Characteristics of High-Pressure Hydrogen Jet Dispersion Along a Horizontal Plate

Creating and updating safety regulations and standards for industrial processes and end-uses related to hydrogen demand a solid scientific foundation, which requires extensive research on unignited hydrogen releases from high-pressure systems across different situations. This study focuses on high-pressure hydrogen releases along a horizontal plate to investigate the surface effects on hydrogen dispersion. Hydrogen releases from high-pressure sources up to 30 MPa were modeled using a computational fluid dynamics (CFD) method, with the CFD models validated by experimental data. The hydrogen dispersion characteristics along the plate were studied for various source pressures and leak nozzle diameters. The results show that the maximum flammable extent along the plate increases linearly with both the source pressure and nozzle diameter, while the combustible mass increases to the power of 1.5 with the increase in leakage flow rate. The locations where the jet centerline attach to the plate are identical (about 0.41 m away from the nozzle exit in the axial direction) for different source pressures (10~30 MPa) and nozzle diameters (0.5~1.5 mm). The flow region was divided into pre-attachment and attachment zones by the attachment point, and the self-similarity characteristics of both zones were analyzed. Finally, correlations for the centerline and lateral concentration distributions were developed for both the pre- and post-attachment zones. The results can help users quickly assess safety distance when hydrogen leaks along the plate.