Bi-Velocity Phase Field Method

2013 ◽  
Vol 333 ◽  
pp. 83-89
Author(s):  
Bartek Wierzba ◽  
Marek Danielewski ◽  
Andrzej Nowotnik ◽  
Jan Sieniawski
Keyword(s):  
Stress Field ◽  
Phase Field ◽  
Life Time ◽  
Field Method ◽  
Phase Field Method ◽  
Phase Zone ◽  
Two Phase ◽  
Gradient Coatings ◽  
Interdiffusion Coefficients ◽  
Kinetics Of

In this paper we couple the bi-velocity with the phase field method. It deals with: (1) the different mobility of the components in the two-phase zone; (2) nonzero steps of molar volumes for each component from phase to phase and (3) the composition dependent interdiffusion coefficients. The method allows to determine the average stress field during the diffusion process, the kinetics of the reactions and estimate the entropy production. The paper presents the numerical computations of diffusion in th eNiAlCr system. The results can serve as a basis in designing gradient coatings of extended life time.

Development of a Phase-field Method for Phase Change Simulations Using a Conservative Allen-cahn Equation

2021 ◽  
Author(s):  
Akinori Tamura ◽  
Kenichi Katono
Keyword(s):  
Phase Change ◽  
Phase Field ◽  
Computational Efficiency ◽  
Power Plants ◽  
Field Method ◽  
Industrial Applications ◽  
Phase Field Method ◽  
Benchmark Problems ◽  
Two Phase ◽  
Cahn Equation

Abstract Two-phase flows including a phase change such as liquid-vapor flows play an important role in many industrial applications. A deeper understanding of the phase change phenomena is required to improve performance and safety of nuclear power plants. For this purpose, we developed a phase change simulation method based on the phase field method (PFM). Low computational efficiency of the conventional PFM based on the Cahn-Hilliard equation is an obstacle in practical simulations. To resolve this problem, we presented a new PFM based on the conservative Allen-Cahn equation including a phase change model. The wettability also needs to be considered in the phase change simulation. When we apply the conventional wetting boundary condition to the conservative Allen-Cahn equation, there is a problem that the mass of each phase is not conserved on the boundary. To resolve this issue, we developed the mass correction method which enables mass conservation in the wetting boundary. The proposed PFM was validated in benchmark problems. The results agreed well with the theoretical solution and other simulation results, and we confirmed that this PFM is applicable to the two-phase flow simulation including the phase change. We also investigated the computational efficiency of the PFM. In a comparison with the conventional PFM, we found that our proposed PFM was more than 100 times faster. Since computational efficiency is an important factor in practical simulations, the proposed PFM will be preferable in many industrial simulations.

Application of Interface-Tracking Method Based on Phase-Field Model to Numerical Analysis of Isothermal and Thermal Two-Phase Flows

2007 ◽  
Author(s):  
Naoki Takada
Keyword(s):  
Phase Field ◽  
Density Ratio ◽  
Phase Field Model ◽  
Field Method ◽  
Diffuse Interface ◽  
Phase Field Method ◽  
Navier Stokes ◽  
Interface Tracking ◽  
Two Phase Flows ◽  
Two Phase

For interface-tracking simulation of two-phase flows in various micro-fluidics devices, the applicability of two versions of Navier-Stokes phase-field method (NS-PFM) was examined, combining NS equations for a continuous fluid with a diffuse-interface model based on the van der Waals-Cahn-Hilliard free-energy theory. Through the numerical simulations, the following major findings were obtained: (1) The first version of NS-PFM gives good predictions of interfacial shapes and motions in an incompressible, isothermal two-phase fluid with high density ratio on solid surface with heterogeneous wettability. (2) The second version successfully captures liquid-vapor motions with heat and mass transfer across interfaces in phase change of a non-ideal fluid around the critical point.

Development of meshless phase field method for two-phase flow

2018 ◽  
Vol 108 ◽  
pp. 169-180 ◽  
Author(s):  
Nazia Talat ◽  
Boštjan Mavrič ◽  
Grega Belšak ◽  
Vanja Hatić ◽  
Saša Bajt ◽  
...  
Keyword(s):  
Phase Field ◽  
Two Phase Flow ◽  
Field Method ◽  
Phase Field Method ◽  
Phase Flow ◽  
Two Phase
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