|
 |
Hi Guest!
As you're not registered, some features could be unavailable. Click here if you want to become a member of SpudFiles |
| Hydrogen |
« View previous topic :: View next topic » |
| Author |
Message
|
| jimmy101 |
 Posted: 05/18/2007 12:38 PM Post subject: |
 |
|
Major General
Joined: 28 Mar 2007
Posts: 1657
7034.12 Spud Bux
|
By my calculations Hydrogen has slightly more energy per mole than do most other fuels. Slightly as in ~10%.
Hydrogen burns much quicker than most fuels at atmospheric pressure. At elevated temperatures and pressures (i.e., part way through combustion) flame speed isn't much faster than other fuels.
The peak adiabatic pressure is a little lower than other fuels (~10% less than propane) but the peak temperature is a little higher.
Hydrogen is more likely to do deflagration to detonation transistion than most other fuels.
A bunch of stuff about fuels. |
|
| Back to top |
|
 |
|
|
|
| dongfang |
| Posted: 05/19/2007 15:45 PM Post subject: |
|
|
Lieutenant Colonel
Joined: 27 Aug 2006
Posts: 446
1656.71 Spud Bux
|
Hi,
OK, good point to consider the oxidizer as the limiter, not the fuel.
Anyway, if there are x moles of O_2 in some chamber:
After a stoichisometric injection of hydrogen, according to the link above, (1-29.5%)x = 0.705x moles of O_2 should remain (assume athmosperic chamber charge pressure. If you do hybrid, just multiply x by the final charge pressure in bar).
That is, heat of combustion is 119 kCal / mol * 0.705 x moles = 83.9 x kCal.
With, say, butane, it is
(1-3.67%)x = 96.33x moles of O_2 * 105 kCal / mol = 101.15 x kCal.
So, still some more energy (as if combustion heat was all there was to it, I know it is not...) in the butane. The large volume of the tiny mass of H_2 displaces about a third of the oxygen.
Of course, by all means play with the hydrogen & have fun... but do not expect any performance miracles.
Regards
Soren |
|
| Back to top |
|
|
| boilingleadbath |
| Posted: 05/20/2007 18:20 PM Post subject: |
|
|
Moderator
Joined: 12 Mar 2005
Posts: 1647
5491.22 Spud Bux
|
Indeed, dongfang.
Energy density has the potential to mislead, so I suggest farming the math out to a more comprehensive utility, like gaseq.
(which, incidentally, supports your analysis) |
|
| Back to top |
|
|
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
|
|
