Why, when cavitation occurs in a pump – for example, when the inlet filter gets clogged and the flow rate decreases – does the head also decrease? Isn’t it such that, according to the pump’s performance curve, the head decreases as the flow rate increases?
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Why, when cavitation occurs in a pump – for example, when the inlet filter gets clogged and the flow rate decreases – does the head also decrease? Isn’t it such that, according to the pump’s performance curve, the head decreases as the flow rate increases?
Insufficient liquid supply – do you know what cavitation is? How is it determined? Generally, a 3% decrease in head is used as an indicator that the pump is experiencing cavitation
Then how should we understand the fact that in a pump’s performance curve, the head decreases as the flow rate increases?
The performance curve of a pump represents the relationship between flow rate and head at the outlet; it is also the parameter that determines how the pump operates under normal conditions. The cavitation you mentioned refers to the suction parameters of the pump. When cavitation occurs, the pump is no longer operating under normal conditions, as gas is present in the fluid being transported. In such cases, the relationship between head and flow rate cannot be determined using the pump’s performance curve
Oh, I see what you mean. Then, if a outlet valve is used to regulate the flow rate, it should be considered a normal operating condition for the pump – with reduced flow rate and increased head pressure
Yes, but the flow rate of the card is too low; if it falls below the minimum flow rate required for thermal control, the medium will heat up over time, eventually leading to cavitation
The characteristic curve of the pump is under conditions where cavitation does not occur
The HQ curve refers to the normal condition. The original poster is referring to abnormal conditions; first, address the unusual situations.
Cavitation in a pump represents an abnormal condition; it does not conform to the normal relationship between flow rate and head under normal operation, and it is no longer possible to use the curves to determine performance. If one insists on applying the relationships outlined in those curves even when cavitation is present, then it becomes irrelevant whether cavitation actually occurs or not