pistons vs. diaphragms

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pistons vs. diaphragms

Postby wormmaster57 » Thu Nov 07, 2002 9:40 pm


-Is it possible to make a "two piston-type" Stirling engine, that
would use two diaphragms instead of the pistons.

-How big does the diameter of the dislplacer have to be if the
cylinder has the diameter of 7.5" (coffee cup Stirling engine)?

Thank you very much for your help !
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Response to pistons vs. diaphragms

Postby ramaral » Fri Nov 08, 2002 6:41 am

Yes , It is perfectly possible to make a two piston or "alfa type" engine with diaphragms instead of the pistons,but you may find some problems using diaphragms, like erosion of the material of your diaphragm and the loss caused by the expansion of this material not pulling or pushing the power rod ( it may cause a low efficiency ) .
If you are trying to make a engine that just works (showing it's basic operation) and produce low output power. that's a good way.

The second question I'm not sure If I understood you correctly, what you call cylinder is were the displacer is inside, right? if yes, the right way to do it is to calculate the gas flow inside the "cylinder" and make the flowing completely disturbance but at the limit of it ( in the begining of this kind of flowing) ( the transition between the laminar flow and disturbamce flow would be perfect but just theoretical) .
If are trying something simpler try to leave 2 to 3 milimeters from the edge of it.

If I'm wrong on something , pls correct me.

Best Regards
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