This is one of the Q&A topics I'm collecting about compressors and antisurge control.
Compressor stall, airplane stall and pump cavitation: are these all the same phenomena?
Well, compressor stall is indeed absolutely the same effect as an airplane stall. Compressor blade and airplane wing utilize the same mechanism of energy transfer between gas and the wing (or blade), just in opposite directions. In case of a compressor, the mechanical force of the shaft rotation is transferred to the gas in a form of kinetic energy. Basically, the blade speeds up the gas. For an airplane, when the wing is moving through the air, it converts the kinetic energy of the gas (air) stream to the mechanical energy of the lift force. In order to maintain this energy transfer, the gas should move along the blade with relatively high velocity and the blade should be positioned against the gas flow with a certain angle of attack. When the gas speed goes down to some critical level or the angle of attack becomes too big, the gas stream separates from the aerofoil and the energy transfer decreases and eventually stops.
This has very little in common with cavitation in a pump or control valve. Cavitation is the formation of bubbles in a liquid, caused by the low pressure with associated lowering of the gas solubility. The gas evaporates from the liquid to these bubbles and the bubbles grow. When the pressure recovers, bubbles collapse and create hydrodynamic shock waves that cause all the damage.
The only similarity between stall and cavitation is that they're both associated with the voids in the steam of gas or liquid, but the further development of the process in gas and liquid is very different.
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