A comparison of existing flow-pattern predictions during forced-convective two-phase flow under microgravity conditions

Abstract The utilization of pumped two-phase flow loops in space-based thermal-power systems has been the subject of considerable attention from researchers in the past few years. Because of their ability to meet high-power-level demands over extended space structures, two-phase flow loops are favored over the conventional single-phase systems. Predictions of the influence of reducing gravity on the flow patterns (and their transitions) in two-phase flow are essential, since changes in the heat-transfer coefficients and the pressure drop are strongly coupled to changes that take place in flow patterns. This study summarizes the work that was done to date in this area and examines the now available flow-pattern maps for microgravity conditions with recommendations for future investigations.