Modeling of convection and heat transfer in a spherical volume filled with supercritical hydrogen under microgravity conditions

A mathematical formulation of the problem of convective heat transfer in a spherical volume filled with supercritical hydrogen in space flight conditions, based on the three-dimensional nonstationary Navier-Stokes equations for a low-velocity compressible medium with a modified equation of state and variable thermophysical properties, is presented. To calculate the micro-accelerations in space flight, a quasi-static approximation is used. The regimes of enhancement and deterioration of heat transfer are found. It is shown that these regimes are associated with the transition of the operating parameters into the neighborhood of a "pseudocritical" point. Due to the additional mixing under the action of micro-accelerations in real flight conditions, the temperature differences in the working volume can be greatly reduced in comparison with the designed cases of low or zero gravity.