Multicomponent Diffusion Revisited

S. H. Lam

Department of Mechanical and Aerospace Engieering

Princeton University

Princeton, NJ 08544


In a multicomponent fluid, the species-specific mass diffuion flux is related to the gradients of all the species (and temperature and pressure) by a diffusion coefficient matrix. Normally, this matrix is derived using kinetic theory, and the derivation involved sophisticated mathematics. This paper rederived the classical results---including thermal diffusion---using only macroscopic concepts and equations. In particular, the non-uniqueness of this diffusion coefficient matrix is emphasized and discussed.


Published in Physics of Fluids, Vol. 18, issue #7, July, 2006.

Click here to download a .pdf file of ths paper.


 Between Eq.(6) and Eq.(7):   "Since mass can neither be created nor destroyed ..."

 Reference 19: Its publication year was 1981, not 1961.