基于粗颗粒体积解析模型的低浓度固液两相泵内流动特性研究

Low efficiency and abrasion exist in solid-liquid two-phase flow transportation by centrifugal pump. For the internal complex flow characteristics are not revealed, the design method for two-phase pump needs to be improved. So this type of pump is designed by modified general method. The volume effect of major particle and inter forces are introduce into analysis except to variety of the two-phase mixture, strong restriction of wall, secondary flow of mixture. So the solid-liquid two-phase flow is very complicated. There are two key problems. The first one is to establish a two-phase two-way coupling model between the disperse phase and the continuous phase. The second one is to study the relationship of pump performance and non-dimensional number represented by operating condition, solid parameter and pump characteristic length. .In this project, the volume effect correction and inter force analysis will be applied to research the low concentration solid-liquid flow in centrifugal pump. The two-phase two-way coupling model is established. Based on simulated results and experiment results of the centrifugal, the internal two -phase flow behaviors are revealed. The relationship of pump performance and different parameters is developed. The conclusion will provide fundamental support for the design of high performance solid-liquid two-phase centrifugal pump.

固液两相输送离心泵一直存在效率低下和磨损导致的可靠性差等问题，主要原因在于其内部复杂两相流场特性尚未被揭示，相应的两相流泵设计方法不够完善，目前主要还是采用清水泵方法设计后加以经验修正。但由于泵所输送固相参数的多样性，壁面对介质的强约束作用和混合介质的二次流动，再加上粗颗粒的其体积效应及相间作用力不能忽略，泵内两相流动异常复杂，存在以下两个关键科学问题：一是粗颗粒离散相和流体连续相之间的两相双向耦合模型的建立，二是基于工况参数、固相参数与泵特征长度表征的无量纲数与泵性能关系的研究。.本项目拟针对泵送过程中的低浓度固液两相流问题，基于体积效应修正和相间力量级分析，建立粗颗粒-流体两相双向耦合流动模型，对泵内两相流动进行数值模拟，结合实验研究揭示泵内复杂两相流动规律，确定各参数与泵输送性能之间的相互关联，为高性能固液输送泵的设计应用提供理论支持。

离心泵在进行固液两相输送时一直存在效率低下和磨损导致的可靠性差问题，主要原因在于其内部复杂两相流场特性尚未被揭示，相应的两相流泵设计方法不够完善，需在揭示泵内流动规律的基础上进行修正。但由于泵所输送固相参数的多样性、复杂流道中的二次流动、再加上粗颗粒的其体积效应及相间作用力，泵内两相流动非常复杂，导致对其进行研究困难很大。重点需要解决粗颗粒离散相和流体连续相之间的两相计算模型确立问题，以及各工况参数、固相参数与泵性能关联关系问题。.本研究针对粗颗粒固液混输泵内部的两相流动进行研究，通过理论分析、数值模拟和实验研究等方法，基于相间力分析，发现粗颗粒体积效应显著，由此获取了适合的颗粒受力模型；基于颗粒与干湿壁面的碰撞反弹实验，发现湿壁面对颗粒的碰撞反弹规律产生重要影响，由此获得相应的碰撞反弹模型；基于不同两相模型的数值计算，结合实验结果对比分析，完善了考虑体积效应的固液两相计算模型，将上述模型用于离心泵内部固液两相流动数值模拟，完成了离心泵内部不同粒径、不同浓度、不同流量等工况下的泵内部流动特性与水力性能和磨损性能之间的关联分析，获得了扬程和效率等水力性能参数、流道内部磨损部位、磨损种类和磨损程度与各工况参数的关系，建立了离心泵固液两相混输的性能参数计算公式。项目研究成果可为基于实际介质的固液混输离心泵三维水力设计提供理论支持。