Analysis of Micro Vapor Bubble Growing Process in Open Capillary Microgrooves

Growing process of an individual micro bubble in open rectangular capillary microgrooves was theoretically analyzed in this study. Several common correlations of bubble growing radius for pool boiling, such as correlations of Zuber et al ^[1], Cooper et al ^[2], Labuntsov et al ^[3], and Zhao et al ^[4], were proved not precise. An improved method based on the dynamic microlayer model was presented in the paper. The method divided growing process of a micro vapor bubble into three stages: initial growing stage, normal and axial confined ellipsoidal growing stage, and axial subcylindrical growing stage. Heat transfer equations were established based on each stage’s characteristics. Growth period and volume increment of the micro vapor bubble were calculated in each stage. The calculation results show that growth of the micro vapor bubble is distinctly confined by geometric structure of microgrooves. The comparison of the results between calculation and experiment shows that the calculated bubble equivalent radius is consistent with the experimental results.