Which type of pump has an impeller that rotates in a channel of constant cross-section area, imparting mixed or radial flow to the water?

The type of pump characterized by an impeller that rotates within a channel of constant cross-section area, resulting in mixed or radial flow to the water, is indeed the vertical turbine pump. This design allows the pump to efficiently transfer water vertically from a well or reservoir, as it employs an impeller that generates centrifugal forces, moving water upward.

Vertical turbine pumps typically consist of a series of impellers mounted on a vertical shaft, allowing them to operate effectively in deep well applications. The impeller's movement creates a pressure differential, drawing water into the pump and pushing it out through the discharge pipe. The constant cross-section area of the channel ensures smooth flow and minimizes turbulence within the system, which is critical for maintaining efficiency and reliability.

While rotary pumps also move water effectively, they rely on mechanisms that rotate to trap water and move it through the system, differing from the mixed or radial flow principle inherent to vertical turbine pumps. Centrifugal pumps do utilize an impeller, but the vertical turbine’s specific design and application create distinct operational features suited for vertical lifting. Submersible pumps operate differently as they are designed to work underwater, without the channel design emphasized in this question.