Abstract
For a steam generator with straight double-walled heat transfer tubes that will be used in a sodium cooled faster breeder reactor, clarification of flow instability in heat transfer tubes is one of the most important research themes. As the first step of the research, thermal hydraulics experiments with water were performed under high pressure condition in JAEA with using a circular tube. Pressure drop, heat transfer coefficients and void fraction data were derived. This paper summarizes the pressure drop characteristics under 15MPa. Several two-phase flow multipliers were checked and then, it was found that both Chisholm two-phase flow multiplier and homogeneous model can predict the present experimental data in high accuracy. A sudden decrease of the pressure drop was observed when flow pattern shifts from bubbly and churn flows to annular flow. The reason for this decrease is tried to be interpreted.
