Mass and momentum transfer at a wall in the presence of turbulence promoters

✍ Scribed by A. Storck; F. Coeuret

• Publisher: Elsevier Science
• Year: 1977
• Tongue: English
• Weight: 546 KB
• Volume: 22
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(77)80055-8

✦ Synopsis

Abstrac

-This paper deals with the infiuence of cylindrical turbulence promoters on mass and energy transfers at the wall of a narrow channel with a Rowing liquid. The experimental distributions of the mass-transfer coefficients and shear stresses along the wall appear to be similar. The results show that an elementary "mesh step" is reproduced periodically when the promoters are very near the wall. For this case, a model assuming symmetrical boundarv lavers between two .neiahbourine orematers, allows a quantitative correlation OF the local mass-transfer coefficient and the lo&l velociry-*gadient at the wall. NOMENCLATURE channel thickness concentration molecular-diffusion coefficient microelectrode diameter cylinder diameter distance between cylinders cylinder-wail distance local mass-transfer coefficient local mass-transfer coefficient defined by (1) overall mass-transfer coefficient dVx s = 7 velocity gradient at the wall SC = ; Schmidt number x length coordinate Y normal coordinate u mean liquid velocity VX length velocity VY . normal velocity p dynamic viscosity V kinematic viscosity z = &S shear stress at the wall