Computer-aided study of the Diesel-water separation efficiency of screen meshes

In the last decade, many changes and regulations were introduced in order to reduce the emissions out of diesel engines, which led to major changes in the chemical composition of the diesel by reducing its sulphur content. In addition, biodiesel fuel is of increasing importance in the automotive and energy sectors. These changes on the fuel helped to reduce hazardous emissions, but at the same time, they affected the performance of water-diesel separators due to their lower surface tension with water. The fact that filtration and separation are by nature phenomena that connect several size scales, imposes a challenge for both modeling and simulation. On the macroscopic scale, we are interested in estimating the pressure drop and overall efficiency. On the other hand, on the microscopic scale, the droplets interact with each other and the mesh wires and furthermore, surface chemistry and local hydrodynamics will influence the separation process. The present work uses the Computational Fluid Dynamics (CFD) package OpenFOAM®*, more precisely a variant of the module interFoam, to simulate the interaction of water droplets in a diesel fuel flow with a screen mesh. For the treatment of the liquid mixture, the module utilizes the Volume of Fluid method (VoF). The focus of the present study is put on the influence of mesh material (contact angle), and flow rate on separation efficiency and pressure drop.