X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-lpp01m010-f52.google.com ([209.85.215.52] verified) by logan.com (CommuniGate Pro SMTP 5.4.3) with ESMTPS id 5366679 for flyrotary@lancaironline.net; Fri, 27 Jan 2012 06:38:14 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.215.52; envelope-from=rwstracy@gmail.com Received: by lagy4 with SMTP id y4so119731lag.25 for ; Fri, 27 Jan 2012 03:37:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=YAfC0CWxxZaedmIRjTc3GjmyJOFeL6Y1r/zRGXHIIGM=; b=WiPXviB4hFhYxJX6RBhNmT0aQSx3WjlYeUTEyxUc8fi36J5cqad/vmHGDDzP9IbY8T aAzgbrhYKE2uBp57D8O/hP8NrU85ckiM9nJjs7TsqarT+lgjHCLlU/gAqASeNJGFeRpx wvO0mQlPknvpxyL3fYDKAKMaQhAEE7WlezgXk= MIME-Version: 1.0 Received: by 10.152.147.137 with SMTP id tk9mr3338904lab.8.1327664255207; Fri, 27 Jan 2012 03:37:35 -0800 (PST) Received: by 10.112.1.200 with HTTP; Fri, 27 Jan 2012 03:37:35 -0800 (PST) In-Reply-To: References: Date: Fri, 27 Jan 2012 06:37:35 -0500 Message-ID: Subject: Re: [FlyRotary] engine exhaust From: Tracy To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=e89a8f2348ab50090404b780ec4f --e89a8f2348ab50090404b780ec4f Content-Type: text/plain; charset=ISO-8859-1 Not sure where you are going from what I read. Are you suggesting that a turbo could be used as a source of cooling air? Hmmm..... a novel approach but the design of the usual turbo would be all wrong in terms of pressure ratio and volume. Would require a new design I think. The volume of cooling air for a typical 200 HP installation is on the order of 3000 CFM. You obviously know more than I about turbine engines. I had no idea that compressor bypass air was used for cooling. I thought is was for thrust. I'm sure it is in the larger high bypass ratio designs (like on 747, etc) Tracy On Thu, Jan 26, 2012 at 11:27 PM, Mark McClure wrote: > Ok bare with me here, I have been digging through all my old engineering > books trying to answer this but have come to no intelligent answer. > > I work behind turbines a lot and they are wonderful when they are needed - > but the fuel guzzling just makes them ill suited for our needs - enter the > rotary. But in designing my engine I am curious about using some theories > from the turbine. > > For this reference I am using a 420hp C-20J Turboprop (just because it is > the smallest I have used) > > Approximately 70% of the energy is used to turn the compressor and > accessories and 30% is used for actually turning the output shaft. Of that > compressed air only 25% is used in combustion while the remaining 75% is > routed around the combustion chamber for cooling. > > The compressor is a six stage axial, single stage centrifugal. Compressing > the air 6.5 times and the temperature is about 500F. The TOT (also TGT or > ITT, measured between the gas turbine and power turbine) is 1500F. > > The 13b MSP is putting out exhaust temps of 1600F. So using the same > principles in reverse, the remaining energy powers a compressor (turbo) and > that air is then used to assist in the cooling. > > So the question is: What have I oversimplified? > > Mark > > > Glasair SII - 30% complete > 13b MSP - 5% complete > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > --e89a8f2348ab50090404b780ec4f Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Not sure where you are going from what I read.=A0 Are you suggesting that a= turbo could be used as a source of cooling air?=A0 Hmmm.....=A0 a novel ap= proach but the design of the usual turbo would be all wrong in terms of pre= ssure ratio and volume.=A0=A0 Would require a new design I think.=A0=A0 The= volume of cooling air for a typical 200 HP installation is on the order of= 3000 CFM.

You obviously know more than I about turbine engines.=A0 I had no idea = that compressor bypass air was used for cooling.=A0 I thought is was for th= rust.=A0 I'm sure it is in the larger high bypass ratio designs (like o= n 747, etc)

Tracy


On Thu, Jan 26, 2012 at 11:= 27 PM, Mark McClure <markmcclure@me.com> wrote:
Ok bare with me here, I have been digging through all my old engineering bo= oks trying to answer this but have come to no intelligent answer.

I work behind turbines a lot and they are wonderful when they are needed - = but the fuel guzzling just makes them ill suited for our needs - enter the = rotary. But in designing my engine I am curious about using some theories f= rom the turbine.

For this reference I am using a 420hp C-20J Turboprop (just because it is t= he smallest I have used)

Approximately 70% of the energy is used to turn the compressor and accessor= ies and 30% is used for actually turning the output shaft. Of that compress= ed air only 25% is used in combustion while the remaining 75% is routed aro= und the combustion chamber for cooling.

The compressor is a six stage axial, single stage centrifugal. Compressing = the air 6.5 times and the temperature is about 500F. The TOT (also TGT or I= TT, measured between the gas turbine and power turbine) is 1500F.

The 13b MSP is putting out exhaust temps of 1600F. So using the same princi= ples in reverse, the remaining energy powers a compressor (turbo) and that = air is then used to assist in the cooling.

So the question is: What have I oversimplified?

Mark


Glasair SII - 30% complete
13b MSP - 5% complete

--
Homepage: =A0http:/= /www.flyrotary.com/
Archive and UnSub: =A0 http://mail.lancaironline.net:81/lists= /flyrotary/List.html

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