Return-Path: Sender: (Marvin Kaye) To: flyrotary Date: Sun, 01 Dec 2002 15:53:22 -0500 Message-ID: X-Original-Return-Path: Received: from [64.4.38.145] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.0.2) with ESMTP id 1892104 for flyrotary@lancaironline.net; Sun, 01 Dec 2002 11:16:13 -0500 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Sun, 1 Dec 2002 08:16:12 -0800 X-Originating-IP: [65.142.114.137] Reply-To: "Tracy Crook" From: "Tracy Crook" X-Original-To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Coolant loss : One more theory. X-Original-Date: Sun, 1 Dec 2002 11:24:50 -0500 Organization: Real World Solutions Inc. MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0027_01C2992C.42FEC9C0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Original-Message-ID: X-OriginalArrivalTime: 01 Dec 2002 16:16:12.0680 (UTC) FILETIME=[F766B080:01C29954] This is a multi-part message in MIME format. ------=_NextPart_000_0027_01C2992C.42FEC9C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable My latest thought on the surprising amount of overflow is based on the = time when it occurs. =20 The overflow (from the 1 qt. bottle) would occur during prolonged = periods of full throttle operation and was a relatively fixed amount (2 = - 3 oz). I now hypothesize that local boiling (nucleate boiling) in the = combustion chamber (CC) area of the cooling jacket is increasing the = volume in the system. Local boiling creates steam bubbles which are = immediately swept away from the wall and are almost immediately = condensed to liquid again because the bulk coolant temperature is well = below the boiling point. =20 The temperature of the CC wall is still above boiling point so another = bubble of steam starts forming after the first is swept away. The "life = span" of these steam bubbles is very short but at any given moment, = there are thousands of them being "born".=20 This activity stops immediately after power is reduced to the point = where heat is carried away fast enough to eliminate nucleate boiling. = Volume then drops in the cooling system to normal conditions. I suspect this rarely happens in a car because the engine is never at = WOT for more than a few seconds. Even race cars back off in the corners = which give the CC walls a chance to cool off a bit. Just another theory, Tracy Crook tcrook@rotaryaviation.com www.rotaryaviation.com Another factor that affects the coolant volume is the expansion of the = metal in the engine. The coolant is essentially contained in an annular = region around the rotors. The inside of that annulus gets pretty hot. = Could be that the coolant capacity in the engine is decreased. =20 I have no idea how big a factor this is, but it seems that that = overall coolant "expansion" is more in a rotary. I'd estimate that the = amount of coolant that gets pushed into the catch bottle on the V-8 in = my van is a pint or less. Al .Tracy and others, what is the theory behind so much liquid in the = external expansion tank? Thermal expansion of the initial coolant volume = doesn't account for such a large overflow. So is vapor building up inside? = If it is there is no longer a liquid filled system. I don't get it. Peter >> Homepage: http://www.flyrotary.com/ ------=_NextPart_000_0027_01C2992C.42FEC9C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
My latest thought on the surprising = amount of=20 overflow is based on the time when it occurs. 
The overflow (from the 1 qt. bottle) = would occur=20 during prolonged periods of full throttle operation and was a = relatively fixed=20 amount (2 - 3 oz).  I now hypothesize that local boiling = (nucleate=20 boiling) in the combustion chamber (CC) area of the cooling jacket is=20 increasing the volume in the system.  Local boiling creates steam = bubbles=20 which are immediately swept away from the wall and are almost = immediately=20 condensed to liquid again because the bulk coolant = temperature is=20 well below the boiling point. 
 
The temperature of the CC wall is = still above=20 boiling point so another bubble of steam starts forming after the = first is=20 swept away.  The "life span" of these  steam bubbles is very = short=20 but at any given moment, there are thousands of them being=20 "born". 
 
This activity stops immediately after = power is=20 reduced to the point where heat is carried away fast enough to = eliminate=20 nucleate boiling.  Volume then drops in the cooling system = to normal=20 conditions.
 
I suspect this rarely happens in a = car because=20 the engine is never at WOT for more than a few seconds.  Even = race cars=20 back off in the corners which give the CC walls a chance to cool off a = bit.
 
Just another theory,
Tracy Crook
tcrook@rotaryaviation.comwww.rotaryaviation.com<= /DIV>

Another factor that affects the coolant = volume is the=20 expansion of the metal in the engine.  The coolant is essentially = contained in an annular region around the rotors.  The inside of = that=20 annulus gets pretty hot.  Could be that the coolant capacity = in the=20 engine is decreased. 
 
I have no idea how big a factor this is, but = it seems=20 that that overall coolant "expansion" is more in a rotary.  I'd = estimate=20 that the amount of coolant that gets pushed into the catch bottle on = the V-8=20 in my van is a pint or less.
 
Al

.Tracy=20 and others, what is the theory behind so much liquid in the=20 external
expansion tank? Thermal expansion of the initial coolant = volume=20 doesn't
account for such a large overflow. So is vapor building = up=20 inside? If it is
there is no longer a liquid filled system. I = don't get=20 it.
Peter


>>  Homepage:  http://www.flyrotary.com/

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