Research into the formation process of hydrogen–air mixture in hydrogen fueled engines based on CFD

The density of hydrogen is much smaller than that of air, so it is hard for hydrogen and air to form high grade mixture. Furthermore, the diffusing speed of hydrogen is so high that the formation state of mixture changes rapidly. Therefore it will become more difficult to carry through the further research of mixture space–time distributing rule. In order to investigate the formation rule of hydrogen–air mixture and improve the mixture quality, in this paper, computation fluid dynamics (CFD) mode is adopted to carry through three-dimensional numerical simulation research of flow field in hydrogen fueled engine cylinder. The numerical simulation is done in a two-stroke hydrogen fueled engine, and the mixture forming state at different hydrogen-injecting time is contrasted. The evolvement rule of flow field in cylinder and mixture forming state is shown in the result. The simulation results show that, when hydrogen-injecting begins at 260 °CA, the forming quality of the mixture is better than other two states, this is the same as the experimental results. It indicates that CFD is one of the effective methods to analyze the formation of mixture in hydrogen fueled engine.