摘要
为探究弯管含沙水流的压力损失与流动特性,采用CFD-Eulerian多相流模型与k-ε湍流模型对45°和90°两种U-PVC弯管进行了数值模拟研究,并通过文献中的试验数据对建立的模型进行了验证.结果表明:含沙水流经过弯管时受转弯的影响,混合流流速分布沿水流方向逐渐不均匀,转弯后出口截面出现较大的流速梯度.随着流速的增加,两种弯管的压力损失均呈增大的趋势;不同流速时出口截面处水平径向的颗粒速度分布变化基本一致,在中间位置颗粒速度较大,在内管壁处颗粒速度较小;弯管出口的颗粒浓度梯度随流速的增大而增大.两种弯管的压力损失随颗粒浓度的增加而增大;不同浓度时出口截面的水平径向颗粒浓度变化趋势基本一致,在外管壁处浓度较低,内管壁处浓度较高;随着浓度的变化颗粒速度分布变化基本相同.两种弯管的压力损失随颗粒粒径的增大而增大;颗粒粒径变化时在出口截面处的颗粒速度分布相似;弯管出口断面的浓度变化梯度随粒径的增大而增大.
To investigate the pressure loss and flow characteristics of sediment flow in elbow,90°and 45°U-PVC elbows were simulated with the CFD-Eulerian multiphase flow model and k-εturbulence model.The established model was verified by experimental data in the literature.The results show that when sediment flow passes through the elbow,the velocity distribution of mixed flow is gradually uneven along the flow direction,and there is a large velocity gradient at the exit section after turning.The pressure loss of both elbows increases with the increase of flow velocity.The distribution of particle velocity in horizontal-radial direction at the exit section is basically consistent at different flow velocities.The velocity is larger in the middle position and it is smaller in the inner tube.The particle concentration gradient at the exit of elbow increases with the increase of flow velocity.The pressure loss of two elbows increases with the increase of particle concentration.The variation trend of horizontal-radial particle concentration in the outlet section is basically consistent at different concentrations.The particle concentration is lower in the outer wall and it is higher in the inner wall.The distribution of particle velocity is basically the same with the change of concentration.The pressure loss of two elbows increases with the increase of particle size.The particle velocity distribution in the exit section is similar when the particle size changes,and the concentration gradient in the exit section increases with the increase of particle size.
作者
石喜
陶虎
任建民
柴媛媛
井浩
SHI Xi;TAO Hu;REN Jianmin;CHAI Yuanyuan;JING Hao(College of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Gansu Institute of Soil&Water Conservation Sciences,Lanzhou 730020,China;Qinghai Communications Technical College,Xining 810000,China)
出处
《应用基础与工程科学学报》
EI
CSCD
北大核心
2021年第6期1418-1428,共11页
Journal of Basic Science and Engineering
基金
国家自然科学基金项目(51469012)
兰州交通大学青年科学基金资助项目(2016018)
青海省科技项目(2018-ZJ-733)
