For Project Hephaestus, a pintle injector was chosen due to its sufficient efficiency and machinability. It has also been shown to mitigate combustion instabilities because of its spray characteristics, but we intend on remaining at or above .15 dP/Pc regardless.Machinability is of utmost importance for nitrous injectors; since extensive testing campaigns are necessary to characterize SPI and HEM Cd's, having an injector area that can be easily iterated upon is important.
This is the current iteration of the pintle injector. The pintle tip is made out of copper, while the baseplate and centerbody center body are made out of steel. The interruption in the fuel manifold is so igniter/PT ports can connect to the chamber offset from the radial holes. Having the pintle tip as an insertable, simple component is highly advantageous: SPI and HEM Cd's can be characterized
Lessons learned from previous iterations:
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