How does a centrifugal pump transport liquid through the rotation of the impeller

Basic structure of centrifugal pump

The main components of a centrifugal pump include the pump body, impeller, pump shaft, bearing, sealing device, and suction and discharge ports. The impeller is the most critical component, which is installed on the pump shaft and driven to rotate by the motor. The impeller is usually designed as a curved blade with multiple curved surfaces. These blades exert centrifugal force on the liquid when rotating, pushing the liquid from the center to the outer edge.

Working process of a centrifugal pump

Before the centrifugal pump is started, the pump chamber needs to be filled with liquid. When the motor drives the pump shaft to rotate, the impeller also rotates at high speed. Due to the curved structure of the impeller blades and the centrifugal force generated by the rotation, the liquid is pushed and thrown from the center of the impeller to the outer edge. In this process, the velocity energy of the liquid increases, and then gradually converted into pressure energy in the pump casing.

When the liquid flows out from the outer edge of the impeller, it will pass through the volute-shaped pump casing channel, which is designed to convert the kinetic energy of the high-speed liquid into pressure energy, thereby increasing the delivery pressure of the liquid. At the same time, a relatively negative pressure area is formed in the center of the impeller due to the liquid being thrown out. This low-pressure area will automatically replenish the liquid at the suction port of the pump, realizing continuous suction and discharge.

The key role of centrifugal force

The name of the centrifugal pump comes from the mechanism of centrifugal force in its work. During the rotation of the impeller, the liquid moves outward from the center under the action of inertia, forming a centrifugal force field. This force field not only drives the flow of liquid, but also enables the liquid to obtain kinetic energy and pressure energy conversion in the pump body. Driven by centrifugal force, the liquid can be sucked into the pump cavity and discharged into the target pipeline without relying on external pressurization. This energy conversion process follows the momentum theorem and Bernoulli principle in fluid mechanics, and is the theoretical basis for the liquid to be driven to flow from a static state.

The process of energy conversion

The impeller converts the mechanical energy provided by the motor into kinetic energy and pressure energy of the liquid through the rotation process. The increase in kinetic energy is reflected in the increase in liquid flow rate, and the increase in pressure energy is reflected in the change in head and outlet pressure. When the liquid passes through the diffusion channel inside the pump casing, the kinetic energy is gradually converted into pressure energy, so that the liquid can overcome the resistance in the conveying pipeline and achieve long-distance or high-level conveying.

Formation of continuous conveying mechanism

Since the rotation of the impeller is continuous, the suction, acceleration and discharge process of the liquid is also continuous. This continuity ensures that the liquid can flow stably and is suitable for various scenarios that require continuous liquid supply. At the same time, by adjusting the diameter, shape and speed of the impeller, different flow rates and heads can be adjusted to meet different working conditions.

The centrifugal pump converts mechanical energy into kinetic energy and pressure energy of the liquid through the rotation of the impeller, thereby realizing the conveying of the liquid from the low position or low pressure area to the high position or high pressure area. The design and rotation speed of the impeller determine the conveying capacity and working efficiency of the pump. In modern fluid conveying systems, centrifugal pumps have become indispensable equipment in various liquid conveying projects due to their compact structure, stable operation and convenient maintenance.