What is the effect of air at the outlet of a centrifugal pump on its outlet pressure and flow rate?
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This post was last edited by Desert Fish on 2021-7-17 at 19:00. Question: What effects does air at the outlet of a centrifugal pump (not at the inlet or within the pump chamber) have on the pump’s outlet pressure and flow rate?
The outlet is at positive pressure; if there is air at the outlet, it must have come from the inlet. It seems that the liquid level at the suction side is low, resulting in negative pressure at the inlet, which allows air to leak in. If too little is drawn in, it will affect flow rate and head; if too much is drawn in, cavitation will occur.
Gas is present at the outlet; assuming that this gas is not carried away along with the material exiting the pump but remains there, it can cause fluctuations in the pressure at the pump outlet. Since gas is compressible, it has little effect on the flow rate