Description

The students will gain knowledge in mechanisms of mass transport by diffusion both in homogeneous and porous media. Analogies and correlations between heat- momentum- and mass transport will be discussed and illustrated.

• Fick’s law of binary diffusion. Fluxes relative to average velocities and relative to fixed frames.
• Diffusivities in low density gases and in liquids
• The case of polymers and colloidal suspensions
• Diffusion in the presence of a phase change
• Diffusion in porous media. Fick vs. Knudsen diffusion
• Coupling of heat and momentum transport. The Nusselt number
• Couplings between mass- and momentum or heat transport
• The Maxwell-Stefan equations for multicomponent diffusion.

Compétences visées

At the end of this course:

• You will learn about order of magnitude of diffusivities in gases and condensed phases and about their temperature and pressure dependence.
• You will be aware of the analogies between mass- momentum- and heat transport, as well as of the couplings between them.
• You will be able to use relevant dimensionless numbers to describe and predict these couplings.
• You will be aware of the limits of Fick’s law of mass diffusion in the case of multicomponent systems and learn about the way to describe them.