跳到主要內容

臺灣博碩士論文加值系統

(44.200.194.255) 您好!臺灣時間:2024/07/18 14:24
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果 :::

詳目顯示

: 
twitterline
研究生:龔育諄
研究生(外文):Yu-Chen Kung
論文名稱:傾斜矩形管中流體經多圓柱質源之質混合對流研究
論文名稱(外文):The Study of Mixed Solutal Convection in the Duct Flow Passing Through an Inclined Channel with Multiple Cylinder Sources
指導教授:王立文王立文引用關係
指導教授(外文):Lin-Wen Wang
學位類別:博士
校院名稱:元智大學
系所名稱:機械工程學系
學門:工程學門
學類:機械工程學類
論文種類:學術論文
論文出版年:2003
畢業學年度:91
語文別:英文
論文頁數:142
中文關鍵詞:質混合對流極限電流電化學系統
外文關鍵詞:Mixed solutal convectionElectrochemical SystemLimiting CurrentCylinders
相關次數:
  • 被引用被引用:0
  • 點閱點閱:299
  • 評分評分:
  • 下載下載:10
  • 收藏至我的研究室書目清單書目收藏:0
在對流現象的研究上,自然、混和、強制對流三種機制常為學術研究上的重點,其中以混和對流因兼備其他兩者效應而常被提出來討論。本實驗研究是將多圓柱狀質源之質量傳遞引入矩形管道主流中,在不同的傾斜角度、強制對流效應以及銅板與圓柱間的陰陽極性變化在極限電流的情況下來進行質混合對流研究。由於大多的研究都是在探討群體圓柱間的純流力研究,或是以數值分析來模擬圓柱加熱下的流場現象,對於研究質混合對流的相關實驗是非常少的。
在做相關的研究時,研究群體圓柱間的排列方式與位置是必要的,所以在本實驗中,第三章所探討的是單圓柱與雙圓柱在上下極板間不同距離下的研究,並且觀察圓柱在靠近極板時的流場現象。第四章所要探討的是多圓柱在不同的間距比下的流場研究,並且量測質傳遞率與雷諾數的關係。至於質傳遞率量測方面,固定傾斜角時,在不同邊界條件下,質傳遞率Sherwood數隨Reynolds數的增加而增加。當我們增加間距比(h/l)從0.88到1.5,對於固定雷諾數的情況下,此時所對應的Sherwood值會有反比的趨勢。由此可知在h/l=0.88的時候有最佳的熱傳遞率,也就是說最佳的群體排列方式以正三角形的幾何形狀最好。這個推測與文獻中所探討在熱混合對流的數值模擬研究中有相同的結果。
本實驗使用的工作流體為硫酸銅水溶液(CuSO4 + H2SO4 + H2O),藉由電化學系統於測試區(test section)之銅板與水道中之銅柱加上端電壓,使其成為電極,達成濃度梯度之建立。
本實驗採用雷射光暗影法(shadowgraph)作流場結構觀察及照相記錄,實驗的無因次參數範圍如下:Pr=5~7, Ar=1, Sc=1700~2400, Re=50~300, Grm = 1.88×105 (Red=7.94 ~ 47.64, Grm* = 4378), h/l=0.88~1.5, l/H=0.4~0.5, d/H=0.125 and d/G=0.45~0.9, θ=0°~15°.
This doctoral thesis is the research on the mixed solutal convection in the duct flow passing through an inclined channel with multiple cylinder sources. Seldom research can be found on this subject. With the mass transport factor on the channel flow, the flow patterns have become more complex. The fluids from the anode or the cathode are denser or less dense so that they do not match the flow patterns in the pure fluid dynamics. In order to observe the cylinders effects inside the channel, a series of the boundary conditions concerning about the cylinders will be involved. Although the Reynolds numbers in this research are from 50 to 300, the complete natural convection, mixed convection and forced convection are presented in the flow patterns. Besides changing the Reynolds numbers, the gap ratio effects of the cylinders on the inclined channel are also investigated.
Some investigations about the mass transfer rate are also clearly found. First, with increasing the Reynolds number, the corresponding Sherwood number is increasing, for the Reynolds number is directly proportional to the Sherwood number. Second, with increasing the height-to-gap ratios (h/l) from 0.88 to 1.5 for the fixed Reynolds number, the corresponding Sherwood number is inversely proportional. It is because the equilateral triangle cylinders arrangement is the best design on the mass transfer. Finally, the Sherwood number is inversely proportional to the electrode area on the cathode. Therefore, the larger the area on the cathode is, the smaller Sherwood number can be.
An experimental study of mixed convection with CuSO4+ H2SO4 + H2O solution in the inclined channel is performed. The shadowgraph technique is used to visualize the flow and to determine the nature and effect of solutal driven secondary flows in the inclined channel with the multiple cylinder sources inside. The ranges of the parameters in the present work are Pr=5~7, Ar=1, Sc=1700~2400, Re=50~300, Grm = 1.88×105 (Red=7.94 ~ 47.64, Grm* = 4378), h/l=0.88~1.5, l/H=0.4~0.5, d/H=0.125 and d/G=0.45~0.9, θ=0°~15°.
Chinese Abstract………………………………….……….....i
English Abstract.………………………………….………....ii
Acknowledgments……………….…………………..…………...iii
Table of Contents..…….………………………..……….…..iv
List of Figures…..………………………………………….…...vi
Nomenclature…………………………...………….…………...xii
Chapter Page
Chapter I Introduction…………………………………….………….1
1.1 Motivation………….…………………………………………......1
1.2 Related Past Work………….…………………….………......2
1.3 Objectives……………………………………..…………………..7
Chapter II Experimental Design……………………..……...……….8
2.1 Coordinate Setup………………………………………….……....8
2.2 Governing Equation………………………………….…….…..….8
2.3 Parameters with Migration Effect……………….……...…....8
2.4 Dimensional Parameters…………………………………..………9
2.5 Fluid Cyclic System…………………………………..….…....10
2.6 Electrochemical System…………………………..…...........11
2.7 Laser Optical System...................................12
2.8 Definition of the Parameters..…………..…………….....12
2.8.1. Definition of the Reynolds Number.…..……….……….12
2.8.2. Definition of the Solutal Grashof Number………………….13
2.8.3. Definition of the Sherwood Number.……....………..13
2.8.4. Definition of the Limiting Current ...……….………...13
2.9 Experimental Procedure…...……………………..……...15
Chapter III The Flow Patterns of Single and Two Cylinders…..16
3.1 The Flow Patterns of Case (A)…………………………..…....16
3.2 The Flow Patterns of Case (B)…………………………..…....19
3.3 The Flow Patterns of Case (C)…………………………..…....23
Chapter IV Results and Discussions of Three Cylinders........28
4.1 Part I-Horizontal Channel θ=0°...................28
4.1.1. The Flow Patterns of Case (A)……………………….28
4.1.2. The Flow Patterns of Case (B)…………………………30
4.1.3. The Flow Patterns of Case (C)…..……..……………....32
4.1.4. The Flow Patterns of Case (D)……...….……………….34
4.2 Part II-Uphill Channel θ=15...........................37
4.2.1 The Flow Patterns of Case (A)……………………37
4.2.2 The Flow Patterns of Case (B)…………………...…39
4.2.3 The Flow Patterns of Case (C)…..……………...…41
4.2.4 The Flow Patterns of Case (D)……………………43
4.3 Part III-Downhill Channel θ=-15..................46
4.3.1 The Flow Patterns of Case (A)…............………...46
4.3.2 The Flow Patterns of Case (B)……………….…….….48
4.3.3 The Flow Patterns of Case (C)….......................50
4.3.4 The Flow Patterns of Case (D)……....................52
4.4 Mass Transfer Rate……………………………………….……..55
4.4.1 The Correlation of the Re and Sh in Case (A)…...…....55
4.4.2 The Correlation of the Re and Sh in Case (B)……….…….55
4.4.3 The Correlation of the Re and Sh in Case (C)……...…..56
4.4.4 The Correlation of the Re and Sh in Case (D).…...…..57
Chapter V Conclusions and Future Works.................58
References……………...………………….…….....60
1. K.C. Cheng and G. J. Hwang, Numerical solution for combined free and forced laminar convection in horizontal rectangular channels. Journal of Heat Transfer, vol. 91, pp.59-66, 1969.
2. F. C. Chou and G. J. Hwang, Combined free and forced laminar convection in horizontal rectangular channels for high ReRa, Can. J. Chem. Eng., vol.62, pp.830-836, 1984.
3. M. Iqbal and J. W. Stachiewicz, Influence of tube orientation on combined free and forced laminar convection in inclined tubes, App. Scient. Res., vol. 27, pp.19-38, 1966.
4. K. C. Cheng and S. W. Hong, Combined forced and free laminar convection in inclined tubes, App. Scient. Res., vol. 27, pp19-38, 1972.
5. K. Futagami and F. Abe, Combined forced and free convection heat transfer in an inclined tube (1st report, laminar region), Trans. Japan. Soc. Mech. Engrs, vol. 38, pp.1799-1811, 1972.
6. J. W. Ou, K. C. Cheng and R. C. Lin, Combined free and forced laminar convection in inclined rectangular channels, Int. J. Heat Transfer, vol. 19, pp.277-283, 1972.
7. K. C. Cheng, S. W. Hong and G. J. Hwang, Buoyancy effects on laminar heat transfer in the thermal entrance region of horizontal rectangular channels with uniform wall heat flux for large Prandtl number field, Int. J. Heat Mass Transfer. Vol. 15, pp. 1819-1836, 1972.
8. J. W. Ou, K. C. Cheng, and R. C. Lin, Natural convection effects on Graetz problem in horizontal rectangular channels with uniform wall temperature for large Pr, Int. J. Heat Mass Transfer, vol. 17, pp.835-843, 1974.
9. C. A. Hieber and S. K. Sreenivasan, Mixed convection in an isothermally heated horizontal pipe, Int. J. Heat Mass Transfer, vol. 17, pp. 1337-1348, 1974.
10. J. W. Ou and K. C. Cheng, Natural Convection effects on Graetz problem in horizontal isothermal tubes, Int. J. Heat Mass Transfer, vol.20, pp. 953-960, 1977.
11. M. Hishida, Y. Nagano and M. S. Montescaros, Combined forced and free convection in the entrance region of an isothermally heated horizontal pipe, J. Heat transfer, vol. 104, pp.153-159, 1982.
12. M.M.M. abou-Ellail and S. M. Morcos, Buoyancy effects in the entrance region of horizontal rectangular channels, J. Heat Transfer, vol. 105, pp. 924-928, 1983.
13. F. P. Incropera and J. A. Schutt, Numerical simulation of laminar mixed convection in the entrance region of horizontal rectangular ducts, Numerical Heat Transfer, vol. 8, pp. 707-729, 1985.
14. F. P. Incropera A. L. Knox and J. R. Maughan, Mixed convection flow and heat transfer in the entrance region of a horizontal rectangular duct, Journal of Heat Transfer, vol. 109, pp. 434-439, 1987.
15. H. V. Mahaney, F. P. Incropera and S. Ramadhyani, Development of laminar mixed convection flow in a horizontal rectangular duct with uniform bottom heating, Numerical Heat Transfer, vol. 12, pp. 137-155, 1987.
16. F. C. Chou and G. J. Hwang, Vorticity-velocity method for Graetz problem with the effect of natural convection in a horizontal rectangular channel with uniform wall heat flux, Journal of Heat Transfer, vol. 109, pp. 704-710, 1987.
17. F. C. Chou and G. J. Hwang, Numerical analysis of the Graetz problem with natural convection in a uniformly heated horizontal tube, Int. J. Heat Mass Transfer, vol.31, pp.1299-1308, 1988.
18. J. N. Lin and F. C. Chou, Laminar mixed convection in the thermal entrance region of horizontal isothermal rectangular channels, Can. J. Chem. Eng. 67, pp. 361-367, 1989.
19. M. M. M. Abou-Ellail and S. M. Morcos, Combined forced and free laminar convection in the entrance region of inclined rectangular channels. In Proceedings of the International Conference on Numerical Methods for Nonlinear Problems (Edited by C. Taylor et al.), pp. 807-821, Pineridge Press, Swansea, 1980.
20. W. M. Yan, Mixed convection heat and mass transfer in inclined rectangular ducts, Int. J. Heat Mass Transfer, vol.37, pp.1857-1866, 1994.
21. M. M. Zdravkovich, Flow around Circular Cylinders. vol. 1: Fundamentals. Oxford: Oxford University Press, 1977.
22. S. Taneda, Experimental investigation of vortex streets, Journal of the Physical Society of Japan, vol. 20, pp.1714-1721, 1965
23. P. W. Bearman and M. M. Zdravkovich., Flow around a circular cylinder near a plane boundary, Journal of Fluid Mechanics, vol.89, pp. 33-47, 1978.
24. A. Roshko, A. Steinolfson and V. Chattoorgoon, Flow forces on a cylinder near a wall or near another cylinder, In Proceedings of the 2nd National Conference on Wind Engineering Research, Colorado State University, paper IV-15. 1975.
25. M. M. Zdravkovich, Forces on a circular cylinder near a plane wall, Applied Ocean Research, vol.7, pp.197-201, 1985.
26. M. M. Zdravkovich, Intermittent flow separation from flat plate induced by a nearby circular cylinder, In Proceedings of the 2nd International Symposium on Flow visualization (ed. W. Merzkirch), Bochum, West Germany, pp. 265-270, 1980.
27. M. M. Zdravkovich, Observation of vortex shedding behind a towed circular cylinder near a wall, In Proceedings of the 3rd International Symposium on Flow visualization, Ann Arbor, Michigan, pp. 391-395, 1983.
28. G. Buresti and A. Lanciotti, Vortex shedding from smooth and roughened cylinders in cross-flow near a plane surface, The Aeronautical Quarterly, vol. 30, pp. 305-321, 1979.
29. F. Angrilli, S. Bergamaschi and V.COSSALTER, Investigation of wall induced modifications to vortex shedding from a circular cylinder, ASME Journal of Fluids Engineering, vol. 104, 518-522, 1982.
30. A. J. Grass, P. W. J Raven, R. J. Stuart and J. A Bray, The influence of boundary layer velocity gradients and bed proximity on vortex shedding from free spanning pipelines, Journal of Energy Resources Technology , vol.106, pp. 70-78, 1984.
31. S. Taniguchi & K. Miyakoshi, Fluctuating fluid forces acting on a circular cylinder and interference with a plane wall, Experiments in Fluids, vol.9, pp. 197-204, 1990.
32. M. Cheng, H. E. Tsuei and K .L. Chow, Experimental study on flow interference phenomena of cylinder/cylinder and cylinder/plane arrangements. In Flow-Induced vibration (ed. M.K. Au-Yang), PVP- vol. 273, pp. 173-184, New York: ASME, 1994.
33. C. Lei, L. Chrng and K. Kavanagh, Re-examination of the effect of a plane boundary on force and vortex shedding of a circular cylinder, Journal of wind Engineering and Industrial Aerodynamics, vol. 80, pp. 263-286, 1999.
34. M. Kiya, M. Tamura and M. Arie, Vortex shedding from a circular cylinder in moderate-Reynolds-number shear flow, Journal of Fluid Mechanics, vol. 141, pp. 721-735, 1980.
35. B. M. Sumer and J. FreDSoE, Hydrodynamics around Cylindrical Structures. Singapore: World Scientific Publishing, 1997.
36. B. L. Jensen, B. M. Sumer, H.R. Jensen and J. FredSoE, Flow around and forces on a pipeline near a scoured bed in a steady current, ASME Journal of Offshore Mechanics and Arctic Engineering, vol. 112, pp. 206-213, 1990.
37. D. Sumner, J. G. Smith, S. J. Price and M. P. Paig Doussis, Vortex shedding from a circular cylinder near a plane wall, In Proceedings of the 17th Canadian Congress of Applied Mechanics (eds S. ZIADA & D. S. WEAVER) pp. 157-158, McMaster University, Hamilton, Ont., Canada, 1999a.
38. S. J. Price, D. Sumner, J. G. Smith, K. Leong and M. P. Paig Doussis, Flow visualization around a circular cylinder near to a plane wall, Journal of Fluids and Structures, vol. 16(2), pp. 175-191, 2002.
39. D. Sumner, S. S. T. Wong, S. J. Price and M. P. Paig Doussis, fluid behavior of side-by-side circular cylinders in steady cross-flow, Journal of Fluids and Structures, vol. 13, pp. 309-338, 1999.
40. J. H. Chou and S. Y. Chao, The flow interaction among three circular cylinders, The Chinese Journal of Mechanics, vol. 7, pp.163-169, 1991.
41. K. Lam and W. C. Cheung, Phenomena of vortex shedding and flow interference of three cylinders in different equilateral arrangements, Journal of Fluid Mechanics, vol. 196, pp.1-26, 1988.
42. T. Igarashi, Aerodynamic forces acting on three circular cylinders having Different Diameters Closely Arranged in Line, Journal of Win Eng. Industrial Aerodynamics, vol.49, pp.369-378, 1993.
43. H. W. Wu, T. C. Jue and S. Y. Huang, Heat transfer predictions around three heated cylinders between two parallel plates, Numerical Heat Engineering, Part A, vol. 40, pp.715-733, 2001.
44. J. C. Feng, A study of duct flow passing in a channel with cylinder sources, Master of Science Thesis, YZU, 2000.
45. S. C. Tsai, A study of duct flow passing in parallel channels with cylinder Sources, Master of Science Thesis, YZU, 2001.
46. S. J. Kline and F. A. McClintock, Describing uncertainty in single-sample experiments, Mech. Eng., pp.3-8, 1953.
47. K. H. Wu, Experimental and analytical study of thermosolutal natural convection in square enclosures, Ph.D. Thesis, NCKU, 1991.
48. J. R. Selman and C. W. Tobias, Mass transfer measurements by the limiting current technique, Adv. Che. Eng., 10, pp.211-318, 1978.
49. J. S. Newman, Electrochemical system, Prentice-Hall, Inc., 1973.
50. C. R. Wilke, M. Eisenberg and C. W. Tobias, Correlation of limiting current under free convection conditions, J. Electrochem. Soc., vol. 100, pp.513-523, 1953.
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top