Microscale modelling and simulation of the removal of water from diesel fuel using hydrophobic separator meshes

Modern water-diesel separators employ a so-called two-stage approach, which combines both hydrophilic and hydrophobic materials to collect and separate the suspension of water. The hydrophobic layer (sieve) is designed to have a low wettability such that the collected mass retains almost spherical and falls along the sieve due to gravity. In general, the droplets exhibit complicated and various interactions with the sieve: partial clogging, retention (breakthrough), and drainage (rolling or sliding). In addition, those interactions interfere with the flow fields yielding an additional pressure drop, which in turn affect the dynamics. On the other hand, the choice of the material of the sieve affects its efficiency and the overall pressure drop. The sieves are characterized by the wettability condition, open-area ratio, and the mean fiber diameter. Thus, studying the effect of the properties of the sieves on the dynamics of a single droplet is vital to quantify the mechanisms in the process of liquid-liquid separation.