Investigation of pre-mature ignition of a hypervelocity fuel/air mixture with nitrogen injection.

摘要

In a previous study, it was found that using a cantilevered ramp injector at a given configuration to inject hydrogen resulted in the pre-mature ignition of the fuel/air mixture. It is the goal of this study to investigate the injection of cryogenic gaseous nitrogen to suppress pre-mature ignition of this hypersonic fuel/air mixture. The numerical chemistry model used is a 9-species, 20-reaction hydrogen-air model developed by Jachimowski. The flame location is found to be 0.60 m downstream from the plane of hydrogen injection. Nitrogen is injected at 200 K and at half the velocity of the injected hydrogen. Two cases are performed, one at 5 000 Pa, and the other at 10 000 Pa. In both of these cases, it is found that the injection of the cool nitrogen is able to suppress the pre-mature ignition of the fuel/air mixture. In addition, the injection of nitrogen only reduced the mixing efficiency by 1.6% and 2.5% for the 5 000 Pa and 10 000 Pa, respectively.