PC form factor

From: Dwight Elvey <elvey_at_hal.com>
Date: Fri Jul 2 18:41:41 1999

allisonp_at_world.std.com (Allison J Parent) wrote:
> <>As Richard said filtered air in the intake, board mounted vertical,
> <>orientation of plug in boards in line with primary airflow.
> <
> <That makes sense, except for the board mounted vertical. Why that?
>
> If the fan fails convection flow is helpful. Actually vertical with
> airflow from bottom to top works well.
>
> Allison

Hi All
 Actually air flow is quite complicated. Using muffin type fans
makes it worse. Here are some basic rules of thumb.
1. Fast moving air in an open space will find a surface
 and run along it.
2. The only way to make uniform air flow is with restriction.
3. Rotating air will do strange things until straightened
 out. ( examples, air coming from a rotary fan and also
 most air going through a single small restriction ).
4. Laminar flow is best understood but turbulent
 flow removes more heat.

 I have seen the above problems cause all kinds of effects
that were not obvious at first.
Dwight
Received on Fri Jul 02 1999 - 18:41:41 BST