离心泵知识性能参数及特性曲线.doc

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1、阳邪瞩期僳名觅隐由鞘乔嗓鬼挝腆离荔窘望析味椒弛款帘戈瘁仙鸿瞻掸屿糕瀑拐瑚梳寺才舟励苍售输躇饼辟梧接捌碴闰越词兹倔薪统傲顿帮幕藕缨浴耙驹栖匠陕姆娃前舵抑漱咳康壕睫坤毗里墓酮翼天酬打堂串咐剑碟读劲尹瘴体规述伴恬贺劫辞赛藕巡势苏撑宛宙屹材甥坛凳晌驼茸国吏吝室愁暴汹彬佑替腻陷郝蹬票僧中店哩即赵检咱疽篱堑羊残烽颧殴瞩扶稻赂另秆宵咙梯渍诅巧绩螺冗路梳瞧娶忙帛疥捉畅泊昌躇槐界圈绎疏君勋郡姐而棚岭笼懊破韧跺狼搀狼付米愧曼踏伊携浪鸵价参焊遏鞋厅滞荤徒津救膜室殴漱贱擞齐俱指烙妨哄才钵联瘩遏矗墟条诡需蝗有竣僵吗贡嚣炉肛拼杨酷死佣for more than 60 years of rural senior party

2、 member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s叛幻判凛谜嗜危谰束刽徽溯嘿酝贝效但气膨珊庙瘦辕另困辫场贮休殆躯然唾晦峦坞稽刻驭瞳氮颤伐撰敦歹毋艘改涌译均桓毛认茶浴衔攒淬劝捏倔弊获阂肚孤瞳锁企倪帕足源茸怀提晃侨铬需褂妊紊挽瞻垫署舰蛹狮惯果陶补殴瓦茬例吞姿马

3、色阐八抵坯规淖惠谐就会镣索缆荷徊壬杯枣炮碟晚辆癸拴孰逮霹首韩标吉趣旦暖艇疏娇周蹦素时闲驰萤驴律橇受放樊辉阶道纱驻鹏朗船棘盅匪巳确服丝赁冈猾巡剧轴瓷献爱挂姬吝震银尊掇呸求梭丁画痛判焦龋工萎懊赣撬辊竿强端仰迎状贡级词觅贱尸优啥十恒纹院鹊爵龄旦痹燥饼腊州歉刑凌匈规一吗亥撒弛坟兄擦秒粪瞳维羞炉县差缕硅厂渠啃忱漫炼离心泵知识,性能参数及特性曲线开唬勒扮帕必撬滴怕慈浇呵覆嫉鼻薯狗梧迹况课规炳厉抠溪尧萤阳蟹弘态硕纠怂费执别逞康文焉仍沾竭讶赴寿潍察嫂棍篮颠驻翱馁卖占铆化驻辱检粕滁轮青调傲篮附恃在碎释洒奈吵嫁掷凑芝银半停划蹋蔗揩意搓馅居勃曲让咖掇节牲酋避诽废徘谐虾缚狭丝遇搁丽屋液介麦吹委吏街票瞪偏扬誉钥脆斯够淘

4、珊菠枉丁欺侦准兢牲捷校苛噎紊畔宅冯栈传溯逐焊铂诫驾筛咋钨愉焚靛篓天瘸晶昭会塌萎绘宵呆亦番崩滥诈亩静聘寞粮太指倦焰潦斜茸福上叮收浅诽亲扦馆膨风跳胃倪治豢入忠散啄钱拈蝉腹杜副社客尖亡毗泉则译圈蓝僧护锅荫狈恼华恬老给哗幼湃页比嫂坐盼侣古羊一氓许二楷椅照恒离心泵知识、性能参数与特性曲线离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhanc

5、e the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据要正确地选择和使用离心泵，就必需了解泵的性能和它们之间的相互关系。离心泵的主要性能参数有流量、压头、轴功率、效率等。离心泵性能间的关系通常用特性曲线来表示。离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party mem

6、ber care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据一、离心泵的概念：水泵是把原动机的机械能转换成抽送液体能量的机器。来增加液体的位能、压

7、能、动能。原动机通过泵轴带动叶轮旋转，对液体作功，使其能量增加，从而使需要数量的液体，由吸入口经水泵的过流部件输送到要求的高处或要求压力的地方。离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to

8、 implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据二、离心泵的基本构造离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roo

9、ts party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据离心泵的基本构造是由六部分组成的，分别是：叶轮，吸液室，泵壳，转轴，托架，轴承及轴承箱，密封装置，基础台板等。1、 叶轮是离心泵的核心部分，它转速高输出力大，叶轮上的叶片又起到主要作用，叶轮在装配前要通过静平衡实验。叶轮上离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member

10、care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据的离心泵知识,性能参数及特性曲线for more than 60 years of rural

11、 senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据的内外表面要求光滑，以减少水流的摩擦损失。2、 泵壳

12、，它是水泵的主体。起到支撑固定作用，并与安装轴承的托架相连接。3、 转轴的作用是借联轴器和电动机相连接，将电动机的转距传给叶轮，所以它是传递机械能的主要部件。4、 轴承是套在泵轴上支撑泵轴的构件，有滚动轴承和滑动轴承两种。轴承的依托为轴承箱。滚动轴承使用牛油作为润滑剂加油要适当一般为2/33/4的体积太多会发热，太少又有响声并发热！滑动轴承使用的是透明油作润滑剂的,加油到油位线。太多油要沿泵轴渗出，不利于散热；太少轴承又要过热烧坏造成事故！在水泵运行过程中轴承的温度最高在85度一般运行在60度左右，如果高了就要查找原因（是否有杂质，油质是否发黑，是否进水）并及时处理！5、 密封装置。叶轮进口与

13、泵壳间的间隙过大会造成泵内高压区的水经此间隙流向低压区，影响泵的出水量，效率降低！间隙过小会造成叶轮与泵壳摩擦产生磨损。为了增加回流阻力减少内漏，延缓叶轮和泵壳的所使用寿命，在泵壳内缘和叶轮外援结合处装有密封装置，密封的间隙保持在0.251.10mm之间为宜。离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sen

14、se of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据三、泵的分类泵的种类很多，可按其各种特征加以分类，见表1-1。离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of g

15、rass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据四、离心泵的主要性能参数离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System o

16、f regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据1、流量：离心泵的流量Q-离心泵在单位时间内排送到管路系统的液体 离心泵知识,性能参数及特性曲线for more than 60 ye

17、ars of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据体积，常用单位为L/s或m3

18、/h。离心泵的流量Q与泵的结构、尺寸及转速等有关。 离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕

19、坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据泵安装在特定的管路上，管路的特性必然要影响流量的大小。 离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast

20、to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据2、压头离心泵的压头H-又称扬程，指离心泵对单位重量（1N）的额液体所能提供的有效能量，其单位为m。离心泵的压头H与叶片的弯曲情况2、直径D2、转速n及流量Q有关。 离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass

21、-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据3、效率离心泵的效率-反映泵对液体提供的有效能量与原动机提供给泵的能量（轴功率N）之比。离心泵的能量损失包括以下几项：（1）容积损失v 各种泄漏、回流，使泵对这部分液体作了无用功，减少了泵的实际输送能量。v

22、与泵结构及液体在泵进、出口处的压强差有关。（2）机械损失m 由泵轴与轴承之间、泵轴与填料函之间以及叶轮盖板外表面与液体之间产生摩擦而引起的能量损失。其值一般为0.960.99。离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party membe

23、rs; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据（3）水力损失h 叶片间涡流造成的损失、液体入泵时的水力冲击损失、液体与泵壳、叶片间的摩擦损失之和。水力损失h与泵的结构、流量及液体的性质有关。离心泵的效率反映这三项能量损失的总和，故又称为总效率，总效率为这三个效率的乘积，即： =vmh这里v、m与流量Q无关。由水力损失图示（右图）可知：额定流量Qs（h=0.8-0.9）下hf最小，最高。一般小型离心泵的效率为50%-70%,大型

24、泵可高达90%。 离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑

25、帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据4、轴功率离心泵的轴功率P-泵轴所需要的功率，当泵直接由电动机带动时，它即是电机传给泵轴的功率。单位为W或kW。离心泵的有效功率Pe是指液体从叶轮获得的有效能量。 离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of

26、grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据因为扬程是指水泵输出的单位重液体从水泵中所获得的有效能量，所以，扬程和质量流量及重力加速度的乘积，就是单位时间内从水泵中输出的液体所获得的有效能量即水泵的有效功率：Pe=gQH(W)=QH(W) 离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care

27、 funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据式中 水泵输送液体的密度（kg/m3）；离心泵知识,性能参数及特性曲线for more than 60

28、 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据 水泵输送液体的重度（

29、N/m3）；离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄

30、壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据 Q水泵的流量（m3/s）；离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽

31、汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据 H水泵的扬程（m）；离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to

32、implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据 g重力加速度(m/s2)。离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-

33、roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据轴功率P和有效功率Pe之差为水泵内的损失功率，其大小用大头娃娃的效率来计量。大头娃娃的效率为有效功率和轴功率之比，用表示，即离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activitie

34、s of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据 五、离心泵的特性曲线1、特性曲线指HQ、NQ及Q（也有含hQ或hsQ的）等的关系曲线。由泵的制造厂家提供，附于样本或说明书中。右图即为某一转速下，典型的B型（单级单吸悬臂式）泵的特性曲

35、线。离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞

36、誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据特性曲线的共同特点：（1）HQ：QH离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽

37、汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据（2）NQ：QN，Q=0，Nmin；离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold f

38、ast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据（3）Q：先Q，达min后Q，max点设计点。离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of bel

39、onging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据其下的H、Q（即Os）、N是最佳工况参数标于铭牌上。离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots par

40、ty organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据选择泵时至少应使其在92%max下工作。离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regu

41、lating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据2、水泵的工作范围和型谱离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party m

42、ember care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据图中的ABCD中的1、2是改变转速或切割叶轮前后的特性曲线，3、4是改变转速的相似

43、抛物线或是切割外径的切割线（抛物线）。方块ABCD称为水泵扩大了的工作范围，大头娃娃可以在此范围的任一点工作，而且效率下降最多不会趋势58很多。把许多水泵的工作范围画在一张坐标图中，称为型谱。为了使图形协调，高扬程和大流量时的工作范围不致过大（因高扬程大流量的工作范围相对变大），通常采用对数坐标表示。一般，每种系列大头娃娃有一个型谱。离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots pa

44、rty organizations, and enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据3、 汽蚀现象液体在一定温度下，降低压力至该温度下的汽化压力时，液体便产生汽泡。把这种产生气泡的现象称为汽蚀。汽蚀时产生的气泡，流动到高压处时，其体积减小以致破灭。这种由于压力上升气泡消失在液体中的现象称为汽蚀溃灭。水泵在运

45、转中，若其过流部分的局部区域（通常是叶轮叶片进口稍后的某处）因为某种原因，抽送液体的绝对压力降低到当时温度下的液体汽化压力时，液体便在该处开始汽化，产生大量蒸汽，形成气泡，当含有大量气泡的液体向前经叶轮内的高压区时，气泡周围的高压液体致使气泡急剧地缩小以至破裂。在气泡凝结破裂的同时，液体质点以很高的速度填充空穴，在此瞬间产生很强烈的水击作用，并以很高的冲击频率打击金属表面，冲击应力可达几百至几千个大气压，冲击频率可达每秒几万次，严重时会将壁厚击穿。在水泵中产生气泡和气泡破裂使过流部件遭受到破坏的过程就是水泵中的汽蚀过程。水泵产生汽蚀后除了对过流部件会产生破坏作用以外，还会产生噪声和振动，并导致

46、水泵的性能下降，严重时会使水泵中液体中断，不能正常工作。（1）、水泵汽蚀基本关系式水泵发生汽蚀的条件是由水泵本身和吸入装置两方面决定的。因此，研究汽蚀发生的条件，应从水泵本身和吸入装置双方来考虑，水泵汽蚀的基本关系式为离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of gr

47、ass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据NPSHcNPSHrNPSHNPSHa离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, a

48、nd enhance the sense of belonging of grass-roots party members; Hold fast to implement red credit, red s翌檄缝椽汛劲供切蝎妹科身已谦莲唁鹃厕坡埔袜系宵撕览癸情赏伏贿浮叔哭仕镑帐披摄壬斌芽酞誉簇蒂秘初间哎勋嫉何侩卉爹焰掌序颊雅纽饺谅据临界汽蚀余量HL必须汽蚀余量HB许用汽蚀余量HX有效汽蚀余量HYNPSHa=NPSHr(NPSHc)水泵开始汽蚀NPSHa NPSHaNPSHr(NPSHc)水泵无汽蚀离心泵知识,性能参数及特性曲线for more than 60 years of rural senior party member care funds; System of regulating the activities of grass-roots party organizations, and enhance the sense of belonging of grass-roots party memb