Two-phase water evaporation MESHFREE CFD method for wet automotive component dry-out time prediction

A new mass transfer model is developed in the Finite Pointset Method (FPM) to simulate the free water surface evaporation phenomenon at the water-air interface. The FPM, a Generalized Finite Difference Method (GFDM) implemented in the software MESHFREE by Fraunhofer ITWM (www.meshfree.eu), is widely used in many different academic and industrial fields [1,2], especially, in automotive water management applications. Thus, it is expected that the newly developed mass transfer model extends its capabilities in these applications. The multiphase simulation results are validated with a series of experiments that measure the water evaporation rate with a relatively simple geometry at different given atmospheric conditions [3]. MESHFREE uses a point cloud to discretize the domain and is able to resolve both fluid dynamics and continuum mechanics. In order to efficiently generalize the developed simulation method to arbitrary geometrical applications such as automotive components as well as to optimize the computation time, an automatized adaptive point cloud refinement feature is developed in this study. Since adaptive refinement of a point cloud is nearly computationally free, while it is generally time-consuming to re-mesh in mesh-based methods such as Volume of Fluids (VoF), the advantage of the meshfree approach is maximized with this newly developed feature. Through time- and location-dependent adaptive refinement with respect to humidity and velocity gradients, decent speedups with compromised accuracy as well as possibilities for potential automation of the entire process could be achieved.