Mesoscopic simulation of three-dimensional pool boiling based on a phase-change cascaded lattice Boltzmann method
Mesoscopic simulation of three-dimensional pool boiling based on a phase-change cascaded lattice Boltzmann method
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DOI：
10.1063/5.0023639
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发表时间：
2020-10-01
影响因子：
4.6
通讯作者：
Luo, Kai H.
中科院分区：
文献类型：
--
作者：
Fei, Linlin;Yang, Jiapei;Luo, Kai H.
本文采用三维级联格子Boltzmann方法(CLBM)模拟了气液相变过程。在改进的CLBM中引入赝势多相模型求解多相流场，用有限差分方法求解温度场，两场通过非理想状态方程耦合。通过对几个典型问题的数值模拟，验证了所提出的相变CLBM方法既适用于等温多相流，也适用于汽液相变过程。利用所提出的方法，模拟了一个完整的三维池沸腾过程，模拟了多达数百个自发产生的气泡，真实地再现了核态沸腾、过渡沸腾和膜状沸腾过程。结果表明，三维模拟预测的临界热流密度与所建立的理论和关联式的吻合程度高于二维模拟的结果。此外，还发现随着壁面过热度的增加，气泡足迹面积分布由指数分布变为幂函数分布，这与实验结果一致。此外，还获得了对前两个最大气泡足迹的瞬时和时间平均特征的见解。
In this paper, a three-dimensional (3D) cascaded lattice Boltzmann method (CLBM) is implemented to simulate the liquid-vapor phase-change process. The multiphase flow field is solved by incorporating the pseudopotential multiphase model into an improved CLBM, the temperature field is solved by the finite difference method, and the two fields are coupled via a non-ideal equation of state. Through numerical simulations of several canonical problems, it is verified that the proposed phase-change CLBM is applicable for both the isothermal multiphase flow and the liquid-vapor phase-change process. Using the developed method, a complete 3D pool boiling process with up to hundreds of spontaneously generated bubbles is simulated, faithfully reproducing the nucleate boiling, transition boiling, and film boiling regimes. It is shown that the critical heat flux predicted by the 3D simulations agrees better with the established theories and correlation equations than that obtained by two-dimensional simulations. Furthermore, it is found that with the increase in the wall superheats, the bubble footprint area distribution changes from an exponential distribution to a power-law distribution, in agreement with experimental observations. In addition, insights into the instantaneous and time-averaged characteristics of the first two largest bubble footprints are obtained.