【单选题】【消耗次数:1】
离心泵输送介质密度改变,随着变化的参数是( )。
轴功率
流量
扬程
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相关题目
【单选题】 离心泵的轴功率与流量的关系——。
①  流量增大,轴功率增大。
②  流量增大,轴功率减小。
③  流量增大,轴功率先减小后增大。
④  流量增大,轴功率先增大后减小。
【单选题】 离心泵扬程的意义 。
①  A、泵的实际升扬高度
②  B、泵的吸液高度
③  C、液体出泵和进泵的压差换算成的液注高度
④  D、单位重量液体出泵和进泵的机械能差值
【单选题】 与离心泵叶轮直径平方成正比的参数是( )。
①  扬程
②  轴功率
③  流量
【单选题】 离心泵铭牌上标明的扬程m可理解为 。
①  A、该泵在规定转速下可以将20℃的水升扬的高度
②  B、该泵在规定转速、最高效率下将20℃的水升扬的高度
③  C、该泵在规定转速下对20℃的水提供的压头
④  D、该泵在规定转速、最高效率下对20℃的水提供的压头
【单选题】 离心泵工作时,流量稳定,那么它的扬程与管路所需的有效压力相比应该( )。
①  小于管路所需有效压力
②  一样
③  大于管路所需有效压力
【单选题】 离心泵的效率与流量的关系为——。
①  流量增加,效率增大。
②  流量增加,效率减小。
③  流量增加,效率先增大后减小。
④  流量增加,效率先减小后增大。
【单选题】 离心泵铭牌上标明的是泵在 时的主要性能参数。
①  (1) 流量最大;
②  (2) 压头最大;
③  (3) 效率最高;
④  (4) 轴功率最小。
【单选题】 离心泵的压头(或扬程)是指单位质量的流体从泵获得的有效能量。( )
①  正确
②  错误
【单选题】 离心泵的工作点决定于 。
①  A、管路特性曲线
②  B、离心泵特性曲线
③  C、管路特性曲线和离心泵特性曲线
④  D、与管路特性曲线和离心泵特性曲线无关
【单选题】 离心泵在启动前必须向壳内灌满输送液体是为了防止( )。
①  喘振
②  气蚀
③  气缚
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【单选题】 Although he did not know London well, he made his way ______ to the airport.
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【单选题】 The world is trying every means to _____the friendship between the two countries.
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③  account
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【单选题】 Let’s make it round 9 o’clock.____________
①  No. I think so.
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③  It’s impossible.
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①  was driving
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①  exact
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【单选题】 It was a(n) _______ achievement ― no one has ever won the championship five times before.
①  single
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①  who
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