Return-Path: Received: from fed1rmmtao08.cox.net ([68.230.241.31] verified) by logan.com (CommuniGate Pro SMTP 4.2.8) with ESMTP id 607874 for flyrotary@lancaironline.net; Fri, 14 Jan 2005 22:26:00 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.31; envelope-from=ALVentures@cox.net Received: from BigAl ([68.7.14.39]) by fed1rmmtao08.cox.net (InterMail vM.6.01.04.00 201-2131-117-20041022) with ESMTP id <20050115032526.HIPS27771.fed1rmmtao08.cox.net@BigAl> for ; Fri, 14 Jan 2005 22:25:26 -0500 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: water cooled matrix in oil pan Date: Fri, 14 Jan 2005 19:25:30 -0800 Message-ID: <000501c4fab1$e01849a0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0006_01C4FA6E.D1F509A0" 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 V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0006_01C4FA6E.D1F509A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Subject: [FlyRotary] Re: water cooled matrix in oil pan =20 `The problem with this is that the oil is essentially stagnant in the = pan' =20 Al, this is only 'cause you haven't looked inside when its running - = there's an oil pump driving this stuff round the engine all the time, it just = starts and finishes at the bottom of the oil pan. The flow rate will be the = same as anywhere else on the system that you would choose to oil/air cooler. = Its true that the `dwell time' in the oil pan will be longer as this is your reservoir but this is a good thing. =20 The key word is =93essentially=94; and it=92s the velocity that counts. = The oil moves in the channels of the oil cooler at about 20 ft/min; enough to = give you good convective heat transfer coefficient. If you assume that the = oil entered the pan at one end and traversed across it might be moving about = =BD ft/min (the actual case would be likely be less because it is moving = more from top to bottom). Convective heat transfer would be =93essentially=94 = zero, and you would have to rely on conduction; but, of course, the thermal conductivity of oil is not very good, so . . .=20 =20 It could be done; but it is not simple. A large pan volume with cooled plates and narrow oil channels could do the job. Sounds a bit expensive = and maybe heavy; so a nice compact, effective oil/air heat exchanger sounds pretty good. =20 And BTW, folks. A good balance of theory and experiment is where it=92s = at. Let=92 not forget that without the theory and engineering; there = wouldn=92t be a rotary engine. =20 Al ------=_NextPart_000_0006_01C4FA6E.D1F509A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Subject: [FlyRotary] Re: water cooled matrix in oil pan

 

`The problem with this is that the oil is essentially stagnant in the = pan'

 

Al, this is only 'cause you haven't looked inside when its running - = there's

an oil pump driving this stuff round the engine all the time, it just = starts

and finishes at the bottom of the oil pan.=A0 The flow rate will be the = same

as anywhere else on the system that you would choose to oil/air cooler.=A0 = Its

true that the `dwell time' in the oil pan will be longer as this is = your

reservoir but this is a good thing.

 

The key word = is “essentially”; and it’s the velocity that counts. The oil moves in the channels = of the oil cooler at about 20 ft/min; enough to give you good convective heat = transfer coefficient. If you assume that the oil entered the pan at one end and = traversed across it might be moving about =BD ft/min (the actual case would be = likely be less because it is moving more from top to bottom). Convective heat = transfer would be “essentially” zero, and you would have to rely on conduction; but, of course, the thermal conductivity of oil is not very = good, so . . .

 <= /font>

It could be = done; but it is not simple.=A0 A large pan volume with cooled plates and narrow = oil channels could do the job.=A0 Sounds a bit expensive and maybe heavy; so = a nice compact, effective oil/air heat exchanger sounds pretty = good.

 <= /font>

And BTW, = folks. A good balance of theory and experiment is where it’s at. =A0Let’ = not forget that without the theory and engineering; there wouldn’t be a = rotary engine.

 <= /font>

Al

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