Unsteady mixed convection in horizontal ducts with applications to chemical vapor deposition processes
✍ Scribed by Robert E Spall
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 371 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0735-1933
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✦ Synopsis
Mixed convection in a horizontal rectangular duct of aspect ratio 4 heated from below with cold side walls was studied numerically for a non-Boussinesq fluid. Results are presented for a reduced temperature of 2.33 and a Rayleigh number of 130,700. The resulting flow field at Re = 25 consisted of four steady longitudinal vortices, symmetric about the duct centerline, with a leading transverse roll cell. A reduction to Re = 10 resulted in the introduction of traveling transverse waves. A further reduction Re = 5 resulted in a loss of symmetry about the duct centerline plane. Further work is underway to verify the Re = 5 results.
Chemical vapor deposition (CVD) involves the deposition of molecules from the fluid phase onto a substrate, with the deposition rate being governed by the rate of diffusion from the fluid to the surface, and by chemical kinetics. C'VD is used in the fabrication of a wide range of industrial components, including optical devices, solid-state electronic devices, cutting and grinding tools, and optical and magnetic recording media. Although tolerances on the quality of the film (for instance, film thickness) vary with