β Scribed by Mingheng Shi; Yanbing Zhao; Zhongliang Liu
No coin nor oath required. For personal study only.
An investigation on the effects of solid particles on boiling heat transfer enhancement is performed. The range of particle diameter is from millimeter to nanometer. The experimental results show that boiling heat transfer can be enhanced greatly by adding the solid particle into the liquid whether in fixed particle bed or in fluidized particle bed. The boiling enhancement is closely related to the particle size, the initial bed depth and the heat flux applied. The experiments show that boiling characteristics are greatly changed when a particle layer is put on the heated surface. The major effects of fixed particle bed on nucleate pool boiling heat transfer are the nucleation, bubble moving and thermal conductivity effect. A boiling heat transfer correlation is obtained to predict the boiling heat transfer coefficients in a liquid saturated porous bed. A volumetric convection mechanism of boiling heat transfer enhancement by fluidized particles is proposed. The calculated results from the model suggested in this paper agree reasonably with the experimental values.
π SIMILAR VOLUMES
The heat transfer coefficients between the particles and the fluidizing medium under unsteady state conditions, are determined by transient heating of cold water stream, with hot solid particles dropped into the fluidizing bed, in a specially designed liquid fluidizing column. Heat transfer coeffici
A physically based model is proposed for heat transfer to immersed surfaces in large particle fluidized beds. ' Large' particlesare distinguished as those with thermal time constants substantially greater than their residencetime at a heat tran sfersurface. At typical fluidized bed combustor operati
Partlcle-to-emulsion and mterpartrcle heat transfer rates were estimated in the range 1 5 G u/u,,,f 6 3 5, 0 69 c $ G 2 15 mm by drymg wet refractory partlcles m fluldlzed beds of smular dry partlcles of the same sues Overall particle-toemulslon heat transfer coefficients decrease roughly as the mve
## Abstract Fluidized beds are particularly favored as chemical reactors because of their ability to exchange heat through immersed heatβexchange surfaces. However, little is known about how the heatβexchange process works on a singleβparticle level. The most commonly applied theory of fluidized be