scholarly journals Hybrid atomistic-continuum simulation of nucleate boiling with domain re-decomposition method

2017 ◽  
Author(s):  
◽  
Bo Zhang
Keyword(s):  
Molecular Dynamics ◽  
Nucleate Boiling ◽  
Bubble Nucleation ◽  
Coupling Method ◽  
Dynamics Simulation ◽  
Small Scale ◽  
Coupling Scheme ◽  
Atomistic Region ◽  
Continuum Mechanic Model ◽  
Promising Solution

The bubble nucleation plays a pivotal role in the boiling process. In order to have a comprehensive understanding of this phenomenon, a critical consideration on fluid-solid interaction at atomistic level is imperative. However, traditional Molecular Dynamics simulation requires prohibited amount of computational efforts to accomplish a full scale study. Hybrid atomistic-continuum method is a promising solution for this problem. It limits the atomistic region to a small scale where detailed information is preferable, while using continuum method for the rest of the domain. Nevertheless, none of the current hybrid method is suitable for solving a rapid expanding system like the bubble nucleation. In this study, a domain re-decomposition hybrid atomistic-continuum method is developed to conduct a multiscale/multiphase investigation on the bubble nucleation. In addition to the conventional coupling scheme, this method is capable to re-partition the molecular and continuum domain once it is necessary during the simulation. That is, the Computational Fluid Dynamics (CFD) and Molecular Dynamics (MD) regions are interchangeable on the fly such that the bubble is absolutely confined within MD region. Giving the fact that accurate modeling of interface tracking and phase change are still problematic for continuum mechanics on microscale, our coupling method directly avoids these issues since CFD domain takes care of a single-phase flow while the molecular domain simulates the bubble growth. With this idea in mind, this approach enables us to investigate the nucleate boiling on nanostructured surface with higher resolution than complete continuum mechanic model based simulation. In the present result, it is observed that bubble grows at a curved surface imposed with a constant super heat after nucleate boiling occurs. Meanwhile, the energy flux flows from solid to fluid is measured during the entire process. It is believed that this coupling method is very promising in studying nano-bubble related multiphase problems on microscale.

Molecular Dynamics Simulation of Homogeneous and Heterogeneous Thermal Bubble Nucleation

2011 ◽  
Author(s):  
Min Chen ◽  
Yunfei Chen ◽  
Juekuan Yang ◽  
Yandong Gao ◽  
Deyu Li
Keyword(s):  
Molecular Dynamics ◽  
Heterogeneous Systems ◽  
Liquid Argon ◽  
Bubble Nucleation ◽  
Dynamics Simulation ◽  
Nucleation Temperature ◽  
The Common ◽  
Solid Walls ◽  
Common Understanding ◽  
Superheat Limit

Thermal bubble nucleation was studied using molecular dynamics for both homogeneous and heterogeneous systems using isothermal-isobaric (NPT) and isothermal-isostress (NPzzT) ensembles. Simulation results indicate that homogeneous thermal bubble nucleation is induced from cavities occurring spontaneously in the liquid when the temperature exceeds the superheat limit. In contrast to published results using NVE and NVT ensembles, no stable nanoscale bubble exists in NPT ensembles, but instead, the whole system changes into vapor phase. For a heterogeneous system composed of a nanochannel with an initial distance of 3.49 nm between the two solid plates, it is found that if the liquid-solid interaction is equal to or stronger than that between liquid argon atoms, the bubble nucleation temperature of the confined liquid argon can be higher than the corresponding homogeneous nucleation temperature, because of the more ordered arrangement of atoms within two solid walls nanometers apart. This observation is in contradiction to the common understanding that homogeneous bubble nucleation temperature sets an upper limit for thermal phase change under a given pressure. Compared to the system where the liquid-solid interaction is the same as that between liquid argon atoms, the system with reduced liquid-solid interaction possesses a significantly reduced bubble nucleation temperature, while the system with enhanced liquid-solid interaction only has a marginally increased bubble nucleation temperature.

Molecular dynamics simulation of Xe bubble nucleation in nanocrystalline UO2 nuclear fuel

2011 ◽  
Vol 419 (1-3) ◽  
pp. 140-144 ◽  
Author(s):  
Emily Moore ◽  
L. René Corrales ◽  
Tapan Desai ◽  
Ram Devanathan
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Nuclear Fuel ◽  
Bubble Nucleation ◽  
Dynamics Simulation

Molecular Dynamics Simulation of Bubble Nucleation in Superheated Liquid

2010 ◽  
Author(s):  
Chao Liu ◽  
Xiaobo Wu ◽  
Hualing Zhang
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Nucleation Rate ◽  
Homogeneous Nucleation ◽  
Argon Atom ◽  
Bubble Nucleation ◽  
Nucleation Theory ◽  
Dynamics Simulation ◽  
Superheated Liquid ◽  
Classic Nucleation Theory

The bubble homogeneous nucleation in superheated liquid argon is studied by molecular dynamics simulation in NVT ensemble. L-J potential is adopted for the interaction of argon atom. The simulated particle numbers of argon atom is 10976. The non-dimensional size of simulated box is 27.8×27.8×27.8. The initial non-dimensional temperature and density are 0.4 and 0.51 separately. The results show that the bubble homogeneous nucleation is divided into the waiting process, the appearing process of numerous small bubble nucleuses and the aggregation process of small bubble nucleuses. By fitting simulated data, we find that the bubble nucleation rate is eight orders of magnitudes bigger than the result of classic nucleation theory. The bubble nucleation rate increases along with the increasing of density and superheated temperature, which agrees well with one of classic nucleation theory.

Investigation of water bubble nucleation by using molecular dynamics simulation

2021 ◽  
Vol 334 ◽  
pp. 116037
Author(s):  
Yu-Jie Chen ◽  
Xue-Jiao Chen ◽  
Bo Yu ◽  
Wen-Jing Zhou ◽  
Qun Cao ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Bubble Nucleation ◽  
Dynamics Simulation

scholarly journals Nanoscale bubble study of cavitation inception on a platinum surface using molecular dynamics simulation

2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2953-2963
Author(s):  
Qiang Fu ◽  
Mengyuan Li ◽  
Xiuli Wang ◽  
Jianen Yu ◽  
Rongsheng Zhu
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Critical Value ◽  
Bubble Nucleation ◽  
Dynamics Simulation ◽  
Inhibitory Influence ◽  
Wall Surface ◽  
Platinum Surface ◽  
System Pressure ◽  
Cavitation Nuclei

The transient properties of liquid argon cavitation nuclei in platinum surface were studied by means of molecular dynamics simulation. The bubble nucleation, with a certain size and stability on the wall surface, was studied by different tensile distances and different wall wettabilities. Also the parameters of cavitation nuclei development, the system pressure, and the total pressure were analysed. The stability of cavitating nucleus growth is closely related to the metastable degree of the system and the wettability of the wall. The tensile distance of the wall surface has a critical value, and stretching greater than the critical value will induce a greater degree of instability in the system, which is conducive to the growth of the cavitation nucleus. A hydrophobic wall is more conducive to the growth of a cavitation nucleus, which is beneficial to spontaneous growth among cavitated nuclei, whereas a hydrophobic exerts has an inhibitory influence on cavitation nuclei.

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