INVESTIGATION OF SUBCOOLED FLOW BOILING HEAT TRANSFER AT 1 ~ 3 BAR
Subcooled flow boiling experiments have been performed to obtain a better understanding of vapor bubble behavior under nucleation and entrainment by liquid flow. The main objective of this work is to obtain data to validate 3-D Interface Tracking Models and CFD models which can predict subcooled flow boiling phenomena in fuel assemblies of Pressurized Water Reactors (PWRs). In the experiment, the test section is a vertically oriented annulus of 6.35mm gap width with electrically heated inner rod with thermocouples embedded on the heated surface. Subcooled water at pressures from 1-3bar flowed upward through the test section under turbulent flow conditions. Liquid Reynolds numbers range between 26,000~55,000, with heat fluxes between 15~42kW/m2. The experiments yielded bubble size and directly measured wall temperature data. Measurements were taken using a high speed video camera with simultaneous temperature acquisition.