ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Heat and mass transfer and coagulation are considered as related to the mean-square relative velocity between particle and fluid uR2 and eddy diffusion as described by the mean-square particle displacement, Xp2. The mathematical methods used are similar to those employed in the early calculations of the Brownian motion.The mean-square relative velocity is obtained as a function of particle characteristics, intensity of turbulence, and a fluid correlation coefficient. In the limiting case of equal particle and fluid density uR2 = 0, and for very heavy particles uR2 → uF2.A general expression for the eddy diffusivity is obtained is obtained which reduces to the same form as that of the fluid for the stationary state. However, the correlation coefficient to be used in the calculations depends on uR2. As a first approximation, it can be assumed that at a sufficiently long time from the introduction of the particles, fluid and particle diffusivities are equal.For short times after injection, the particle spread may be much less than that of the fluid. An illustrative calculation for the initial spreading of a jet of suspended particles is offered. In all cases an effort is made to organize the available experimental data within the framework of the theory.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690030318
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