Fluidyne Engines


These are Stirling cycle engines with a fluid piston acted upon by a heat-induced pressure oscillation resulting from cyclic heating and cooling of a fixed amount of a working gas (air) inside the engine.


While a fluidyne can be made to oscillate, and even to pump water, it does not perform well at low pressure under load because as the loading increases the engine uses more and more of its mechanical energy to modulate the pressure of the air in its hot head.

In simple terms, the difficulty appears to be that thermal expansion is offset by mechanical compression of the air resulting from the loading forces.

It may be possible to circumvent this problem behavior by operating the engine at significantly higher pressure and temperature, but when those conditions are acceptable, there are better options than fluidynes. To see some of my exploration of those options, go back to "Engines" and browse "Hydrodyne Engines" and "Hydradyne Engines".

I find air/water fluidynes unsuitable as a practical pump engine solution.

The Ideal Gas Law

Ideal Gas Law  Temperature, Pressure, and Volume of an ideal gas are described by the Ideal Gas Law.

The Stirling Cycle

Stirling Cycle Stirling cycle description using the Ideal Gas Law.

Fluidyne Engines

Fluidyne Examples Fluidynes engines are Stirling cycle engines with a single fluid piston. Here is some development history with fluidyne photos, videos, and findings.

Copyright © 2011 Morris R Dovey

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