Hi everyone. I just finished reading this article about laser ignition development. http://www.liv.ac.uk/researchintelligence/...serignition.htm I was wondering what everyone's thoughts were on this. It looks very promising. I am kinda surprised this technology is just now being developed though.
Full Version: Laser ignition
QUOTE (The_R1_Kid @ Oct 9 2009, 06:29) 
Hi everyone. I just finished reading this article about laser ignition development. http://www.liv.ac.uk/researchintelligence/...serignition.htm I was wondering what everyone's thoughts were on this. It looks very promising. I am kinda surprised this technology is just now being developed though.
Need to be careful you don't start a thermonuclear reaction.
National Ignition Facility
Ford has been looking at this hard. IIRC they would like to go to production in next couple years
Hi The_R1_Kid,
Well,To exemplify the magnitude of the discrepancy between experimental and numerical results, Lewis and von Elbe reported an experimental value of MIE of 0.4 mJ for a stoichiometric CH4 -air mixture at 1 atm while the computational prediction of Sloane and Ronney using detailed chemical, hydrodynamic, and transport models, is 0.10 mJ. Also, Lewis and von Elbe infer that the minimum flame kernel diameter is about 2 mm, based on the spark gap providing the lowest MIE, whereas Sloane and Ronney predict 0.6 mm. Also, while Lewis and von Elbe clearly recognized the importance of heat losses to the spark electrodes, they did not report the diameter of the electrodes they used. These discrepancies between experiments and computations may possibly be due to an inadequate characterization of the ignition source, given the limitations of the instruments available at the time of Lewis and von Elbe's experiments.
Thanks
Well,To exemplify the magnitude of the discrepancy between experimental and numerical results, Lewis and von Elbe reported an experimental value of MIE of 0.4 mJ for a stoichiometric CH4 -air mixture at 1 atm while the computational prediction of Sloane and Ronney using detailed chemical, hydrodynamic, and transport models, is 0.10 mJ. Also, Lewis and von Elbe infer that the minimum flame kernel diameter is about 2 mm, based on the spark gap providing the lowest MIE, whereas Sloane and Ronney predict 0.6 mm. Also, while Lewis and von Elbe clearly recognized the importance of heat losses to the spark electrodes, they did not report the diameter of the electrodes they used. These discrepancies between experiments and computations may possibly be due to an inadequate characterization of the ignition source, given the limitations of the instruments available at the time of Lewis and von Elbe's experiments.
Thanks
QUOTE (gruntguru @ Oct 8 2009, 14:46)
Need to be careful you don't start a thermonuclear reaction.
National Ignition Facility
National Ignition Facility
Why oh why didn't I pursue a physics doctorate so I could work somewhere truly crazy like that.
I suppose there's a little value in the combustion chamber shape too, given that there is no electrode poking down into it.
QUOTE (zac510 @ Oct 29 2009, 07:36)
I suppose there's a little value in the combustion chamber shape too, given that there is no electrode poking down into it.
And if the laser beam was able to travel through the mixture far enough, could it be aligned sideways across the top of the piston at TDC, so as to provide a line of combustion rather than just a point?
QUOTE (Bill S @ Oct 29 2009, 08:34)
And if the laser beam was able to travel through the mixture far enough, could it be aligned sideways across the top of the piston at TDC, so as to provide a line of combustion rather than just a point?
Agree - that would be good but I don't think they are achieving sufficiently high energy levels to do that yet. The beam travels into the chamber - wide and unfocused, but converges to a small region (focal point) where the energy density is high enough to initiate ignition. A colimated (parallel) beam with sufficient energy for ignition might be capable of damage to metal components, but I 'm surethe effect you are talking about could be achieved with a long focal length.
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