A Validation Methodology for the 3D-CFD Model of a Hydrogen Injector

Direct injection H\(_2\) engine represents a potential solution towards decarbonisation, combining high power output with efficiency. However, mixing process is worth of thorough investigation, since, even in overall lean mixtures, locally rich zones result in high heat release rates and temperatures, leading to abnormal combustion and high NOx production. Within this scope, an H\(_2\) outward-opening injector, manufactured by BorgWarner, providing mass flow rates close to 6 g/s when operating at 36 bar of injection pressure, is studied. An experimental campaign has been carried out, injecting H\(_2\) into a N\(_2\)-filled vessel, the presented results being at ambient temperature and pressures of 3, 5 and 10 bar. H\(_2\) initially enters this domain as a hollow-cone jet and its development differs for each condition. Predictive modelling of the injection event is of interest to further investigate the spray development, besides its integration within engine cylinder simulations. To this end, a validation regarding the 3D-CFD implementation of the referred injector and real test vessel in the software CONVERGE is presented, against the experimental results. This methodology includes preliminary 2D and 3D-simplified simulation cases, to initially define the numerical setup in a time effective manner. Furthermore, the accuracy of modelling the injection via 2D simulations is discussed, as well as the robustness of the applied strategy.