Impact and penetration dynamics of inkjet droplet within paper-like fibrous substrate by mesoscopic modeling

Droplet impact and penetration into the paper-like medium are essential physical phenomena in variety of natural and industrial processes. The lattice Boltzmann model coupled with random-walk-based stochastic scheme is presented to calculate the interactions between inertial dominated droplet and fibrous medium. Results show that the droplet spreading regime is independent of surface wettability, volume fraction, and Ohnesorge number at very early impact stage. For fibrous medium with volume fraction ~ 50% and wettability 85°, three stages of penetration process are observed. Whereas for low-volume-fraction fibrous medium, the phases of droplet spreading and penetration are coupled which results in a small spreading width for hydrophilic wettability. It is found that the spaces of spreading width and penetration rate are divided by the curve of \( Oh = 0.038 \) and \( Re = 144 \). The effects of Ohnesorge and Reynolds numbers largely influence the behaviors of droplet spreading and penetration process. The in-depth insight of inkjet droplet impact onto the paper-like fibrous medium is beneficial for improving printed products in Paper Electronics.