Perry Mick wrote:

Paul:

I'm really intrigued by this.  I think I would prefer to make the
fan blades composite, maybe with just an aluminum heat-shield
cover near the tips.  Any details on making that steel turbine
ring?  Could be a lot of weight out where you don't want it.
Would you run this at full RPM, or maybe a lower RPM
for lower centrifugal force?  Maybe you can put some more
numbers on it to see if it's feasible?

--
Perry Mick
Duckt N7XR
http://www.ductedfan.com

You have a heat issue with composite blades. That turbine section will
run hot. So far no numbers but I'll bet Monty will work on it :-)>
50% of the energy in a gallon of fuel goes out the exhaust in the
form of waste heat. Lots of potential to recover some of that
energy here. There are also lots of engineering challenges with
differential expansion being a big one.

Paul Lamar

This was one of the favorite ideas of Joe Alford chief engineer at GE
AGT back in the 50's - mostly as a lift fan for VTOL. It was never
pursued to full scale hardware to my knowledge. Your 50 percent
number is  pretty much "vapor ware" with a bottoming turbine you
can only capture the energy related to continued expansion to
atmospheric exir pressure, and that is a LOT smaller number.
Thermal bottoming cycles (ie a steam plant) do a little better
but the infamous boundaries of the Carnot cycle still prevail.
Vance

I did not say I was going to capture 50%. 20% is what they got out of
the R3350TC. The 50% number is the waste heat in the exhaust more or less.

Paul Lamar
 
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