X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 30 [X] Return-Path: Received: from fed1rmmtao01.cox.net ([68.230.241.38] verified) by logan.com (CommuniGate Pro SMTP 5.1.4) with ESMTP id 1735488 for flyrotary@lancaironline.net; Thu, 04 Jan 2007 11:51:53 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.38; envelope-from=alventures@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao01.cox.net (InterMail vM.6.01.06.03 201-2131-130-104-20060516) with ESMTP id <20070104165104.TERH9173.fed1rmmtao01.cox.net@fed1rmimpo01.cox.net> for ; Thu, 4 Jan 2007 11:51:04 -0500 Received: from BigAl ([72.192.132.90]) by fed1rmimpo01.cox.net with bizsmtp id 74qE1W00E1xAn3c0000000; Thu, 04 Jan 2007 11:50:16 -0500 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Ideal cooling Date: Thu, 4 Jan 2007 08:51:10 -0800 Message-ID: <000001c73020$8ac017c0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C72FDD.7C9CD7C0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C72FDD.7C9CD7C0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Now for the optimum part: =20 The absolute best possible performance would be a system that used just enough air Mdot to heat the cooling air to the same temperature as the = water radiator exit temp ( water going back to the engine from the radiator). = This condition is impossible to achieve in practice. So you try to get as = close as you can. How close you get is called the heat exchanger = effectiveness. The closer the air and water exit temps are, the better the = effectiveness. =20 Monty: I'll respectfully disagree on this part. It may apply if you have = unlimited dynamic pressure to work with, because it doesn't consider radiator thickness and air-side pressure drop. We don't have this case =20 Al=20 ------=_NextPart_000_0001_01C72FDD.7C9CD7C0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Now for the optimum = part:

The absolute best possible performance would be a system that used just enough = air Mdot to heat the cooling air to the same temperature as the water radiator exit temp ( water going back to the engine from the radiator). = This condition is impossible to achieve in practice. So you try to get as = close as you can. How close you get is called the heat exchanger effectiveness. = The closer the air and water exit temps are, the better the effectiveness.

Monty:

I’ll respectfully disagree = on this part. It may apply if you have unlimited dynamic pressure to work = with, because it doesn’t consider radiator thickness and air-side = pressure drop. We don’t have this case

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