Rayleigh-Benard convective instability: concentration Rayleigh number for isothermal passive transmembrane transport processes
Slezak, A.
Polimery W Medycynie 34(1): 27-37
2004
ISSN/ISBN: 0370-0747 PMID: 15222225 Document Number: 569581
We derive a formula of the concentration Rayleigh number for isothermal membrane transport processes. The formula include diffusive permeability coefficient (omega ks), concentration polarization coefficient ([symbol: see text] ki) and solution parameters: density (rho), kinematic viscosity (nu), diffusion coefficient (Dks). Coefficients omega ks and [symbol: see text] ki were determined for configurations A and B of the single-membrane cell system, which consisted a flat polymeric membrane and glucose in 0.2 mol.l-1 aqueous ethanol solutions. In configuration A water was placed in compartment above the membrane and the solution below. In configuration B the arrangement of water and solution was reversed. The results of calculation showed that critical value of concentration Rayleigh number (Rsi) in configuration A is (R1A)crit. = 277.1 and in the configuration B--(R1B) = 225.2.