Message-ID: <005501c3bc0d$e5c9a4e0$1702a8c0@WorkGroup>
From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-2801038@logan.com>
Subject: Re: [FlyRotary] Re: spray bars
Date: Sat, 6 Dec 2003 10:30:36 -0500
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> A quick solution might be those spayers that they sell to sunbathers to
> keep cool.  A pump sprays an extremely fine mist, that is really quite
cold.
>
> Would a 'mist-assist' cooling system work better with a long plenum and
> thick radiator?  My thinking is that the extra distance would give the
> water sufficient time to evaporate completely.
>
> --
> http://www.ernest.isa-geek.org/
> "Ignorance is mankinds normal state,
>    alleviated by information and experience."
>                                    Veeduber


Don't know for certain, but I would think that since the temp of the air
stream before the radiators is way below the evaporation temperature for
water,  you wouldn't have the heat energy to change much of the water into
vapor.  So not certain just how much cooling of the air you would get.  Just
changing it into a fine mist alone does not do the job, of course, it must
be changed into a vapor in order to benefit form the latent heat of
vaporization.

Now changing it into a mist rather than spraying a stream of water on the
metal of the radiator might have some benefits -smaller dropplets of water
undoubledly will change state faster than large drops.  But consider that
the temperature in the air going through the core changes as the log of the
distance from the metal walls it is absorbing heat from, its possible that
mist flowing through the center of the "holes" might not get exposed to
sufficient heat to change state.

I would think that whether misting or spraying directly on the metal, that
using water in such a manner would provide benefit.  Perhaps some
experimentation on the same installation would clarify the benefits of one
approach vs the other.

Perhaps some of our thermodynamic experienced folks could advise.

Ed