Numerical Investigation of the Spreading and Permeation Characteristics of Inkjet Droplets on Porous Substrate Surfaces

In inkjet printing, ink droplets are sprayed from nozzles and impact the surface of the substrate. Under the combined influence of droplet properties and substrate characteristics, the droplets spread and penetrate into the paper, forming printed dots. The spreading and penetration characteristics of ink droplets on porous substrates profoundly influence the quality of the final printed product. In the paper, the volume of fluid (VOF) method was employed to establish a numerical computational model for the impact and spreading of a droplet on the surface of a porous medium, analyzing the dynamic behavior of droplet impact, spreading, and penetration. As droplet diameter and impact velocity increase, the maximum spreading factor increases and occurs earlier, while penetration depth also increases. An increase in porosity reduces the maximum spreading factor but increases penetration depth. Changes in liquid film thickness exhibit relatively complex behavior. This results provide a theoretical basis for determining the optimal parameters, thus enhancing the inkjet printing quality.