Re: [Vo]:Ignition
When I was a teenager I tried to burn some brush with gasoline. I added some gas, It did not lite. I added more, same thing. More then, K-boom, but not in the brush pile but rather in a dip 15 feet away from the brush pile. The fumes, heaver than are went into the dip. Lesson learned the hard way for a young man. Frank
RE: [Vo]:Ignition
Curious side note on some of our mistaken assumptions on ignition and combustion. (oxygen free) Did you know that CO2 can be a useful oxidizer? There are actually a few chemicals that will burn quite violently in CO2. The main one is silane - which is a molecule like methane but with silicon at the core instead of carbon. Robert Zurbin suggest this in The Case for Mars: The Plan to Settle the Red Planet and Why We Must and NASA has picked up on it, so I guess it is accurate. http://www.amazon.com/The-Case-Mars-Settle-Planet/dp/0684835509 The atmosphere of Mars is mostly of carbon dioxide 95+%.
RE: [Vo]:Ignition
I’m not sure if this is outdated knowledge, but in order for the liquid fuel to ‘burn’ in the combustion chamber (CC) of an ICE, it must have oxygen attached. One major function of a carburetor is to mix the liquid droplets with O2 from the air. The problem is that the liquid fuel (regardless of how small the droplets are) has considerably more mass than the O2, and if there are any sharp bends in the intake manifold, the O2 has less inertia and can make those turns whereas the heavy liquid fuel droplets cannot, and you get fuel-air-separation. Liquid droplets w/o attached O2 will not ‘burn’. There are several ways that the industry has reduced the fuel-air-separation problem: - Fuel injection which does a much better job of atomizing the liquid fuel, and injecting it closer to CC so less likely to get separation. - Intake manifolds which eliminate (as much as possible) any bends in the passageways. -Mark From: Eric Walker [mailto:eric.wal...@gmail.com] Sent: Sunday, April 22, 2012 10:05 PM To: vortex-l@eskimo.com Subject: Re: [Vo]:Ignition On Sun, Apr 22, 2012 at 9:59 PM, mix...@bigpond.com wrote: Actually, the liquid gasoline never burns. Only vapor burns. This is true in an engine as well. The smaller the droplets, the more easily they evaporate and provide the necessary vapor. Does this follow from the fact that the reaction is an oxidation reaction, in which oxygen is required? Since insufficient oxygen is contained in the liquid, only vapors oxidize? Eric
Re: [Vo]:Ignition
Now, all we need to do in-order to get to Mars quickly, so we can colonize or occupy it, would be to dramatically increase our consumption of coal, oil, diesel, gas, right here on Earth,,, thus turning human-compatable atmosphere into that of Mars,,, thus saving the cost and rather lengthy process of trying to convert Mars atmosphere into a more Human suitable one, like Earths... Brilliant I tell you,,, absolutely brilliant! The main one is silane - which is a molecule like methane but with silicon at the core instead of carbon. Robert Zurbin suggest this in The Case for Mars: The Plan to Settle the Red Planet and Why We Must and NASA has picked up on it, so I guess it is accurate. http://www.amazon.com/The-Case-Mars-Settle-Planet/dp/0684835509 The atmosphere of Mars is mostly of carbon dioxide 95+%. /HTML
RE: [Vo]:Ignition
Sunlight will cause ignition, with only slight focusing. Magnifying glass is sufficient. Be my guest to try it, but stand back... This indicates that it is not only energy per photon that is important, but energetic photon-density per unit area. -Original Message- From: mix...@bigpond.com Hi, Here's a little conundrum that has troubled me for some time. Take a cup of gasoline and place it in open sunlight. It will slowly evaporate. Bring a flame near it and it will suddenly ignite. Why don't the UV rays from sunlight cause ignition? Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
Re: [Vo]:Ignition
In reply to Jones Beene's message of Sun, 22 Apr 2012 15:14:40 -0700: Hi Jones, You are probably correct, but that just shifts the definition of the problem. The question then becomes, why is density important? (I'm looking for an answer involving a molecular level analysis.) Sunlight will cause ignition, with only slight focusing. Magnifying glass is sufficient. Be my guest to try it, but stand back... This indicates that it is not only energy per photon that is important, but energetic photon-density per unit area. -Original Message- From: mix...@bigpond.com Hi, Here's a little conundrum that has troubled me for some time. Take a cup of gasoline and place it in open sunlight. It will slowly evaporate. Bring a flame near it and it will suddenly ignite. Why don't the UV rays from sunlight cause ignition? Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
Re: [Vo]:Ignition
Let me give this a try. I suspect that the magnitude of energy delivered by the UV rays is not quite enough to allow ignition of a small region of the gasoline. It reminds me of the ignition of gunpowder where a flame can be placed upon a small amount of powder and it takes some time before ignition occurs. I have always felt that if you consider a small volume of the material you would have the following occur. Heat or explosive effect is generated within the volume of material, but the energy escapes through the surface area of that volume. If the heat is reduced too much after flowing through the surface, then it can not cause the adjacent volume to ignite. Just my two cents worthmaybe wrong but this is what I have always thought. Dave -Original Message- From: mixent mix...@bigpond.com To: VORTEX vortex-l@eskimo.com Sent: Sun, Apr 22, 2012 6:02 pm Subject: [Vo]:Ignition Hi, Here's a little conundrum that has troubled me for some time. ake a cup of gasoline and place it in open sunlight. It will slowly evaporate. ring a flame near it and it will suddenly ignite. Why don't the UV rays from sunlight cause ignition? Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
Re: [Vo]:Ignition
A further thought. Consider the fuel intake valve of an automobile. We all know that these can not be perfect and thus allow absolute isolation between the extremely hot gases within the cylinder and the intake mixture. Some explosive gas and heat must get to the intake mix but it does not ignite. I suspect that the heat injected within each small volume of input mixture does not reach that required to trigger a reaction. If the leak becomes too large then backfires would most likely result. I think of the LENR reaction as being similar. The melted cavities that are seen on active experiments appear to me to be a cascade of individual small reactions. There is enough energy released within an active volume to spread outside of that region into the next sensitive one. This process would continue until the heat generated per volume no longer supports the heat loss through its surface area at which time the reaction quenches. There may be methods of controlling the energy generation volumes such as with magnetic fields which may be DGT's technique. The energy transfer through the surface areas of the tiny volumes of active LENR regions may be in some other form than heat such as radiation but the cascade would be similar. I can imagine that a focused beam might even occur where the reactions proceed along a relatively narrow path similar to a laser amplification. If this were the case then a cone shaped expulsion of melted material could appear which looks suspiciously like the pictures I have seen. Dave -Original Message- From: mixent mix...@bigpond.com To: vortex-l vortex-l@eskimo.com Sent: Sun, Apr 22, 2012 6:21 pm Subject: Re: [Vo]:Ignition In reply to Jones Beene's message of Sun, 22 Apr 2012 15:14:40 -0700: i Jones, You are probably correct, but that just shifts the definition of the problem. he question then becomes, why is density important? I'm looking for an answer involving a molecular level analysis.) Sunlight will cause ignition, with only slight focusing. Magnifying glass is sufficient. Be my guest to try it, but stand back... This indicates that it is not only energy per photon that is important, but energetic photon-density per unit area. -Original Message- From: mix...@bigpond.com Hi, Here's a little conundrum that has troubled me for some time. Take a cup of gasoline and place it in open sunlight. It will slowly evaporate. Bring a flame near it and it will suddenly ignite. Why don't the UV rays from sunlight cause ignition? Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html egards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
Re: [Vo]:Ignition
At 05:02 PM 4/22/2012, mix...@bigpond.com wrote: Here's a little conundrum that has troubled me for some time. Take a cup of gasoline and place it in open sunlight. It will slowly evaporate. Bring a flame near it and it will suddenly ignite. Why don't the UV rays from sunlight cause ignition? I don't know the specific energies involved, but my sense of this is as follows: First of all, yes, it's obvious: gasoline does not ignite just because an individual molecule is oxidized, as it will be if, say, a cosmic ray with hign energy hits it. You can have a mixture of hydrogen and oxygen, an explosive mixture and it will just sit there, even if you expose it to, say, a few high-energy photons or energetic particles. There is obviously a hump to get over to allow the oxidation reaction to occur. Under conditions well below ignition temperature, if a single reaction occurs, it cannot raise the temperature of the local environment enough, the products are immediately cooled. However, at -- or very close to -- the ignition temperature, only a little extra heat is needed. The closer to ignition temperature, the less the needed heat, until, at ignition temperature, the oxidation starts happening en masse, it all heats up and a wave of ignition passes through the material. Badly explained, perhaps. But the basic idea is that at low temperatures, a little puff of heat doesn't do anything. A single reaction is just that, it has no observable effect. UV light probably isn't energetic enough, by the way. I don't think it would be absorbed by the gasoline. But I don't know. The gasoline, by the way, doesn't ignite just because you bring a flame near it, not directly. Rather, the vapors will ignite from contact with the flame, and the ignition, from that mixture of gasoline and air, can ignite the gasoline.
Re: [Vo]:Ignition
In reply to Abd ul-Rahman Lomax's message of Sun, 22 Apr 2012 21:52:35 -0500: Hi, [snip] I don't know the specific energies involved, but my sense of this is as follows: First of all, yes, it's obvious: gasoline does not ignite just because an individual molecule is oxidized, as it will be if, say, a cosmic ray with hign energy hits it. You can have a mixture of hydrogen and oxygen, an explosive mixture and it will just sit there, even if you expose it to, say, a few high-energy photons or energetic particles. There is obviously a hump to get over to allow the oxidation reaction to occur. Under conditions well below ignition temperature, if a single reaction occurs, it cannot raise the temperature of the local environment enough, the products are immediately cooled. However, at -- or very close to -- the ignition temperature, only a little extra heat is needed. The closer to ignition temperature, the less the needed heat, until, at ignition temperature, the oxidation starts happening en masse, it all heats up and a wave of ignition passes through the material. Badly explained, perhaps. But the basic idea is that at low temperatures, a little puff of heat doesn't do anything. A single reaction is just that, it has no observable effect. This appears to tie in with Dave's reply. The ratio of surface area to volume increases as the radius decreases, until at the molecular level the heat released by a single reaction escapes in all directions and the amount captured by any given molecule in the neighborhood isn't sufficient to ignite it. However when many reactions occur in close proximity to one another the heat has nowhere to go and a chain reaction is initiated. UV light probably isn't energetic enough, by the way. I don't think it would be absorbed by the gasoline. But I don't know. I think it is energetic enough, it only has to trigger a chemical reaction (e.g. sun burn). (UV-A is 3-4 eV which is as much as you get from most chemical reactions. Production of e.g. H2O yields less.). BTW Jones' point about a magnifying glass is also a good one. Since it will ignite combustible substances, and all it does is concentrate photons in a small region, those photons are clearly energetic enough on an individual basis. The gasoline, by the way, doesn't ignite just because you bring a flame near it, not directly. Rather, the vapors will ignite from contact with the flame, and the ignition, from that mixture of gasoline and air, can ignite the gasoline. Actually, the liquid gasoline never burns. Only vapor burns. This is true in an engine as well. The smaller the droplets, the more easily they evaporate and provide the necessary vapor. I have seen an oil fire quenched simply by rapidly cooling (water) the outside of the metal container that held the oil, thus stopping the evaporation. Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
Re: [Vo]:Ignition
I was considering the gasoline vapor ignition question further and thought that a simple math example of the effect would shed light upon the subject. An intense amount of local heating is generated when a small region of vapor mix is ignited by some means. This released heat energy then proprogates outward from the ignition volume into the surrounding material and if the intensity is adequate the flame will proceed onward. Recall that volume of a sphere is proportional to radius cubed while surface area is proportional to radius squared. A result of these relationships is that less heat per unit area escapes into the surrounding medium as the size of the active sphere becomes smaller. This implies that a certain minimum volume of material must be ignited before the surrounding mix can see enough energy for it to ignite as well. The UV rays apparently do not activate a volume that is great enough for further activity. Lets choose an easy example to calculate which actually bears little comparison to the actual case at hand but demonstrates the process. Assume that we have ignited the gas vapor mix within a volume that releases 1 joule of heat energy. Our test region has a radius of 1 cm for the example. The area of a sphere is 4*pi*R*R or 4 * 3.14159 * 1 centimeter * 1 centimeter = 12.566 square cm. The energy density leaving the sphere is thus 1 joule / 12.566 square cm. Perhaps this is enough to ignite the material at the surface of the sphere and the flame would proprogate. Now lets only ignite a ½ cm radius sphere of vapor mix. The heat released would now be ½ * ½ * ½ or 1/8 joule. But the area would also shrink to the new value of 4 * pi * ½ * ½ = 3.1416 square cm. Thus the net energy density leaving our new smaller volume is exactly ½ the original amount which might not be enough to ignite the adjacent material. Dave -Original Message- From: mixent mix...@bigpond.com To: VORTEX vortex-l@eskimo.com Sent: Sun, Apr 22, 2012 6:02 pm Subject: [Vo]:Ignition Hi, Here's a little conundrum that has troubled me for some time. ake a cup of gasoline and place it in open sunlight. It will slowly evaporate. ring a flame near it and it will suddenly ignite. Why don't the UV rays from sunlight cause ignition? Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html -Original Message- From: mixent mix...@bigpond.com To: VORTEX vortex-l@eskimo.com Sent: Sun, Apr 22, 2012 6:02 pm Subject: [Vo]:Ignition Hi, Here's a little conundrum that has troubled me for some time. ake a cup of gasoline and place it in open sunlight. It will slowly evaporate. ring a flame near it and it will suddenly ignite. Why don't the UV rays from sunlight cause ignition? Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
Re: [Vo]:Ignition
On Sun, Apr 22, 2012 at 9:59 PM, mix...@bigpond.com wrote: Actually, the liquid gasoline never burns. Only vapor burns. This is true in an engine as well. The smaller the droplets, the more easily they evaporate and provide the necessary vapor. Does this follow from the fact that the reaction is an oxidation reaction, in which oxygen is required? Since insufficient oxygen is contained in the liquid, only vapors oxidize? Eric
Re: [Vo]:Ignition
Yes, that is correct. Liquid gasoline does not burn without oxygen present. Explosives have all of the needed ingredients 'built in so they do not require extra oxygen from the air. Dave -Original Message- From: Eric Walker eric.wal...@gmail.com To: vortex-l vortex-l@eskimo.com Sent: Mon, Apr 23, 2012 1:05 am Subject: Re: [Vo]:Ignition On Sun, Apr 22, 2012 at 9:59 PM, mix...@bigpond.com wrote: Actually, the liquid gasoline never burns. Only vapor burns. This is true in an engine as well. The smaller the droplets, the more easily they evaporate and provide the necessary vapor. Does this follow from the fact that the reaction is an oxidation reaction, in which oxygen is required? Since insufficient oxygen is contained in the liquid, only vapors oxidize? Eric
