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Date: Wed, 09 Feb 2005 17:38:35 -0600
From: Jim Sower <canarder@frontiernet.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Heating the Fuel
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<... For a 10 degree rise in gasoline temperature you would get a 
630/12000 = 0.0525 deg F drop in coolant temperature ...>

OTOH, you'd soon heat your fuel to very near the coolant temp and have 
the mother of all vapor locks.
If that's what you're looking for ... Jim S.

William wrote:

> Dave,
> If you burn 10 g/hr, and are returning 15 g/hr to the tanks, that is 
> 15*6 = 90 #/hr of gasoline, with a specific heat of ~.7Btu/#, that 
> means you can transfer 90* 0.7 = 63 Btu/hr/degF rise in gasoline 
> temperature. Your coolant flow is probably about 25 gallons/minute, = 
> 25*60 = 1500 gallons/hour = ~1500*8 = 12000 #/hour. For a 10 degree 
> rise in gasoline temperature you would get a 630/12000 = 0.0525 deg F 
> drop in coolant temperature.  Doesn't seem worth it.
>  
> * note: I used rounded figures for densities and flow rates and heat 
> capacities. The fact remains that the flow mismatch makes this not do 
> much.
> Bill Schertz
> KIS Cruiser # 4045
>
>     ----- Original Message -----
>     *From:* DaveLeonard <mailto:daveleonard@cox.net>
>     *To:* Rotary motors in aircraft <mailto:flyrotary@lancaironline.net>
>     *Sent:* Sunday, February 06, 2005 11:46 PM
>     *Subject:* [FlyRotary] Heating the Fuel
>
>     In anticipation of the new turbo, I am considering ways to improve
>     coolant cooling.  Besides the obvious more air, more ducting, more
>     radiator; I have been again toying with the idea of a heat
>     exchanger.  This time coolant to fuel.  The plan would be to use a
>     typical oil/water exchanger but use fuel instead of oil.  I would
>     use the fuel on the way back to the tank, and the coolant after it
>     has already been cooled by the radiator.  The fuel would then go
>     back to the nice metal tank of the RV.
>      
>     I am looking for input on the implications of heating the fuel.  I
>     expect it would reach max temps of about 190 (usually a
>     little cooler) but quickly cool once in the tank.  Can the fuel
>     tolerate that temp without vaporizing?  It will probably expand in
>     the tank but I don't expect that will occur faster than it is used
>     up.  I have no guess as to what temp will become steady state for
>     the fuel pumped out of the tank.  My guess is that it will not be
>     much warmer than normal, but a slight increase in temp may help
>     with vaporization.
>      
>     The last question is how much will it cool the coolant.  My hope
>     is about 10 deg but I doubt it will be quite that much.  I know
>     others have considered using the fuel to cool (Tracy) and I would
>     appreciate your thoughts.
>      
>     Dave Leonard
>