Nonequilibrium thermodynamic behavior at the interface between steam film on the surface of high temperature premixing liquid drop and the surrounding water during steam explosion

摘要

To clarify the mechanism of steam explosion phenomenon, thermodynamic behavior at and around the interface between the vapor film on the surfaces of premixing high temperature liquid drops and the surrounding low boiling point liquid is one of the most important study items. In the present study, transient heat transfer experiments were performed with copper heater rod simulating a premixing liquid drop, of which heating surface was contacted to water. Two types of heat transfer mode were found. The one is almost pure heat conduction mode without phase change and the other is subcooled film boiling mode with violent bubble formation and collapse. The first type heat transfer mode is considered typical of the preixing stage of steam explosion. And the result of experimental analysis for such mode shows that the estimated interfacial temperature between the steam film and liquid water were much higher than the saturation temperature, T_(sat), but never reached the spontaneous nucleation temperature, T_(sn).