High current in centrifugal pump, low outlet pressure
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For high-speed centrifugal pumps, when operating at a constant mass flow rate, it is observed that the current gradually increases while the pressure at the pump outlet slowly decreases; once the current reaches a high level, the pump shuts down. Please help analyze this situation, experts
Has the pump casing temperature increased? Many high-speed pumps operate unstably due to temperature changes
The temperature hasn’t changed; I suspect it’s related to density
1. In high-speed pumps, if there are mechanical problems, vibration and noise will indicate abnormalities. 2. If only the current increases, it is more likely that the properties of the medium have changed, especially with increases in density and viscosity, which can also have an impact. 3. LZ mentioned “operating at a constant mass flow rate”; it is more reasonable to say “operating at a constant volume flow rate”. When operating at a constant volume flow rate, an increase in density leads to an increase in mass flow rate, resulting in a more significant increase in current
It is that the mass flow rate remains constant, the density decreases, the volumetric flow rate increases, and the head pressure decreases. I’m not sure if this understanding is correct
It is the mass flow rate that remains constant. If the density is low, the volumetric flow rate increases while the head decreases; I’m not sure if that’s correct
From the perspective of the pump’s performance curve, it makes sense that as the flow rate increases, the head decreases. Is the density change so significant that it results in a noticeable increase in flow rate and a decrease in pressure?
The so-called constant mass flow rate is calculated by first determining the density of the medium based on the volume flow rate; it is very likely that changes in density are the cause of this
The flow rate is too high; the pressure should be a bit lower.