ABSTRACT
This chapter explores the mass transfer in moving fluids. The presence of the convective term in the equation of continuity for species A usually introduces nonlinearity into the governing equation. Since the choice of a characteristic velocity is arbitrary, it is more convenient to select a characteristic velocity that will make the convective term zero and thus yield a simpler problem. The chapter analyses the steady-state and pseudosteady-state cases of the Stefan diffusion problem. Ozguler et al. studied the applicability of the Stefan tube in the diffusion coefficient measurements of nonvolatile solids in supercritical fluids. G. Taylor studied the dispersion of a soluble salt when injected into a stream of solvent in laminar flow through a long capillary. Later, R. Aris generalized the development by removing some of the restrictions imposed by Taylor. The chapter presents the development of the so-called Taylor-Aris theory based on the averaging technique.
