Investigation of interfacial area concentration transport of bubbly flows in small diameter pipe at normal and micro-gravity environment

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The two-fluid model is considered most accurate and rigorous model as a two-phase flow analysis utilized in various engineering fields such as mechanical, nuclear and chemical engineering. The two-fluid model consists of six equations of mass, momentum and energy equations for each phase. In order to make the two-fluid model useful, the interfacial transfer term given by the product of the interfacial area concentration and the driving force should be given accurately.This study focuses on the development of the interfacial area transport equation of bubbly flows in a small diameter pipe at normal and microgravity conditions, and the construction of the database.The following researches have been made at relatively low Reynolds number where the effect of the gravity on the flow parameters would be enhanced.1. Construction of the database at normal gravity condition2. Modeling of source and sink terms of the interfacial are a concentration3. Evaluation of the interfacial area transport equationBased on the above results, the following conclusions are obtained as1. The dominant interfacial area transport mechanism at low Reynolds number under normal gravity environment is wake entrainment.2. The dominant interfacial area transport mechanism at low Reynolds number under micro gravity environment is pseudo-wake entrainment.3. The relative velocity between phases is not zero even at micro gravity conditionsThis research is expected to contribute the design criteria of two-phase flow machines at micro gravity conditions.