球阀固-液两相流流动特性与压力损失数值模拟

来源期刊:中南大学学报(自然科学版)2021年第5期

论文作者:石喜 贡力 陶虎 李露 李江涛

文章页码:1681 - 1692

关键词:Eulerian模型;PVC球阀;流动特性;压力损失

Key words:Eulerian model; PVC ball valve; flow characteristics; pressure loss

摘    要:为了研究PVC球阀中固-液两相流流动特性与压力损失变化规律,采用Eulerian多相流模型对DN75球阀进行数值模拟,探讨球阀的流场特性、颗粒分布特征以及压力损失的变化规律,评价其影响因素。研究结果表明:球阀开度对流场影响较大,随着开度减小,阀芯内混合流流速梯度增大,在阀后形成漩涡,漩涡尺度随阀门开度减小而增大;开度不同时,球阀进口断面颗粒体积分数分布基本相似,而阀芯截面和出口截面在小开度时颗粒体积分数分布较乱;混合流压力损失随流速增大而增大,随球阀开度增大而减小,随颗粒体积分数增大而增大;而压力损失随颗粒粒径的变化趋势与阀门开度有关,当开度为70°~90°时,压力损失随着粒径增大而增大;当开度为40°~60°时,压力损失随粒径的增大减小;以显著性水平α=0.05为检验标准,多因素方差分析结果表明颗粒体积分数和颗粒粒径对压力损失的影响不显著;而进口流速和球阀开度对压力损失具有显著影响,其中球阀开度对压力损失的影响最显著。

Abstract: To study the flow characteristics of solid-liquid two-phase flow and pressure loss of PVC ball valves in PVC ball valve, Eulerian multiphase flow model was adopted to simulate DN75 ball valve. The flow field characteristics, particle distribution and pressure loss of ball valve were discussed, and the influencing factors were evaluated. The results show that the opening of ball valve has great influence on flow field. The gradient of mixed flow velocity in the valve core increases with the decrease of valve opening, and a whirlpool forms behind the valve. The scale of the whirlpool increases with the decrease of valve opening. The distribution of particle volume fraction in the inlet sections of the valve is basically similar at different openings, while in the core and outlet sections, it is disorder at small openings. The pressure loss of mixed flow increases with the increase of flow velocity, and decreases with the increase of ball valve opening and increases with the increase of particle volume fraction. The changes of pressure loss with particle size is related to valve opening, which increases with the increase of particle size when the opening is 70°-90° and decreases when the opening is 40°-60°. Taking the significance level α=0.05 as test standard, multi-factor variance analysis shows that the influence of particle volume fraction and particle size on pressure loss is not significant. However, the flow rate and the ball valve opening have significant effects on the pressure loss, and the valve opening is the most significant factor.

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