Numerical simulation of droplet behavior on an inclined plate using the Moving Particle Semi-implicit method

Abstract

This paper presents the numerical simulation methods used to reproduce droplet retention and sliding on an inclined surface by using the Moving Particle Semi-implicit (MPS) method. The MPS method is useful for simulating free surface flows with highly deformed gas-liquid interfaces, such as the behavior of condensed water in an evaporator. However, the existing MPS method cannot correctly reproduce the behavior of a droplet retention and droplet sliding on an inclined surface. In the simulation of a droplet on a wall using the existing MPS method, the simulated droplet starts sliding as soon as the wall is inclined even slightly and falls down at a very high speed. In this study, the details of the forces acting from the wall to a droplet are considered, and the boundary condition models that contain the resistance forces acting on the contact line of a droplet are proposed. Droplet retention and droplet sliding on an inclined plate are successfully simulated by using the proposed models. Furthermore, the simulation results are compared with the experimental results reported in literature. The relationship between the droplet volume and critical sliding angle and that between the inclination angle of a slope and droplet sliding velocity are each compared using the experimental results and evaluated both qualitatively and quantitatively; they show good agreement with the experimental results.

Changes in the Microstructure and Wettability of Water-Containing Coal after Hot Flue Gas (CO2–N2) Injection

“…As microscopic detection technology progresses, some scholars have shifted their research focused on the tensility balance at the gas–liquid–solid three-phase junction of the contact angle. Based on Young’s equation, Gan et al , further proposed the line tension balance theory that explains the relationship at the above-mentioned tensility balance point. In an environment where liquid and gas phases are fixed, only changes on the solid surface can break the balance described above and trigger the formation of new contact angles.…”

Exploring Wedge and Bulk Viscous Dissipation in Droplets Moving on Inclined Surfaces by Means of Direct Numerical Simulations

“…This then allows the discrimination between the contributions of wedge and bulk dissipation. To verify the free surface assumption, Figure 11 depicts the comparison of the total viscous force integrated over the droplet volume according to (19) with the boundary viscous force integrated over the contact area according to (22). One observes that the magnitude of the surface-averaged viscous dissipation force is slightly larger than that of the volume-averaged one.…”

“…Another question that we address is how these channels of dissipation are influenced by the droplet velocity. Previous studies have employed numerical simulations to investigate the spreading and sliding behavior of droplets [1,19,20]. These simulations have primarily focused on the development of numerical methods capable of accurately capturing these processes, involving investigations of critical contact angles, droplet shape, and steady-state velocities, which are then compared to experimental and numerical results [21][22][23].…”