Exact solution of the capillary diffusion equation for a three-component mixture
O. E. Aleksandrov
Ural State Technical University, Ekaterinburg 620002
Pages: 391-396
Abstract
The paper gives an exact solution of the
steady system of equations for stable
three-component diffusion in the entire
range of concentrations for a long
capillary under a controlled capillary
pressure differential. The solution
allows one to calculate the
distributions of component
concentrations and mixture density along
the capillary. It is shown that if the
diffusion coefficients are markedly
different, an extremum of mixture
density can arise inside the capillary.
In particular, if the density of the
mixture in the upper flask is higher
than that in the lower flask and the
stratification of the system is
generally stable, a region with a
reverse density gradient that is
unstable against gravity convection can
appear inside the capillary. A
comparison with experimental results
shows that the resistance to gravity
convection is disturbed when an extremum
of mixture density arises in the channel
during steady diffusion.
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