What are the two main types of fan design?

What are the two main types of fan design?

• A. Axial-flow and Centrifugal
• B. Forward-curved and Backward-curved
• C. Radial and Axial
• D. Mixed-flow and Centrifugal

Answer: (A)

In fan design, the main distinction is how air moves through the impeller relative to the axis. An axial-flow design pushes air parallel to the shaft, with air entering and leaving along the same general direction. This yields high flow rates but relatively small pressure rise, making axial fans common in ceiling fans and straight duct HVAC runs. A centrifugal design draws air into the center and then throws it outward (radially) into the housing, where velocity is converted to higher static pressure. This setup is better at overcoming duct resistance and delivering air through longer or more complex duct systems. Blades can be curved in various ways—forward-curved or backward-curved—within centrifugal designs, and those differences affect efficiency and pressure characteristics, but they don’t define the two broad families of flow paths. Centrifugal fans are also often called radial fans, but the two fundamental categories most people use are axial-flow and centrifugal.

In fan design, the main distinction is how air moves through the impeller relative to the axis. An axial-flow design pushes air parallel to the shaft, with air entering and leaving along the same general direction. This yields high flow rates but relatively small pressure rise, making axial fans common in ceiling fans and straight duct HVAC runs.

A centrifugal design draws air into the center and then throws it outward (radially) into the housing, where velocity is converted to higher static pressure. This setup is better at overcoming duct resistance and delivering air through longer or more complex duct systems.

Blades can be curved in various ways—forward-curved or backward-curved—within centrifugal designs, and those differences affect efficiency and pressure characteristics, but they don’t define the two broad families of flow paths. Centrifugal fans are also often called radial fans, but the two fundamental categories most people use are axial-flow and centrifugal.