Short Answer:

A centrifugal pump is used to move liquids by converting rotational energy, typically from an electric motor, into energy in a moving fluid. It uses a rotating impeller to increase the velocity of the fluid and then converts that velocity into flow.

The main function of a centrifugal pump is to transport fluids from one place to another by creating pressure. It is commonly used in water supply systems, irrigation, drainage, and industrial processes. Its simple design, low maintenance, and ability to handle large volumes make it ideal for civil engineering applications.

Detailed Explanation

Function of a Centrifugal Pump

A centrifugal pump is a type of dynamic pump that moves fluids using centrifugal force. It is the most widely used pump in fluid mechanics and civil engineering due to its efficiency and simplicity. The pump consists of a rotating impeller enclosed within a casing. When the impeller spins, it draws liquid into the center (eye) of the impeller and then throws it outward by centrifugal force, increasing its velocity. This velocity is then converted into pressure energy as the fluid exits the pump.

Working Principle

The centrifugal pump operates on the principle of centrifugal force. When the impeller rotates, it imparts kinetic energy to the fluid. This energy causes the fluid to move outward from the center of the impeller to its edge. As the fluid moves outward, it gains speed and pressure. The fluid then flows through the casing to the discharge pipe. The design of the casing (volute or diffuser) helps in converting the high-velocity fluid into a steady flow with increased pressure.

Key Functions in Civil Engineering

Water Supply and Distribution
One of the primary uses of centrifugal pumps is in water supply systems. They are used to lift water from wells, reservoirs, and tanks to overhead storage or directly into the pipeline network.
Irrigation Systems
Centrifugal pumps are commonly used in agricultural fields to pump water from canals or underground sources to irrigate crops efficiently.
Drainage and Dewatering
In construction sites, basements, and low-lying areas, centrifugal pumps help remove excess water quickly and prevent flooding.
Sewage and Wastewater Management
These pumps are used in sewage treatment plants to move wastewater through various treatment stages. Special types of centrifugal pumps can handle semi-solid or dirty fluids.
Industrial Applications
In various industries like chemical plants, refineries, and food processing, centrifugal pumps are used to transport different types of liquids safely and efficiently.

Advantages of Centrifugal Pump

Simple Design: Fewer moving parts make it easy to operate and maintain.
High Flow Rate: Capable of moving large volumes of fluid.
Smooth Flow: Provides a steady and continuous flow without pulsation.
Cost-Effective: Economical for most civil and industrial applications.
Compact Size: Suitable for confined spaces and easy to install.

Limitations

Not suitable for high-viscosity fluids.
Performance depends on the operating speed and head.
Not self-priming; needs to be filled with liquid before starting.

Conclusion

The main function of a centrifugal pump is to move fluid by converting rotational energy into pressure energy through the action of a rotating impeller. It plays a crucial role in civil engineering systems like water supply, irrigation, drainage, and sewage management. Its simple design, efficiency, and ability to handle large volumes make it an essential part of modern infrastructure and fluid transport systems.