【Daily Question】July 27: Question on the relationship between centrifugal pump efficiency and flow rate (+2 for the first 80 participants, +3–8 extra for correct answers...)
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This post was last edited by whthday on 2015-7-28 at 10:31. The Mechanical Section has introduced the \"Question of the Day\" feature, which not only helps to foster an active atmosphere for technical discussions and guide the direction of such exchanges but also provides users with financial rewards, enabling them to experience various cool features. 【Daily Question】 What is the relationship between the efficiency η of a centrifugal pump and its flow rate Q? ( ) A. As Q increases, η increases ； B. As Q increases, η first increases and then decreases ； C. As Q increases, η decreases ； D. As Q increases, η first decreases and then increases. Answer: B. Requirements and hints for answering the question: Reply with the answer you think is correct; if you provide a detailed explanation or analysis of the question or answer, an additional reward will be given. Extra rewards will be awarded if your answer is correct and your explanation is thorough and accurate. Feel free to answer. Please note: We will close this thread after 24 hours, and at that time we will announce the best reply (the best assistance), as well as the answer and explanation. Please do not submit answers repeatedly. As a reward for your effort, if you post a topic in this section within two days that provides a detailed explanation of the knowledge points covered by this question, please reply or leave a comment in this post to inform us, and we will have a moderator award you + charm points. It is not allowed to simply copy and paste; original content is preferred, with at least some organization by the user and the addition of personal insights. After registration, we will rank based on the content of the posts: the last-place contestant will receive +1 charm, the second-to-last +2 charm, and so on, with the highest score earning +5 charm. Call for weekly topics and daily questions (prizes for participation) [Mechanical Section] Collection of essential knowledge [Seeking manufacturer sponsorship] (long-term campaign) [Rewards for recommending valuable content] Summary of daily questions and answers related to mechanical equipment for 2015
The relationship between the efficiency η of a centrifugal pump and its flow rate Q is ( ). C. As Q increases, η decreases ；
The relationship between the efficiency η of a centrifugal pump and its flow rate Q is given by (B). A. As Q increases, η increases ； B. As Q increases, η first increases and then decreases ； C. As Q increases, η decreases ； D. As Q increases, η first decreases and then increases. The η-Q curve represents the relationship between the pump’s efficiency and flow rate. As can be seen from the characteristic curve, when Q=0, η=0 ； As the flow rate increases, the pump’s efficiency rises as well and reaches a maximum value ； Thereafter, as the flow rate increases further, the efficiency declines. This indicates that a centrifugal pump has a maximum efficiency point at a certain speed, which is usually referred to as the design point. The pump operates most economically at the flow rate and head corresponding to its highest efficiency; therefore, the Q, H, and N values corresponding to this point of highest efficiency are referred to as the optimal operating parameters. The performance parameters indicated on the nameplate of a centrifugal pump refer to those values at which the pump operates at its highest efficiency.
Personally, B doesn’t know very much about centrifugal pumps
This post was last edited by whthday on 2015-7-27 at 12:59. The Machinery Section has introduced the \"Question of the Day\" feature, which not only helps to foster an active atmosphere for technical discussions and guide the direction of such exchanges but also provides users with financial rewards, enabling them to experience various cool features. 【Daily Question】 The relationship between the efficiency η of a centrifugal pump and its flow rate Q is (B). A. As Q increases, η increases ； B. As Q increases, η first increases and then decreases ； C. As Q increases, η decreases ； D. As Q increases, η first decreases and then increases.
B. As Q increases, η first increases and then decreases；
The relationship between the efficiency η of a centrifugal pump and its flow rate Q is ( ). B. As Q increases, η first increases and then decreases ；
The correct answer should be B. Simply put, the efficiency η of a centrifugal pump is related to the flow rate Q in a parabolic manner that opens downward (resembling a parabola).
B. As Q increases, η first increases and then decreases
The relationship between the efficiency η of a centrifugal pump and its flow rate Q is given by (B). A. As Q increases, η increases ； B. As Q increases, η first increases and then decreases ； C. As Q increases, η decreases ； D. As Q increases, η first decreases and then increases.
The relationship between the efficiency η of a centrifugal pump and its flow rate Q is given by (B). A. As Q increases, η increases ； B. As Q increases, η first increases and then decreases ； C. As Q increases, η decreases ； D. As Q increases, η first decreases and then increases.