An Experimental Investigation of Fluidization of Pebble Beds by Flows of Single-Phase and Two-Phase Media and Conditions for Prevention of this Fluidization

An experimental investigation is performed of the process of fluidization of pebble beds by single-phase (water) and two-phase media. Both free beds and those loaded from above (with constant and variable loads) are investigated. Results are given for the critical velocity of the beginning of fluidization. A significant difference is revealed between the processes of fluidization by single-phase and two-phase media. A strong effect of the bubbling of gas through water is observed in the case of a two-phase medium. A calculation procedure based on the value of average dynamic velocity of the mixture is suggested for the description of the process of fluidization in a two-phase medium. The dependence of the critical velocity of the beginning of fluidization on the load value is found for a loaded bed. The forces required to prevent fluidization in a bed are analyzed with an arbitrary orientation of the apparatus. The load dependence of the friction force of the bed is determined experimentally.