NASASpaceFlight.com Forum
General Discussion => Q&A Section => Topic started by: RocketmanUS on 09/26/2014 06:47 pm
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As it has been on other threads ( in reference to Centaur US ).
What is Cold sink technology?
Also it has been stated as cold technology.
How and were is it used?
What is it's principles?
What is the theory on it?
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As it has been on other threads ( in reference to Centaur US ).
What is Cold sink technology?
Also it has been stated as cold technology.
How and were is it used?
What is it's principles?
What is the theory on it?
It isn't cold sink. Read the other threads that you cite, it is explained there, no need for this threads.
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As it has been on other threads ( in reference to Centaur US ).
What is Cold sink technology?
Also it has been stated as cold technology.
How and were is it used?
What is it's principles?
What is the theory on it?
It isn't cold sink. Read the other threads that you cite, it is explained there, no need for this threads.
They don't explain anything about it. They just say cold technology and something to do with insulating between the bulkheads of the LH2 and LOX tanks on the Centaur. That does not explain what cold technology is.
Does it have anything to do with propellant boil off?
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They don't explain anything about it. They just say cold technology and something to do with insulating between the bulkheads of the LH2 and LOX tanks on the Centaur. That does not explain what cold technology is.
That is what " cold technology" is. The method of insulation between the bulkheads of the LH2 and LOX tanks on the Centaur and how it is done. It is all there in the posts.
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They don't explain anything about it. They just say cold technology and something to do with insulating between the bulkheads of the LH2 and LOX tanks on the Centaur. That does not explain what cold technology is.
That is what " cold technology" is. The method of insulation between the bulkheads of the LH2 and LOX tanks on the Centaur and how it is done. It is all there in the posts.
If that all it is then I don't get why no one has been able to duplicate or improve on the insulation between two bulkheads of this type.
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Been able to duplicate, or duplicate in a cost effective manner?
The US spent a pretty penny back in the 60's developing Centaur and the Common Bulkhead and has not been eager to share the secret sauce.
Also, why do they need to improve the insulation? If it is good enough to keep a LOX tank in contact with a LH tank for hours on end, what needs improvement?
Other than weight (which is a function of better materials and lighter alloys) and lower manufacturing cost (Which is just better manufacturing technology) what would need improvement?
I assume you have read: Taming Liquid Hydrogen: The Centaur Upper Stage Rocket 1958-2002 http://history.nasa.gov/SP-4230.pdf
It goes over many of the items you are asking about in great detail.
Edit: btw, Look at page 19 (.pdf page 36), gives a brief overview of how the bulkhead insulation works.
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Been able to duplicate, or duplicate in a cost effective manner?
The US spent a pretty penny back in the 60's developing Centaur and the Common Bulkhead and has not been eager to share the secret sauce.
Also, why do they need to improve the insulation? If it is good enough to keep a LOX tank in contact with a LH tank for hours on end, what needs improvement?
Other than weight (which is a function of better materials and lighter alloys) and lower manufacturing cost (Which is just better manufacturing technology) what would need improvement?
I assume you have read: Taming Liquid Hydrogen: The Centaur Upper Stage Rocket 1958-2002 http://history.nasa.gov/SP-4230.pdf
It goes over many of the items you are asking about in great detail.
Edit: btw, Look at page 19 (.pdf page 36), gives a brief overview of how the bulkhead insulation works.
Thanks for PDF and the page number.
I'm not saying they need to improve on it. I'm just saying I'm surprised no one has been able to duplicate it ( that would also mean or improve on it ). Using a vacuum space ( or dead space ) to separate two temperatures has been around for some time.
So the dry nitrogen gas keeps the needed pressure between the two bulk heads till the two tanks are filled with fuel and oxidizer and create the needed inside pressure for the balloon tanks. With the right timing the LH2 freezes the dry nitrogen gas creating a vacuum ( thermal block ).
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I would suspect the vacuum forms as soon as the LH hits the tank... That bulkhead needs to be able to support the pressures it sees with or without the vacuum.
Like I said, they spent a fair amount of money developing the technology in the 60's. I suspect no one is currently replicating it because it most likely it is quite a bit more expensive than having two separate tanks. Eating the extra inter-tank dry mass is worth the savings.
Think about it, you need two domes that are almost touching that need to keep a gap while under vacuum. Don't forget you also have to keep Hydrogen from leaking into the gap. Easier to just have two tanks with spray foam, one sitting on top of the other. Any Hydrogen leaking through the welds just vents to space.
Jim can correct me, but I think the advantage is slightly better dry mass (no inter-tank support) and with the common bulkhead the LOX is chilled resulting in only LH boil off. The advantage here is because Hydrogen is lighter, you lose less mass to boil off.
Remember when Boeing (wasn't it McDonnell Douglas who started the project) created the DCSS for Delta III and Delta IV, they did not use a common bulkhead. For some reason they decided it was more cost effective to go with separate tanks. It either cost less to develop and/or was cheaper/easier to construct without a common bulkhead.