A centrifugal pump is taking suction from an open water storage tank.
The pump is located at the base of the tank, takes a suction from the bottom of the tank, and discharges to a pressurized system.
Given:
- The tank is filled to a level of 26 feet with 60°F water.
- The pump is currently operating at 50 gpm.
- The pump requires 30 feet of net positive suction head.
Which one of the following describes the current pump status, and how the pump flow rate will be affected as the level in the storage tank decreases?
A. The pump is currently cavitating; pump flow rate will decrease continuously as tank level decreases.
B. The pump is currently cavitating; pump flow rate will remain about the same until the tank empties.
C. The pump is currently not cavitating; pump flow rate will gradually decrease with tank level and then rapidly decrease when cavitation begins at a lower tank level.
D. The pump is currently not cavitating; pump flow rate will gradually decrease with tank level and then rapidly decrease as the pump becomes air bound when the tank empties.
Show Answer
Answer: D
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