Question 413General Subjects - Assistant Engineer

The correct answer is B) vapor pockets. Cavitation in a centrifugal pump occurs when the local pressure in the fluid being pumped drops below the vapor pressure of the fluid, causing the formation of vapor pockets or bubbles. These vapor pockets collapse when they enter regions of higher pressure, resulting in the characteristic vibration, noise, and reduced capacity of the pump. The other options are incorrect: A) Steam knock is not related to cavitation, which involves the formation of vapor pockets, not steam. C) Fluid friction is a separate phenomenon that can contribute to pump performance issues but is not the primary cause of cavitation. D) Water hammer action is a separate type of pressure surge and is not directly related to the formation of vapor pockets during cavitation.