Mass Transport - 4PMPTDM9

Goal(s)

Describe and quantify the mass transport phenomena from a macroscopic approach, with special emphasis on the most usual limit cases in chemical engineering and electrochemistry

Content(s)

A - Fundamental concepts

• AI - Notion of flux and mass balance. Analogy between heat and mass fluxes. Particular case of the steady state regime
• AII - Decomposition of a mass flux into three contributions: diffusion, migration, convection (natural and unforced). Correlation with non-equilibrium thermodynamics: chemical potential gradient. Nernst-Einstein law (migration vs. diffusion)
• AIII - Ordre of magnitude and principal experimental techniques of determinations for diffusion coefficients, electric mobility and fluid velocity in different media (solid, liquid & gas phases)

B - Important particular cases

• BI - Fick law. A few examples of concentration profil shape (stationary & transient regimes) for different boundary conditions and cell geometries
• BII - Ohm law. Primary current distribution in a conducting system. Application to various geometries
• BIII - Film theory/Nernst model. Correlation with hydrodynamics (Levich, Sherwood,...). Double film model
• BIV - Diffusion with homogeneous chemical reactions : Hatta number, acceleration factor, etc.

C - More complex examples

• CI - Multi-component media (gas ou solution blends). From an ideal to a real system; multi-component diffusion (Maxwell-Stefan model)
• CII - Polyphases media (ex. Porous media). Notion of effective diffusion coefficients
• CIII - Coupled heat and mass transport

Basics in thermochemistry and heat transfer