Mass Transfer—6 —-Fick’s Second Law of mass transfer SECOND FICK’S LAW OF DIFFUSION———-Applies to non- steady state diffusion. It states that the rate of change of concentration difference (dCx/dt ) is equal to the diffusivity times the rate of the change of the concentration gradient (D ∂2Cx/∂x2) provided diffusion coefficient ‘ D ’ is not a […]
MASS TRANSFER – 4–Convective Mass Transfer, its Empirical correlations, equimolar counter diffusion and Mass transfer Coefficients CONVECTIVE MASS TRANSFER AND ITS EMPIRICAL CORRELATIONS Before discussing convective mass transfer, it is necessary to compare convective heat transfer and convective mass transfer since there is a similarity between these two. In heat transfer, there is convective heat […]
MASS TRANSFER -3—-Fundamentals of Mass Transfer and Fick’s First Law Of Mass Transfer Fundamentals of Mass Transfer Maxwell-Stefan equations are used for the mass transfer in multi-component mixtures. Fick’s laws equations are limiting equations of Maxwell-Stefan equations. In these, it has been assumed that the mixture is extremely dilute and every chemical species is interacting […]
MASS TRANSFER Types of Diffusion (a) Concentration diffusion: Concentration diffusion is due to concentration gradient. Fick’s law gives a linear relation between the rate of diffusion of chemical species and the concentration gradient of that species. (b) Thermal diffusion: Diffusion due to a temperature gradient. Usually negligible unless the temperature gradient is very large. (c) […]
MASS TRANSFER- 1—Introduction to Mass Transfer, Mole and mass concentration, Mole and mass fractions Introduction Mass transfer may occur in a gas mixture Mass transfer may occur in a liquid solution Mass transfer may occur in a solid. The basic mechanisms of mass transfer are the same whether the phase is a gas, or a […]