Dynamics of viscous coalescing droplets in a saturated vapor phase

Abstract

The dynamics of two liquid droplets coalescing in their saturated vapor phase are investigated by Lattice Boltzmann numerical simulations. Attention is paid to the effect of the vapor phase on the formation and growth dynamics of the liquid bridge in the viscous regime. We observe that the onset of the coalescence occurs earlier and the expansion of the bridge initially proceeds faster when the coalescence takes place in a saturated vapor compared to the coalescence in a non-condensable gas.We argue that the initially faster evolution of the coalescence in the saturated vapor is caused by the vapor transport through condensation during the early stages of the coalescence.

Collision-induced jet-like mixing for droplets of unequal-sizes

“…It is worth noting that, the present methodology, by using the potential form of surface tension and the isotropic finite difference, is able to suppress the notorious spurious current to a relatively low level even at large density ratios [26]. Consequently, it has been successfully applied to a variety of droplet dynamics problems, including but not limited to droplet collision [25,30], droplet impact on surface [36], as well as droplet coalescence [21,40]. According to our test, the spurious current of the present model is on the order of 10 -5 (lattice unit, LU), which is significantly smaller than the characteristic velocity of the colliding droplet (on the order of 10 -2 LU),…”

Development of an Efficient Meso- scale Multi-phase Flow Solver in Nuclear Applications

“…In addition to the stability issue, we have found out that the Cahn-Hilliard type equation cannot conserve mass when drops or bubbles become smaller than the certain critical radius [3][4][5]. We have recently proposed a model that conserves the mass of small drops and bubbles in YEAR 4 [6]. 4) Vremans LES model was incorporated into the FE-LBM code.…”

“…Figure12: Kelvin-Helmholtz instability of two immiscible fluids. Left: AMR-LBM; Right: benchmark [6].…”

Comment on “Viscous coalescence of droplets: A lattice Boltzmann study” [Phys. Fluids 25, 052101 (2013)]

“…The differences in the numerical models and how they relate to the liquid bridge growth are described in Ref. 7. We used the compressible LBE model 6 to model coalescence in a saturated vapor and the two-phase fluid (nearly) incompressible LBE model 8 to model coalescence in a non-condensable gas.…”