Numerical Simulations on Hydrodynamic Process of Melt Jet Breakup and Fragmentation With the Two-Phase Lattice Boltzmann Method

Jet breakup and fragmentation are important phenomena to be well understood during a core-disruptive accident of sodium-cooled fast reactors. The three-dimensional two-phase lattice Boltzmann model developed previously by the authors is improved in numerical stability used to simulate the hydrodynamic process of melt jet breakup. Nonorthogonal central moments is successfully introduced into the model. Numerical simulations of FARO-TERMOS experiments demonstrate the enhancements in stability of the present model. The simulations with two types of grid resolutions show the effect of spatial resolution on the results.

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Modeling of collapsing cavitation bubble near solid wall by 3D pseudopotential multi-relaxation-time lattice Boltzmann method

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406217740167 ◽

2017 ◽

Vol 232 (3) ◽

pp. 445-456 ◽

Cited By ~ 3

Author(s):

Minglei Shan ◽

Yu Yang ◽

Hao Peng ◽

Qingbang Han ◽

Changping Zhu

Keyword(s):

Relaxation Time ◽

Lattice Boltzmann ◽

Cavitation Bubble ◽

Solid Wall ◽

Three Dimensional ◽

Lattice Boltzmann Model ◽

Bubble Collapse ◽

Lattice Boltzmann Simulation ◽

Boltzmann Method ◽

Boltzmann Model

Understanding the dynamic characteristic of the cavitation bubble near a solid wall is a fundamental issue for the bubble collapse application and prevention. In the present work, an improved three-dimensional multi-relaxation-time pseudopotential lattice Boltzmann model is adopted to investigate the cavitation bubble collapse near the solid wall. With respect to thermodynamic consistency, Laplace law verification, the three-dimensional pseudopotential multi-relaxation-time lattice Boltzmann model is investigated. By the theoretical analysis, it is proved that the model can be regarded as a solver of the Rayleigh–Plesset equation, and confirmed by comparing the results of the lattice Boltzmann simulation and the Rayleigh–Plesset equation calculation for the case of cavitation bubble collapse in the infinite medium field. The bubble collapse near the solid wall is modeled using the improved pseudopotential multi-relaxation-time lattice Boltzmann model. We find the lattice Boltzmann simulation and the experimental results have the same dynamic process by comparing the bubble profiles evolution. Form the pressure field and the velocity field evolution it is found that the tapered higher pressure region formed near the top of the bubble is a crucial driving force inducing the bubble collapse. This exploratory research demonstrates that the lattice Boltzmann method is an alternative tool for the study of the interaction between collapsing cavitation bubble and matter.

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Lattice Boltzmann Simulation of Nucleation

Volume 2: Symposia, Parts A, B, and C ◽

10.1115/fedsm2003-45163 ◽

2003 ◽

Author(s):

Takeshi Seta ◽

Kenichi Okui ◽

Eisyun Takegoshi

Keyword(s):

Lattice Boltzmann ◽

Lattice Boltzmann Model ◽

Two Phase Flows ◽

Two Phase ◽

Lattice Boltzmann Simulation ◽

Expansion Procedure ◽

Theoretical Predictions ◽

Boltzmann Method ◽

Boltzmann Model ◽

Pseudo Potential

We propose a lattice Boltzmann model capable of simulating nucleation. This LBM modifies a pseudo-potential so that it recovers a full set of hydrodynamic equations for two-phase flows based on the van der Waals-Cahn-Hilliard free energy theory through the Chapman-Enskog expansion procedure. Numerical measurements of thermal conductivity and of surface tension agree well with theoretical predictions. Simulations of phase transition, nucleation, pool boiling are carried out. They demonstrate that the model is applicable to two-phase flows with thermal effects. Using finite difference Lattice Boltzmann method ensures numerical stability of the scheme.

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