不同粒度颗粒在非恒定管流中跟随性试验

发布时间：2018-05-05 14:26

本文选题：非恒定流 + 低浓度　；参考：《水科学进展》2017年03期

【摘要】：管道中固液两相流水击对管道和输送系统可能产生严重的破坏,而固液两相在这种非恒定流中的运动特性是计算最大水击压力变化的重要依据。采用粒子图像测速技术(Particle Image Velocimetry,PIV),通过试验研究水击发生时,水平圆管中不同平均流速、颗粒粒径条件下,流体介质和粗颗粒在管道断面的速度分布以及粗颗粒跟随性的变化规律。研究结果表明:(1)在水击发生的不同时刻,圆管流中粗颗粒的流速在管道断面分布呈不规则的抛物线型分布,主要表现为靠近管道壁面底部的颗粒流速略小于靠近管道顶部流速,当颗粒粒径大于1.5 mm,平均流速小于2.5 m/s时,粗颗粒表现出明显的沉降特性;(2)粗颗粒的跟随性与颗粒受力有密切关系,其中颗粒速度与流体速度的变化量是影响颗粒受力的重要参数;(3)基于试验数据拟合得到了水击条件下粗颗粒跟随性系数k的经验公式,并分析了颗粒粒径、管道直径、两相流平均流速以及水击发生时间等不同参数对粗颗粒跟随性系数的影响,公式计算值与实测值之间的误差在5%以内。
[Abstract]:The solid-liquid two-phase flow impingement may cause serious damage to the pipeline and transportation system, and the motion characteristics of the solid-liquid two-phase in this unsteady flow are the important basis for calculating the maximum water hammer pressure change. Particle Image velocimetry technique is used to study the velocity distribution of fluid medium and coarse particle in pipeline section and the variation of coarse particle following property under the condition of different average velocity of velocity and particle size in horizontal circular pipe during the occurrence of water hammer. The results show that at different times of water hammer, the velocity distribution of coarse particles in the pipe flow is irregular parabola distribution, which mainly shows that the velocity of particle near the bottom of the wall of the pipe is slightly lower than that near the top of the pipe. When the particle size is larger than 1.5 mm and the average velocity of velocity is less than 2.5 m / s, the coarse particle has obvious subsidence characteristics. Among them, the variation of particle velocity and fluid velocity is an important parameter affecting the force of particles. Based on the experimental data fitting, the empirical formula of the coefficient k of coarse particle following under water hammer condition is obtained, and the particle size and pipe diameter are analyzed. The effect of different parameters such as the average velocity of two-phase flow and the time of water hammer occurrence on the coarse-particle follow coefficient is found. The error between the calculated value and the measured value is less than 5%.
【作者单位】：中央民族大学环境系;
【基金】：国家自然科学基金资助项目(51339008;51209238)~~
【分类号】：TV134

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