Nucleate Boiling Modes of Subcooled Water on Fine Wires Submerged in a Pool

Abstract

An experimental investigation was conducted to observe nucleate boiling modes and their characteristics during pool boiling of subcooled water on very small wires. Different nucleate boiling modes, or large bubble and explosive small bubble boiling, were clearly and repeatly observed using a high-speed photography technology, and their coexistence was described and discussed for nucleate boiling, Dissolved air was found to play an important role in large bubble boiling mode and coexisting nucleate boiling. The heat generation characteristics also showed a great difference for different boiling modes. From the observation of the transition process from the large bubble boiling to explosive small bubble boiling, the equilibrium current and associated phenomena were experimentally investigated, and they all had very close relationship with the different boiling modes. Heat transfer model were also proposed to explain the phenomena and measured results, and the heat flux of the coexistence boiling had linear relation with the temperature.

Effect of Marangoni flow on subcooled pool boiling on micro-scale and macro-scale heaters in water and surfactant solutions

“…This result agrees with observations reported by Lu and Peng [10]. In looking at them very closely and carefully, the small jet flows existed around the heated wire, these findings agree with data reported by Lu et al [5]. The authors presented experimental observations for water boiling on a platinum wire of d = 100 lm at bulk liquid temperature 27°C, pressure 1.01 Â 10 5 Pa and at moderate heat fluxes q w = 0.8-1.6 MW/m 2 .…”

“…For water systems at near atmospheric pressure the heat fluxes of 10 MW/m 2 and higher can be achieved, (Inoue et al [3], Fukuda and Sakurai [4], Lu et al [5]). Full utilization of this mode of heat transfer requires reliable knowledge of its limitations such as heated surface geometry and the properties of the fluid.…”

Research progresses and future directions on pool boiling heat transfer

“…Experiments were conducted to investigate the efficiency of two distinctly different heat transfer enhancement methods using a thin vessel coating and an enhanced insulation structure for external reactor vessel cooling under severe accidental conditions [55]. Nucleate pool boiling characteristics during pool boiling of sub-cooled water on very small wires were studied [56]. The nucleate boiling of saturated water at high heat fluxes was numerically studied [57].…”