Wettability Model Considering Three-Phase Interfacial Energetics in Particle Method

Abstract

Wettability of a solid by a liquid plays a key role in achieving the purpose of the process in moving bed-type reactors. In recent years, particle method has been proposed for the design of processes which include multiphase flows. Using this method, it is possible to analyze a free surface flow without explicitly tracking the interface. Although surface tension and wettability models using the particle method have already been proposed, the complexity of calculations of normal line and curvature of the surface particle has been pointed out as a problem. In this study, surface tension and wettability model were introduced in terms of interparticle potential, and theoretical and experimental verifications were performed for a 3-dimensional particle method which stabilizes the internal pressure distribution in fluids. The analytical solution for the droplet oscillation period by this method showed good agreement with the theoretical solution, and the surface tension between a gas and liquid could be calculated correctly. Because the difference in the number density of a liquid phase and solid phase becomes remarkable in a 3-dimensional space, a technique which corrects for this in particles at a three-phase interface was introduced. Time change in the droplet shape was compared with the experimental results by changing the droplet impact velocity to obtain agreement of the Weber number. It is considered possible to express the droplet shape correctly during rotating falling on a solid surface.

Multiphase Particle Simulation of Gas Bubble Passing Through Liquid/Liquid Interfaces

“…Natsui et al 22) verified that this form can estimate the absolute value of surface tension; and in the case of multi-phase flow, different phases are formed in pairs with interface particles, as shown in Fig. 3.…”

“…According to previous research, the exact form of this force is not important provided it is anti-symmetric and short-range repulsive, or long-range attractive. 21) In this study, f s was constructed following the previous study, 22) who employed this same type of interaction force to dissipative particle dynamics (DPD) models:…”

Three-Dimensional Modeling of Interfacial Tension with Smoothed Particle Hydrodynamics by Using Pairwise Potential

“…To verify the developed simulation model, the dynamic behavior of a water droplet was experimentally observed under the conditions reported by Natsui et al 7) and was compared with the calculation. As mentioned before, an equilibrium contact angle θ is used as the wettability parameter in this model.…”

“…The relation between the interparticle force and the interfacial energy was theoretically derived, and the coefficient C can be calculated from the surface tensions and equilibrium contact angle. Natsui et al 7) developed Kondo's method and applied it to a three-dimensional simulator using the MPS method. They compared the simulation results with experiments on the dynamic behavior of a water droplet and reported good agreement.…”

Characterization of Liquid Trickle Flow in Poor-Wetting Packed Bed

“…The influence radius which calculate the surface tension of each surface particle was set to 2.3d p in this particle simulation. 10) Particle diameter d p is fixed as 1.0 mm, so the calculation accuracy is guaranteed around 3 particles at the surface, i.e., 3.0 mm will be the minimum value of droplet diameter. Droplet of less than 3.0 mm of diameter will drop like a rigid body ball.…”