Gravitational Convection of a Liquid Mixture in a Horizontal Cylindrical Gap at Moderate Grashof Numbers

Weak concentration convection which arises in the process of diffusion of impurities into the solvent filling a gap between two coaxial cylinders is studied experimentally. It is found that convective motion in the range of Grashof numbers 10³–5 × 10⁴ has a clear boundary-layer character. Near the inner porous cylinder, which is a source of impurity, a diffusion boundary layer passing into a two-dimensional convective plume is formed. The data on the structure and thickness of this layer are presented depending on the integral flux of impurity. The prospects of making an experiment in order to discover concentration convection onboard an orbital station are discussed.