H2 + O2 burning cannon

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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burning_water
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Mon Feb 16, 2015 9:27 pm

G'day everyone,
I am new to Spud files and I thought I would share my Hydroxy spud gun.
I am posting this to show everyone that water burns !!
IMG_5177.jpg
IMG_5177.jpg (33.74 KiB) Viewed 3924 times
This was originally designed to be a tennis ball launcher, the ignition is a BBQ igniter which works fine because of the low ignition energy of Hydrogen.
At half power it launches a tennis ball at 360 kph (Measured with Go-Pro camera), any more and it obliterates the tennis ball.
Hydrogen mixture is produced with a dry cell (1.5 lpm) from water and KOH mix.

Please feel free to comment and let me know what you think !
water was made to burn
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Juggernaut12121
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Sun Mar 22, 2015 9:25 am

That muzzle blast is beautiful, welcome to spufiles! :)
What sort of generator are you using? Homemade? I've wanted to make a small one for a while but I got lazy lately
Whatever the mind can conceive and believe, it can achieve
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burning_water
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Sun Mar 22, 2015 7:35 pm

Hi Juggernaut12121,
Here is a link to the cell I have http://www.aliexpress.com/item/21-Plate ... 99761.html but I wouldn't recommend it because it is 304 SS instead of 316SS
Regards Burning_water
water was made to burn
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DYI
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Thu Mar 26, 2015 10:39 pm

Nice photo of the muzzle blast. And good production rate on the electrolysis rig, that's impressively cheap, even if you have to replace the plates with 316 yourself. I've considered doing this a few times, but I ended up taking the route of just renting oxygen and hydrogen tanks, mostly because my application required significantly higher supply pressure.
Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
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burning_water
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Fri Mar 27, 2015 12:39 am

Thanks DYI,
I am glad you like it.
What sort of pressures have you been using on your setup ?
water was made to burn
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DYI
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Sat Mar 28, 2015 7:38 pm

burning_water wrote:Thanks DYI,
I am glad you like it.
What sort of pressures have you been using on your setup ?
Between 1000 and 2000psi fuel pressure with a 0.85:0.15 hydrogen/oxygen mix.
Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
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burning_water
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Sun Mar 29, 2015 8:45 am

Ok,
Ha ha...electrolyser could do it, but you would need substantial materials, eg stainless everything.
Regards burning_water
water was made to burn
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burning_water
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Mon Jul 20, 2015 12:59 am

Hi everyone
just wondering if any of you have some info on the burn rate of hydrogen oxygen mix (as produced from water), it is supposed to be 1000 times petrol ?
water was made to burn
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equusvenustas
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Mon Jul 20, 2015 1:20 pm

burning_water wrote:Hi everyone
just wondering if any of you have some info on the burn rate of hydrogen oxygen mix (as produced from water), it is supposed to be 1000 times petrol ?
Well 1000 times the flame speed of a petrol-oxygen sounds like a detonation, hydrogen has a really fast burning rate, under certain conditions it can "deflagrate" at almost 1000 m/s without really going into detonation regime, here is a paper that could be useful, several papers about hydrogen deflagration to detonation are due the Fukushima accident. :roll:
http://www.researchgate.net/publication ... _pressures

These paper doesn't really give you a fixed number as reference but if you are interested in hydrogen-oxygen DDT behavior you can have a little insight about what happens regarding shock fronts and rarefaction waves when a DDT occurs
http://norosx52.nordita.org/~brandenb/d ... rman13.pdf

Here is a comparison of hydrogen to other common gaseous fuels used in household as heat source, there hydrogen flame speed is listed as 3.06 m/s compared to the .39m/s of methane and .45 m/s for propane, they sound too slow for me but they really don't say under what conditions, and presumably are at atmospheric pressure with air as oxidant in a stationary flame.
http://www1.eere.energy.gov/hydrogenand ... /45408.pdf
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burning_water
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Mon Jul 20, 2015 10:18 pm

Thanks for the info mate, I will look into it.
water was made to burn
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