3D CFD simulation methodology for safe and efficient hydrogen refueling for hydrogen internal combustion engines

As conventional fossil fuels are on the verge of depletion, the search for alternative fuel for automotive applications has intensified. Among these, hydrogen stands out due to its high energy content per unit mass, high octane number, and compatibility with Internal combustion engines (ICE). However, the volatility of hydrogen (H2) presents challenges, particularly during the refueling process, where uncontrolled temperature rise occurs because of negative Joule-Thomson (JT) effect. This brings an alarming bell for the safety of fueling stations, vehicles and mankind. This paper investigates the physics involved in hydrogen tank filling, focusing on maintaining the hydrogen gas temperature below 85 °C during the process. A 3D Computational Fluid Dynamics (CFD) analysis was performed to model the temperature and pressure behavior of hydrogen during filling. The study provides insights into the optimal fill rates, temperature distribution, and the evolution of peak temperature locations inside the tank, contributing as a critical dataset for safe and efficient hydrogen refueling strategies. This study was carried out using two simulation software - ANSYS Fluent 2024R1 and Simerics 6.0.0. The results from both the software show strong agreement, while Simerics demonstrated a significant computational advantage with runtimes as compared to Ansys Fluent. Additionally, a mesh and time-step sensitivity study were conducted to ensure the accuracy and stability of simulations.