Enhancing safety in rapid hydrogen refueling: a numerical study on cylinder injector parameters and filling strategies

During the rapid filling of hydrogen cylinders, the geometric parameters related to the cylinder configuration significantly influence the gas temperature rise and the final filling state. However, the existing literature still needs to sufficiently explore the internal structure of hydrogen cylinder injectors. Therefore, this study aims to address this gap by developing a numerical model for the rapid filling process of a 35 MPa, 74 L cylinder (includes both 2D axisymmetric and 3D models). The investigation focuses on analyzing the impacts of the internal length, diameter, and angle of the injector on the temperature rise and gas distribution within the cylinder. The results indicate that optimizing the injector angle can effectively mitigate the temperature increase, while improper angle configurations may exacerbate the temperature rise. Furthermore, this study introduces a novel time-divided filling strategy designed to control the maximum temperature within the cylinder while minimizing energy consumption. By optimizing both the injector configuration and the filling strategy, this research can enhance the efficiency of the hydrogen filling process, thereby contributing to the advancement of hydrogen energy utilization.