机电一体化毕业论文泵轴的可靠性设计方法的探讨13037

1、毕业设计论文( 2021届 )题目：泵轴的可靠性设计方法的探讨分 院 机电信息分院 专业班级 09 机电一体化技术(2)班 学生姓名 学 号 0911040225 导师姓名 成 绩 2012 年 4 月 14 日目 录摘要- 1 -一、引言- 2 -二、泵轴失效的影响因素- 3 -一单级离心泵结构特点- 3 -二作用在泵轴上的载荷- 3 -三泵轴内的应力- 4 -四泵轴失效特征- 5 -五泵轴失效的因素及危险断面- 5 -三、试验情况- 6 -一设计工况的扭转角及持久强度试验- 7 -二零流量工况的挠度与转角试验- 7 -三试验结果- 7 -四、设计准那么与强度计算方法- 7 -一设计准那么-

2、 7 -二强度计算方法- 7 -五、提高泵轴刚度的措施- 11 -(一) 改良泵轴的结构形式，减小弯矩数值- 11 -(二) 缩短跨度或增加支撑- 11 -(三) 选择合理的截面形状- 12 -六、总结- 12 -参考文献：- 13 -致谢- 14 -泵轴的可靠性设计方法的探讨机电信息分院 09机电一体化(2)班 邱发有指导教师：陈茂庆摘要：泵轴是组成离心泵的重要零件之一，一切作回转运动的零件都要装在轴上才能实现其回转运动，同时实现动力的传递，因此，泵轴工作时会受到重力G、径向力Pt、轴向力A、离心力Pv及扭矩Mn的作用。而且这些力还与转速有关。在这些力的作用下，引起轴的弯曲、扭转和剪切，超过

3、许多应力时，泵轴失效，轻者引起轴上零件磕碰、磨损，重者使零件卡滞，甚至影响泵的正常工作。为此，提出了轴的设计方法：1.在低速时，轴应以扭曲强度作为设计准那么；2.在高速时，应以扭矩刚度作为设计准那么。并进行了理论计算与试验验证，其结果根本一致。关键词： 泵轴 可靠性 设计方法 探讨一、 引言离心泵在现代工业开展中很早就起到了它的作用，现在离心泵应用范围广泛。其根据主要用途又可划分为多种离心泵，分类方法常见的有以下几种方式：1.按叶轮吸入方式分：单吸式离心泵 双吸式离心泵。2.按叶轮数目分：单级离心泵 多级离心泵。3.按叶轮结构分：敞开式叶轮离心泵 半开式叶轮离心泵 封闭式叶轮离心泵。4.按工作

4、压力分：低压离心泵 中压离心泵 高压离心泵边 立式离心泵。而单级离心泵又是其中的较根本的类型。单级离心泵主要适用于工农业及城市、排水、消防供水等，有高效节能、安装维修方便、运行平稳等特点。因此本次设计将主要以单级离心抽油泵为研究对象，对泵轴的可靠性进行设计与试验。论文的研究意义：离心泵随着转速的提高，工作条件变差，转速越高，工作环境越恶劣。然而高速化又是开展的必然趋势，因为高速化可大大提高运行效率，同时可缩小泵的体积、减轻重量，从而大大提高泵运行的经济性，但对泵的可靠性提出了更高的要求。要求科学合理的设计方法，准确的设计精度，否那么会影响到泵使用的可靠性。泵在工作过程中，泵轴受力复杂，过去对泵

5、轴可靠性的计算和试验不多，缺乏成熟的计算方法。此次设计通过试验研究，分析泵轴失效的影响因素，论述了泵轴强度的计算方法，说明了提高泵轴刚度的措施，进一步完善了可靠性计算的理论。论文的主要内容：本文主要介绍泵轴的可靠性设计与试验，在泵轴失效的影响因素中首先讲述了单级离心抽油泵在工作过程中泵轴是如何失效以及失效的原因，接着是对泵轴可靠性试验的具体情况进行描述，其中先对设计工况状态下的扭转角及持久强度的试验，接着是零流量工况的挠度与转角试验，然后对两种状态下试验结果综合分析，对设计准那么和强度计算方法进行描述。最后介绍了提高泵轴可靠性的措施。二、 泵轴失效的影响因素泵轴失效是由于各种复杂载荷共同作用的

6、结果，而各种载荷的影响程度是不同的。（一） 单级离心泵结构特点单级离心泵包括泵体，泵盖，带输出轴的电动机，在泵体内装设的泵轴、轴承座、叶轮、机械密封和机封压盖，其特征在于，它还包括位于电动机输出轴与泵轴之间设置的对夹式联轴器，以及安装在轴承座上的以辅助支承泵轴的导轴承；所述对夹式联轴器分别与电动机输出轴和泵轴刚性连接，在电动机输出轴与泵轴之间留有便于机械密封和机封压盖装拆的空间距离。在维修或更换机械密封时，无须拆卸电动机及泵盖。（二） 作用在泵轴上的载荷泵在工作中，轴受到重力G、径向力Pt、轴向力A、离心力Pu及扭矩的作用。这些载荷与转速有关，其中径向力，轴向力和扭矩还与泵运行工况有关。由统计

7、和计算作出了零流量工况和设计工况在不同比转速时，重力、径向力和离心力的关系曲线见图2.1。图2.2给出了比转速与扭矩和轴向力的关系曲线图中所给数据均以80mm口径、用静强度确定的泵轴为例，Q=0为零流量工况，为设计工况。图2.1 与 的关系曲线图2.2 与A和的关系曲线（三） 泵轴内的应力泵轴内的应力与泵轴受力有关，一般产生在泵轴内的应力有弯曲、扭转和剪切等应力。静强度应力用表示，疲劳强度平安系数用表示，刚度分别用挠度转角和扭转角表示。图2.3给出了比转速与强度和平安系数的关系曲线，图2.4表示与挠度转角和扭转角的关系曲线。图2.3 与和的关系曲线图2.4 与 和的关系曲线（四） 泵轴失效特征

8、由图2.3、图2.4可知，在零流量工况或设计工况时，静强度无论用第三或第四强度理论计算，强度富裕量都很大。但在零流量工况时，会因疲劳强度、挠度、及转角达不到要求而失效。在设计工况时，会因扭转角满足不了要求而失效，如图中虚线所示。（五） 泵轴失效的因素及危险断面 在设计工况扭矩作用结果使扭转角满足不了要求，扭矩是设计工况泵轴失效的主要因素。在图2.5中，促使泵轴点扭转振动，引起口环磨损。在零流量工况，径向力作用结果使轴的挠度过大，最大挠度及转角发生在点，这将引起密封环磨损加快，所以涡形体内产生的径向力是零流量工况泵轴失效的主要因素。如果泵长期在零流量工况运行，泵轴在图2.5 点处会引起疲劳破坏。

9、图2.5 泵轴示意图三、 试验情况为检验泵轴持久强度和刚度对泵运行可靠性及效率的影响，用100CYZ65泵强度计算结果见表3.1在零流量和设计两种工况作了试验。表3.1 100CYZ-65泵两种工况的强度、刚度计算计算工程用第三强度理论计算MPa用第四强度理论计算MPa扭转角rad挠度m转角疲劳强度平安系数设计工况，零流量工况，（一） 设计工况的扭转角及持久强度试验1. 扭转角试验泵轴在级封闭试验台上按以下方法进行试验。每试验100h检测一次叶轮与口环的间隙，同时由控制台测出其效率值，结果如图3.1中曲线所示。图3.1 扭转角、挠度和转角与口环磨损关系2. 持久强度试验 对钢来说，轴经受次应力

10、循环后，如尚未断裂，那么可认为再增加循环次数试件也不会断裂。持久强度试验进行了260h运转，一切正常。（二） 零流量工况的挠度与转角试验试验方法与扭转角的试验方法相同，结果如图3.1中、曲线所示。 三实验结果泵在设计工况下运转，由于扭转角达不到刚度要求而引起振动，使口环在整个圆周上磨损。由挠度和转角引起口环磨损的主要磨损位置是在与隔舌成处实验结果与理论分析计算是一致的。四、 设计准那么与强度计算方法（一） 设计准那么泵的结构应能保证泵流量从零到最大值时都能可靠地工作。因此，要求泵轴在扭转和径向力作用下，挠度不应超过密封环内的间隙值；扭转角、转角不应超过许用值。也就是说，泵轴不仅要有足够的强度，

11、也要有足够的刚度。在实践中，泵轴满足静强度要求时，不一定能满足刚度要求；而在满足刚度要求时，那么一定能满足静强度要求。因此，仅以静强度为依据进行设计是不合理的，必须以刚度条件为设计的准那么。（二） 强度计算方法1. 扭转角 泵轴设计应根据扭矩作用下的刚度条件确定最小轴径，计算公式见4.1最大扭转角，最大扭矩。 由表4.1知，扭转角与轴功率、轴径尺寸有关，图4.1给出了相互关系曲线。当值取在曲线上方时，均能满足扭转角的刚度条件。表4.1 按刚度条件确定轴径的计算公式扭转角由 得 N*m (kW)N额定工况轴功率 kWn泵轴转速 r/minG材料抗剪弹性模量，取 (Pa) 精密机器的轴 =.025

12、0.50 一般传动的轴 =0.51.0 精度要求不高的轴 =12.5 图4.1 扭转角与轴功率、轴径临界曲线2. 挠度和转角的计算公式由设计工况的扭转角确定最小轴径和轴的形状及尺寸后，应对零流量工况的挠度和转角进行校核。最大挠度和转角的几何意义如图4.2所示。泵轴的挠度和转角计算公式见表4.2图4.2 泵轴最大挠度、转角示意图表4.2 泵轴挠度、转角计算公式挠度转角P重力、径向力和离心力的合力，NE弹性模量， (Pa)L二轴承跨距 ma叶轮重心到前轴承支点的距离 m ：一般用途的轴，=0.0003需要提高轴刚度时，=：滑动轴承，=0.001 rad 向心球轴承，=0.005 rad向心球面轴承

13、=0.05 rad圆柱滚子轴承=0.0025 rad圆锥滚子轴承=0.0016 rad3. 疲劳强度泵轴长期在零流量工况运行会引起疲劳破坏。疲劳强度计算公式见表4.3最大弯应力，最大剪应力。表4.3 泵轴疲劳强度计算公式疲劳强度平安系数 其中： Pa 其中： Pa不锈钢647MPa40 铬981MPa45号钢 598MPa：4静强度 在两向应力状态下，对塑性材料，试验资料说明：按第四强度理论计算的结果根本与实验结果相符。计算公式见表4.4、的几何意义如图4.3所示，、为最大主应力和最小主应力。表4.4 用第四强度理论计算泵轴静强度公式静强度PaPa：不锈钢32443140 铬49065445号

14、钢299399 MPa图4.3 泵轴应力图五、 提高泵轴刚度的措施从上述分析可知，泵轴的刚度缺乏是引起泵零件失效的主要原因之一。因此，提高刚度具有现实意义，具体措施如下：一 改良泵轴的结构形式，减少玩具数值弯矩是引起泵轴弯曲变形的主要因素，所以，减小作用在轴上的弯矩值，也就提高了轴的弯曲刚度。二 缩短跨度或增加支撑泵轴的挠度与轴两支承间的跨度的3次方成正比。如果跨度缩短为原来的，挠度那么减小为原来的，刚度提高非常显著。在轴的跨度不能缩短的情况下，可采取增加支承的方法提高轴的刚度。三选择合理的截面形状在材料一定的情况下，泵轴选用空心圆形截面形状，其刚度较好。 六、总结通过这次实践，我了解了离心泵

15、的结构、用途及工作原理，熟悉了离心泵轴的设计步骤，锻炼了工程设计实践能力，培养了自己独立设计能力。此次毕业设计是对我专业知识和专业根底知识一次实际检验和稳固，同时也是走向工作岗位前的一次热身。 毕业设计收获很多，比方学会了查找相关资料相关标准，分析数据，提高了自己的设计与制作能力，懂得了许多经验公式的获得是前人不懈努力的结果。同时，仍有很多课题需要后代去努力去完善。 脚踏实地，认真严谨，实事求是的学习态度，不怕困难、坚持不懈、吃苦耐劳的精神是我在这次设计中最大的收益。我想这是一次意志的磨练，是对我实际能力的一次提升，也会对我未来的学习和工作有很大的帮助。在这次毕业设计中也使我们的同学关系更进一

16、步了，同学之间互相帮助，有什么不懂的大家在一起商量，听听不同的看法对我们更好的理解知识，所以在这里非常感谢帮助我的同学。 在此更要感谢我的导师和专业老师，是你们的细心指导和关心，使我能够顺利的完成毕业论文。在我的学业和论文的研究工作中无不倾注着老师们辛勤的汗水和心血。老师的严谨治学态度、渊博的知识、无私的奉献精神使我深受启迪。从尊敬的导师身上，我不仅学到了扎实、宽广的专业知识，也学到了做人的道理。在此我要向我的导师致以最衷心的感谢和深深的敬意。参考文献：1 关醒凡 ?泵的理论与设计? 机械工业出版社 1987年2月2 浙江大学等 ?材料力学? 人民出版社 1981年4月3 顾志荣 吴永生 ?材

17、料力学学习方法及解题指导?第二版 同济大学出版社 2003年4月 319-3334庄东汉 ?材料失效分析? 华东理工大学出版社 2021年6月 147-2475 崔占全 孙振国 ?工程材料? 机械工业出版社 2007年9月 217-2326徐格宁 ?机械装备金属结构设计? 机械工业出版社 2021年9月 88-1267邱潇潇 ?工业设计材料与加工工艺? 高等教育出版社 2021年11月 8傅衣铭 ?材料力学? 湖南大学出版社 2007年1月 300-3109鄢国强 ?材料质量检测与分析技术? 中国计量出版社 2005年5月 381-40110孙新利 ?工程可靠性教程? 国防工业出版社 2005

18、年1月 7-1111北京科技大学 ?工程力学-材料力学?第4版 高等教育出版社 2021年1月 196-21612毛慧明 ?机械根底? 机械工业出版社致谢：在这次的毕业设计中，我要衷心地感谢我的指导老师陈茂庆老师，我从他身上学到了很多东西。他认真负责的工作态度，严谨的治学精神和深厚的理论水平都使我受益匪浅。尤其是认真负责的工作的态度，让我感到他是一位对我无私奉献的老师。无论在理论分析上，还是在实践指导中，他都给与我很大的帮助，使我得到不少的提高，这对于我以后的工作和学习都有很大的帮助。感谢他耐心的辅导与帮助，使我能够及时、顺利地完成此次的毕业设计，在这里表示衷心的感谢。在论文即将完成之际，我的

19、心情无法平静，从开始进入课题到论文的顺利完成，有多少可敬的师长、同学、朋友给了我无言的帮助，在这里请接受我诚挚的谢意！邱发有 2011年10 月 31日ag an employment tribunal clai Emloyment tribunals sort out disagreements between employers and employees. You may need to make a claim to an employment tribunal if: you dont agree with the disciplinary action your employer

20、has taken against you your employer dismisses you and you think that you have been dismissed unfairly. For more informu, take advice from one of the organisations listed underFurther help. Employment tribunals are less formal than some other courts, but it is still a legal process and you will need

21、to give evidence under an oath or affirmation. Most people find making a claim to an employment tribunal challenging. If you are thinking about making a claim to an employment tribunal, you should get help straight away from one of the organisations listed underFurther help. ation about dismissal an

22、d unfair dismissal, seeDismissal. You can make a claim to an employment tribunal, even if you haventappealedagainst the disciplinary action your employer has taken against you. However, if you win your case, the tribunal may reduce any compensation awarded to you as a result of your failure to appea

23、l. Remember that in most cases you must make an application to an employment tribunal within three months of the date when the event you are complaining about happened. If your application is received after this time limit, the tribunal will not usually accept i. If you are worried about how the tim

24、e limits apply to you If you are being represented by a solicitor at the tribunal, they may ask you to sign an agreement where you pay their fee out of your compensation if you win the case. This is known as adamages-based agreement. In England and Wales, your solicitor cant charge you more than 35%

25、 of your compensation if you win the case.youre clear about the terms of the agreement. It might be best to get advice from an experienced adviser, for example, at a Citizens Advice Bureau. To find your nearest CAB, including those that give advice by e-mail, click onnearest CAB.For more information

26、 about making a claim to an employment tribunal, seeEmployment tribunals.The (lack of) air up there Watch m Cay man Islands-based Webb, the head of Fifas anti-racism taskforce, is in London for the Football Associations 150th anniversary celebrations and will attend Citys Premier League match at Che

27、lsea on Sunday.I am going to be at the match tomorrow and I have asked to meet Ya ya Toure, he told BBC Sport.For me its about how he felt and I would like to speak to him first to find out what his experience was.Uefa hasopened disciplinary proceedings against CSKAfor the racist behaviour of their

28、fans duringCitys 2-1 win.Michel Platini, president of European footballs governing body, has also ordered an immediate investigation into the referees actions.CSKA said they were surprised and disappointed by Toures complaint. In a statement the Russian side added: We found no racist insults from fa

29、ns of CSKA.Age has reached the end of the beginning of a word. May be guilty in his seems to passing a lot of different life became the appearance of the same day; May be back in the past, to oneself the paranoid weird belief disillusionment, these days, my mind has been very messy, in my mind const

30、antly. Always feel oneself should go to do something, or write something. Twenty years of life trajectory deeply shallow, suddenly feel something, do it.一字开头的年龄已经到了尾声。或许是愧疚于自己似乎把转瞬即逝的很多个不同的日子过成了同一天的样子；或许是追溯过去，对自己那些近乎偏执的怪异信念的醒悟，这些天以来，思绪一直很凌乱，在脑海中不断纠缠。总觉得自己似乎应该去做点什么，或者写点什么。二十年的人生轨迹深深浅浅，突然就感觉到有些事情，非做不可

31、了。The end of our life, and can meet many things really do?而穷尽我们的一生，又能遇到多少事情是真正地非做不可？During my childhood, think lucky money and new clothes are necessary for New Year, but as the advance of the age, will be more and more found that those things are optional; Junior high school, thought to have a crus

32、h on just means that the real growth, but over the past three years later, his writing of alumni in peace, suddenly found that isnt really grow up, it seems is not so important; Then in high school, think dont want to give vent to out your inner voice can be in the high school children of the feelin

33、gs in a period, but was eventually infarction when graduation party in the throat, later again stood on the pitch he has sweat profusely, looked at his thrown a basketball hoops, suddenly found himself has already cant remember his appearance.童年时，觉得压岁钱和新衣服是过年必备，但是随着年龄的推进，会越来越发现，那些东西根本就可有可无；初中时，以为要有一

34、场暗恋才意味着真正的成长，但三年过去后，自己心平气和的写同学录的时候，突然就发现是不是真正的成长了，好似并没有那么重要了；然后到了高中，觉得非要吐露出自己的心声才能为高中生涯里的懵懂情愫划上一个句点，但毕业晚会的时候最终还是被堵塞在了咽喉，后来再次站在他曾经挥汗如雨的球场，看着他投过篮球的球框时，突然间发现自己已经想不起他的容颜。Originally, this world, can produce a chemical reaction to an event, in addition to resolutely, have to do, and time.原来，这个世界上，对某个事件能产生

35、化学反响的，除了非做不可的坚决，还有，时间。A persons time, your ideas are always special to clear. Want, want, line is clear, as if nothing could shake his. Also once seemed to be determined to do something, but more often is he backed out at last. Dislike his cowardice, finally found that there are a lot of love, there

36、 are a lot of miss, like shadow really have been doomed. Those who do, just green years oneself give oneself an arm injection, or is a self-righteous spiritual.一个人的时候，自己的想法总是特别地清晰。想要的，不想要的，界限明确，好似没有什么可以撼动自己。也曾经好似已经下定了决心去做某件事，但更多的时候是最后又打起了退堂鼓。嫌恶过自己的怯懦，最终却发现有很多缘分，有很多错过，好似冥冥之中真的已经注定。那些曾经所谓的非做不可，只是青葱年华里

37、自己给自己注射的一支强心剂，或者说，是自以为是的精神寄托罢了。At the moment, the sky is dark, the air is fresh factor after just rained. Suddenly thought of blue plaid shirt; Those were broken into various shapes of stationery; From the corner at the beginning of deep friendship; Have declared the end of the encounter that havent

38、 start planning. Those years, those days of do, finally, like youth, will end in our life.此刻，天空是阴暗的，空气里有着刚下过雨之后的清新因子。突然想到那件蓝格子衬衫；那些被折成各种各样形状的信纸；那段从街角深巷伊始的友谊；还有那场还没有开始就宣告了终结的邂逅方案那些年那些天的非做不可，终于和青春一样，都将在我们的人生中谢幕。Baumgartner the disappointing news: Mission aborted. r plays an important role in this miss

39、ion. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb

40、 higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence. We often close

41、ourselves off when traumatic events happen in our lives; instead of letting the world soften us, we let it drive us deeper into ourselves. We try to deflect the hurt and pain by pretending it doesnt exist, but although we can try this all we want, in the end, we cant hide from ourselves. We need to

42、learn to open our hearts to the potentials of life and let the world soften us.生活发生不幸时，我们常常会关上心门；世界不仅没能慰藉我们，反倒使我们更加消沉。我们假装一切仿佛都不曾发生，以此试图忘却伤痛，可就算隐藏得再好，最终也还是骗不了自己。既然如此，何不尝试翻开心门，拥抱生活中的各种可能，让世界感化我们呢？Whenever we start to let our fears and seriousness get the best of us, we should take a step back and re-

43、evaluate our behavior. The items listed below are six ways you can open your heart more fully and completely.当恐惧与焦虑来袭时，我们应该退后一步，重新反思自己的言行。下面六个方法有助于你更完满透彻地敞开心扉。Whenever a painful situation arises in your life, try to embrace it instead of running away or trying to mask the hurt. When the sadness stri

44、kes, take a deep breath and lean into it. When we run away from sadness thats unfolding in our lives, it gets stronger and more real. We take an emotion thats fleeting and make it a solid event, instead of something that passes through us.当生活中出现痛苦的事情时，别再逃跑或隐藏痛苦，试着拥抱它吧；当悲伤来袭时，试着深呼吸，然后直面它。如果我们一味逃避生活中的

45、悲伤，悲伤只会变得更强烈更真实悲伤原本只是稍纵即逝的情绪，我们却固执地耿耿于怀By utilizing our breath we soften our experiences. If we dam them up, our lives will stagnate, but when we keep them flowing, we allow more newness and greater experiences to blossom.深呼吸能减缓我们的感受。屏住呼吸，生活停滞；呼出呼吸，更多新奇与经历又将拉开序幕。2. Embrace the uncomfortable We all k

46、now what that twinge of anxiety feels like. We know how fear feels in our bodies: the tension in our necks, the tightness in our stomachs, etc. We can practice leaning into these feelings of discomfort and let them show us where we need to go.我们都经历过焦灼的煎熬感，也都感受过恐惧造成的生理反响：脖子僵硬、胃酸翻腾。其实，我们有能力面对这些痛苦的感受，从

47、中领悟到出路。The initial impulse is to run away to try and suppress these feelings by not acknowledging them. When we do this, we close ourselves off to the parts of our lives that we need to experience most. The next time you have this feeling of being truly uncomfortable, do yourself a favor and lean in

48、to the feeling. Act in spite of the fear.我们的第一反响总是逃避以为否认不安情绪的存在就能万事大吉，可这也恰好阻碍了我们经历最需要的生活体验。下次感到不安时，不管有多害怕，也请试着勇敢面对吧。3. Ask your heart what it wants倾听内心Were often confused at the next step to take, making pros and cons lists until our eyes bleed and our brains are sore. Instead of always taking this

49、approach, what if we engaged a new part of ourselves that isnt usually involved in the decision making process?我们常对未来犹疑不定，反复考虑利弊直到身心俱疲。与其一味顾虑重重，不如从局外人的角度看待决策之事。The supersonic descent could happen as early as Sunda.The weatheThe balloon will slowly drift to the edge of space at 120,000 feet (Then, I

50、would assume, he will slowly step out onto something resembling an Olympic diving platform.Below, the Earth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, hell be traveling fast, so despite the distance, it will not be like diving into the deep end

51、of a pool. It will be like he is diving into the shallow end. Skydiver preps for the big jumpWhen he jumps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches the more dense air closer

52、to Earth. But this will not be enough to stop him completely.If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes its not needed. Instead, he plans to deploy his 270-square-foot (25-square-meter) main chute at an altitude

53、 of around 5,000 feet (1,524 meters). In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds.Even if everything goes as planned, it wont. Baumgartner still will free

54、 fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters).cause there9JWKffwvG#tYM*Jg&6a*CZ7H$dq8KqqfHVZFedswSyXTy#&QA9wkxFyeQ!djs#XuyUP2kNXpRWXmA&UE9aQGn8xp$R#͑GxGjqv$UE9wEwZ#QcUE%&qYpEh5pDx2zVkum&gTXRm6X4NGpP$vSTT#&k

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