The holes don't go to the interior, they are above the dome seam.
It may be they attach to the holes and push/ pull the wall, possibly vertically.
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It may be they attach to the holes and push/ pull the wall, possibly vertically.
It appears that yesterday B9 got a full prop/oxidizer load while on the OLM. That booster has already been cryotested at Masseys so maybe this was also a test of GSE? Link to video
Or a full LN2 or LOX/LN2 load to validate the upgraded OLM tank farm.
Was the methane recondenser ever active?
Didn’t see anything about that in the video. Maybe NSF will release something specifically about that booster test and give us more info.
I believe it was. Take a look at this video clip. The right side of the image appears to show the recondenser in action.
The NSF guys were wondering if they'd see a spin-prime test, suggesting that they believed that fuel and oxidizer were being loaded.
Thanks for posting that video. It appears that both tanks were fully loaded for about an hour and 40 minutes. But no sign of a spin prime test that I could see (I skipped through the video, didn’t watch the whole thing).
Maybe a partial static fire soonish?
Maybe a partial static fire soonish?
Right, no spin prime. Spin primes are normally not energetic, but SpaceX found out that they can go sideways. I would hope that they'd remove the scaffolding first, and probably move the engine lift platform from under the launch mount.
They need a spin prime first. While they can do cryogenic testing at Massey's, I don't believe they do spin primes there. All the potentially energetic stuff takes place at the launch site. So spin prime first. If everything goes well, a static fire a few days later. Starting with a few engines and working up to a 33 engine test. It will all be complicated by the water deluge system. If they find any problems with the interaction between the two, then there will be delays.
Earlier I dropped in some napkin math about the deluge system needing 127 psi to directly oppose the thrust from the engines. The water deluge system test showed that they're not jetting the water straight up. That's because just as they don't want the engine exhaust to impinge the metal plate, they don't want the water jetting up into the engines (the deluge system will start before the engines fire). So the water is going up at an angle. While that might suggest needing a greater pressure, I suspect that flashing a whole lot of water over to steam is going to produce plenty of pressure below the engines, and they may be relying on that to ensure that the engine exhaust doesn't reach the metal plate.
I hope that we'll get an explanation from SpaceX on the physics of it all. It seems a much more complex environment than having a water cooled flame diverter.
Booster outer (and maybe the fixed inner engines now) rely on the OLM for spinup gas. Massey's doesn't have that infrastructure.
My super simple appoxination:
9 meter diameter = 29.5 feet = 98k sq inches. With 15 million pounds of thrust, around 150 psi.
Steam generation creates back pressure of its own and won't reduce the pressure needed.
Angled holes increase surface area but not the needed pressure, unless going for a specific height.
The OLM doesn't have the same amount of fill to get it above the water table that KSC/ Canaveral does, so digging down for a flame trench is less feasible. It also results in a more focused exhaust that needs dealt with.
adiggs
Well-Known Member
And here I was just thinking "Why is SpaceX working so hard to not dig a flame trench - it seems like such an obvious solution to such an obvious problem, and has decades of flight testing".
A flame trench that fills with water - yeah, that could be a problem. Pumps to empty it when needed, sure, but it still needs to be empty when its built. Dig a moat around the trench and keep that dry while digging the trench? Yeah - starts becoming annoying at best.
Thanks. I thought the engine lift platform had been moved out of the way already. As for the scaffolding I would guess it could remain in place for spin prime test, though my OCD would insist on removing it first, just for neatness.
NASASpaceFlight says that the methane tank was loaded with liquid nitrogen for the test.
There are hundreds of holes in the plate and they all point outwards, so only the center is open to view. I'm curious to know why the exhaust isn't going to find a free path right down to the plate in the center. Perhaps full pressure changes the flow a bit.
There is never a free path to the plate beyond the inital startup. A stagnation zone develops as the exhaust must travel away from the center to escape. With the steam generation at the water/ flame boundary, there will be a tremendous amount of gas pushing in all directions creating a buffer above the plate. Pressure at the center will be higher than the edges.
1000x expansion of the water means one cubic foot of water becomes a sphere of stream 12 feet on diameter. One gallon a sphere approximately 6 feet across.
Further, as long as there is liquid water at the plate surface, it can't heat above 100C or so. Melting point is 1400 C.
Yes, I knew there are many holes, but thought they were drilled into the plates at right angles to the surface. How do you know they are angled? From the photo in that SpaceX tweet?
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