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From: "Ron Soave" <soavero@yahoo.com>
Sent: Sunday, September 27, 2009 6:27 AM
To: <spridgets@autox.team.net>
Subject: Re: [Spridgets] Weber DCOE vs OER DCOE
> --- On Sun, 9/27/09, Robert E. Shlafer <pilotrob@webtv.net> wrote:
>> "Reynolds Numbers" apply to liquids
>> as far as I know (which is not that far in these respects)
>> however,
>
> Reynold's number applies to all fluids, air included. Off the top of my
> head at 6am - It is dimensionless, and is equal to the density times the
> velocity of the fluid times effective diameter of the fuid passage divided
> by the kinematic viscosity (rho*V*De/mu). For air, Reynold's number is
> used to calculate the friction factor, and that's equal to .046/Re^.2 if
> memory serves. The simplified form of Bernoulli in the case we are talking
> about is that flow: W=density * Area * velocity. As you can see, there are
> common terms in each equation, so you can manipulate them to come up with
> a friction factor, but that factor will only tell you the friction per
> unit length, hence my "nope". In fact, the throat reduction here makes the
> air behave somewhere in between a swage and a sudden contraction. In both
> cases, the friction factor varies non-linearly with the ratio of the
> upstream and downstream areas. You want to keep it gradual, with a
> reduction angle of less
> than seven degrees for the inner edge of the boundary layer of flow. Throw
> in additional effects of non-uniform flow fields due to the contraction
> and the effect on the vena-contracta in the venturi throat and the
> homogeneity of the flow and downstream mixture suffer.
>
> Or you could switch back to SUs.
>
> Off to the races,
> Ron
> _______________________________________________
I knew that.
Not.
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