X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ispmxmta06-srv.windstream.net ([166.102.165.167] verified) by logan.com (CommuniGate Pro SMTP 5.1.10) with ESMTP id 2186176 for flyrotary@lancaironline.net; Wed, 18 Jul 2007 21:44:56 -0400 Received-SPF: pass receiver=logan.com; client-ip=166.102.165.167; envelope-from=montyr2157@alltel.net Received: from ispmxaamta04-gx.windstream.net ([71.29.243.194]) by ispmxmta06-srv.windstream.net with ESMTP id <20070719014418.RVOP4133.ispmxmta06-srv.windstream.net@ispmxaamta04-gx.windstream.net> for ; Wed, 18 Jul 2007 20:44:18 -0500 Received: from Thorstwin ([71.29.243.194]) by ispmxaamta04-gx.windstream.net with SMTP id <20070719014418.TSEW12979.ispmxaamta04-gx.windstream.net@Thorstwin> for ; Wed, 18 Jul 2007 20:44:18 -0500 Message-ID: <000601c7c9a6$559e99c0$6501a8c0@Thorstwin> From: "M Roberts" To: "Rotary motors in aircraft" Subject: Oil cooler inlet Date: Wed, 18 Jul 2007 20:44:23 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0003_01C7C97C.6C9DB130" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_0003_01C7C97C.6C9DB130 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Al, I think you need to do something to energize the boundary layer. If you = can't divert it you need to put some energy into it. It is probably = getting slow and separating from the face of the duct. That is what your = data seems to indicate to me.=20 I like the shape that Thomas proposes better than what you have now, = however, I still think you will need some VG's in front of the inlet.=20 I know it may seem counter intuitive, but turbulence may actually help = in this case. You will not get very efficient internal diffusion, but it = will be a lot better than what you have now. I don't think that putting = a turning vane will help too much without doing something to energize = the boundary layer first. You'll just have a slow thick low energy = layer, and a high energy layer separated by a turning vane. It is really easy to duct tape some aluminum VG's in front of the inlet = and see what it does.=20 You may need a combination of Thomas' contour, VG's and a turning vane. = Go with the easy fix and work your way up in complexity. Monty ------=_NextPart_000_0003_01C7C97C.6C9DB130 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Al,
 
I think you need to do something to = energize the=20 boundary layer. If you can't divert it you need to put some energy into = it. It=20 is probably getting slow and separating from the face of the duct. That = is what=20 your data seems to indicate to me.
 
I like the shape that Thomas proposes = better than=20 what you have now, however, I still think you will need some VG's in = front of=20 the inlet.
 
I know it may seem counter intuitive, = but=20 turbulence may actually help in this case. You will not get very = efficient=20 internal diffusion, but it will be a lot better than what you have now. = I don't=20 think that putting a turning vane will help too much without doing = something to=20 energize the boundary layer first. You'll just have a slow thick low = energy=20 layer, and a high energy layer separated by a turning vane.
 
It is really easy to duct tape some = aluminum VG's=20 in front of the inlet and see what it does.
 
You may need a combination of Thomas' = contour, VG's=20 and a turning vane. Go with the easy fix and work your way up in=20 complexity.
 
Monty
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