X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.121] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3817243 for flyrotary@lancaironline.net; Tue, 18 Aug 2009 15:24:49 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.121; envelope-from=eanderson@carolina.rr.com Received: from computername ([75.191.186.236]) by cdptpa-omta03.mail.rr.com with ESMTP id <20090818192412207.BZAK16591@cdptpa-omta03.mail.rr.com> for ; Tue, 18 Aug 2009 19:24:12 +0000 From: "Ed Anderson" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Swirl pots/box fans Date: Tue, 18 Aug 2009 15:22:48 -0400 MIME-Version: 1.0 Content-Type: multipart/related; boundary="----=_NextPart_000_0003_01CA2017.BECF8C50" X-Mailer: Microsoft Office Outlook, Build 11.0.5510 Thread-Index: AcogNXHq9rZALzoQR2ir0/SJUFHwJwAAxWWQ In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 Message-Id: <20090818192412207.BZAK16591@cdptpa-omta03.mail.rr.com> This is a multi-part message in MIME format. ------=_NextPart_000_0003_01CA2017.BECF8C50 Content-Type: multipart/alternative; boundary="----=_NextPart_001_0004_01CA2017.BECF8C50" ------=_NextPart_001_0004_01CA2017.BECF8C50 Content-Type: text/plain; charset="iso-8859-7" Content-Transfer-Encoding: quoted-printable Here is a formula for a centrifugal pump that clearly? Shows that Tracy = and Lynn are correct =20 Energy Usage The energy usage in a pumping installation is determined by the flow required, the height lifted and the length and characteristics of the pipeline. The power required to drive a pump (Pi), is defined simply = using SI units by: by: P_i=3D \cfrac{\rho\ g\ H\ Q}{\eta} where: Pi is the input power required (W)=20 =F1 is the fluid density (kg/m3)=20 g is the gravitational constant (9.81 m/s2)=20 H is the energy Head added to the flow (m)=20 Q is the flow rate (m3/s)=20 =E7 is the efficiency of the pump plant as a decimal=20 =20 One can see that if Q the flow rate becomes zero (by blocking the exit) = then the power required to drive the pump Pi also becomes zero. So block the pump and lower the flow and the power required drops - or with the same power, the pump can spin faster. There is always some flow around the = vanes of a centrifugal pump in reality, so the power does not cause the pump = to spin to infinity rpm but it equalizes at a higher rpm than when = considerable (unblocked) flow is the condition. =20 Is this fun or what? Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm =20 _____ =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Lynn Hanover Sent: Tuesday, August 18, 2009 2:55 PM To: Rotary motors in aircraft Subject: [FlyRotary] Swirl pots/box fans =20 NO! I meant exactly what I wrote. It is admittedly counter-intuitive = but true none the less. Did you attempt to prove it to yourself with the suggested test? Only takes a few seconds :>) Tracy On Tue, Aug 18, 2009 at 11:57 AM, Jeff Luckey = wrote: Tracy, =20 When a box fan falls over onto its suction side, it revs up as the work = it is performing drops off to near zero.....................same idea. =20 Lynn E. Hanover ------=_NextPart_001_0004_01CA2017.BECF8C50 Content-Type: text/html; charset="iso-8859-7" Content-Transfer-Encoding: quoted-printable

Here is a formula for a centrifugal = pump that clearly? Shows that Tracy and Lynn are = correct

 

Energy = Usage

The energy usage in a pumping installation is determined by the flow = required, the height lifted and the length and characteristics of the pipeline. The = power required to drive a pump (Pi<= /i>), is defined simply using SI units by: = by:

3D"P_i=3D

where:

Pi is the = input power required (W)

=F1 is the fluid density (kg/m3) =

g is the gravitational = constant (9.81 m/s2)

H is the energy Head = added to the flow (m)

Q is the flow rate = (m3/s)

=E7 is the efficiency of the pump plant as a decimal =

 

One can see that if Q the flow rate becomes zero (by blocking the exit) then the power required to drive the = pump Pi also becomes zero.=A0 So block the pump and lower the flow and the = power required drops – or with the same power, the pump can spin = faster.=A0 There is always some flow around the vanes of a centrifugal pump in reality, = so the power does not cause the pump to spin to infinity rpm but it equalizes = at a higher rpm than when considerable (unblocked) flow is the = condition.

 

Is this fun or = what?

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Lynn Hanover
Sent: Tuesday, August 18, = 2009 2:55 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] = Swirl pots/box fans

 

NO!  I = meant exactly what I wrote.  It is admittedly counter-intuitive but true none the less.  Did you attempt to prove it to yourself with the suggested test?   Only takes a few seconds :>)

Tracy

On Tue, Aug 18, 2009 at 11:57 AM, Jeff Luckey <JLuckey@pacbell.net> wrote:

Tracy,

 

When a box fan falls over onto its suction side, it revs up as = the work it is performing drops off to near zero.....................same = idea.

 

Lynn E. Hanover



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The message = was checked by ESET NOD32 Antivirus.

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