Prediction of Semi-fluidization Velocity of Irregular Particles in Liquid-Solid System

Abstract

I n an earlier paper (2), the authors have given two nomographs for the prediction of minimum and maximum semifluidization velocities. While it is necessary to know the ve- locity at which semi-fluidization begins (the first particle of the bed touches the top retraint) and also the velocity at which all the particles are transferred to the packed bed below the top screen, it is also necessary to know the variation of the height of the top packed bed with the change in velocity of the fluid, the two limits of the velocity being the onset of semi-fluidiza- tion velocity and the maximum semi-fluidization velocity. The values of fluid velocity in between the two extreme limits (the onset and the maxi- mum) are termed as semi-fluidization velocities which, along with other system variables, also depend on the particle oncentrations in the two sections of the bed. A glance into literature re- veals scanty informations in this aspect. Based on their experimental data, Roy and Sarma have given the following correlation for the prediction of semi-fluidization velocity of irregular parti- cles in liquidsolid systems from a knowledge of the properties of the system and the solid and fluid properties (3).