固体颗粒在竖直向上管内流场中的运动规律

对单个颗粒在竖直向上管内层流、紊流中及在液体发生相变时的运动规律进行了较为系统全面的分析，建立了计算方程。研究结果表明，颗粒在随流体轴向运动的同时还存在向管中心方向的径向迁移。固体颗粒到达管中心后会随流体一直向上运动。在近壁面处存在一个流化死区，流化死区的大小与流体流态、固体颗粒的大小和密度有关。固体颗粒尺寸及密度愈大，流速愈小，则流化死区愈大。液体相变对颗粒的运动也产生重要的影响。当热流密度不是很大，液体流量较小且在起始截面处的液相为单相饱和液体时，管内相变会对固体颗粒的运动规律产生明显的影响；而当液体流量较大且为紊流流动时，这一影响较弱

NUMERICAL SIMULATION OF MOTION OF A SOLID PARTICLE UP FLOWING VERTICALLY AT THE LIQUID FLOW FIELD INSIDE THE TUBE

The motion trajectory of a solid particle up flowing vertically at in tube liquid field of laminar and turbulent flows with/without steam generation is studied. The results show that the particle migrates in radial direction to the central region as it moves up with liquid flow. Under the given flowing conditions, there exists a region in the vicinity of the wall where the solid particle can not be fluidized. The size of this dead fluidization region is directly related to the diameter, the density of the particle and the liquid flow pattern. The smaller the particle and the lower the liquid velocity are, the smaller the region will be. It is also revealed by the computation results that the liquid phase change has an important effect on particle motion.