Abstract

Ostwald ripening refers to a process of a particle/droplet/bubble system under thermal equilibrium state adjusting the size distribution spontaneously to reduce the total surface energy. With knowing lack in numerical studies, a lattice Boltzmann approach is used to simulate the ripening process of two dimensional vapour bubble cluster dominated by phase transition kinetics. By comparing the numerical results with the theoretical prediction derived in two dimensional space, it is shown that the lattice Boltzmann method is accurate in the simulations. The results also indicate that the mass transfer in liquid phase is driven by hydrodynamic pressure distribution and the hydrodynamic collapse of bubbles influences the size distribution function in small size region. The impact of the parameters of the equation of state of the material is studied further. A positive relation between phase transition speed and specific internal energy is proposed, which enhances the thermal fundamental of phase transition.

Highlights

  • A linear fitting shows the slope of ks = 0.6845, and the arrows show the directions of the ripening processes for large and small bubbles, respectively

  • W − ks relation, where W denotes mechanical work done in phase transition

  • 将上式代入 (二维)析出相体积守恒方程, R2F dR = tβ+3α R2fdR = const, (A.1)

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Summary

Introduction

1) (西北工业大学, 航海学院, 西安 710072) 2) (浙江大学, 航空航天学院, 杭州 310027) 研究同时表明, 蒸汽泡系统演化过程中物质输运为液相压力不平衡所驱动, 并且在 小汽泡“溃灭”过程中水动力学作用会影响汽泡群半径分布函数的局部细节; 汽–液状态方程参数对熟 化过程的影响效果分析显示, 汽液两相比内能差是驱动相变的核心要素, 此差异越大相变速率越快— 该结论进一步诠释了化学势驱动熟化过程的物理图像. ‫ ؼ‬Ostwald熟化, 格子Boltzmann方法, 相变, Lifshitz-Slyozov-Wagner理论 PACS: 05.70.Fh, 05.20.Dd, 05.70.Np, 47.55.dp * 国家自然科学基金 (批准号: 11872315, 51879218, 52071272)、基础前沿项目(JCKY2018-18)、陕西省自然科学基 础研究计划资助项目(项目编号: 2020JC-18)资助.

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