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Centrifugal pump impeller design: Typical maximum vane exit angle at outlet. Select the most appropriate range for the maximum vane exit angle (degrees) used in practice. Choose the correct range.

Difficulty: Easy

10° to 15°
15° to 20°
20° to 25°
25° to 30°
30° to 40°

Correct Answer: 25° to 30°

Explanation:

Rule of thumb

For radial-flow centrifugal pumps, the outlet (vane exit) angle is commonly in the range of ~20°–30° to balance head, efficiency, and cavitation performance.

Why 25°–30°
Angles smaller than ~20° may increase recirculation losses; much larger angles can cause shock and higher losses. Designers often cap the maximum near 30°.

Final Answer
25° to 30°

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