The paper presents the results of numerical simulation of the separation process of liquid oxygen and gaseous helium under microgravity conditions in a spherical tank rotating about a transverse axis. The mathematical model is based on the Navier–Stokes equations for a two-phase incompressible fluid in a rotating reference frame. The volume of fluid (VOF) method in combination with the continuum surface force (CSF) model, which accounts for capillary effects and wall wetting, is used to track the interface. Turbulent characteristics are calculated using the two-equation k–ω SST turbulence model. A series of simulations was performed on successively refined unstructured polyhedral meshes (300k, 600k, and 1.5 million cells). A specialized clustering algorithm written in C was developed to automatically determine the separation time – the moment when more than 99% of the gas volume accumulates near the wall. It was found that insufficient spatial resolution leads to a simulation error in separation time of up to 20%. Transition from the intermediate mesh (600k cells) to the fine mesh (1.5 million cells) reduces the error to 7.7%. It is shown that the shift of the system’s center of mass along the X and Y axes reaches 6 mm and 5 mm, respectively, for a tank radius of 150 mm, and the projections of forces onto the walls reach a steady state after the completion of transient processes. The results are compared with data from the FLUIDICS space experiment.

EDN FNZZZO