2023年全國碩士研究生考試考研英語一試題真題(含答案詳解+作文范文)_第1頁
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1、<p><b>  外文資料</b></p><p>  High-handed intercourse pump characteristic</p><p>  High pressure between 100 MPa moving back and forth responding to like pump sigmatism pressure in

2、 10 MPa . It belongs to volume dyadic pump , the purpose drawing support from volume inside the cavity working coming to reach transportation liquid cyclicity change; The prime mover mechanical energy can by that the pum

3、p changes into the pressure transporting liquid's directly; Only, the pump capacities depend on job cavity volume changing value and their change number of times within unit time , ha</p><p>  Microtime

4、rate of flow is systolic.</p><p>  This is in the pump because of being moving back and forth, and liquid medium sucking in discharging process being to be in progress alternately, and the piston can't b

5、e in field change ceaseless in displacement process middle , whose speed among. In the pump only having a cavity working, not only the pump microtime rate of flow vary with with time, and be discontinuous. With job cavit

6、y increasing by, microtime rate of flow pulsation extent is more and more small, and even pragmatic upper not ba</p><p>  Average rate of flow is constant</p><p>  Theoretically, the pump rate o

7、f flow depends on main pump structure physics , chemical property independences such as parameter n (every minute intercourse number of times) , S (piston travel) , D (piston diameter) , Z (piston number) , the temperatu

8、re , viscosity with the independence discharging pressure, and with transporting medium only. Therefore saying a pump's, rate of flow is constant.</p><p>  The pump pressure depends on pipeline character

9、istic property</p><p>  Unable pressure been to depend on a pump unit because the pump sets a limit for per se, pipeline characteristic property, has nothing to do with rate of flow pump snapout moving back

10、and forth moreover. Just say, if thinking that transporting liquid is incompressible,in terms of theory think that pump moving back and forth's discharge pressure will not accept any restricting , be OK to discharge

11、pressure according to the pump unit pipeline characteristic property , the what any needs building a </p><p>  Have stronger adaptability to transporting medium</p><p>  The pump moving back and

12、 forth can transport any medium , physics function and chemistry function restricting hardly accepting medium in principle. Certainly, since hydraulic whole course of restricts as well as material and the manufacturing e

13、ngineering sealing off a technology's, also may come across the condition being able to not fit in with sometimes.</p><p>  Have fine self attracts a function.</p><p>  The pump moving back

14、and forth has fine sucking in not only function, and there are still fine self attracts a function. Have no need of irrigation pump therefore , to the pump moving back and forth most, generally before starting.</p>

15、<p>  Machine efficiency height , energy conservation.</p><p>  High-handed intercourse pump rate of flow</p><p>  The pump theory rate of flow: Qt = AsnZ</p><p>  Style is h

16、it by Qt pump theory rate of flow; A bar piston (or section of piston) area; S route or distance of travel; The n crank shaft rotation rate (or the bar piston every minute intercourse number of times) Z unites a number (

17、bar piston or piston number)</p><p>  Actual pump rate of flow: Q = Qt-Q.</p><p>  Style is hit by Q pump rate of flow; Qt pump theory rate of flow; The pump rate of flow loses Q.</p><

18、;p>  The factor that the rate of flow bringing about a pump loses has: The volume bringing about since liquid compresses or expands is lost; The volume bringing about since the valve lags when being closed down is los

19、t; Since the valve closes the day afer tomorrow do not lose strictly, by sealing off the volume that leakage soft and floury brings about; The volume by the fact that the bar piston , piston rod or the piston ring leakag

20、e bring about is lost.</p><p>  The pump microtime rate of flow</p><p>  Single cylinder Shan effect pump rate of flow curve: </p><p>  Three jar Shan effects pumps rate of flow is

21、the single cylinder Shan effect pump rate of flow overlying on three phases</p><p>  Whose curve as follows: </p><p>  The pump power</p><p>  The pump effective power: The energy t

22、hat the inner , the liquid being discharged by the pump gain time the unit from the pump is called an effective power.</p><p><b>  Ne=PQ </b></p><p>  In style, the Ne effective pow

23、er , P satisfy pressure , Q rate of flow</p><p>  Unit queen formula becomes substitution:</p><p>  Ne(KW)=1/36.7×P(Kgf/cm2)×Q(m3/h)。The power thinking that the temperature rises to a

24、ctuator efficiency , machinery friction , volumetric efficiency , medium waiting for cause to bring about loses , chooses the pump moving back and forth when prime mover power, to low pressure, N=1/(0.85~0.9)N;</p>

25、<p>  To high-handed the pump moving back and forth , N = 1/ (0.75 ~ 0.85) N.</p><p>  The pump application range moving back and forth</p><p>  The pump moving back and forth applies to

26、high-handed small rate of flow mainly , requires that the pump rate of flow is constant or the quantify , proportionality transport various different medium , demands occasion to suck a function in well, or demands to th

27、ere is self attracting a function's or. Under in the nowadays world sources of energy is short-supplied circumstances, the pump moving back and forth is the energy conservation product, the mine has exploited , petro

28、leum has got in a lot </p><p><b>  中文翻譯</b></p><p><b>  高壓往復(fù)泵的特點(diǎn)</b></p><p>  高壓往復(fù)泵的使用壓力一般應(yīng)在10MPa~100MPa之間。它屬于容積式泵,借助工作腔里的容積周期性變化來達(dá)到輸送液體的目的;原動機(jī)的機(jī)械能經(jīng)泵直接轉(zhuǎn)化為輸送液

29、體的壓力能;泵的容量只取決于工作腔容積變化值及其在單位時(shí)間內(nèi)的變化次數(shù),理論上與排出壓力無關(guān)。往復(fù)泵是借助于活塞在液缸工作腔內(nèi)的往復(fù)運(yùn)動(或通過隔膜、波紋管等撓性元件在工作腔內(nèi)的周期性彈性變形)來使工作腔容積產(chǎn)生周期性變化的。在結(jié)構(gòu)上,往復(fù)泵的工作腔是借助密封裝置與外界隔開,通過泵閥(吸入閥和排出閥)與管路溝通或閉合。其特點(diǎn)歸納如下:  瞬時(shí)流量是脈動的     這是

30、因?yàn)樵谕鶑?fù)泵中,液體介質(zhì)的吸入和排出過程是交替進(jìn)行的,而且活塞在位移過程 中,其速度又在不斷地變化之中。在只有一個工作腔的泵中,泵的瞬時(shí)流量不僅隨時(shí)間而變化,而且是不連續(xù)的。隨著工作腔的增多,瞬時(shí)流量的脈動幅度越來越小,乃至在實(shí)用上可以認(rèn)為是穩(wěn)定流。  平均流量是恒定的 理論上,泵的流量只取決于泵的主要結(jié)構(gòu)參數(shù)  n(每分鐘往復(fù)次數(shù))、S(活塞行程)、D(活塞直徑)、Z(活塞數(shù)目),與排出壓力無關(guān),

31、且與輸送介質(zhì)的溫度、粘度等物理、化學(xué)性質(zhì)無關(guān)。所以說</p><p>  泵的壓力取決于管道特性往復(fù)泵的排出壓力不能由泵本身限定,而是取決于泵裝置的管道特性,并且與流量無關(guān)。 也就是說,如果認(rèn)為輸送液體是不可壓縮的,那么,在理論上可認(rèn)為往復(fù)泵的排出壓力將不受任何限制,即可根據(jù)泵裝置的管道特性,建立泵的任何所需的排出壓力。當(dāng)然,所有往復(fù)泵都有一個泵的排出壓力的規(guī)定,這不是說該泵的排出壓力不會再升高,而只

32、是說,由于原動機(jī)額定功率和泵本身的結(jié)構(gòu)強(qiáng)度的限制,不允許在超出這一排出壓力下使用而己。     對輸送介質(zhì)有較強(qiáng)的適應(yīng)性     往復(fù)泵原則上可以輸送任何介質(zhì),幾乎不受介質(zhì)的物理性能和化學(xué)性能的限制。當(dāng)然,由于液力端的材料和制造工藝以及密封技術(shù)的限制,有時(shí)也會遇到不能適應(yīng)的情況。 有良好的自吸性能。 往復(fù)泵不僅有良好的

33、吸入性能,而且還有良好的自吸性能。因此,對多數(shù)往復(fù)泵來說,在啟動前通常不需灌泵。 機(jī)器效率高,節(jié)能。  高壓往復(fù)泵的流量泵的理論流量:Qt=AsnZ 式中Qt泵的理論流量; A柱塞(或活塞)的截面積;S行程; n曲軸轉(zhuǎn)速(或柱塞的每分鐘往復(fù)次數(shù))Z聯(lián)數(shù)(柱塞或活塞數(shù)) 泵的實(shí)際流量:Q=Qt-Q。 式中Q泵的流量; Q</p><p>

34、  三缸單作用泵的流量是單缸單作用泵的流量在三個相位上的疊加其曲線如下: </p><p>  泵的功率泵的有效功率:單位時(shí)內(nèi),被泵排出的液體從泵獲得的能量稱為有效功率。Ne=PQ       式中    Ne有效功率, P全壓力, Q流量。代入單位后公式變?yōu)椋篘e(KW)=1

35、/36.7×P(Kgf/cm2)×Q(m3/h)??紤]到傳動裝置的效率、機(jī)械摩擦、容積效率、介質(zhì)溫升</p><p>  等原因造成的功率損失,選擇原動機(jī)功率時(shí),對低壓往復(fù)泵,N=1/(0.85~0.9)N;對高壓往復(fù)泵,N=1/(0.75~0.85)N。</p><p>  往復(fù)泵的應(yīng)用范圍    往復(fù)泵主要適用于高壓小流量

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