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Sound energy from liquid engines
Is there a way to quantify the amount of noise created by an engine such as
an SSME? In a vehicle for use for manned long range exploration, would it be possible to dampen the sound enough to allow engineers to work on a live engine(well maybe the feed systems, control gear etc)? Thanks, David |
#2
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Sound energy from liquid engines
"David Findlay" wrote in message
. au... Is there a way to quantify the amount of noise created by an engine such as an SSME? In a vehicle for use for manned long range exploration, would it be possible to dampen the sound enough to allow engineers to work on a live engine(well maybe the feed systems, control gear etc)? If I remember right, the SSME's generate about 140db and the aft section of the Shuttle is rated for ~170. I don't know how much of that is engine machinery and how much is caused by the exhaust. If you could hypothetically block off all sound created aft of the engine core, what would it sound like? How loud would it be? I don't know the answers to those questions... In any case, I don't think working on a live running engine would be such a good idea. If something as complicated as an engine was that badly broken that it would need human repairs, it wouldn't be running anyway. |
#3
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Sound energy from liquid engines
If you could hypothetically block off all sound created aft of the engine
core, what would it sound like? How loud would it be? I don't know the answers to those questions... In any case, I don't think working on a live running engine would be such a good idea. If something as complicated as an engine was that badly broken that it would need human repairs, it wouldn't be running anyway. Well I was actually thinking more from the aspect of maintinence of a second engine while one was running. A mars spacecraft would really need the ability to be maintained in flight, so having pressurised access to almost everything would be useful. An ion or vasimr drive would be quite easy to quieten enough for inflight monitoring and maintinence. Thanks, David |
#4
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Sound energy from liquid engines
This thread reminds me of the tourist in Ireland who asked a passer by how
to get to Dublin, to which the response was... If I were going there, I would not start from here. What i mean is that you are unlikely to be continuously using a liquid fuelled engine continuously on a deep space mission with men on board, they are just not suited for that purpose. Far more likely is some form of Ion engine. If you have to service liquid fuelled engines in flight, you would do it when they were not working. Also, I'd think that it would be unlikely that any craft would pressurise the engine pump area etc, it would be expensive and difficult to maintain in itself, so as sound can, in the absence of air, only travel through structure, there is no noise anyway! Brian -- Brian Gaff.... graphics are great, but the blind can't hear them Email: __________________________________________________ __________________________ __________________________________ --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.521 / Virus Database: 319 - Release Date: 23/09/03 |
#5
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Sound energy from liquid engines
What i mean is that you are unlikely to be continuously using a liquid
fuelled engine continuously on a deep space mission with men on board, they are just not suited for that purpose. Far more likely is some form of Ion engine. Yes, but a liquid engine would still be useful for jumping out of orbits of planets, or manuerving to miss something nasty. Also, I'd think that it would be unlikely that any craft would pressurise the engine pump area etc, it would be expensive and difficult to maintain in itself, so as sound can, in the absence of air, only travel through structure, there is no noise anyway! How hard is it to pressurize an area? Is it considered a major engineering challenge? It can't be as hard as going to the bottom of the sea. Thanks, David |
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Sound energy from liquid engines
David Findlay wrote:
What i mean is that you are unlikely to be continuously using a liquid fuelled engine continuously on a deep space mission with men on board, they are just not suited for that purpose. Far more likely is some form of Ion engine. Yes, but a liquid engine would still be useful for jumping out of orbits of planets, or manuerving to miss something nasty. It's almost always best (for orbital mechanics reasons) to make all manouevers at the maximum thrust you can. Combine this with the low energy of chemical fuels and you'r looking at burns of several minutes at most. There is little point in trying to repair something when it's in use if it's going to stop being in use before you can get the cover off. -- http://inquisitor.i.am/ | | Ian Stirling. ---------------------------+-------------------------+-------------------------- "The device every conquerer, yes, every altruistic liberator should be required to wear on his shield... is a little girl and her kitten, at ground zero" - Sir Dominic Flandry in Poul Andersons 'A Knight of Ghosts and Shadows' |
#7
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Sound energy from liquid engines
David Findlay wrote:
If you could hypothetically block off all sound created aft of the engine core, what would it sound like? How loud would it be? I don't know the answers to those questions... In any case, I don't think working on a live running engine would be such a good idea. If something as complicated as an engine was that badly broken that it would need human repairs, it wouldn't be running anyway. Well I was actually thinking more from the aspect of maintinence of a second engine while one was running. A mars spacecraft would really need the ability to be maintained in flight, so having pressurised access to almost everything would be useful. An ion or vasimr drive would be quite easy to quieten enough for inflight monitoring and maintinence. Thanks, The drive does not need to be maintained in action. At any time other than takeoff you have at least days, possibly months before getting the engine working again is critical. And there is limited stuff you can do to an operating liquid fueled engine, as it tends to be kind of hot and high-pressure. -- http://inquisitor.i.am/ | | Ian Stirling. ---------------------------+-------------------------+-------------------------- If you've been pounding nails with your forehead for years, it may feel strange the first time somebody hands you a hammer. But that doesn't mean that you should strap the hammer to a headband just to give your skull that old familiar jolt. -- Wayne Throop, during the `TCL Wars' |
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