Experimental Comparison of Heat Transfer Data With Flow Visualization on a Flat Surface in an Air Fluidized Bed

Abstract

A new experimental technique is introduced which facilitates visualization of the fluid flow phenomena occurring on a small surface immersed in an air fluidized bed. The flow visualization was correlated qualitatively with heat transfer data from the surface. Heat transfer coefficients versus air velocity curves were obtained and found to be strongly dependent on the angle of inclination of the surface relative to the air flow direction. Flow visualization has facilitated the identification of three mechanisms of heat transfer to a surface as a function of the angle of inclination and the air flow velocity. These include, conduction through a stationary layer of particles, convection through a flow of solid particles, and heat transfer by sequential contact with voids and a well mixed conglomerate of solid particles.