【Daily Question: Pump Equipment】Fill-in-the-blank question, 3/29/2019

Thread Content

This post was last edited by 3983596_FPPZ on 2019-3-29 at 14:27: for bk14.jpg, 1) If both questions are answered incorrectly, +2 wealth is given as a reward for active participation; if one question is answered incorrectly and the other correctly, +5 wealth is given; if both questions are answered correctly, +8 wealth is given. 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 awards +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. Studying* and winning awards again; come by here every day. 1. Among the various losses in centrifugal pumps, the volumetric loss gradually ( ) as the flow rate increases ； 2. The rated parameters of the centrifugal pump are: flow rate of 50 m3/h, head of 32 m, and rotational speed of 2900 r/min. Then, the specific speed ns of this pump is ( ). Answer: 1. It becomes smaller (the flow rate increases, the head decreases, the pressure difference diminishes, the leakage at all return points decreases, the volumetric loss is reduced, and the volumetric efficiency improves) ； 2, 92.72 (ns = 3.65nQ^0.5/H^0.75; where ns is the specific speed) ； Q —— flow rate, m^3/s, ； H—— Head in meters ； n — rotational speed, r/min).