Effect of Gravity on Modeling for Gas-liquid Two-phase Flow in Pipe

In a thermal system of spacecraft, two-phase flow system now is an excellent alternative to the conventional single-phase system in transporting large amount of thermal energy at a uniform temperature regardless of variations in the heat loads. In addition, two-phase flows exist in a wide range of applications and enabling technologies in space. If, however, "understanding'' we mean that the phenomenon in two-phase flow system can be predicted in terms of governing parameter, it should be concluded that two-phase flow is poorly understood item for in space use, and many questions are still open. A thorough theoretical approach with such microscopic experimental results as three-dimensional and high spatiotemporal measurements is needed to assess the performance of two-phase flow for in space. Our recent study of gas-liquid two-phase flows at microgravity condition is outlined in this report, especially for which regarding to interfacical area transport and drift flux. Research on two-phase at micro- or reduced-gravity conditions is expected to be conducted more widely in the future, shedding light light on two-phase flow phenomena for in space use.