离心泵流动不稳定性机理及其控制

Hydraulic instability is the inherent factor that influences the safe operation of centrifugal pumps. This project will have a deep research into the mechanism of flow instability of centrifugal pumps and present corresponding control methods by combining theoretical analysis, numerical simulation and model test. The main research contents are as follows: 1) Experimental measurement and analysis of blades surface water pressure and dynamic stress under cavitation conditions. 2) Rotating boundary layer separation instability mechanism considering the curvature effect of blades, and the corresponding separation control methods. 3) Instability mechanism derived from interaction between jet-wake structure and tongue as well as rotor-stator interaction between impeller and volute, and the corresponding control methods. 4) Rotation stall mechanism and the control methods in some certain conditions. 5) Mechanism of flow instability, including rotating cavitation, considering the influence of cavitation with different cavitation numbers, and the corresponding control methods. 6) Multiphase flow government equations considering the interaction between cavitation, solid particles and water, and mechanism of multiphase flow instability with different cavitation numbers, and the corresponding control methods. The expected research findings will provide theoretical reference and technical support to raise the research and application level of centrifugal pumps.

水力不稳定是影响离心泵安全运行的内在原因，申请开展水力激励力分析数理模型、数值模拟、模型试验及方法验证评估研究，深入分析引起水力不稳定的流动机理及典型控制方法，内容有：1）含空化工况的叶轮叶片表面水压力和动应力实验测量分析；2）离心泵叶轮旋转边界层失稳机理及控制方法；3）叶轮出口射流-尾迹结构干涉作用机理及其控制方法；4）偏工况旋转失速发生机理及其控制；5）空化工况的流动不稳定性机理及其控制；6）水沙空化多相非定常流动数理模型、数值方法及多相流动失稳机理研究。可深入理解离心泵流动不稳定性机理及控制方法，促进提高离心泵应用基础研究水平。

水力不稳定是影响离心泵安全运行的内在原因，本研究综合运用数值模拟技术与试验测量手段对离心泵内部的流动不稳定性开展了深入研究，具体包括离心泵旋转边界层失稳机理、动静干涉机理及其控制；极低流量工况下的旋转失速发生机理、空化流动不稳定性机理、输送含沙水流时的流动不稳定性机理及其控制。建立了基于热力学方法的能量耗散分析体系，修正了空化模型，建立了描述水-沙-汽三相非定常流动的控制方程，提出了适用于离心泵内部流动的能量耗散研究方法，用以量化涡旋等流动现象；针对不同流量条件下离心泵单相与多相流动下叶轮分离涡旋、旋转失速、动静干涉、进口回流涡旋和隔舌冲击脱流等流动现象，定量比较了相应的能量耗散和压力脉动特性，对不同工况下的流动不稳定性特点进行了归纳与机理性分析，促进提高了行业内离心泵应用基础研究水平。