Which sequence correctly orders impeller types from highest head to lowest head?

Which sequence correctly orders impeller types from highest head to lowest head?

• A. Radial flow, Mixed flow, Axial flow
• B. Open, Mixed, Radial
• C. Axial flow, Radial flow, Mixed flow
• D. Radial flow, Axial flow, Mixed flow

Answer: (A)

Impeller geometry determines how much head a pump can produce. Axial flow impellers behave like propellers, pushing fluid mainly along the axis, which yields a large flow but only a small pressure rise—so the head is low. Radial flow impellers push fluid outward from the center and convert more of the rotational energy into pressure, giving a higher head. Mixed flow impellers sit between these two, combining axial and radial components to provide intermediate head. Because of this progression, the sequence from highest head to lowest head is radial flow, followed by mixed flow, then axial flow. In practice, exact head depends on speed, diameter, and design, but the general trend is consistent.

Impeller geometry determines how much head a pump can produce. Axial flow impellers behave like propellers, pushing fluid mainly along the axis, which yields a large flow but only a small pressure rise—so the head is low. Radial flow impellers push fluid outward from the center and convert more of the rotational energy into pressure, giving a higher head. Mixed flow impellers sit between these two, combining axial and radial components to provide intermediate head. Because of this progression, the sequence from highest head to lowest head is radial flow, followed by mixed flow, then axial flow. In practice, exact head depends on speed, diameter, and design, but the general trend is consistent.