着泥沙浓度的增大，轴向振动强度呈先减小后增大的变化趋势，是泥沙制紊和泥沙在叶轮中不均匀分布综合作用的结果。本项目研究成果可为沿黄提灌泵站双吸式离心泵的优化设计、安全高效运行提供科学参考。