kramer714
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- Jan 20, 2009
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This is my 'favorite' picture of the fired grain. Lots going on in here In this picture the injector is on the left and the nozzzle on the right.
I used a turbulator insted of a a pre combusion section. The idea of the turbulator is to have some burning and have the flow from the simple nozzle become spread and turbulant. There is regression in this area, but less than 'down stream'
Far left, you can see the krytox line on the bore where the fitting sealed to the bore of the grain, no evidence of any blow by
Preheater ring - (the area to the right of the bore and before the swirls) this started out as one ofthe thinner sections, looks likethere was minimal regression in this area - that is what i was planning on
RTV Bond - I put a bond in using red RTV, I wanted to see about sealing grains or other features together, there is a stright and a taper. Looks like it worked well. The missing RTV in the gaps, pulled out whan I was cutting the sample.
Turbulator - The grain includes a molded in place turbulator section that runs from the preheater ring down. I added a 'neck down' feature in the grain as part of the turbulator, where the swirls fair into the minor diameter and then flare back out inti the spiral pattern. The neck is at approximately from 3.5 - 4 " (seethe ruler below the part)
It is really interesting to look at the three zones, turbulator (1.25 - 3.5) neck (3.5-4), combustion chamber (4.0 plus)
Observations

I used a turbulator insted of a a pre combusion section. The idea of the turbulator is to have some burning and have the flow from the simple nozzle become spread and turbulant. There is regression in this area, but less than 'down stream'
Far left, you can see the krytox line on the bore where the fitting sealed to the bore of the grain, no evidence of any blow by
Preheater ring - (the area to the right of the bore and before the swirls) this started out as one ofthe thinner sections, looks likethere was minimal regression in this area - that is what i was planning on
RTV Bond - I put a bond in using red RTV, I wanted to see about sealing grains or other features together, there is a stright and a taper. Looks like it worked well. The missing RTV in the gaps, pulled out whan I was cutting the sample.
Turbulator - The grain includes a molded in place turbulator section that runs from the preheater ring down. I added a 'neck down' feature in the grain as part of the turbulator, where the swirls fair into the minor diameter and then flare back out inti the spiral pattern. The neck is at approximately from 3.5 - 4 " (seethe ruler below the part)
It is really interesting to look at the three zones, turbulator (1.25 - 3.5) neck (3.5-4), combustion chamber (4.0 plus)
Observations
- the burned surface looks very different on each side of the neck in the turbulator section the nylon is 'glassy and black' on the combustion chamber side it is pocked and has the grey - brown color. Obvious difference between the two zones.
- The neck has obvious erosion lies that start at the end of the turbulator groves, transit the neck at a more axial angle, then reconnect with the groves in the combustion chamber
- scalloping in the combustion chamber, it is pretty obvious from the texture that there was a lot of turbulence coming out of the neck section, thats a good thing.
- The color change is really interesting. To the left of the neck the O/F ratio would be high, and lower to the right, im not sure what is really going on but it is obvious that there is a transition right at the neck.

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