Can a screw such as the one below be used as an air engine in pressure range between 700 kPa and 2500 kPa
on other words Can I reverse compression process with a screw to work as air engine
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1$\begingroup$ Please be more specific. Instead of "low pressure," give us the range of pressure you expect or require in your application. Instead of "used as an air engine," give us a description of the engine that is complete enough for an expert to understand exactly what you're proposing. You could describe the engine with a schematic, with an analogy or in some other way, as long as you clearly communicate what problem you're trying to solve. More details about the screw wouldn't hurt, either; material, dimensions, etc. $\endgroup$– AirFeb 2, 2016 at 17:23
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$\begingroup$ I think this is asking is a screw compressor can be used as pneumatic motor. The answer is no. $\endgroup$– Chris JohnsFeb 2, 2016 at 22:08
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$\begingroup$ @ Chris Johns Can you explain Why? $\endgroup$– JustMeFeb 2, 2016 at 22:36
2 Answers
Some processes are reversible, but this one isn't. When a compressor compresses a fluid, it can do so via increasing the stream velocity (such as a piston or a rotor), or it can do by increasing the pressure/density from direct compression (such as a peristaltic pump). The first is reversible - the high stream velocity can push back on the solid object, slowing down, and transferring momentum back into a shaft. The second is irreversible - the high pressure fluid can't compress the in-compressible solid and get it to move preferentially in one direction.
I can't imagine an Archimedes screw ( figure) being effective moving air/ gas. If you want to get work out of high pressure air , A reciprocal machine, ie a "steam" engine would be about the only effective mechanism.