BOILING HEAT TRANSFER IN A SHALLOW FLUIDZED PARTICULATE BED

Experimental data are presented which indicate the effects of a thin layer of unconfined particles on saturated pool boiling heat transfer from a horizontal surface. Results are presented for two different types of particles. These two particle types are the extremes of particles found as corrosion products or contaminants in boiling systems. For both particle types, vapor was observed to move upward through chimneys in the particle layer, tending to fluidize the layer. Compared with ordinary pool boiling at the same surface heat flux level, the experiments indicate that addition of light, low conductivity particles significantly increases the wall superheat, whereas addition of heavier, high conductivity particles decreases wall superheat. Heat transfer coefficients measured in experiments with a layer of copper particles were found to be as much as a factor of two larger than those measured for ordinary pool boiling at the same heat flux level. (Edited author abstract. )