Modeling of droplet train impact on a moving surface




In droplet-based industrial processes such as spray coating, wherein liquid droplets impinge onto a stationary/moving surface, it is important to understand the interaction between the small scale droplets and the surface (see Fig. 1). 

Fig. 1: The most common outcomes upon droplet impact on a stationary surface: deposition, rebounding and splashing

In the droplet-based coating processes, the impact behavior at the front of the bead being deposited by the droplet train and the surface motion is of importance for final layer geometry and surface finish. In this project, we aim to study the impact behavior of droplet train on a moving surface. The effect of surface velocity and wettability (hydrophobic/hydrophilic), as well as droplet size, surface tension and impinging frequency, are investigated. Figure 2 shows an uncovered section of a coating substrate caused by a low droplets deposition rate.

Fig. 2: Uncovered sections in the droplet spreading at too low deposition rate (Fathi, S., Dickens, P.M. and Fouchal, F., 2010. Regimes of droplet train impact on a moving surface in an additive manufacturing process. Journal of Materials Processing Technology, 210 (3), pp. 550-559).

A multiphase lattice Boltzmann technique is used for simulations. This project is available from September 2016.



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