Nonbuoyancy density-driven convective mass and heat transfer : scaling analysis and solution methodology
Density change during mass or heat transfer can cause convection in the absence of buoyancy forces. Prior studies have shown that this convection can be significant in the determination of diffusion coefficients and in the casting of polymeric membranes. Including this effect is challenging even...
Saved in:
| Main Authors: | , , , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | English |
| Published: |
2013
|
| Online Access: | https://hdl.handle.net/10356/99702 http://hdl.handle.net/10220/11017 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Institution: | Nanyang Technological University |
| Language: | English |
| Summary: | Density change during mass or heat transfer can cause convection in the absence of
buoyancy forces. Prior studies have shown that this convection can be significant in
the determination of diffusion coefficients and in the casting of polymeric membranes.
Including this effect is challenging even for advanced numerical codes. A general
methodology for obtaining the mass-average velocity for unsteady-state, one-dimensional,
multicomponent mass and/or heat transfer circumvents the problem of numerically
solving the coupled continuity equation. Scaling analysis permits assessing the
importance of this convection for a generic equation-of-state. Numerical predictions
for evaporation from a liquid layer for components having density ratios of 1:1 and
0.7:1 indicate that ignoring convection results in errors of 34% and 24% in the evaporation
time and final thickness, respectively. This convection also influences the evaporation
in the percutaneous application of cosmetics, medications, and insecticides, curing
of paints, varnishes, and lacquers, and formation of thin films. |
|---|