1、外文翻譯譯文 1：氣液兩相流在小直徑斜管內的特征研究原文 1：Characteristics of gasliquid two-phase flow in small diameterinclined tubes譯文 2：氣液兩相在毛細內的特征研究原文 2：Characterization of gasliquid two-phase flow inside capillaries原文 1Characteristics of gasliquid two-phase flow in small diameterinclined tubesAbstract Flottern and the bub

2、ble velocity in 28 mm diameter inclined tubeswere studied in the present work. Experimental Observations showt the flowpattern is elongated bubble flow and no small dispersed bubbles exist in the liquidslug in conditions of 0.1680.672m/s superfil liquid velocity and 0.040.32m/ssuperfil gas velocity.

3、 The shof the gas slug in tube is influenced by thediameter of tube, the flow rate, and the inclination angle. Furthermore, the length of gas slug increases with the superfil gas velocity. The length of gas slug in theinclined tube is longernthe vertical or horizontal tube, and the gas slugvelocity

4、in the inclined tube is fasternt.he vertical or horizontal tube. 2001 Elsevier Science.sKeywords: Two-phase flow; Small diameter; inclined tube1.roductionGas sparing is an effective method for decreasing the filtrationofconcentration polarization and enhancing the permeate flux in a membrane ultrafi

5、ltration pros (Lee, Chang, & Ju, 1993; Cui & Wright, 1994, 1996; Cabad,Laborie, & Laine, 1997; Mercier, Fonade, & Laffue-Delorme, 1997; Cheng, Yeh,& Gau, 1998). Theroduction of air slugo the liquid stream of filtration couldincrease turbulence on the membrane surface and suppress the formation of th

6、e concentration boundary layer, leading to an enhancementhe flux of the filtrationpros. This method is suitable for the pros operated in a horizontally or avertically installed membrane. Recent study (Cheng, Yeh, & Wu, 1999) has shown t the enhancement in flux by gas slug in an inclined tubular memb

7、rane is moresignificantnt in a horizontal or vertical tube. Therefore, the characteristics ofgasliquid two-phase flowhe tube are important in relation to the performance ofan ultra filtration operated in an inclined tubular membrane. The diameter of hollowfiber or tubular ultra filtration membrane i

8、s usuallyhe order of millimeters. Mostof the flow regime studies on gasliquid two-phase flow have dealt with either horizontal or vertical tubes, and limited results have been reported for inclined tubes with large diameter.The flow pattern of gasliquid two-phase flow in small diameter tube, in theh

9、orizontal or vertical orienion, has been measured by Barnea,inski, and Tai(1983).Four flotterns (stratified,ermittent, annular, and dispersed bubble) havebeen characterized for the horizontal tube according to the superfil liquid velocityand the superfil gas velocity, while three flotterns (ermitten

10、t, annular, anddispersed bubble) have been characterized for the vertical tube. Theermittentpat-tern includes elongated bubble, slug and churn flow patterns. The distinction ist the elongated bubble flottern is considered the limiting case of the slug flowwhen the liquid slug is free of entrained ga

11、s bubbles. The churn flow is known as the gas slug bubbles are deformed and do not have a spherical nose any more. Theexperimental result showedt the slug flow existshe flow rate range of uG he in for d,5m/s and uL1.0m/s in a 4-mm vertical tube. A similar result was also shownwork of Mishima and Hib

12、iki (1996). The capillaries of 14 mm inner diameter show valuesofinjectionratiovaryingbetobservations of two-phase flow t the flow pattern was slug flow n 0.17and0.67 (Laborie,CabaDurand-Bourr, & Laine, 1999). The hydrodynamics identification of slug flow inthe vertical tubes showedt the flux enhanc

13、ement was due to an increasehe wallshear stress as well as other hydrodynamic phenomena:ermittency, reversal of thewall shear stress, Instantaneous prere variations, and an enhanced local mixing(Mercier-Bonin, Maranges, Laffue, & Fonade, 2000).The investigations on the flow pattern of gasliquid upwa

14、rd flow in inclinedtubes with larger diameter(10 mm) notedt the inclination of tube affects theflottern transitions(Spedding & Nguyen,1980; Barnea, Shoham, & Tai, 1980;Weisman &Kang, 1981; Barnea, Shoham, Tai, & Dukler, 1985;Stanislav, Kokal, &Nicholson, 1986). It is noticeablet small angular deviat

15、ion from the horizontal hasa significant influence on the transition from stratified toermittent or annular flow pattern (Barnea et al., 1985). Some researches (Wallis, 1969; Bendiksen, 1984;Maxworthy, 1991; Carew, Thomas, &Johnson, 1995) show slug bubble in inclined tube or rectangular channel is h

16、igher in vertical one. Due to the higher rise velocity of bubblet the rise velocity ofnt in horizontal orhe inclined tube, the rateof mass transfer (Nigandit, & Niranjan, 1995) or heat transfer (Hetsroni et al.,1998)he inclined tube system is highernt itical or horizontal one.However, the study on t

17、he flow regime fasliquid two-phase flow in an inclinedtube with small diameter is still lacking in literature. It is the subject of this study to investigate flo tterns and characteristics of two-phase flow in an upward inclined, small diameter tube. Experimental measurements were obtained for vario

18、us tube inclinations and tube diameters.2. Result and discussFor the range of flow rate and tube diameter usedhe tests, observations made ttern is elongated bubbleunder various inclinations of tubes showedt the floflow and no small dispersed bubbles exist in liquid slug. The present observations inv

19、ertical or horizontal tubes agree with the flottern maps proed by Barnea et al.(1983). The transition from one flow pattern to another is usually linked to the airinjection ratio. The study of Laborie et al. (1999) showedt the slug flow exists asair injection ratio varying betn 0.2 and 0.9.The resul

20、t from this work showedt for slug flow is as low as 0.06. Furthermore, ourthe range of air injection observations also showedratioa specified flow rate the shof gas slug and theradialition of gas slughe tube are influenced by the inclination angle and thediameter of the tube.The thickness of the liq

21、uid film around the gas slug was not measuraby thepresent visualization, however, the lengths of gas slug and liquid slug, and the frequency of gas slug can be measured from the images when reproduced in slowmotion buhigher liquid velocity (uL=0.672 m/s). About adred gas slugs and adred liquid slugs

22、 were measured for obtaining the mean lengths of gas slug, LG, and liquid slug, LL, as well as the slug frequency.3.sCharacteristics of gasliquid two-phase flow in 28 mm diameter inclined tubes wereinvestigated and measured under variouperfil liquid velocities and superfilgas velocities. The flotter

23、n is elongated bubble flow for the range of conditionsexamined and no small dispersed bubbles are detectedhe liquid slug. The shofgas slug varies with the diameter of tube, the flow rate as well as the inclination angle.Our result show the range bett the ratio of gas slug velocity over the mean flow

24、 velocitys inn 1.0 and 2.0. This range is largernt proed by Mishima andHibiki (1996). It also confirmst the gas slug velocity in an inclined tube is highernt itical or horizontal tube.Tung-Wen Cheng, Ta-Li LinDepartment of Chemical Engineering, Tamkang University, Tamsui, Taipei 251, ROC譯文 1氣液兩相流在小直

25、徑斜管內的特征研究摘要:目前的工作是研究直徑為 2-8 毫米斜管內的流型和速度。實驗觀測結果表明，該流型是在條件 0.168-0.672m/s 的表面液速度和在 0.04-0.32m/s 的表面氣體速度下細長的泡狀流和液塞內沒有小分散。在管中氣體塞的形狀是由管的直徑，流量和傾角影響的。此外，氣體塞的長度隨著表面的氣體速度的增加而增加。氣體塞的長度在斜管，比垂直或水平管的長，氣體塞在斜速度遠快于在垂直或水平管。：兩相流；小直徑；斜管1. 引言氣體噴射是一種有效減少過濾阻力的濃差極化和在膜超濾過程中提高滲透通量的方ee，Chang 與 Ju，1993 年；Cui 和 Wright，1994 年，1

26、996 年；Cabad，Laborie 和 Laine，1997 年；Mercier，Fonade 和 Laffue-Delorme，1997 年；Cheng，Yeh 和 Gau，1998 年）。引入過濾過的氣塞進液流可以增加湍流膜表面的形成和抑制濃度邊界層，從而通量在不斷變換的過濾過程中增強。這種方法適用于在一個水平或垂直安裝的膜流程操作。最近的研究（Cheng，Yeh和 Wu，1999 年）表明，氣體塞的通量在一個斜管式內比在水平或垂直管內更加顯著。因此，管中氣液兩相流的特點，對于在一個斜管式內膜性能的超濾操作是很重要的。中空超濾膜或管狀的直徑通常是以毫米為的。大多數氣液兩相流的流態研究都

27、是在水平或垂直管內處理的，以及有限的結果都證明了斜徑太大。在小直徑管內，水平或垂直方向的氣液兩相流的流型，已經被 Barnea，inski 和 Tai（1983 年）測量。四個流模式(分層，間歇，環形，分散)的特點是根據水平管表面液速度和表面的氣流速度判定的，雖然三個流模式(間歇，環形，分散)的特征一直是垂直管。間歇模式包括細長的，模式和流失。區別是，當液塞是夾帶的氣泡時，伸長的泡狀流模式被認為是極限情況的彈狀流。而被稱為氣體塞的渦流是畸形的，甚至完全沒有一個球形的鼻子。實驗結果表明，活塞流存在于流量范圍在 uG5m/s 和 uL10 毫米)的流型結果指出，是由傾斜管影響流模式的轉換（Sped

28、ding 和 Nguyen，1980 年；Barnea，Shoham和 Tai，1980 年；Weisman 和 Kang，1981 年；Barnea，Shoham，Tai和 Dukler，1985 年；Stanislav，Kokal 和 Nicholson，1986 年）。值得注意的是，對于小角偏離水平過渡到間歇或環狀流的分層模式有顯著的影響（Barnea 等，1985 年）。一些研究（Wallis，1969 年；Bendiksen，1984 年；Maxworthy，1991 年；Carew，Thomas 和 Johnson，1995 年）表明，彈頭在斜管或矩形通道的上升速度是高于水平或垂直

29、上的。由于在斜管具有更高的上升速度,更快的傳質速率（Nigandit 和 Niranjan，1995 年）或更好的傳熱（Hetsroni 等，1998 年），所以上升速度在斜管系統高于垂直或水平管系統。然而，這項在一個小直徑斜管內氣液兩相流流態的研究在文學上還是比較缺乏的流模式和小直徑管氣液兩相流向上傾斜的特點是這項研究的。實驗測量結果顯示，均獲得各種管傾向和徑。2. 結果和分析對于在測試范圍內的流速和管徑，觀察不同傾向的管子表明，流模式是細長的泡狀流和在液塞內沒有發現小分散。目前通過在垂直或水平管的觀測，同意了 Barnea 等人（1983 年）模式。從一個流模式過渡到另一個通常是聯系到空氣

30、噴射比率的模式。Laborie 等人(1999 年)研究表明，彈狀流通常存在于空氣注入比在 0.2 和 0.9 之間。結果表明，空氣噴射的范圍比彈狀流是低了 0.06。此外，觀察還顯示，在管內指定流量的形狀彈頭和徑向位置氣體的氣體彈頭是受傾角和管的直徑的影響。不能僅靠視覺來衡量圍繞在氣彈頭上的液膜厚度，但是，可以從慢鏡頭的中測量氣彈頭和液塞的長度，還有氣彈頭的頻率，除了更高的液體流速（uL=0.672m/s）外。通過差不多一百的氣彈頭和一百的液塞測量可獲得平均長度的氣彈頭，LG，平均長度的液塞，LL，以及氣彈頭和液塞的頻率。3. 結論通過觀察2-8 毫米直徑斜管內氣液兩相流的特征和測量在不同表

31、面液速度和表觀氣速下氣液兩相流的特征。在條件允許的范圍內流模式是細長的泡狀流和在液塞內沒有發現小分散。氣彈頭的形狀與管的直徑，流量以及傾角有關。我們的結果表明，該氣彈頭的速度比率超過了平均流速，范圍在 1.0 和 2.0 之間。這范圍比由 Mishima 和 Hibiki(1996)提出。它還證實了氣體塞速度在一個斜管是高于垂直或水平管的。作者：Tung-Wen Cheng出處：Department of Chemical Engineering國別：中國原文 2Characterization of gasliquid two-phase flow inside capillariesAbs

32、tract Continuous gas sparging inside ultra filtration hollow fibers (with the feed)has been shown to be effective in enhancing permeate flux by reducing particledeit on the membrane wall. The present study focuses on the hydrodynamiccharacterization of gasliquid two-phase flow inside glass capillaries in order tounderstand the mechanisms involved in the pros improvement. In capillaries ofinner diameter less slug flow: a sucn 410