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ignitor position

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ignitor position

Unread postAuthor: sprayandplay08 » Wed Jun 11, 2008 10:18 am

my theory is that the further back the ignitor is , the stronger the explosion
.I believe that it allows the flame front to travel in one direction rather that 2 smaller ones.
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Unread postAuthor: iPaintball » Wed Jun 11, 2008 10:21 am

Well ideally the perfect chamber would be a sphere with the ignitor placed in the dead center. You most likely will not notice any increase in power if you move it.
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Unread postAuthor: sprayandplay08 » Wed Jun 11, 2008 10:50 am

ok will note it
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Re: ignitor position

Unread postAuthor: Carlman » Wed Jun 11, 2008 11:00 am

sprayandplay08 wrote:my theory is that the further back the ignitor is , the stronger the explosion
.I believe that it allows the flame front to travel in one direction rather that 2 smaller ones.


but if it is placed in the middle then the pressure built up faster because it can burn everything faster.
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Re: ignitor position

Unread postAuthor: jimmy101 » Wed Jun 11, 2008 12:26 pm

sprayandplay08 wrote:I believe that it allows the flame front to travel in one direction rather that 2 smaller ones.

Uh, directions don't have "size" so "one direction rather that 2 smaller ones" doesn't make much sense.

The advantage of two flame fronts is that since they are basically the same size the rate of fuel burn is ~twice as fast with two fronts as with one. A candle lit at both ends releases it's combustion energy twice as fast as a candle lit at only one end.

Now there are some questions about what the best location is for the ignition event. Many factors and many unknowns contribute to fuel burn speed so it isn't obvious what the optimal spark location is in a combustion spudgun. A closed chamber burns fastest with a central spark but a spudgun isn't the same as closed chamber.

EDIT: It is "generally accepted", but not "universally accepted", that a central spark (if only one spark is used) is best for a combustion spudgun.
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Unread postAuthor: rp181 » Wed Jun 11, 2008 4:06 pm

The only reasonable solution is to have a really long arc through the whole chamber :shock:

On a serious note: I say dont worry with the optimum place, since its so insignificant. I saw just put it where ever is the most convinient.
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Unread postAuthor: Carlman » Thu Jun 12, 2008 10:40 am

rp181 wrote:The only reasonable solution is to have a really long arc through the whole chamber :shock:

On a serious note: I say dont worry with the optimum place, since its so insignificant. I saw just put it where ever is the most convinient.


its not so insignificant, there have been tests done.
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Re: ignitor position

Unread postAuthor: psycix » Fri Jun 13, 2008 5:11 am

sprayandplay08 wrote:my theory is that the further back the ignitor is , the stronger the explosion
.I believe that it allows the flame front to travel in one direction rather that 2 smaller ones.

To correct you, when its at the back, you will get ONE small flamefront instead of two!
Thus your burn time increases and you performance drops.
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Unread postAuthor: sniper hero » Fri Jun 13, 2008 6:16 am

in the middle is the best place
because the the power comes from the chamber walls stopping the "explosion" so the only outway is the barrel.
the less time it takes to fill the chamber with flames the less power is wasted so performance goes up.
but like ipaintball said it doesn't effect the power very much if it is placed not exactly in the middle.
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Unread postAuthor: ramses » Thu Jun 19, 2008 10:06 am

i know you were talking about combustions, but i have a somewhat related idea about hybrid ignition. if the spark is at the front, the flame travels to the back until the chamber pressure exceeds the burst disk. then the unburned fuel flows to the barrel, pushing the flame front back and burning slower. i think the optimal placement for a hybrid is near the back, but not all the way.

sorry if what i said makes no sense.
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Unread postAuthor: psycix » Sun Jun 22, 2008 5:40 am

But also, if you've got alot of unburned fuel in the barrel, you could also place a (or the) spark gap near the front.
When the flamefront travels back, no unburned fuel is flowing in the barrel.
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Unread postAuthor: jimmy101 » Sun Jun 22, 2008 2:43 pm

Or, put the spark at the back of the chamber. The flame front has to chase the ammo down the barrel, which you might think is bad. But as the ammo moves in the barrel the gases move in the rest of the gun. When the gas flow switches from laminar to turbulent you get a big increase in flame front propagation rate when the flame front switches from laminar to turbulent.

Spark in front, in back, in the middle, 2/3rds... lots of theories, very little actual data.
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