Terminal Velocities of Single Spherical Particles Falling in a Water-Filled Vertical Pipe.

Abstract

Terminal velocities of single solid particles or bubbles are one of the most fundamental knowledges required for modeling and simulation of dispersed two-phase flows in vertical pipes. However, there are few available correlations which can cover a wide range of parameters, i.e., the ratio of a particle diameter to a pipe diameter, particle density as well as the falling motions of particles such as rectilinear and rocking. In this study, we proposed a semi-empirical model of terminal settling velocity which can cover a wide range of parameters, based on a singular pressure loss about a particle. Experiments were also carried out to develop an empirical correlation based on the proposed semi-empirical model of terminal settling velocity of a particle falling through a liluid-filled pipe. It was confirmed through comparisons of terminal velocities between the measurements and the developed correlation that the proposed model can give good estimations of terminal velocities under various terminal settling conditions.