Centrifugal pump
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What is the working principle of a centrifugal pump? What is cavitation? What is vapor entrapment?
Working principle (1): The impeller is rotated by the pump shaft, doing work on the fluid located between the blades; due to centrifugal force, the fluid is pushed from the center of the impeller toward the periphery. When the fluid reaches the outer periphery of the impeller, the flow velocity is very high. (2) The pump casing collects the liquid ejected from between the blades; this liquid flows within the casing along spiral-shaped channels that gradually widen, converting the kinetic energy of the fluid into static pressure energy and thereby reducing energy losses. Therefore, the function of the pump casing is not only to collect liquid; it is also an energy conversion device.
Gas binding phenomenon: If the pump casing is filled with gas before startup, when the gas at the center of the impeller is expelled after startup, a sufficiently large vacuum cannot be created there, and as a result, the liquid in the tank cannot be drawn in. This phenomenon is known as gas entrapment.
Cavitation refers to the process in which bubbles in low-pressure areas of a flow system are carried by the water flow to high-pressure areas, where they are compressed and collapse rapidly, resulting in a deterioration of hydraulic performance and damage to the flow components.