【摘要】 在河道清淤、全尾砂充填以及深海采矿等很多工程应用中,需要利用管道输送粗颗粒物料,以往对粗颗粒在管流中的运动特性研究较少,工程设计缺少参考依据.本文基于PIV技术对管流中粗颗粒浓度分布进行试验研究.试验中,采用了0.5、1.5、2.5mm三种粒径的石英砂作为输送物料,利用PIV记录了1.5、2.5、3.5m/s三种不同管流速度下颗粒在断面上垂向浓度分布特征.结果表明:在一定流速条件下,颗粒粒径越大,浓度分布越不均匀,浓度最大点的高度越低,最大浓度值越大;一定粒径条件下,流体平均流速越大,浓度分布越均匀,浓度最大点位置越高,最大浓度越小.基于量纲分析法和试验结果拟合,得到了颗粒垂向最大浓度点出现的相对高度与水流平均流速、颗粒粒径、管径的关系.最大浓度点位置计算值与实测值最大误差为10%.更多还原

【Abstract】 In many engineering projects,such as dredging river,total tailings backfill and deep sea mining,pipeline transportation is needed to transport coarse particles. Few researches about coarse particle kinetic characteristic have been done which makes engineering design inaccuracy.We use PIV to get the particle concentration distribution in vertical section under three velocities 1. 5、2. 5、3. 5 m/s and three different particle sizes 0. 5、1. 5、2. 5 mm respectively.The result shows that when the average flow velocity is the same,larger particle size will cause concentration distribution more uneven,lower height of the maximum concentration and the greater maximum concentration; When particle size keeps the same and average velocity of the fluid increases,the concentration distribution is more uniform,the location of maximum concentration is higher,and the maximum concentration is smaller. Based on dimensional analysis and experimental results fitting,the relationship between the comprehensive lift and the maximum particle concentration,the average velocity of flow,the particle size and the diameter of the particle are obtained by fitting,and the maximum error between the calculating point and the measurement point of maximum concentration point is 10%.更多还原