Smoothed mapping scheme for the VOF-DEM method in multiphase flow simulation

The unresolved CFD-DEM approach is developed to simulate the mixed flow of fluid and particles, which is very common in both industry and nature. As an extension, if the VOF model is implemented, multiple fluid phases would be enabled for CFD domain. To achieve that, the main challenge lies in the discontinuity of field mapping from the DEM domain to the CFD domain. Due the discontinuity, the minimum cell size of CFD is limited by the particle size, and the numerical stability is also affected greatly. To overcome the above issues, the kernel function is introduced to resolve the scalar variables of a particle into continued fields. Thus, the mapped terms due to coupling in CFD domain would be smoothed which improves the stability significantly. All the cells in the smoothing length of a particle would be considered in variable exchanging, so the limit on cell size is also released. Besides, this method doesn’t care about the type of mesh, the size variation over the whole CFD domain, and the particle gradation, which means it’s a versatile method. This smoothed VOF-DEM method is validated by the 2 cases.