Abstract: Two-phase gas-liquid flow is important for both scientific research and engineering application. The study of flow pattern is one of the most basic topics in this area. It is, however, an unfortunate fact that there isn't a generally recognized theory for flow pattern transition prediction because of its complexity at normal gravity. In microgratvity environment due to the absence of gralvity the dynamical interaction between different factors in the flow will be simplified and then flow patterns will becom...