The Effect of Natural Convection on the Measurement of Mass Transport Coefficients in the Liquid State

摘要

This paper focuses on the effect of natural convection on the accuracy of solute diffusion coefficient measurements in liquid alloys in microgravity. We consider the cases of both isothermal diffusion and thermodiffusion (Soret effect). Numeri-cal simulations indicate that the error induced by additional convective transport scales with the square of the fluid velocity. Our main conclusion is that it is in principle possible to perform accurate measurements in space, but that the size of the capillaries used in the experiments should always be limited, especially in the case of highly concentrated alloys.