Visualization study on characteristics of hydrogen jet injected through gas admission valve in marine engine

This paper presents an experimental investigation into the morphological behavior of a hydrogen jet via visualization. First, hydrogen is injected into a crossflow field emulating the intake of marine hydrogen engines. Both conventional and background-oriented schlieren methods are employed for visualization in an observation chamber. Assessment of the crossflow condition reveals velocity distributions at various cross-sections in the observation chamber. A low-velocity zone emerges in the wake of the nozzle protruding from the ceiling of the chamber. Momentum flux ratio analysis show significant variations (from 16 to 1164) in the effect of the hydrogen jet on the crossflow, particularly at lower crossflow velocities. Visualizations from different perspectives highlight the correlation between hydrogen and the crossflow, showcasing the distinctive phenomenon of hydrogen crawling up along the outer surface of the nozzle. The time-dependent evolution of the penetration and jet width after impingement shows similar characteristic trends: their increasing rates amplify when the jet impinges on the bottom surface of the observation chamber. The velocity of the hydrogen jet after impingement is approximately 1.5 times that before the impingement, around 150 m/s. These findings facilitate the understanding of the characteristics of hydrogen jets used in marine engine applications.