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REFLECTOR: Another bounce from Al

Forwarded message:
> Bob wrote:
> >time to replace the 1/2 inch oil lines. However, I  wonder why because the
> >entrance and exit holes from the by-pass valve have the same inside
> diameter.
> >To someone that does not know very much about fluid dynamics under pressure
> it seem you can only move as much as will go thru the smallest openings, the
> ones in and out of the by-pass valve.
> >
> >Is the extra cooling provided buy the larger cooling surface of the 5/8
> inch
> >tubing?  Can someone out there explain this?
> The pressure drop in a fluid circuit is the sum of the pressure drops in
> each part; elbows, orifices and lines.  The entrance and exit from the
> by-pass maybe smaller, but they are also for a very short distance.  The
> line is very, very long, and for viscous oil represents a large part of the
> pressure drop around the loop.  Also, the flow area in the line increases as
> the square of the diameter, so going from 1/2" to 5/8" will give you a 56%
> increase in flow area and a corresponding decrease in pressure drop in the
> line.
> 90 degree drilled elbows cause significant pressure also, so aviod them if
> you can.  A 90 degree minimum radius bend in a tube will probably have less
> than 1/4 the pressure drop of an elbow.
> The outside surface area of the line is directly proportional to the
> diameter, so if you're using the line as cooling surface, that area
> increases by 25%.
> I don't know; however, that the 5/8" line is required.  I do know that you
> have to have bypass valve setup for a high enough pressure to force
> sufficient oil through the cooling loop.
> Good luck.
> Al Gietzen  RGE

Brian Michalk  <http://www.awpi.com/michalk>
Life is what you make of it ... never wish you had done something.
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