From: Jefrem Iwaniw <jiwaniw@iigo.com>
>On Thu, 11 Feb 1999 SlyFoxRc@aol.com wrote:
> <snip>
>> My point earlier was that the fluid, be
>> it glycol based or silicone based is not compressible in its fluid state,
only
>> when it has boiled or had some form of gas introduced into it.
>
>While thinking about this makes my head hurt (compressible fluids was
>one of the reasons I switched from aerospace to EE lo those many years
>ago), I seem to recall that a liquid can only be treated as
>incompressible if there are no conditions causing a density change in
>it -- things like pressure change, or heat differentials. Given that
>both of these are a large part of a braking system, brake fluid within
>a braking system *must* be treated as a compressible fluid.
>
>Now, those of you who know more about this may summarily chastise me
>for my oversimplification. :=)
EE made your head hurt less than aero? That's warped, Jef....
The temperatures and pressures we encounter in autocrossing (or even road
racing) are insufficient to significantly change the density of brake
fluid -- so it *is* incompressible. The temperature changes are far more
likely to affect the elasticity of the rubber brake lines (if you have 'em)
before the brake fluid's density. And even that is small next to the
effects of having steam bubbles in the fluid -- so effectively, all the slop
in the system is due to water boiling out of the fluid.
Jamie (stayed in aero because EE electives made my head hurt)
'92 Prelude Si
Speed Demon Racing
http://www.mindspring.com/~jsculerati/sdr
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