On Heat Transfer Mechanism of Nucleate Boiling with MEMS Sensors : 3rd Report, Evaluation of the Approach Method and Heat Transfer Characteristics of Isolated Boiling Bubble(Thermal Engineering)

Abstract

This paper describes a novel approach method to the heat transfer mechanism beneath isolated bubble during nucleate boiling with MEMS (Micro-Electro-Mechanical Systems) sensors. Fast and local temperature variation beneath an isolated bubble measured with the MEMS sensor obviously showed the microlayer formation, evaporation, dry-out and rewetting phenomena. The heat transfer due to the bubble growth process was numerically evaluated by two-dimensional transient heat conduction simulation with the measured data as a boundary condition. Heat transfer from surrounding superheated liquid layer was also estimated. The approach method was verified through a comparison between a bubble growth process and the heat transfer analysis results both from the heating wall and from the liquid phase. Moreover, the measurement and analysis showed some heat transfer characteristics related to the mechanism of microlayer evaporation, heat transport by an isolated boiling bubble, initial thickness of the microlayer and liquid-vapor interface superheat for high heat flux evaporation.