Thermal-Hydraulic Experiments Under High Pressure Condition

For steam generator with straight double-walled heat transfer tube that used in sodium cooled Faster Breeder Reactor, flow instability is one of the most important items need researching. 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 multiplier models were checked and Chisholm model and homogeneous model were found being the best ones for the prediction of present data. A sudden pressure drop decreasing tendency was observed when flow pattern shifts from bubbly/churn flow to annular flow. The reason for this decrease is tried interpreted.