A Study on Auto-Ignition/Combustion Characteristics of High Pressurized Hydrogen Jets

Abstract

In this study, authors investigated the characteristics of auto-ignition/combustion of high pressurized hydrogen jets to improve performances of a direct-injection, diesel engine fueled with hydrogen. The experiments were conducted by simulating a diesel-like combustion field in a constant-volume combustion vessel. The objective of the study was to clarify physical and chemical effects on auto-ignition delay and heat release by changing the variables of injection pressure, orifice diameter, ambient gas temperature and ambient gas oxygen concentration in the experiments. The results show that auto-ignition delays of hydrogen jets are strongly dependent on the ambient gas temperature and that the ambient gas oxygen concentration has a weak effect on the auto-ignition delays. And it is also clarified that when the ambient gas temperature is relatively high, auto-ignition delays of hydrogen jets are almost the same for various conditions of ambient gas oxygen concentration and injection, but that injection conditions have a significant effect on the rate of heat release of hydrogen jets. It can be concluded that the mixture formation process plays an important role for the auto-ignition/combustion of hydrogen jets.