Modeling and simulation of particles in gas–liquid interface

• Non-dimensional parameterization of capillary interactions.
• New models for capillary forces of immersed submicron particles.
• DEM simulations of mono-layer coating.
• Quantification of self-organization process.

A new model for the capillary interaction of immersed submicron particles is developed and integrated into DEM code. The models were divided into lateral and vertical directions and both were based on dimension analysis approximation. The model’s governing parameters are particle size, surface tension, inter-particle distance, particle–surface relative location, and contact angle. This approach yields an immediate evaluation for the capillary interaction that eliminates the necessity of capturing the complex process of contact line formation. The advantage of the expressions developed in this work is that they are simple to implement and they are not computationally expensive.Several cases were examined to quantify the crystallization structure of sub-micron particles on a substrate in a water liquid film using coupled computational fluid dynamics-discrete element method (CFD-DEM) modeling and simulation. The simulation included the major interactions of surface forces, electrostatic interaction and Brownian motion. The effects of particle size, cover ratio, liquid height, contact angle, and drag force coefficient on the process are presented in terms of two characteristics of particle structure, the isotropic ordering factor (IOF) and the non-dimensional boundary length (NBL). The transition to an assembled array is found to be slower with increases in particle size, but only small differences are observed in the final structures. Furthermore, in contrast to the minor variation found at small contact angles and in response to drag modification, the cover ratio and liquid film height have considerable effects on the assembled array.

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