octane and flame speed

[bjdm151]

Help me out. I'm writing a term paper on race gas for a 450 level engineering class. I know octane is only a comparisson of knock rating but i'm getting stumped on flame speed and volatiliy/distillation curves. Has anybody done any research on this or know any sources/sites. I've been staring at charts and graphs of distillation curves all week but I can't find anything outthere on relation to flame speed.

thanx

bj

[public]

Woah.. That is not in my "Car repair for dummies" book. I will have to ask the Snap-On tool girl in the garage. :-)

[SaabJohan]

Originally Posted by bjdm151

Help me out. I'm writing a term paper on race gas for a 450 level engineering class. I know octane is only a comparisson of knock rating but i'm getting stumped on flame speed and volatiliy/distillation curves. Has anybody done any research on this or know any sources/sites. I've been staring at charts and graphs of distillation curves all week but I can't find anything outthere on relation to flame speed.

thanx

bj

Flame speed, I ussume you then mean laminar flame speed. For pumpgas you have a laminar flame speed of about .35 m/s for a lambda 1 mixture. But the flame speed inside the engine will get much higher due to the difference in density between the burned mixture and the unburned mixture and the turbulence which increase the heatflow to the unburned mixture becasue of a higher flame area.
Due to this the combustion velocity can typically be between 20 and 50 m/s but higher is also possible (like in a F1 engine).

Do a search on NACA's technical report server, there should be some info there about flame velocity.
http://naca.larc.nasa.gov/

[civickiller]

Originally Posted by SaabJohan

Flame speed, I ussume you then mean laminar flame speed. For pumpgas you have a laminar flame speed of about .35 m/s for a lambda 1 mixture. But the flame speed inside the engine will get much higher due to the difference in density between the burned mixture and the unburned mixture and the turbulence which increase the heatflow to the unburned mixture becasue of a higher flame area.
Due to this the combustion velocity can typically be between 20 and 50 m/s but higher is also possible (like in a F1 engine).

Do a search on NACA's technical report server, there should be some info there about flame velocity.
http://naca.larc.nasa.gov/

whoa, too cool

[bjdm151]

thanks johan