Quote:
Originally Posted by RETed
You're right, but here's the problem...
How do you get (the silica - "silca"[sic?]) to stick to the metal housings?
RTV'ing the passages (on rotor housing, side irons, and intake manifolds) has been done before, but RTV only has a claimed 700F intermittent temperature resistance.
Almost anything else will either:
1) burn due to temps?
or, 2) come loose due to heat expansion / contraction from the engine.
The good thing is that once everything is plugged up, it's a dead end.
So, the plugs that are closest to the engine (i.e. rotor housings and side irons) are getting the hottest.
The plugs at the intake manifold should hold up fine?
-Ted
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Edit: Sorry didn't realize I had missed an 'i'
Silica is glass (or more commonly known as: sand or silicon dioxide). I chose that media as the insulation because it can be small and remove about 99% of the air that would be in the chamber (since the silica particulate is so small). Thermal expansion shouldn't matter much if at all because the particulate itself is so small. When the chamber volume expands the silica will move to compensate, when the chamber volume decreases the silica *should* be able to move to compensate.
http://en.wikipedia.org/wiki/Silica
Another alternative would be Aerogel. It is mostly composed of air which makes it tremendously light. It also has an increased strength compared to other similar materials of equal dimensions. The real benefit is that they are wonderful insulators. This is the stuff that astronauts have in their suits to protect them from solar radiation (the heat, not the gamma). The trouble is I do not know the thermal expansion rate nor any of it's physical properties.
http://en.wikipedia.org/wiki/Aerogel
What I would find interesting and I think a little beyond anyone's skill on this forum would be to use thermoelectric coolers to cool the chamber wall and dissipate the heat directly into the insulation that holds them there. Granted you'd need to run wires and find a way to protect them from being melted/fried (probably have to encase them in the insulating material itself). Beyond that you should see a decrease in temperatures without increase in coolant temps (though this is not something for nothing). The trouble is as the heat increases and the thermoelectric device attempts to cool it, the more current will be drawn until either the wires burn up or the ceramic breaks apart. But it's interesting to consider.
http://en.wikipedia.org/wiki/Thermoelectric_cooling
http://www.fujitaka.com/pub/peltier/...FRJM5Qodnjbf9A