Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7058507 | International Journal of Heat and Mass Transfer | 2013 | 7 Pages |
Abstract
The objective of the experimental investigation was to quantify the axial dispersion of a dilute secondary gas that was subjected to orthogonal thermal and solutal buoyancy gradients in a horizontal annular-like enclosure. Test results showed that a linear axial concentration profile existed at steady-state for the secondary gas. Unheated tests with only solutal buoyancy gradients resulted in a dispersion multiple, DM, of approximately 8 times molecular diffusion. The combined thermal and solutal buoyancy tests, in which a thermal plume from the simulated heater packages aided in mixing, yielded an axial dispersion multiple coefficient of approximately 23 times molecular diffusion, a 188% increase as compared to solutal buoyancy alone. A correlation describing the experimental data trend for the dispersion multiple as a function of buoyancy ratio, NÂ =Â RaS/RaT, was computed to be DMÂ =Â 19.2Nâ0.061, which is valid for for binary mixtures where the solutal and thermal gradients are orthogonal with Pr and Le of order 1, 0Â <Â RaTÂ <Â 3.5Â ÃÂ 106, and 0.1Â <Â NÂ <Â 0.6.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Fluid Flow and Transfer Processes
Authors
D.L. James, W.F. Leggett, S.W. Webb,