>>
>>Hey
Guys,
>>
>>Another piece of the puzzle we must talk about is the heat transfer
>>through the rotor housing. We need to understand what we want this to
>>be. Lets take a look at some extremes
>>
>>If we have a super low heat transfer value I assume we get higher rotor
>>surface temps and less heat transfer to oil which may negate the need
>>for rotor cooling. That's a benefit for sure and materials with
such a
>>low transfer value tend to survive high heat well. What are the
downside
>>to really hot rotor surfaces?
>>
>>Assuming we get a super high heat transfer value I assume we get lower
>>rotor surface temps but might require increased oil cooling
>>requirements. Not such a benefit and also materials with high heat
>>transfer values tend to be rather weak.
>>
>>I am just starting a conversation
here on this topic and I might be
>>wrong on some of my assumptions. FEA modeling would be best for this
but
>>a combustion chamber model would be needed as well. Also lets extend
>>this topic into the housing surfaces as well.
>>
>>Rob Woods
>>
>>Lubrication breaks down for apex seals.
>>
>>Paul Lamar
>>
> Rob,
>
> A hotter rotor doesn't help as much as a hotter combustion chamber
area.
> The best theoritical place to keep hot is to isolate and insulate the
> combustion sectional arc of the outer housing. That could only be done
> with very precise water flow controls. The second best place is to
> improve the heat retaining charteristics of the rotor bathtub. For that
> we need a strong insulating material that also has the strength to hold
> the apex seals in place. Titanium alloys
are contenders. If a steel
> plate could be cast into the rotor depression that would give us the
> best of both worlds. A very hot plate that is insulated and kept hot.
> The research would be in determining the temperature regulation of the
> plate. We don't want it to remain so hot that when fuel mists
contacts
> it on the intake stroke we have ignition.
>
> Another idea that needs to followed up on is to contact the company that
> licenced the BAM coating technology from NASA and see if we can get some
> info on heat tolerance and modulus of elasticity. That technology could
> be a major breakthrough for the rotary engine. Apex seals with the
> strength of iron but a sliding co efficienct half that of Teflon. And
> if it works on Apex seals why not side housings?
>
> Doug in Japan.
Doug,
I was also thinking in terms of the slide in a slide
carb.
George ( down under)
Doug,
I guess I was getting at using a engineering ceramic for the rotor. Lets
assume there is a billet ceramic rotor can be made that has suitable
mechanical properties to take the environment since it is something I am
looking at with someone who has a material I think will work. One with
no internal cooling that has the density of aluminum but has the ability
to take huge heat levels. This material would also have a very low
conductivity and expansion numbers. So the advantages of aluminum
without the disadvantages of aluminum. Lets talk about the downsides of
such a rotor in a OEM Mazda housing set.
I wonder if this BAM coating would be the coating to use for an all
ceramic engine. A ceramic rotor using BAM coated seals and a ceramic
housings using BAM coated surfaces without oil should theoretically have
a friction coefficient equal to itself of 0.02 which is much lower than
Mazda states in their rotary oil paper SAE # 922375 which they state is
about .12 for normal oil and as low as .04 for high moly content oil. In
the quest for an adiabatic engine the downfall is how do you seal it if
it is a bazilion degrees too hot to use oil for friction reduction. The
answer is not to use it. I looked up who has license on the stuff and
will be shooting them an email about the coating. It looks very
promising especially if it would survive 600c and up temps.
Rob Woods
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