【Daily Question: Pump Equipment】Fill-in-the-blank question, 2019.2.13

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This post was last edited by 3983596_FPPZ on 2019-2-13 09:52. Rules for the bg2.png fill-in-the-blank questions: 1. If both blanks are answered incorrectly, +2 wealth for active participation; if one blank is answered incorrectly and the other correctly, +5 wealth; if both blanks are answered correctly, +8 wealth. 2. If only one answer is provided, unless it is clear which question’s answer it is, a correct answer earns +5 wealth points, while an incorrect answer earns +2 wealth points; in all other cases, it is counted as active participation and grants +2 wealth points. 3. Rewards for answers are available once per person only. 4. Each reply allows scoring for only one person. 5. The answer and its explanation will be visible after responding. 6. The reward is valid for 48 hours; no reward will be given after that period. The student won another award; come by regularly to check out this single-stage centrifugal pump. Its designed head is 47 m, the impeller diameter is 202 mm, and the rotational speed is 2900 r/min. The actual measured head was 51 m. According to the proportionality law, the diameter of the impeller after cutting it is ( ) mm. The efficiency of the pump after impeller cutting will decrease slightly by ( ) – please fill in ‘decrease’, ‘increase’ or ‘unchanged’. Answers: 194, Decrease