Numerical simulation of the collision of two microdroplets with a pseudopotential multiple-relaxation-time lattice Boltzmann model
Numerical simulation of the collision of two microdroplets with a pseudopotential multiple-relaxation-time lattice Boltzmann model
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DOI：
10.1007/s10404-013-1202-0
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发表时间：
2014
影响因子：
2.8
通讯作者：
E. Monaco;G. Brenner;K. Luo
中科院分区：
文献类型：
--
作者：
E. Monaco;G. Brenner;K. Luo
采用晶格玻尔兹曼方法对两个等尺寸液体微滴在气相中的碰撞进行了数值研究。采用的多相公式是对状态方程和力合并进行改进处理的伪势模型，然后与多重松弛时间格式相结合。这样就可以详细研究以高密度比和相关惯性效应为特征的微液滴碰撞。为了涵盖先前实验研究中提出的所有碰撞机制，报告了与大范围流动参数（例如韦伯数和雷诺数）相关的模拟。从表面张力驱动的聚并（包括惯性聚并和粘性聚并）到伴随子微滴形成的灾难性破裂，模拟表明LBM正确地再现了几乎所有机制下的碰撞动力学和最终结果。观察到不同的破裂机制，如末端挤压和毛细波诱导的破裂。最后，对惯性主导的正面碰撞过程的初始阶段进行了研究，再次证明了这种多相LBM实现的有效性和可靠性。
Collisions of two equally sized liquid microdroplets in gaseous phase are numerically studied by the lattice Boltzmann method (LBM). The multiphase formulation adopted is a pseudopotential model with improved treatment of the equation of state and force incorporation which is then coupled with the multiple-relaxation-time scheme. That allows a detailed investigation into microdroplet collisions characterized by high-density ratios as well as by relevant inertial effects. Simulations related to a wide range of flow parameters (e.g. Weber and Reynolds numbers) are reported, in order to embrace all the collisional regimes presented in previous experimental studies. From surface tension-driven coalescence (both inertial and viscous coalescence have been examined) to catastrophic break-up with the formation of children microdroplets, the simulations demonstrate that the LBM correctly reproduces the collision dynamics and the final outcomes in almost all the regimes. Different break-up mechanisms like end-pinching and capillary wave-induced break-up have been observed. Finally, the initial stages of the inertia-dominated head-on collision process have been studied, showing once more the effectiveness and reliability of this multiphase LBM implementation.