Diffusion in the laminar boundary layer with a variable density

✍ Scribed by Owen T. Hanna

• Publisher: American Institute of Chemical Engineers
• Year: 1965
• Tongue: English
• Weight: 690 KB
• Volume: 11
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690110426

✦ Synopsis

The problem of isothermal diffusion in a variable molecular-weight binary gas mixture is considered for the case when the process occurs in a laminar boundary layer. Viscosity and diffusion coefficient are assumed constant. Solutions are given for both forced and free convection at large Schmidt numbers and large mass transfer rates toward the surface. Use of the molar average velocity considerably simplifies the results. These results suggest that the constant density solution in terms of mole fractions, evaluated a t free stream conditions, may be a good approximation for variable density. This technique, improved by an approximate correction derived herein, is shown to agree reasonably well with the results of exact numerical solutions of the boundary layer equations.