Behavior and auto-ignition characteristics of hydrogen jet injected into high temperature and high pressure atmosphere

By making up the Diesel engine conditions of high temperature and high pressure in a RCEM, we investigated behavior and anto-ignition characteristics of hydrogen jet injected into 79%Ar-21%O2 or 75%H2O-25%O2 mixture. The visualization of hydrogen jet revealed that the jet angles fell intD approximately 20degrees similar as in the previous works under relatively low pressure. The comparison of these results with a momentum theory showed that the fundamental characteristics of a hydrogen jet such as the penetration length of the jet were predictable. In the Ar-O2 mixture between 800K and 950K, the ignition delays scattered widely and the auto-ignitions appeared as a statistical phenomenon. In the higher temperature range, the ignition delay shortened and stable auto-ignitions were observed. The ignition delays hardly depended on the injection pressure, the ambient pressure and the geometry of the chamber, while they showed tendency to become long especially under the high temperature conditions, as the diameter of injection nozzle becomes small.