Centrifugal Pump Casings and Flow Recovery In centrifugal pump design for clear liquids, the impeller can be paired with different casing arrangements to control velocity-to-pressure conversion and hydraulic losses. Identify which casing arrangements are used in practice for centrifugal pumps.

Introduction:
Centrifugal pumps convert rotor-imparted velocity head into useful pressure head. The casing determines how efficiently this conversion happens. This question checks recognition of common casing types used with radial-flow impellers and why all of them are valid in appropriate contexts.

Given Data / Assumptions:

• Radial-flow, single-stage centrifugal pump with closed or semi-open impeller.
• Newtonian liquid; steady, incompressible flow.
• Focus on hydraulic energy conversion and loss control within the casing.

Concept / Approach:
The impeller discharges high-velocity fluid. The casing must diffuse this velocity to pressure with minimal loss. Three arrangements are standard: volute (collects flow in an expanding spiral), diffuser or guide-vane casing (stationary vanes form passages to diffuse flow more gradually), and vortex/whirlpool casings (reduce eddy losses by shaping a secondary chamber). All are legitimate choices depending on duty, efficiency targets, and cost.

Step-by-Step Solution:
Volute: As area increases along the spiral, local velocity falls and static pressure rises; simple, robust, widely used.Diffuser (volute with guide blades): Stationary guide vanes recover pressure more efficiently at the expense of complexity and tighter clearances.Vortex casing: Introduces a vortex chamber to smooth out whirl and reduce shock/eddy losses near the tongue region.Conclusion: All three are used with centrifugal impellers depending on design priorities.

Verification / Alternative check:
Standard pump handbooks list these casing families and discuss their trade-offs in efficiency, head–capacity curve shape, and manufacturing cost.

Why Other Options Are Wrong:

• Each of A, B, C singly is correct, but the most complete answer is that any of them can be used in practice.

Common Pitfalls:
Assuming only volutes are “real” casings. Diffusers are common in multi-stage pumps; vortex features appear in designs targeting smoother operation.

Final Answer:
any one of these