Abstract Diffusive mass transfer has interested scientists for at least three centuries. Accurate, user‐friendly, and inexpensive methods are constantly being developed to estimate binary gas diffusion coefficients required to analyze chemical engineering processes. This proof‐of‐concept study combines in a novel approach radial mass transfer with rotating concentric vertical cylinders forming an annular compartment in which laminar Couette flow prevails. The mass transport theory is well‐established in the literature, while the rotating fluid mechanics have been described mathematically and documented photographically by several groups. The present work computed the steady mole fraction profile of gas A across the annular space, originating at a sublimating inner cylinder surface which rotates while the outer one is stationary. Cylinder dimensions were chosen arbitrarily, but based on the relevant literature. The molar flux of species A at the interface obtained analytically was equated to that given by a published mass transfer correlation for rotating vertical cylinders, leaving the binary gas diffusivity, D AB , as the only unknown. The “experimental” diffusivity, D ABexp , was thus estimated and compared with reference values like those given by the Chapman–Enskog kinetic theory for low‐density gases. Sublimating solids naphthalene and camphor were tested along with three published mass transfer correlations obtained by their proponents for the turbulent flow regime. Even with these limitations, D ABexp absolute errors were calculated for all parameter combinations, the lowest being +1.6% for naphthalene‐air and −0.3% for camphor‐air. These results validate the proof‐of‐concept theory presented, which awaits experimental verification to make it a useful method for D AB estimation.
Carlos A. Ramı́rez (Mon,) studied this question.