The phenomenon of cavitation in a centrifugal pump is triggered when:
Options:
(A) The local absolute pressure at the eye of the impeller drops to or below the vapor pressure of the liquid
(B) The pump is operated against a completely closed delivery valve
(C) The operating speed exceeds the critical speed by $50\%$
(D) Discharge exceeds the shut-off head
Answer Key:
A
Step-by-Step Solution & Explanation
Cavitation occurs when local static pressure falls to the saturation vapor pressure ($p_v$) of the fluid at the operating temperature, causing vapor bubbles to form. As these bubbles move into regions of higher pressure, they collapse violently, eroding the impeller blades.