Combined Residual Natural and Marangoni Convection in a Liquid Sphere Subjected to a Constant and Variable Micro‐Gravity Field

Abstract The combined effect of thermal Marangoni convection induced by a gradient of temperature imposed upon the free surface of a liquid sphere and the residual natural convection steming from the still existing micro‐gravity field in an orbiting space laboratory has been investigated. The case of a constant and linearly dependent axial residual gravity field has been considered, for which the Stokes equation in the approximation of Boussinesq have been solved. By the introduction of a dynamic Bond‐number derived as the ratio of the Grashof number to the Reynoldsnumber based upon the Marangoni flow the predominance of Marangoni‐ (for B̃o → 0) or natural convection (for B̃o → ∞) could be determined. Streamlines, radial‐ and angular velocity distributions have been obtained analytically. The combined effect of Marangoni‐ and natural convection is of importance for space processings. In addition the isothermal lines are presented for various imposed temperature distributions at the free surface of the liquid sphere.