A THEORETICAL AND EXPERIMENTAL-STUDY ON SUBCOOLED FLOW BOILING AT HIGH HEAT-FLUX

In a subcooled flow boiling system at high heat flux, the major heat t ransfer mechanism places emphasis on a very thin liquid layer, known a s the 'sublayer' which is trapped between the heated surface and the v apor blankets. Base on the convective boiling heat transfer dominated by the heat conduction through the liquid sublayer, a theoretical mode l for subcooled flow boiling heat transfer has been developed. To prov ide useful data in the simulation of Light Water Reactors (LWRs) condi tions, heat transfer experiments for up-flow boiling water through a v ertical tube at the pressure ranging from 6.9 to 15.5 MPa have been co nducted. The experimental results are compared with the predictions of the present model and other five famous correlations. For the LWRs su bcooled flow boiling, the comparison reveals that the present model sh ow the best agreement with the measured data.