Mahdi Saeedipour, Achuth Balachandran Nair, Stefan Pirker,
"A coupled volume of fluid-fictitious domain method to study droplet-particle interactions at different impact conditions"
: Proceedings of International Conference on Liquid Atomization and Spray Systems (ICLASS-2021), 2021
Original Titel:
A coupled volume of fluid-fictitious domain method to study droplet-particle interactions at different impact conditions
Sprache des Titels:
Englisch
Original Buchtitel:
Proceedings of International Conference on Liquid Atomization and Spray Systems (ICLASS-2021)
Original Kurzfassung:
Multiphase flows involving interactions between spray droplets and moving solid particles are frequently encountered in many industrial and environmental processes. Upon collision, the droplet may experience different regimes depending on the impact conditions as a balance between capillary and inertial forces. In this study, we present a coupled interface capturing-fictitious domain method for the fully-resolved interaction of fluid-fluid interfaces with solid particles. We follow the one-fluid formulation for the volume of fluid (VOF) method to capture the interface between the liquid droplets and surrounding gas. Also, an immersed boundary concept is employed to account for the solid particle motion and track the interactions with the droplets at the contact line. In this fictitious domain approach, the finite volume cells occupied by the solid particle are identified by a smooth particle representation algorithm. The presence of the particle in those cells is introduced by a void fraction scalar function that is zero at the particle regions and one elsewhere. The hydrodynamic body and surface forces acting on the particle are computed separately over the particle-covered cells, and the particle moves under Newton?s second law. Then, a continuous force field is applied at particle-covered cells as a penalty term in the momentum equation. Consequently, the VOF algorithm is also adjusted to prevent from penetration of interface into the particle region. This guarantees the mass conservation of the method. To evaluate the method performance, first, a 3D benchmark problem of the free fall of a solid particle onto the water-air interface is tested. Then, a 3D configuration is considered for droplet-particle interaction where a water droplet and a solid particle start approaching each other in the surrounding gas medium. The collision behavior at different impact velocities and particle to droplet diameter ratios are pictured, and the outcome regimes are characterized based on pre-impact Weber numbers. The present approach is developed within the open source C++ libraries of OpenFOAM and LIGGGHTS® codes and can be further employed for the fully-resolved description of the interfacial physics in droplet-laden flows in the presence of poly-dispersed moving particles, which is an essential step for multiscale simulation techniques.
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