Checking on use of spark plugs with high pressure hydrogen: http://en.wikipedia.org/wiki/Paschen%27s_law http://en.wikipedia.org/wiki/File:Paschen_Curves.PNG
Hydrogen appears to have a lower breakdown voltage of about 60-70% of air at same pressure. So should be able to use an air gap that is bigger. Spark plugs are usually about 0.8mm gap, and if you are using 25bar H2 that will require about 30kV at room temperature, but for 25bar 600°C I would estimate it will probably be closer to 12kV due to lower H2 density (density equivalent of about 8bar). Most automotive ignition systems do about 20-30kV, so at elevated temperatures it seems likely you could drive a 1.5-2mm spark gap, though not at colder temps and not at higher H2 pressures. Anyway a standard spark plug looks like it should work fine producing sparks in H2 at 25 bar using an automotive coil. On 21 May 2012 19:00, ecat builder <ecatbuil...@gmail.com> wrote: > Interesting link on the http://en.wikipedia.org/wiki/Atomic_hydrogen_welding > > It also appears that you can buy "vintage" tungsten spark plugs. Terry > mentioned Iridium spark plugs... Any thoughts on one versus the other > or using off-the-shelf.. I would prefer to use NPT plugs. > > Obviously I don't want to create too much heat in my reactor... or > blow anything up... (There may be some air/O2 in my system..) > > Guenter, thanks for the schematic links.. > > - Brad > p.s. While not worth a new thread, I think it is interesting that > Rossi says he has been in contact with Siemens. I've long thought that > they would be a good corporate fit for Rossi. >
