STUDY ON SUBCOOLED-FORCED FLOW BOILING HEAT TRANSFER AND CRITICAL HEAT FLUX OF SOLID-WATER TWO PHASE MIXTURE

摘要

The effect of solid particle introduction onsubcooled-forced flow boiling heat transfer and a critical heatflux was examined experimentally. In the experiment, glassbeads of 0.6 mm diameter were mixed in subcooled water.Experiments were conducted in a range of the subcooling of 40K, a velocity of 0.17-6.7 m/s, a volumetric particle ratio of 0 -17 percent. When particles were introduced, the growth of asuperheated liquid layer near a heat trasnsfer surface seemed tobe suppressed and the onset of nucleate boiling was delayed.The particles promoted the condensation of bubbles on the heattransfer surface, which shifted the initiation of a net vaporgeneration to a high heat flux region. Boiling heat trasnfer wasaugmented by the particle introduction. The suppression of thegrowth of the superheated liquid layer and the promotion ofbubble condensation and dissipation by the particles seemed tocontribute that heat transfer augmentation. The wall superheatat the critical heat flux was elevated by the particleintroduction and the critical heat flux itself was also enhanced.However, the degree of the critical heat flux improvement was not drastic.