Cavitation and gas entrapment

Cavitation occurs when, at a certain temperature, the pressure at the inlet is lower than the vaporization pressure (saturation vapor pressure) of the liquid; this causes the liquid to vaporize and form bubbles. As the fluid moves into areas of higher pressure, these bubbles collapse, and the surrounding liquid quickly fills in the space left by the bubbles, resulting in a hydraulic shock. The phenomenon of this liquid vaporizing to produce bubbles and then those bubbles collapsing is cavitation. Characteristics of cavitation: ① The pump experiences significant vibration and noise. ② The outlet pressure of the pump decreases, and the flow rate drops; increasing the valve opening does not raise the flow rate. ③ Pumps that operate in a state of cavitation for an extended period suffer from noticeable honeycomb-like erosion on their pump casing and impellers. Cavitation is a phenomenon that is very harmful to pumps! Preventive measures: Install the centrifugal pump at an appropriate height such that the static pressure at the lowest point inside the pump exceeds the saturated vapor pressure of the liquid being transported at the operating temperature, or increase the pressure upstream. The gas binding phenomenon refers to the situation where, if the pump casing is filled with gas before startup, the gas at the center of the impeller is expelled after startup, and a sufficient vacuum cannot be created there; as a result, the liquid cannot be drawn in. This phenomenon is related to the operation, and it can be avoided as long as the filling pump works properly.

I completely agree with what was said above. To add, air binding is caused by the pump not being filled properly.

Are there any requirements, or none, regarding the liquid level height in the storage tank as well? Pump pipes generally have a large suction lift, for example: 4m. Please discuss

The introduction to \"Principles of Chemical Engineering\" is very detailed; it’s worth reading if you haven’t studied it before.