Spray Cooling Model Study Based On Bubble Dynamics

With high heat transfer coefficient and uniform cooling temperature, spray cooling technology was widely used in high-power laser and micro-electronics fields. Spray cooling was a complex process which was affected by many factors, as the mechanism of heat transfer in spray cooling is complicated, most theories hitherto are immature.Based on the fundamental principle of boiling bubble dynamics, The two key parameters characteristic time and film thickness were got. The dynamic model with boiling was also established. a secondary nucleation model was developed to describe spray cooling process. This suggests that the number of aerosol particles is the most critical factor in spray cooling. The paper also provided an innovative characteristic time method to obtain secondary nucleation number. Numerical simulation study on the dynamics of a bubble rising in a viscous liquid was presented.The results illustrated that secondary nucleation as an important role in spray cooling. The calculation results explained why spray cooling always have a higher critical heat flux:droplets carried a large number of secondary nucleation, which take part in final heat transfer. Therefore, the second nucleation was the main heat transfer mechanism in spray cooling. Corresponding to different conditions, there are optimal values of nucleation factor and nucleation range factor. the results also showed that the critical heat flux spray cooling reduced under the influenced of the bubble deformation.