Influence of heater thermal capacity on bubble dynamics and heat transfer in nucleate pool boiling

摘要

Using the Ghost Fluid Method for sharp interface representation, the complete single bubble pool boiling process including the transient thermal response of the solid wall is simulated numerically. Two level set functions are used for capturing the liquid-vapor-solid interfaces. Bubble dynamics and local heat transfer influenced by thickness and material parameters of the solid wall are analyzed at constant temperature on its bottom. For the same material and the same bottom temperature, growth time and departure diameter of bubble change slightly with the thickness. A clear local low-temperature region is produced inside the wall under the bubble base, which expands and recedes periodically with the movement of the three phase contact line. The movement of the local low-temperature region lags gradually comparing to that of the contact line with increasing thermal diffusivity of solid walls. Waiting time increases with decreasing thermal diffusivity of solid walls, resulting in thickened thermal boundary layer at nucleation, and then short bubble growth time and large departure diameter. (C) 2014 Elsevier Ltd. All rights reserved.