Return-Path: Received: from [65.54.241.207] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.2.3) with ESMTP id 433094 for flyrotary@lancaironline.net; Sun, 26 Sep 2004 16:04:32 -0400 Received-SPF: none receiver=logan.com; client-ip=65.54.241.207; envelope-from=lors01@msn.com Received: from hotmail.com ([65.54.169.60]) by hotmail.com with Microsoft SMTPSVC(5.0.2195.6713); Sun, 26 Sep 2004 13:04:01 -0700 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Sun, 26 Sep 2004 13:04:01 -0700 Received: from 65.54.98.100 by bay3-dav30.bay3.hotmail.com with DAV; Sun, 26 Sep 2004 20:03:04 +0000 X-Originating-IP: [65.54.98.100] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: oil filter, pressure test, ewp Date: Sun, 26 Sep 2004 16:03:02 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0055_01C4A3E2.4D1C1940" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V9.10.0006.2205 Seal-Send-Time: Sun, 26 Sep 2004 16:03:02 -0400 Message-ID: X-OriginalArrivalTime: 26 Sep 2004 20:04:01.0234 (UTC) FILETIME=[F7324320:01C4A403] Return-Path: lors01@msn.com This is a multi-part message in MIME format. ------=_NextPart_000_0055_01C4A3E2.4D1C1940 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message Aren't these types of oil pumps considered positive displacement = pumps? In other words, they displace a certain volume with every turn. = If that's the case, it would seem that a higher volume pump would be a = good thing for cooling. The extra volume would get bypassed at the = regulator, and would get sucked right back out of the pan and sent back = to the oil cooler. Just seems like this would be a way to get more = cooling out of a given cooler size. It might not quite work that way = in reality, but I'm just trying to think of anything that could help oil = temps. Not likely I'll be changing oil pumps. =20 A higher flow rate can help, but for the same core, all it can do is = decrease the delta T inlet to outlet (ignoring 2nd order effects like = changes in heat transfer coeficient. For the same oil temp out of the = engine, decreasing the delta T will increase the average rejection temp, = thereby increasing the total heat rejected. If the system is air-side = limited, and the delta T is already small, more flow isn't going to help = much. Al My take on the high volume oil pump & cooling is that churning the oil = will heat the oil as much or more than increased flow will help. = Conservation of energy thing. It also takes power from the engine to do = that pumping. =20 Give me the minimum pump volume to keep the oil pressure in the = green. Tracy ------=_NextPart_000_0055_01C4A3E2.4D1C1940 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
 

Aren't=20 these types of oil pumps considered positive displacement pumps?  = In=20 other words, they displace a certain volume with every turn.  If = that's=20 the case, it would seem that a higher volume pump would be a good = thing for=20 cooling.  The extra volume would get bypassed at the = regulator,=20 and would get sucked right back out of the pan and sent back to = the oil=20 cooler.  Just seems like this would be a way to get more cooling = out of a=20 given cooler size.   It might not quite work that way in = reality,=20 but I'm just trying to think of anything that could help oil = temps. =20 Not likely I'll be changing oil pumps. 

 

A higher flow rate can help, = but for the=20 same core, all it can do is decrease the delta T inlet to outlet = (ignoring=20 2nd order effects like changes in heat transfer coeficient. =  For the same oil temp out of the engine, decreasing the delta T = will=20 increase the average rejection temp, thereby increasing the total heat = rejected.  If the system is air-side limited, and the delta T is = already=20 small, more flow isn=92t going to help much.

 

Al

 

My take = on the high=20 volume oil pump & cooling is that churning the oil will heat = the oil=20 as much or more than increased flow will help.  Conservation of = energy=20 thing.  It also takes power from the engine to do that=20 pumping.  

 

Give me = the minimum=20 pump volume to keep the  oil pressure in the = green.

 

Tracy

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