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Here, you see that the region in which the fuel circulates (the annulus) is positioned below the region in which the oxidizer circulates. The cross-sectional area of a circulation flow region is optimized at 4 times the area of the orifices contained within that region, which we calculated to be TBD and TBD. The reason why the oxidizer annulus height is so small is because its x distance is very large.
Additionally, you will see that there are screws that screw in the oxidizer and fuel annuli into the faceplate. This is a point of uncertainty; there needs to be cylinders that protrude out of the fuel manifold that contain a screw hole and an O-ring around it to ensure to fluid leaks into the screw threads. Ideally, there is no obstruction in an annulus, so we are currently working on a way to get rid of these cylinders. We will probably just have the screws go through the fuel manifold instead of the ox manifold so that only the screw head would be obstructing flow, not an entire cylinder. However, there also needs to be a sealant to prevent fluid from leaking through the screw; we think that gaskets will do the trick. We are also using gaskets to prevent fluid from leaking from the fuel annulus; originally we had O-rings there, but due to spacing constraints we decided a gasket would be better. Although the screws in the oxidizer annulus don't secure the oxidizer manifold to the faceplate, we can ultimately just place a bunch more bolts radially around the edge of the oxidizer manifold if needed. The screws are also offset from the orifices because they run into each other if not.
Yet another thing you will notice is the placement of the igniter hole. It was quite difficult (if not impossible) to fit O-rings and screws along the faceplate surface to prevent leakage from the igniter exhaust and nitrous. It was discovered that a better way to do this was to extend the faceplate and oxidizer annulus upwards and have the O-rings be radial seals and bolts be radial bolts.
We created a Jupyter Notebook to calculate parameters for the injector.
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