Patino Narino, Edgar Andres
[Verfasser:in];
Galvis, Andres F.
[Verfasser:in];
Pavanello, Renato
[Verfasser:in];
Gongora-Rubio, Mario Ricardo
[Verfasser:in]
Bi-Phase Smoothed Particle Hydrodynamics Simulation of Co-Axial Bubbles Coalescence for the Moderate Reynolds Regimes
Beschreibung:
Phenomena involving bubble flow play a significant role in numerous industrial, natural, and scientific systems. Thus, liquid-gas interfaces must be considered the influence of the surface tension and buoyancy. A mesh-free method with Lagrangian formalism and successful simulations of problems with relations at various scales, phases, topology changes, and fluid-structure interactions is the Smoothed Particle Hydrodynamics (SPH) method. This work analyzes a complete numerical model for the simulation of bi-fluid flow for problems in the deformation evolution of two bubbles coalescing in a viscous liquid. Therefore, a proposed bi-phase 2D methodology using the Navier-Stokes equations approximated with SPH and associated with the Continuous Surface Force (CSF) method was employed to approach the interaction between the bubbles, the surrounding liquid, and cavity walls. This approach with SPH and CSF for fused bubbles and their liquid interaction are validated employing traditional numerical benchmarks (mesh-based methods) in situations with high and moderate regimes of the Reynolds (Re) and Eotvos (Eo) numbers, and different sizes of diameter between coalescence bubbles. However, examples of bubbles merging around a liquid owing to gravitational are rarely treated in the literature of mesh-free methods, especially to characterize different viscosity and surface tension regimes at the bubble–liquid interface, the effect of the method precision (distance between particles, ∆ x ), the size of the surrounding liquid cavity and the initial distance between lighter domains. Consequently, this study discusses diverse configurations of the coalescence bubbles dynamics parameters and their effect on the displacement of the center of mass, velocity, streamlines (vortex shedding), and evolution of the morphologies deformation. Hence, the resulting simulations revealed the process of the coalescence bubbles regarding three steps: approaching, drainage, and rupture of the interface. These steps reach different morphologies, defined as oblate ellipsoid, prolate ellipsoid, and ellipsoidal cap shapes between the trailing, leading, and merging bubbles. According to the bubbles deformation, during the coalescence is observed significant influence of ∆ x resolution and the cavity size, there are instances of instabilities, such as lateral tails, droplets inside the lighter domain, break-up, and satellite bubble formation. Finally, this study provides a characterized and robust bi-phase SPH algorithm for different surfaces tension regimes (5 ≤ Eo ≤ 200) and density ratio (10 and 100) in merging bubbles problems with moderates Reynolds numbers (5 ≤ Re ≤ 50)