When the liquid is at a certain temperature, when the pressure is reduced to the vaporization pressure at that temperature, the liquid produces vapor bubbles. This phenomenon of generating bubbles is called cavitation.
The curve that shows the relationship between the main performance parameters is usually called the performance curve or characteristic curve of the centrifugal pump.
It refers to the ratio of the pump effective power to the shaft power. The power usually refers to the input power, that is, the power transmitted from the prime mover to the pump shaft, so it is also called shaft power.
The volume of the liquid discharged by the pump per unit time is called the flow rate. The flow rate is expressed by Q. The unit of measurement: cubic meter/hour (m3/h), liter/second (l/s).