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At My House We Call Them "Uh-Oh's"
Kowgod writes "For those of you who have never checked out the NCSA's Access Magazine, this issue's cover story will hopefully spark your interest. It seems an aerospace engineer, Cyrus K. Madnia, over at the State University of New York at Buffalo is trying to use super-computers to model fire. By tinkering with the mechanics and components of a flame he hopes to discover ways to burn fuel more efficiently, thus emitting less pollution. Kind of an odd twist on the quest for the zero emission internal combustion engine."
IC-engines will produce emisions, always. In the ideal case there will be no harmful emissions (i.e. only water.)
An IC-engine that burns hydrogen with air will produce at least nitrous oxides (nitrogen burnt under high temperatures.) assuming absolutely no pollutants in the air... If there is hydro-carbons or other combustible pollutants in the air, well who knows what fun emissions comes out of the zero-emissions engine.
Never mind the problems and risks of storing hydrogen as fuel in your car.
I am however cautiously optimistic to the prospect of safe and clean fuel-cell engines.
For those of you who might not get the joke, Ralph Wiggum of the Simpsons says "At my house we call them uh-oh's".
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Hey guys! There are a lot of people throughout the world trying to model combustion with the goal of improved efficiency.. Madnia at SUNY UB is pretty good (a little close-minded) but he's not the only guy out there this sort of work...
For those who haven't read much about CFD (Computational Fluid Dynamics) here's a little overview.. DNS (Direct Numerical Simulation) solves the equations of motion for a flow to obtain information for all the scales (wavenumber information).. The problems with DNS include restrictions on Reynolds number, limited run time (very few statistically independent samples), and domain size. I believe that currently the largest DNS that has been performed was on a 1024^3 element grid.. Unfortunately, it still really isn't fine enough to deal with a Reynolds number beyond a few hundred (many practical flows have Re #'s ~1e6+).. To model higher Reynolds number flows many researchers have moved to LES (Large Eddy Simulation) type approaches, where the equations are solved directly for scales above a certain range, and the subgrid scales are handled using a variety of models. LES has a handful of problems too.. The big problem when using LES for combustion work is that a large percentage of the mixing that these researchers need to manipulate in order to improve their efficiency occurs in the subgrid scales that they're modelling...
we didnt need supercomputers to model fire. ... and it ran on our little 386s.
We had a simple formula
Mem[x] = Mem[x - 1] + Mem[x + 1] + Mem[x - 320] / 3
Them there at NASA probably ought to experiment with this!
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Video meliora proboque deteriora sequor - Ovidius
They had a segment on the Michael Holigan show (not nearly as cool as Hometime, but that was a rerun on TLC...) where some research institute was developing natural gas burners that burned 20x cleaner than traditional natural gas burners. They use a convection current to super saturate the gas flow with air, burning less fuel in the process for the same output. Even better was the fact that you can hold onto the burner without getting burned because the current pushes the flame away from the burner itself. Try that with a Bunsen burner.
"Why do you consent to live in ignorance and fear?" - Bad Religion
For a second I was sure that this article was about ICQ...
How are you wrong? Let me count the ways:
1) The Hindenburg did not burn because it was full of hydrogen. It would have burned had it been filled with helium. Some guy at NASA proved it.
2) Gas tanks do not tend to burn. There are hundreds of thousands (if not millions) of them not burning all over the world right now. You probably have several hundred very near you as you read this (in automobiles, in lawnmowers, etc.).
3) Pressurized gas cylinders do not tend to explode. There are hundreds of thousands (if not millions) of them not exploding all over the world right now. You probably have several dozen very near you as you read this (fire extinguishers, propane tanks, medical oxygen tanks, helium tanks to blow up [inflate] children's ballons, etc.).
4) The Hindenburg was not a gas tank, nor was it a pressurized gas cylinder.
5) Nothing about the Hindenburg has anything to do with the idea of using hydrogen as a fuel. The Hindenburg ran on kerosene. Saying the Hindenburg "proves" hydrogen is dangerous is like saying the Kursk "proves" nuclear power is dangerous since it was a nuclear sub (or that Three Mile Island "proves" that electricity is dangerous since that's what it was making).
And as for your first point about all the energy used to "make" the hydrogen, you miss the point entirely. There are dozens of ways we can (and do) make hydrogen, some better than others. There is only one way to make gasoline. At least hydrogen will give us some options, one of which is make it from gasoline as needed.
If all this should have a reason, we would be the last to know.
I doubt it, since special effects types and directors always seem to favor things that look "cool" over anything realistic. And the rest of the realism goes the wayside due to concerns about "drama" and filming requirments.
Good examples of this include 2-D "shock waves" in space explosions (heck, Lucas went to the trouble of adding these unrealistic effects into the Special Edition of Star Wars) and sound effects in a vacuum.
I can easily envision a director throwing out someones new, accurately-calculated flames because they don't look "firey enough."
Whaaa? Man, how can someone screw up such a classic line!?
FIRST of all, its not Smokey the Bear, its Hosey the Bear.
And second, as you can clearly read here, the line truly is:
Hosey: You're not going to start any fires, are you?
Ralph: At my house, we call them, "uh-ohs."
Why oh why don't they avoid this by teaching Simpsons in school?
-- Mesmer is the Dairy King Remove your panties to email me.