X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from SMTP03.INFOAVE.NET ([165.166.0.28] verified) by logan.com (CommuniGate Pro SMTP 5.0c2) with ESMTP id 718841 for flyrotary@lancaironline.net; Sun, 11 Sep 2005 22:42:21 -0400 Received-SPF: none receiver=logan.com; client-ip=165.166.0.28; envelope-from=Jewen@Comporium.net Received: from engineer1 ([199.222.166.147]) by SMTP00.InfoAve.Net (PMDF V6.2-X31 #30772) with SMTP id <01LSX6LFK5429F8ZP2@SMTP00.InfoAve.Net> for flyrotary@lancaironline.net; Sun, 11 Sep 2005 22:41:30 -0400 (EDT) Date: Sun, 11 Sep 2005 22:40:12 -0400 From: Joe Ewen Subject: Re: [FlyRotary] Re: Optimal GPM water pump flow. To: Rotary motors in aircraft Message-id: <000901c5b743$4cf602d0$800101df@engineer1> MIME-version: 1.0 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 X-Mailer: Microsoft Outlook Express 6.00.2800.1437 Content-type: multipart/alternative; boundary="----=_NextPart_000_0006_01C5B721.C5AD4D40" X-Priority: 3 X-MSMail-priority: Normal References: This is a multi-part message in MIME format. ------=_NextPart_000_0006_01C5B721.C5AD4D40 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Dave, With respect to plumbing them in series; The heat transfer rate is = dependant upon the delta (temperature difference) temperature between = the coolant and the air (for simplicity the thermal conductivity of the = radiator medium is snot being considered.) By plumbing in series the = second exchanger will have a lower rate of thermal transfer and result = in lower BTU rejection if the total system. Plumbing in series is likely = to also reduce flow rate ( as you noted by higher pressure.) The lowest = return temp may not indicate the optimum system for heat removal. IMO = (given the same radiator area, thickness, renolds number, etc.) the = higher the coolant to air temp difference and the highest flow rate = should yield the system that removes the greatest BTUs. =20 JOe ----- Original Message -----=20 From: David Staten=20 To: Rotary motors in aircraft=20 Sent: Sunday, September 11, 2005 9:41 PM Subject: [FlyRotary] Re: Optimal GPM water pump flow. Al. What I am after is trying to determine what the minimum required = flow is for the horsepower generated. More than anything else, I do not = want to be BELOW that amount, and consider it a minimum. Understandably, = trying to place twice or nearly 3 times the flow through the same = circuit will result in higher pressures and perhaps some pump = cavitation. I will deal with that as I have to.. more than anything else = I want to make sure I am not starting off with a DEFICIT of water flow = ability. =20 I am considering 2 smaller radiators, and originally I intended to = plumb them in series to get the best cumulative Delta-T across them, but = if I have "pressure" problems due to the pump's flow, I may go to a = parralel arrangement.=20 =20 Feel free to critique, Al.. My cooling system is a work in progress = that is evolving. I live in a place that has 100 degree temps with 90% = humidity at times, and given the other folks demonstrated problems with = inadequate cooling, I am very much in favor of designing in excess = cooling capacity, to the point I may even incur a slight weight or drag = penalty, such that I don't have to give constant attention to the risk = of overheating. =20 Dave Al Gietzen wrote: Subject: [FlyRotary] Re: Optimal GPM water pump flow. www.racemate.com They were unable to find the photo of the Mazda = install but they say the did a few. I am going to take the plunge and = get one..=20 Dave Just curious what you're after with the racemate. You were asking = about "optimal" flow - double the needed flow is not optimum; high = pressure gradients around the loop, unnecessary pumping power. Al-- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ =20 -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ ------=_NextPart_000_0006_01C5B721.C5AD4D40 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Dave,
With respect to plumbing them in = series; The heat=20 transfer rate is dependant upon the delta (temperature=20 difference) temperature between the coolant and the air (for = simplicity the=20 thermal conductivity of the radiator medium is snot being = considered.) By=20 plumbing in series the second exchanger will have a lower rate of = thermal=20 transfer and result in lower BTU rejection if the total=20 system. Plumbing in series is likely to also reduce flow rate ( as = you=20 noted by higher pressure.)  The lowest return temp may not indicate = the=20 optimum system for heat removal.  IMO (given the same radiator = area,=20 thickness, renolds number, etc.) the higher the coolant to air temp = difference and the highest flow rate should yield the system that = removes the=20 greatest BTUs.   
 
JOe
----- Original Message -----
From:=20 David=20 Staten
Sent: Sunday, September 11, = 2005 9:41=20 PM
Subject: [FlyRotary] Re: = Optimal GPM=20 water pump flow.

Al.
   What I am after is trying to = determine what=20 the minimum required flow is for the horsepower generated.  More = than=20 anything else, I do not want to be BELOW that amount, and consider it = a=20 minimum. Understandably, trying to place twice or nearly 3 times the = flow=20 through the same circuit will result in higher pressures and perhaps = some pump=20 cavitation. I will deal with that as I have to.. more than anything = else I=20 want to make sure I am not starting off with a DEFICIT of water flow=20 ability.
 
I am considering 2 smaller radiators, and = originally I=20 intended to plumb them in series to get the best cumulative Delta-T = across=20 them, but if I have "pressure" problems due to the pump's flow, I may = go to a=20 parralel arrangement.
 
Feel free to critique, Al.. My = cooling=20 system is a work in progress that is evolving. I live in a place that = has 100=20 degree temps with 90% humidity at times, and given the other folks=20 demonstrated problems with inadequate cooling, I am very much in favor = of=20 designing in excess cooling capacity, to the point I may even incur a = slight=20 weight or drag penalty, such that I don't have to give constant = attention to=20 the risk of overheating.
 
Dave

Al Gietzen = wrote:

Subject: = [FlyRotary]=20 Re: Optimal GPM water pump flow.

 

www.racemate.com   They =
were unable to find the photo of the Mazda install but they say the did =
a few. I am going to take the plunge and get one..=20



Dave
 
Just curious what you=92re after with the =
racemate.  You were asking about =93optimal=94 flow =96 double the =
needed flow is not optimum; high pressure gradients around the loop, =
unnecessary pumping power.
 
Al
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