X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imr-m07.mx.aol.com ([64.12.138.209] verified) by logan.com (CommuniGate Pro SMTP 5.2c2) with ESMTP id 2471003 for flyrotary@lancaironline.net; Tue, 13 Nov 2007 21:20:38 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.138.209; envelope-from=WRJJRS@aol.com Received: from imo-d04.mx.aol.com (imo-d04.mail.aol.com [172.18.150.228]) by imr-m07.mx.aol.com (v107.10) with ESMTP id RELAYIN5-6473a5b51362; Tue, 13 Nov 2007 21:20:01 -0500 Received: from WRJJRS@aol.com by imo-d04.mx.aol.com (mail_out_v38_r9.3.) id q.c09.260e64a2 (65099) for ; Tue, 13 Nov 2007 20:49:24 -0500 (EST) From: WRJJRS@aol.com Message-ID: Date: Tue, 13 Nov 2007 20:49:22 EST Subject: Re: [FlyRotary] Re: Rebutal to the rebutal {:>) Thick vs Thin was : Diffuser ... To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1195004962" X-Mailer: 9.0 SE for Windows sub 5044 X-Spam-Flag: NO X-AOL-IP: 172.18.150.228 -------------------------------1195004962 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 11/13/2007 5:15:26 PM Pacific Standard Time, lendich@optusnet.com.au writes: On another tack there is a rule of thumb that the first 1/2 of the Rad does 3/4 of the cooling - is there some truth to that claim? George (down under) Yes, George that one is true. If you think about it for a second I'm sure you will get why. Think delta T. Delta T is the greatest asset to disposing of unwanted heat. The first part of the radiator is where the AIR is the coolest, the temp difference the greatest, and therefore most effective. FWIW George, there has never been anything as effective as pure water for heat transfer. Ed was correct that there is a bunch of transfer that can be done with phase change but a gas in the "water" jacket has shown insulating qualities so the transfer from the metal isn't great. Most Phase change systems require a fairly high pressure environments too. Not really practical. Bill Jepson ************************************** See what's new at http://www.aol.com -------------------------------1195004962 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 11/13/2007 5:15:26 PM Pacific Standard Time,=20 lendich@optusnet.com.au writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
On another tack there is a rule of thumb=20= that the=20 first 1/2 of the Rad does 3/4 of the cooling - is there some truth to that= =20 claim? 
George (down=20 under)
Yes, George that one is true. If you think about it for a second I'm su= re=20 you will get why. Think delta T. Delta T is the greatest asset to disposing=20= of=20 unwanted heat. The first part of the radiator is where the AIR is the cooles= t,=20 the temp difference the greatest, and therefore most effective. FWIW George,= =20 there has never been anything as effective as pure water for heat transfer.=20= Ed=20 was correct that there is a bunch of transfer that can be done with pha= se=20 change but a gas in the "water" jacket has shown insulating qualities so the= =20 transfer from the metal isn't great. Most Phase change systems require a fai= rly=20 high pressure environments too. Not really practical.
Bill Jepson 



See= what's new at AOL= .com and Make AOL Your Homepage.
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