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 cap acity of equipment for use in space, the thermal management system usi ng vapor-liquid two-phase flow has been attracting greater attention i n recent years. This has led to a decrease in system weight and pump p ower as a result of improvements in the heat transfer performance. How ever, new information on the flow and heat transfer characteristics un der microgravity conditions is required. In particular, the local dist ribution 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 (silicon e 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 diminish ed due to buoyancy. In this paper, the experimental results related to flow pattern, void fraction, and pressure losses are reported, and co mpared with other investigators' results.