An impeller is a rotating component used in various fluid handling systems, particularly pumps and turbines. It consists of a series of curved blades or vanes that are mounted on a central hub. The impeller's primary function is to impart energy to the fluid by increasing its velocity and pressure, allowing for the movement or transfer of the fluid.

Here are some key aspects and applications of impellers:

1. Pump Impellers: In pump systems, the impeller is the key component responsible for drawing in fluid and then accelerating and pressurizing it. As the impeller rotates, the fluid enters through the inlet and is pushed outward by the rotating blades. This generates a centrifugal force, which increases the fluid's velocity and creates pressure, ultimately facilitating its movement through the pump and into the system.

2. Turbine Impellers: In turbine systems, the impeller operates in reverse compared to pump impellers. Instead of pumping fluid, turbine impellers are driven by a fluid flow or high-velocity gas, such as steam or water, to convert kinetic energy into mechanical energy. The fluid's force causes the impeller to rotate, generating power that can be harnessed for various applications, such as generating electricity in hydroelectric power plants.

3. Types of Impellers: Impellers can come in different designs and configurations to suit specific applications. Common types include open impellers, closed impellers, semi-open impellers, and multistage impellers. Each type has its own advantages and is selected based on factors such as the fluid properties, desired flow rate, pressure requirements, and system efficiency.

4. Material Selection: Impellers are typically constructed from durable materials that can withstand the demands of fluid handling applications. Common materials include metals like stainless steel, cast iron, bronze, or aluminum, as well as certain types of plastics or composites. The material choice depends on factors such as fluid compatibility, corrosion resistance, strength, and cost.

5. Efficiency and Performance: The design and characteristics of the impeller greatly influence the efficiency and performance of a fluid handling system. Factors such as impeller shape, blade angle, blade count, and clearance between the blades and housing affect the pump or turbine's flow rate, pressure generation, energy consumption, and overall efficiency.

6. Maintenance and Repair: Over time, impellers can experience wear and damage due to factors like erosion, cavitation, or corrosion. In such cases, impellers may need to be repaired or replaced to maintain optimal performance. Regular maintenance, including cleaning, inspection, and balancing, is necessary to ensure smooth operation and prolong the impeller's lifespan.

Impellers are critical components in various industries, including water and wastewater treatment, oil and gas, chemical processing, HVAC systems, and power generation. Their ability to move and manipulate fluids efficiently makes them integral to a wide range of fluid-handling applications.