[AMPS] Airflow

[w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net)]

> ...snip...
> >My ONLY comment on this reflector is that I did not like the idea of one
> >muffin fan blowing across a pair of 3-500Z's that are in line with the
> >air flow. ... ...
> >
> >73...Carl   KM1H

That's correct Carl. It takes more airflow to maintain the same seal 
temperatures because much of the airflow is wasted. Most of the air 
misses the tubes. The problem is exactly like a car going through 
air. If it goes smoothly through, there is little turbulence. The 
goal in cooling is to have a proper balance of turbulence and 
restriction.. 

If you look at a car radiator, or the cooler of a large tube, or a 
high efficiency heat sink you'll see the air is often deflected to 
break up any slip stream where the air become stagnant.  

If that isn't bad enough, the air does NOT move from the 
coolest but most sensitive area (the base pins) to the hottest area 
(the anode seal) in correct order. Pre-heated air does not cool well. 

While you can cool the tube with side draft cooling, it takes more 
airflow to do it.

I wonder how many people giving "information" that disagrees with 
physics have actually measured seal temperatures? I'll bet none.

73, Tom W8JI 

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