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In this cross section showing the regenerative injector assembly, 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 eyeball concentricity. Our annular gap is 0.01".
You can also see two three ports; the left port is for probing fuel manifold temperature and pressure, and the right is for the igniter (see the ASI section). The fuel sensing port is a 1/8" NPT, and the ASI port is a 1/2-20 ORB. The top axial port routes N2O to the pintle tip.
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.
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