Larry,
An apt example and one that I believe supports the position I've taken. In
your case, the header takes the place of the engine with heat input. I
believe the major concern, especially with a flame heated header, would be
to avoid hot spots and boiling. It's not a case of "Oh, we got too big a
pump here, so we better add a restriction to slow down the flow." I'll bet
the restriction is AFTER the header so as to build some pressure. What you
really want is flow AND pressure, so there's a compromise. Fortunately, in
your case the difference between the flame temp and header temp is so
great, you can stand a few degrees hotter water without affecting the heat
transfer efficiency much. What you don't want, though is air pockets and/or
boiling. If slower water flow was the goal, then you could save a bunch of
money by simply using a smaller pump (or cutting of vanes, loosening the
belt, etc. as is often suggested as a cure for car overheating problems).
The argument that "the water does not have time to pick up the heat
transfer" is, simply put, wrong.
Bob
At 09:50 AM 1/20/00 -0500, Larry Paulick wrote:
>Bob, I are an engineer also (thank God for spell checkers), and deal
>with heat transfer to water. Pool heaters. Simply put, the water does
>not have time to pick up the heat transfer.
>
>In pools, you valve the header to reduce the flow, and in car's a
>restrictor is put into the system. Done all the time.
>
>Red Line Water Wetter, improves this issue, more so with straight water,
>that water with antifreeze. Check the Red Line web site, and they have
>an explinaation of this process that covers some of the physics.
>
>Been too long to remember the physics, but it works, and it is true.
>
>Larry, PE
Robert L. Palmer
UCSD, Dept. of AMES
619-822-1037 (o)
760-599-9927 (h)
rpalmer@ucsd.edu
rpalmer@cts.com
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