DDT - Revision history

Benstern: moved to category concepts

2008-06-04T10:11:05Z

moved to category concepts

← Older revision		Revision as of 05:11, 4 June 2008
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	[http://www.gexcon.com/index.php?src=handbook/GEXHBchap6.htm#sect6.3 GexCon article on DDT]		[http://www.gexcon.com/index.php?src=handbook/GEXHBchap6.htm#sect6.3 GexCon article on DDT]

			[[Category:Concepts]]

Benstern at 16:05, 24 October 2007

2007-10-24T16:05:57Z

← Older revision		Revision as of 11:05, 24 October 2007
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	In a normal combustion situation, the flame front in a burning fuel/air mixture does not exceed the speed of sound, classifying it as a deflagration (see [http://en.wikipedia.org/wiki/Deflagration Deflagration on Wikipedia]). The combustion inside a gasoline or diesel engine, gunpowder, and low-grade explosives are all deflagrations.		In a normal combustion situation, the flame front in a burning fuel/air mixture does not exceed the speed of sound, classifying it as a deflagration (see [http://en.wikipedia.org/wiki/Deflagration Deflagration on Wikipedia]). The combustion inside a gasoline or diesel engine, gunpowder, and low-grade explosives are all deflagrations.

	Under rare circumstances (generally in respectively long, thin combustion chambers containing pressurized fuel/oxidizer mixtures), the flame front can exceed the (local) speed of sound, as does the flame front of high explosives, classifying it as a [http://en.wikipedia.org/wiki/Detonation Detonation]. This transition from subsonic to supersonic can create an immense pressure spike that has damaged even well-constructed metal chambers, and is certain to cause a PVC chamber to fail.		Under rare circumstances (generally in respectively long, thin combustion chambers containing pressurized fuel/oxidizer mixtures), the flame front can exceed the (local) speed of sound, as does the flame front of high explosives, classifying it as a [http://en.wikipedia.org/wiki/Detonation Detonation]. This transition from subsonic to supersonic can create an immense pressure spike that has damaged even well-constructed metal chambers, and is certain to cause a PVC chamber to fail. Usually pipe will fail at the point where DDT happens. This is because the point is subject to a localized rapid high pressure change.

	It is the goal of anyone who constructs a [[hybrid]] launcher to avoid DDT. It is thought that a short, fat (theoretically closer to spherical) chamber is less likely to incur DDT than a long, thin chamber. Using oxygen enriched mixtures or exotic fuels such as acetylene increase the risk of DDT.		It is the goal of anyone who constructs a [[hybrid]] launcher to avoid DDT. It is thought that a short, fat (theoretically closer to spherical) chamber is less likely to incur DDT than a long, thin chamber. Using oxygen enriched mixtures or exotic fuels such as acetylene increase the risk of DDT.

	Here we can see the first normal pressure spike at 2510 µsec compressed the fuel and air and caused a DDT at 2555 µsec.		Here we can see the first normal pressure spike at 2510 µsec compressed the fuel and air and caused a DDT at 2555 µsec.

	[[Image:6_6.gif]]		[[Image:6_6.gif]]

Benstern at 20:58, 23 October 2007

2007-10-23T20:58:26Z

← Older revision		Revision as of 15:58, 23 October 2007
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	For more information on DDT, try [http://www.google.com/search?hl=en&q=deflagration+detonation+transition&btnG=Search Google]		For more information on DDT, try [http://www.google.com/search?hl=en&q=deflagration+detonation+transition&btnG=Search Google]

	[http://www.gexcon.com/index.php?src=handbook/GEXHBchap6.htm#sect6.3 GexCon article on DDT]		[http://www.gexcon.com/index.php?src=handbook/GEXHBchap6.htm#sect6.3 GexCon article on DDT]

Benstern at 20:57, 23 October 2007

2007-10-23T20:57:31Z

← Older revision		Revision as of 15:57, 23 October 2007
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	It is the goal of anyone who constructs a [[hybrid]] launcher to avoid DDT. It is thought that a short, fat (theoretically closer to spherical) chamber is less likely to incur DDT than a long, thin chamber. Using oxygen enriched mixtures or exotic fuels such as acetylene increase the risk of DDT.		It is the goal of anyone who constructs a [[hybrid]] launcher to avoid DDT. It is thought that a short, fat (theoretically closer to spherical) chamber is less likely to incur DDT than a long, thin chamber. Using oxygen enriched mixtures or exotic fuels such as acetylene increase the risk of DDT.

	Here we can see the first normal pressure spike at 2510 µsec compressed the fuel and air and caused by DDT at 2555 µsec.		Here we can see the first normal pressure spike at 2510 µsec compressed the fuel and air and caused a DDT at 2555 µsec.
	[[Image:6_6.gif]]		[[Image:6_6.gif]]

	For more information on DDT, try [http://www.google.com/search?hl=en&q=deflagration+detonation+transition&btnG=Search Google]		For more information on DDT, try [http://www.google.com/search?hl=en&q=deflagration+detonation+transition&btnG=Search Google]
	[http://www.gexcon.com/index.php?src=handbook/GEXHBchap6.htm#sect6.3 GexCon article on DDT]		[http://www.gexcon.com/index.php?src=handbook/GEXHBchap6.htm#sect6.3 GexCon article on DDT]

Benstern at 20:57, 23 October 2007

2007-10-23T20:57:02Z

← Older revision		Revision as of 15:57, 23 October 2007
Line 7:		Line 7:
	It is the goal of anyone who constructs a [[hybrid]] launcher to avoid DDT. It is thought that a short, fat (theoretically closer to spherical) chamber is less likely to incur DDT than a long, thin chamber. Using oxygen enriched mixtures or exotic fuels such as acetylene increase the risk of DDT.		It is the goal of anyone who constructs a [[hybrid]] launcher to avoid DDT. It is thought that a short, fat (theoretically closer to spherical) chamber is less likely to incur DDT than a long, thin chamber. Using oxygen enriched mixtures or exotic fuels such as acetylene increase the risk of DDT.

	For more information on DDT, try [http://www.google.com/search?hl=en&q=deflagration+detonation+transition&btnG=Search Google].		Here we can see the first normal pressure spike at 2510 µsec compressed the fuel and air and caused by DDT at 2555 µsec.
			[[Image:6_6.gif]]

			For more information on DDT, try [http://www.google.com/search?hl=en&q=deflagration+detonation+transition&btnG=Search Google]
			[http://www.gexcon.com/index.php?src=handbook/GEXHBchap6.htm#sect6.3 GexCon article on DDT]

Pete Zaria at 08:18, 23 October 2007

2007-10-23T08:18:49Z

← Older revision		Revision as of 03:18, 23 October 2007
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	"DDT" stands for Deflagration to Detonation Transition and is the technical term for the little-understood phenomenon occurs when the flame-front inside a burning fuel/air mixture reaches and exceeds the (local) speed of sound. Note that the speed of sound changes with pressure, temperature, and even humidity, so the speed of sound inside the combustion chamber can be very different from the atmospheric speed of sound.		"DDT" stands for Deflagration to Detonation Transition and is the technical term for the little-understood phenomenon that occurs when the flame front inside a burning fuel/air mixture reaches and exceeds the (local) speed of sound. Note that the speed of sound changes with pressure, temperature, and even humidity, so the speed of sound inside the combustion chamber can be very different from the atmospheric speed of sound.

	In a normal combustion situation, the flame front in a burning fuel/air mixture does not exceed the speed of sound, classifying it as a deflagration (see [http://en.wikipedia.org/wiki/Deflagration Deflagration on Wikipedia]).		In a normal combustion situation, the flame front in a burning fuel/air mixture does not exceed the speed of sound, classifying it as a deflagration (see [http://en.wikipedia.org/wiki/Deflagration Deflagration on Wikipedia]). The combustion inside a gasoline or diesel engine, gunpowder, and low-grade explosives are all deflagrations.

	Under rare circumstances (generally in respectively long, thin combustion chambers containing pressurized fuel/oxidizer mixtures), the flame front can exceed the speed of sound, as does the flame front of high explosives, classifying it as a [http://en.wikipedia.org/wiki/Detonation Detonation]. This transition from subsonic to supersonic can create an immense pressure spike that has damaged even well-constructed metal chambers, and is certain to cause a PVC chamber to fail.		Under rare circumstances (generally in respectively long, thin combustion chambers containing pressurized fuel/oxidizer mixtures), the flame front can exceed the (local) speed of sound, as does the flame front of high explosives, classifying it as a [http://en.wikipedia.org/wiki/Detonation Detonation]. This transition from subsonic to supersonic can create an immense pressure spike that has damaged even well-constructed metal chambers, and is certain to cause a PVC chamber to fail.

	It is the goal of anyone who constructs a [[hybrid]] launcher to avoid DDT. It is thought that a short, fat (theoretically closer to spherical) chamber is less likely to incur DDT than a long, thin chamber. Using oxygen enriched mixtures or exotic fuels such as acetylene increase the risk of DDT.		It is the goal of anyone who constructs a [[hybrid]] launcher to avoid DDT. It is thought that a short, fat (theoretically closer to spherical) chamber is less likely to incur DDT than a long, thin chamber. Using oxygen enriched mixtures or exotic fuels such as acetylene increase the risk of DDT.

	For more information on DDT, try [http://www.google.com/search?hl=en&q=deflagration+detonation+transition&btnG=Search Google].		For more information on DDT, try [http://www.google.com/search?hl=en&q=deflagration+detonation+transition&btnG=Search Google].

Pete Zaria: New page: "DDT" stands for Deflagration to Detonation Transition and is the technical term for the little-understood phenomenon occurs when the flame-front inside a burning fuel/air mixture reaches ...

2007-10-23T08:12:01Z

New page: "DDT" stands for Deflagration to Detonation Transition and is the technical term for the little-understood phenomenon occurs when the flame-front inside a burning fuel/air mixture reaches ...

New page

"DDT" stands for Deflagration to Detonation Transition and is the technical term for the little-understood phenomenon occurs when the flame-front inside a burning fuel/air mixture reaches and exceeds the (local) speed of sound. Note that the speed of sound changes with pressure, temperature, and even humidity, so the speed of sound inside the combustion chamber can be very different from the atmospheric speed of sound.

In a normal combustion situation, the flame front in a burning fuel/air mixture does not exceed the speed of sound, classifying it as a deflagration (see [http://en.wikipedia.org/wiki/Deflagration Deflagration on Wikipedia]).

Under rare circumstances (generally in respectively long, thin combustion chambers containing pressurized fuel/oxidizer mixtures), the flame front can exceed the speed of sound, as does the flame front of high explosives, classifying it as a [http://en.wikipedia.org/wiki/Detonation Detonation]. This transition from subsonic to supersonic can create an immense pressure spike that has damaged even well-constructed metal chambers, and is certain to cause a PVC chamber to fail.

It is the goal of anyone who constructs a [[hybrid]] launcher to avoid DDT. It is thought that a short, fat (theoretically closer to spherical) chamber is less likely to incur DDT than a long, thin chamber. Using oxygen enriched mixtures or exotic fuels such as acetylene increase the risk of DDT.

For more information on DDT, try [http://www.google.com/search?hl=en&q=deflagration+detonation+transition&btnG=Search Google].