Three-dimensional hybrid mesh generation method for the ejector used in proton exchange membrane fuel cells

As a key component of the proton exchange membrane fuel cell (PEMFC) anode hydrogen circulation system, the flow performance in the ejector largely determines the efficiency of the anode hydrogen circulation system. Therefore, it is important to predict the flow characteristics in the ejector and to supply design analysis by using a numerical simulation. This study presents a three-dimensional hybrid mesh generation method for numerical simulation using ICEM CFD software. Firstly, the ejector geometry model is processed by creating an auxiliary surface, which serves as a hybrid interface. The mesh generation method is highlighted on this hybrid interface. The computational domains are then divided into both structured and unstructured meshes. The causes of low-quality mesh might be the wrong arrangement of nodes or unreasonable maximum size of mesh, and thus a quality improvement method for mesh-smoothing is proposed according to different types of meshes. Finally, the generation method of the hybrid mesh is evaluated by ICEM CFD software quality metrics and the simulation result of Fluent software. The numerical simulation results show good agreement with the experimental data with a maximum error of only 4.62%. The proposed method can reduce the difficulty of mesh generation and ensure a certain mesh quality. The method is also applicable to mesh generation for other complex geometric models.