We dont have enough fuel to effectively use as a heat sink in the applications we are using, particulary near the end of our flights.. Its not like a Gulfstream, that lands with  more fuel than WE do when we are departing with full tanks. We also arent getting up to the -30 degree temps that cold soak the fuel tanks like on the biz jets. When I rode in the back of a Lear, we were declaring an emergency if we had less than 500 lbs.. if I remember correctly. Thats what.. 80+ gals?
 
Truthfully, from an effectiveness standpoint you are going to add another level of complexity to your system for minimal return. I think you would make better headway in increasing your cooling airflow to the rad, even if it means a cowling mod or redesign.
 
Dave Staten

DaveLeonard wrote:

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