For Project Osiris, two injectors were designed and manufactured: one for the ablative chamber, and one for the regenerative chamber. Each injector was composed of three parts (baseplate, centerbody, pintle tip) but only the baseplate was different across the two designs.

In this cross section, the three components that make up the injector can be seen (baseplate, centerbody, tip). The pintle tip threads into the centerbody via an ORB fitting. The centerbody interfaces with the baseplate via a bolted taper, which we chose to mitigate pintle concentricity issues. However, we still shim the annulus during assembly to make sure the annulus is fine (its width is 0.01").

You can also see two ports; the left port is for probing fuel manifold temperature and pressure, and the right is for the igniter (see the ASI section).  

Fuel comes up from the regen channels and feeds into the injector manifold, and then through the annulus. A small part of the fuel (~15% total fuel mdot) is used as film cooling, and is discharged through the ring of 10 0.5mm holes. 

Face Seal

In the assembly, there is one face seal, which interfaces with the combustion chamber. We were a bit concerned that there would be plastic deformation here when torquing the bolts, as we sized the injector such that the face with the face seal on it contacts the chamber before the injector flange contacts the chamber flange. However, we were able to validate that the lip with the face seal on it would not snap or plastically deform with +/- 0.002" tolerances.

Centerbody

Pintle Tip