A centrifugal pump increases pressure by transferring rotational energy from an impeller to a fluid, thereby increasing the fluid's velocity and converting that velocity into pressure.
Here's a breakdown of the process:
- Impeller Rotation: The impeller, a rotating component with vanes, spins within the pump casing. This rotation is driven by an external power source, like an electric motor.
- Fluid Intake: Fluid enters the pump near the impeller's center (the "eye").
- Velocity Increase: As the impeller rotates, its vanes push the fluid outwards. This mechanical action imparts kinetic energy to the fluid, significantly increasing its velocity. Think of it like a spinning water wheel flinging water outwards.
- Conversion to Pressure: The high-velocity fluid then enters the volute (a spiral-shaped casing) or diffuser vanes surrounding the impeller. These components are designed to gradually increase the cross-sectional area of the flow path.
- Bernoulli's Principle: As the fluid velocity decreases within the volute or diffuser (due to the increasing area), its pressure increases, according to Bernoulli's principle. Bernoulli's principle states that an increase in fluid velocity occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy. The kinetic energy gained from the impeller is converted into pressure energy.
- Discharge: The now-higher-pressure fluid is then discharged from the pump outlet.
Essentially, the centrifugal pump transforms mechanical energy into kinetic energy (increased fluid velocity) and subsequently converts kinetic energy into pressure energy, resulting in a higher pressure at the pump's outlet. The design of the impeller and volute or diffuser are crucial for efficient energy transfer and pressure generation.
