THE BEHAVIOR OF AN IMMISCIBLE EQUAL-DENSITY LIQUID-LIQUID 2-PHASE FLOW IN A HORIZONTAL TUBE

Because of further increase in waste heat due to the greater power capacity of equipment for use in space, the thermal management system using vapor-liquid two-phase flow has been attracting greater attention in recent years. This has led to a decrease in system weight and pump power as a result of improvements in the heat transfer performance. However, new information on the flow and heat transfer characteristics under microgravity conditions is required. In particular, the local distribution of void fractions in the cross section under the microgravity condition is expected to differ from that on earth. The flow behavior is investigated using an equal-density liquid-liquid mixture (silicone oil and water) as the working fluid in a horizontal pipe 25 mm in ID., which causes the effect of gravity on the two phases to be diminished due to buoyancy. In this paper, the experimental results related to flow pattern, void fraction, and pressure losses are reported, and compared with other investigators' results.