Paul,
What do you know about these?
What is Rotron Pressurised Cooling (RPC) system?
http://www.rotronuav.com/engines/rt-350rpc
This "patent" seems to be a variant or builds on the work of the
Norton-Garside cooler bur makes it a closed loop if you will.
http://www.enterprise-europe-network.ec.europa.eu/src/matching/templates/completerec.cfm?BBS_ID=176296&org=0&back=true&is_external=0&valid=0
( Details below the break-line)
These are on top of the other efforts ( Diamond ? ) etc are engaged in...
My best,
Anthony
The cooling fan requires HP reducing the net HP out.
Therefor the BSFC is around .52 rather than .47 in the oil cooled rotor
Mazda.
Notice they don't mention the HP required by the cooling fan in the
propaganda :)
From my book How to Cool Your Wankel
"However, for low-density fluids, such as gases, it is very easy to
expend as much mechanical energy in overcoming friction power as is
transferred as heat."
[What is being said here is HP is consumed by cooling drag. Since
cooling drag can be as high as 30% of over all drag the HP could be as
much as 30% of 200 HP or 60 HP. As you can see cooling drag becomes a
very important issue.] "And it should be remembered that in most thermal
power systems mechanical energy is worth 4 to 10 times as much as its
equivalent in heat."
[Here they are referring to the heat balance of most internal combustion
engines that only derive about 25% to 10% of the heat energy in a gallon
of fuel as mechanical HP.]
Paul Lamar
Paul,
The fan power loss is offset somewhat by the elimination of the corner,
side and oil seals' friction.
Interesting,
Barry
The friction is very low in a rotary to begin with.
The Austro/Midwest/Diamond engines use air cooled rotors.
Paul Lamar
Hi Paul,
I hope all is well - and keep fingers crossed on your TC system.
Here is the patent on SPRACS (mis-spelled as "SPARCS" in the link you
forwarded). It's actually a David Garside patent, and the trick is that
it is air cooling with added oil mist in a closed loop rather than
charge cooling, so it is an evolution of the "lost air" UAV Engines /
Austro system. The self-pressurized cooling air has a higher density and
hence higher cooling capacity than ambient pressure. Also the fan just
needs to keep the air circulating without producing pressure, and it's
not necessary to filter oil from the air outlet as you would on the UAV
/ Austro system.
The cooling air's pressure reduces the pressure difference between the
inside of the rotor and the combustion chamber and therefore
theoretically reduces the side and corner seal leakage, but the system
still needs seals.
Whether the system is as good as it should I don't know, but we have
actually issued a little optimization patent on this, in the best case
simply making a little slot in the compression area of a side plate to
automatically regulate the pressure rather than relying on leakage and a
pop-off valve.
David Garside also has a patent on a "Wankel" 2:1 expander as a
compounding device by the way. The turbo is the better way to go IMHO
though, because it can handle the heat more easily.
Best Regards,
Poul
Poul Henrik Woelfle
Woelfle Engineering GmbH
Randstraße 109 • D - 47804 Krefeld • Germany
Tel +49 2151 151020 • Fax +49 2151 151019
www.woelfle-engineering.com
HRB 7369, Amtsgericht Krefeld • Director / Geschäftsführer: Paul A. Woelfle
Gents,
Paul thanks for all the pictures and explanation of the cooled shaft
paper. I have read it in detail before, but your highlights put it in a
new context, especially about the bearing loads.
Poul, thanks for the explanation and the referencing to Mr. Garside. It
is funny I reversed looked up the patent, found it, and was trying to
read it ( sometimes they read like an ancient text) when I received the
email.
This patent seems like a closed system, with a heat transfer agent air,
a lubricant, a means of pressurizing it, and a way to get rid of waste
heat. It almost sounds like an Air-Conditioner / Refrigerator! Is their
losses of the air used? If not ( I am going to go out on a limb here,
yes it is off the wall ) why not use something that transfers heat
better, like auto air-conditioning in AU uses, Propane (!?) :-)... Yes
I know it is flammable, not a good combo.
My question is, is this lubricant enough for both the rotor and
bearings, or are the bearings using a separate system, as in 2 stroke
total loss similar to what was used on the last generation Suzuki's 2
stroke muscle bikes before they disappeared.
Speaking of gaseous fuels, I am beginning to think I am not crazy asking
about these fuels for Gen-Av over a year ago...
http://www.airventure.org/news/2013/130730_cng-husky-av-fuel-game-changer.html
Poul, any updates on the potential use of cryogenics, isotropic
super finishing, ceramic bearings, and or WS2 coatings for further
improvements in the Charge Cooled area to get rid of heat and friction?
My best,
Anthon