三种泥沙扩散系数模型对双吸离心泵内固液两相流流场计算的影响  

Influences of three types of sediment diffusion coefficient model on thecalculation of solid-liquid two-phase flow in double suctioncentrifugal pump

作　　者：张自超 李延频[1,2] 张兰金[1,2] 陈德新[1,2] ZHANG Zichao;LI Yanpin;ZHANG Lanjin;CHEN Dexin(College of Energy and Power Engineering,North China University of Water Resources and Electric Power,Zhengzhou 450045,China;Henan Fluid Machinery Engineering Technology Research Center,North China University of Water Resources and Electric Power,Zhengzhou 450045,China)

机构地区：[1]华北水利水电大学能源与动力工程学院,郑州450045 [2]华北水利水电大学河南省流体机械工程技术研究中心,郑州450045

出　　处：《农业工程学报》2023年第7期77-88,共12页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(51909094);华北水利水电大学高层次人才科研启动项目(201705010)。

摘　　要：作为模拟双吸离心泵内固液两相流的一种常用方法,欧拉-欧拉法中的泥沙扩散系数常通过多种模型进行计算。为选择适宜的泥沙扩散系数模型进而提高固液两相流数值计算的精度,该研究采用3种常见泥沙扩散系数模型Non-diffusion coefficient model(NON-DC);Diffusion-in-volume of fluid model(Diffusion-in-VOF);Diffusion coefficient affected by particle diameter and particle concentration model(DC-PDPC),在25、100和200μm 3种含沙粒径和不同流量(0.6和1.0倍额定流量)条件下,对双吸离心泵内固液两相流场进行数值模拟,分析其对泵内固相浓度和固相速度的定常和非定常结果的影响。结果表明:1)当颗粒粒径不大于100μm时,3种模型计算得到的双吸离心泵内固液两相流的固相浓度和速度定常结果基本相同;当颗粒粒径大于100μm时,定常结果有所差异,随着颗粒粒径的增大,差异逐渐增大,差别最大可达60%。2)在不同颗粒粒径的条件下,采用3种模型得到的固液两相流场的固相浓度和速度非定常结果差异较大,且随着颗粒粒径的增大,差异逐渐增大,差别最大可达30%。含沙颗粒粒径不大于100μm时,3种模型得到的定常结果基本相同;而大于100μm时,定常结果差异较大;同样地,在不同含沙粒径条件下的非定常计算结果也差异较大,需要选择合适的泥沙扩散系数模型。3)定常计算时,当颗粒粒径不大于100μm时,推荐NON-DC模型;随着颗粒粒径的增大,推荐使用DC-PDPC模型;当非定常计算时,推荐使用DC-PDPC模型。研究为准确地进行离心泵内固液两相流数值计算提供参考。Euler-Euler models can be used to describe the fluid and particulate phase suitable for the two-phase flow in a double-suction centrifugal pump.The sediment diffusion coefficient is one of the most important moduli to express the interaction between the solid-liquid phases.There are the commonly-used three models of the semi-empirical sediment diffusion coefficient.In this study,the NON-DC,Diffusion-in-VOF,and DC-PDPC models were used separately to numerically simulate the solid-liquid two-phase flow field in the double suction centrifugal pump.A systematic analysis was also made to clarify the effects of the three models of sediment diffusion coefficient on the steady and unsteady solid phase concentration and velocity at different flow rates under three particle sizes of 25,100,and 200μm.The results show that there was a similar steady calculation of solid-liquid two-phase flow in the double-suction centrifugal pump using different models of sediment diffusion coefficient under different particle sizes and rated operating conditions.However,there was a greatly different unsteady distribution in the solid phase concentration using different models of sediment diffusion coefficient.Specifically,the difference increased gradually under low flow conditions with the increase of particle size.Different models of sediment diffusion coefficient shared little influence on the steady solid-liquid two-phase flow for the small diameter particle no more than 100μm,but there was a great influence on the large diameter particle greater than 100μm under low flow conditions.Meanwhile,the steady solid-liquid two-phase flow was basically the same,when the particle size ds was less than or equal to 100μm.Once the particle size was more than 100μm,the difference of steady increased gradually with the increase of particle size.The greatly different unsteady solid-liquid two-phase flow field was found under the conditions of different particle sizes,where the difference increased gradually with the increase of particle size.Ther

关 键 词：泥沙 数值分析 模型 双吸离心泵 扩散系数模型 定常 非定常 

分 类 号：TH311[机械工程—机械制造及自动化] S224[农业科学—农业机械化工程]