Numerical characterization of hydrogen under-expanded jets: influence of the nozzle cross-section shape

Abstract This historical moment is characterized by a great awareness regarding the need to reduce Greenhouse Gas emissions (GHG), which are responsible for climate change and its detrimental consequences. Green hydrogen produced means of Power-to-Gas technologies from renewables gaining momentum as possible clean fuel future mobility. In such context, traditional injectors hydrocarbon fuels currently being tailored be used with hydrogen. The short time available injection process leads employment high inlet pressure, resulting in formation an under-expanded jet. this work, main characteristics these jets analyzed Computational Fluid Dynamics (CFD) Nozzle Pressure Ratio (NPR) equal 10. Then, provide insights dependence air-hydrogen mixing on section shape nozzle, comparisons have been performed changing nozzle cross-section (circular, rectangular, elliptical), keeping constant mass flow rate highlight different levels axial penetration radial spread observed when varying aspect ratio (1.5, 5.0, 8.0).