EXPERIMENTAL INVESTIGATION OF HEAT TRANSFER TO A METALLIC ROD IN A FLUIDIZED BED OF SMALL PARTICLES

The effect of heat carriers on heat transfer to a cylindrical metal bar was investigated in a pilot scale fluidized bed with small spherical solids (2.7 mm glass beads and steel balls). Rods of aluminum and steel, each with 10 and 20 mm diameter and 60 mm length, were heated by means of hot air. In each experiment the temperature of the center of solid was measured at various intervals of time. The effect of various parameters such as air velocity, air temperature, mass ratio of fluidizing material to solid, type of fluidizing material, diameter of fluidizing material and diameter of solid were investigated. It was found that presence of small spherical fluidizing solids enhances the rate of heat transfer. The rate of heat transfer increases with decreasing solid diameter, increasing the fluidizing material thermal conductivity, and increasing air temperature, but air velocity and amount of fluidizing material have no significant effects on the rate of heat transfer in well- fluidized systems.

کلیدواژه ها:

Fluidization ، Heat carrier ، Heat transfer coefficient