Centrifugal force is what moves fluids through a centrifugal pump. Centrifugal force is an apparent force experienced by an object moving in a circular path, that acts outwardly away from the center of rotation. The term originates from 1659, combining the Latin words centrum meaning “center” and fugare meaning “fleeing” or “avoiding”, thus centrifugus means “fleeing from the center”.

Key Characteristics

Centrifugal force is characterized by:

• Direction: Acts outward from the center of the rotation.
• Frame of reference: Observed only in a rotating reference frame.
• Dependence: Varies based on the object’s mass, speed of rotation, and the radius of the circular path.

Understanding Centrifugal Force

Centrifugal force is the apparent outward force on an object when it is rotating. Imagine a ball tied to a string being spun in a circle. As the ball moves, it seems to be pushed outward, away from the center.

However, there is no actual force pushing the ball outward. According to physics, in an inertial (non-rotating) frame of reference, objects naturally move in straight lines unless influenced by an external force. The ball tied to a string, for example, attempts to move in a straight line. The string, however, applies inward force that prevents the ball from traveling linearly. Instead, this tension keeps the ball moving in a circular path, with the radius determined by the string’s length and the speed set by the rotation provided by the individual.

Centrifugal Force in Daily Life

Centrifugal force appears in many everyday activities involving rotation or circular motion. Here are some common examples:

• Washing machines: During the spin cycle, centrifugal force pushes water out of the clothes through tiny holes in the drum, helping to dry clothes faster.
• Amusement park rides: On rides like carousels or spinning swings, riders feel pushed outward from the center because of centrifugal force. The faster the ride spins, the stronger this outward pull feels.
• Driving around curves: When a car takes a sharp turn, passengers feel pushed outward because their bodies resist change in direction due to inertia, creating the effect of centrifugal force.

Centrifugal Force in Pumps

In centrifugal pumps, centrifugal force moves liquids. Inside the pump as the impeller rotates, it imparts kinetic energy (velocity) to the fluid, causing it to move outward away from the center of the impeller due to centrifugal force. Like a spinning wet tennis ball (image), the faster the spin, the faster the liquid moves away from the center.

This outward movement increases fluid velocity. However, in the case of the pump, the pump's casing by means of a cutwater directs this fast-moving liquid and turns its kinetic energy into pressure, allowing the liquid to flow out through the pump’s outlet (Image 1).

A simple example of centrifugal force as it relates to a pump can be observed by stirring a glass of water. As you spin the water, it rises from the center and moves toward the edge of the glass. The faster you stir, the more forcefully the water is pushed outward, creating a flow and increasing pressure – an effect known as “head”. This rotation transfers energy to water, generating centrifugal forces that push the liquid outward.

Wilo is Your Solutions Provider

When it comes to harnessing the power of centrifugal force in fluid management, Wilo stands out as a trusted solutions provider. With expertise in centrifugal pump technology, Wilo offers reliable, efficient, and innovative pumping systems for a variety of applications. Whether you need pumps for residential, commercial, or industrial use, Wilo's advanced engineering ensures optimal performance and long-term durability. Choose Wilo for cutting-edge centrifugal pump solutions designed to meet your specific needs.

tlk | December 2024

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