Is there a type of rotary positive displacement pump that can pump hot exhaust gases (~900°C), that is, not requiring lubrication that would otherwise be burnt off?
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$\begingroup$ The piston engine has an exhaust stroke that pushes the expanding gases. $\endgroup$– Solar MikeJun 26 at 16:45
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$\begingroup$ Does not a turbocharger fit the bill? I realize it's not a positive displacement device, but it certainly can handle the temperatures. $\endgroup$– fred_dot_uJun 26 at 17:19
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$\begingroup$ Im trying to make an analogue of a gas turbine for land vehicles that uses positive displacement pumps to vastly improve throttle reponse. Piston pumps offer of too low of a flowrate to offer increased power density compares to a piston engine $\endgroup$– Francis L.Jun 26 at 18:42
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$\begingroup$ PD pumps are used to force air in, not to pull air out. Look up induced draft fans, maybe with a controlled damper inlet? $\endgroup$– Tiger GuyJun 26 at 19:29
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$\begingroup$ @FrancisL. check out the gas turbines produced for vehicles. Designed to run at constant speed though - road speed can be varied... $\endgroup$– Solar MikeJun 27 at 7:56
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1 Answer
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There is a type of pump called a screw pump which was once considered as a power extraction device for hot exhaust gas, using ceramic screws. This was to pull shaft work out of the exhaust stream of a fluidized-bed combustor fueled with landfill waste. This idea dates back almost 50 years and I do not know if the firm developing it (Combustion Engineering, Inc.) successfully implemented the screw pump idea.
answered Jun 27 at 6:41