scholarly journals Numerical Simulation of Two-Phase Flows with Phase Change Using a Phase-Field Method

2007 ◽  
Vol 2 ◽  
pp. 173-180 ◽  
Author(s):  
Naoki TAKADA ◽  
Akio TOMIYAMA
Keyword(s):  
Numerical Simulation ◽  
Phase Change ◽  
Phase Field ◽  
Field Method ◽  
Phase Field Method ◽  
Two Phase Flows ◽  
Two Phase

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.

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