Wes, you know how the exhaust stream feels coming out of a pipe, it is pretty
much "constant flow". I mean one cylinder puts out one egg with each cycle, and
considering how many eggs are put out each second, and then coupling-multiplying
that by 4-6-8 cylinders and you have a varitable warp flow of egg, and for all
intensive purposes - constant. Joe :) :)
Wester S Potter wrote:
> "Doc Gas" who is a local exhaust expert who literally changed the sound of
> Daytona, explains that exhaust is like a series of "eggs" being pushed out
> of the headers. With the pulsations I wonder how effective the Bernoulli
> effect is because of the interruptions of the total flow? An atomizer works
> best with a constant flow. An exhaust header does not put out a constant
> flow.
> Wes
> ----------
> > From: dferguso@ebmail.gdeb.com
> > To: FastmetalBDF@aol.com, land-speed@autox.team.net
> > Subject: Re: Exhaust Extraction
> > Date: Tue, 4 Jan 2000 17:54:03 -0500
> >
> >bernoulli's principle is not dependent on having a small exhaust dump to be
> >effective. the bernuolli equation shows that the decrease in pressure will
> >be the same ( IF the engine is shut off ) weather the exhaust dump has a
> >small diameter (area) or large diameter (area) for a given velocity of air
> >rushing by . where the trick comes in is how fast are you compensating for
> >(negating) this effect with the exhaust flow with the engine running. if
> >your engine is forcing out enough exhaust compared to the area of the dump
> >( a small collector), then the bernoulli principle looses its effectiveness
> >and will reach a point where it no longer applies as the exhaust gasses are
> >exiting the dump so forcefully that the air flowing around the car can no
> >longer flow over the end of the dump. actually, the bigger the exhaust dump
> >the better, since the venturi effect of the bernoulli principle can
> >possibly work its magic over a much bigger area to hopefully compensate for
> >the pressure and flow of gasses exiting the engine. besides the bernoulli
> >principle, other factors such as the shape and orientation of the dump
> >relative to the air flow over the end of it also play an effect on net
> >pressure inside the dump via frictional and momentum interactions between
> >the exhaust gas and the air flowing by the end of the dump. at wide open
> >throttle bernoullis principle probably does not play a role in reducing
> >exhaust pressure since exhaust will be exiting the dump very forcefully,
> >but im sure the frictional force of the air rushing by the end of the dump
> >may play an "extractive " or " venturi" role depending on the geometry and
> >relative orientation of the dump.
> >
> >food for thought for anyone who cares, not presented as gospel physics -
> >regards-
> >doug @ black radon engineering
> >
> >
> >
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