Hybrid Rocket Design Study Utilizing Nozzle Cooling and Aft-End Vortex Oxidizer Injection

The current study focused on two innovations intended to reduce the cost and enhance the performance of hybrid rockets. The majority of the emphasis was placed on the design, fabrication and testing of a 3-D printed, water cooled nozzle. This work was done as proof of concept to show that complex, high temperature components could be manufactured using these new techniques, thereby substantially bringing down fabrication costs and allowing configurations that are not feasible using traditional machining. A water-cooled calorimeter nozzle was made and used in thrust stand tests to verify analytic and numerical heating models used in the design of the nozzle. Agreement was good between the predicted and measured heating rates. This experimental work helped to validate the nozzle design approach which will now be used to devise a 3-D printed, regeneratively cooled nozzle for a hybrid engine. The secondary phase of the study was an analysis of aft-end vortex oxidizer injection as a means of enhancing fuel regression rates. Components are currently being fabricated as part of an ongoing study to compare engine performance results for traditional head end and aft-end vortex injection.