Spark length at 20x mix


Postby GalFisk » Thu Oct 26, 2006 3:16 am

For air, and gaps on the order of a millimeter, the breakdown is roughly a linear function of the gap length: V = 30pd + 1.35 kV, where d is in centimeters, and p is in atmospheres.
(<a href="http://home.earthlink.net/~jimlux/hv/paschen.htm">source</a>)
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Postby SPG » Thu Oct 26, 2006 8:00 am

Out of interest, won't your propane just liquify well before you get to 20 ATM?
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Postby GalFisk » Thu Oct 26, 2006 8:43 am

The partial pressure of propane must exceed its vapor pressure before it will liquify. At 4.03% by volume and a vapor pressure of 122 psi at 70°F, you can go up to about 122/4.03% = ~3000 psi (204x).
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Postby spuzi14 » Thu Oct 26, 2006 3:11 pm

I don't know the pressure rating on those tanks but if I was going to anywhere past 1000 PSI I would have a 3000PSI safety margin on the tanks.

I think you can be succesful with this but I think you should triple check everything.
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Postby boilingleadbath » Thu Oct 26, 2006 4:21 pm

That applies for water too - right, galfisk?
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Postby benstern » Thu Oct 26, 2006 5:40 pm

I was thinking about propane turning to liquid, thanks Galfisk. The main problem is ignition because a fan would not be possible because of the extreme temperature and pressure.
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Postby sgort87 » Thu Oct 26, 2006 5:51 pm

I think you should shake it by hand to mix it up! :p
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Postby GalFisk » Thu Oct 26, 2006 5:51 pm

BLB: correct, that's how air can contain moisture at normal temperatures. Even below freezing water has a vapor pressure, which allows ice to sublimate (see what happens to ice cubes that are kept long in the freezer).

Have fans ever been used in hybrids? Pressure shouldn't affect one much, though temperature could be a problem with high mixes. I was planning to include one and have a wiring for it, but I don't have one small enough.
A metallic fan could work even if a computer fn would melt.
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Postby sgort87 » Thu Oct 26, 2006 6:49 pm

I used a fan in my hybrid. I don't know if it works anymore or not, but there's a fan in it.
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Postby benstern » Thu Oct 26, 2006 8:53 pm

But where would I find a large (8") all metal fan?
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