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This post was last edited by 3983596_FPPZ on 2018-12-11 at 10:32. Rules for multiple-choice questions: 1. If the answer to each question is incorrect, participants will still receive a reward of 2 Wealth points； 2. A correct answer rewards 6 wealth points ； 3. Rewards for answers are available once per person only ； 4. Each reply allows for one management rating only ； 5. The answer and its explanation will be visible after responding ； 6. The reward is valid for 48 hours. The student has won another award; come by here every day. A centrifugal pump is used to transport clean water in coastal areas. The temperature of the water is 90°C (at 90°C, the saturated vapor pressure of water is 70 KPa, and its specific gravity is 0.965). The absolute pressure at the inlet is 0.08 MPa. The NPSHR of the pump at its rated flow rate is 3.0 m. Will cavitation occur when this pump operates at its rated capacity after it is started? (Multiple choice) A: Cavitation will occur, and the pump cannot be used. B: Critical cavitation condition; the pump cannot continue to operate. C: No cavitation will occur, and the pump operates normally. D: Uncertain. Answer: A. If the inlet pressure minus the net positive suction head – 0.5 (safety margin) is greater than the saturated steam pressure, then no cavitation will occur. Inlet pressure: 0.08 MPa = 80 KPa / (9.81 * 0.965) = 8.45 m of head pressure ； Saturated vapor pressure: 70KPa = 70/(9.81*0.965) = 7.39 m of head pressure ； Result: 8.45-3.0-0.5=4.95