Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/2229
標題: 撞擊在乾玻璃面上變形液滴之數值模擬
Simulation Of Deformed Droplet Impinging On Dry Glass Surface
作者: 莊育賢
Chung, Yu-Siang
關鍵字: Volume of Fluid (VOF);流體體積法;impinging droplet;energy;dynamic contact angle;撞擊液滴;能量;動態接觸角
出版社: 機械工程學系所
引用: 1.Gerardo, T. and Julian, S., Mathematical Modeling of the Isothermal Impingement of Liquid Doplets in Spraying Processes. Met.Trans. B, 1991. 22B, pp. 901-914. 2.Chandra, S. and Avedisian, C. T., On The Collision of A Droplet With A Solid Surface. Proc. R. Soc. London Ser. A, 1991. 432, pp. 13-41. 3.Fukai, J., et al., Modeling of the Deformation of a Liquid Droplet Impinging Upon a Flat Surface. Phys. Fluids A, 1993. 5(11), pp. 2588-2599. 4.Yarin, A. L. and Weiss, D. A., Impact of Drops on Solid Surfaces: Self-Similar Capillary Waves and Splashing as a new type of Kinematic Discontinuity. J.Fluid Mech, 1995. 283, pp. 141-173. 5.Fukai, J., Shiiba, Y., Yamamoto, T. and Miyatake, O., Wetting Effects on the Spreading of a Liquid Droplet Colliding With a Flat Surface: Experiment and Modeling. Phys. Fluids, 1995. 7(2), pp. 236-247. 6.Hatta, N., Fujimoto, H., and Takuda, H., Deformation Process of A Water Droplet Impinging on a Solid Surface. Trans. of the ASME, 1995. 177, pp. 394-401. 7.Pasandideh-Fard, M., Qiao, Y. M., Chandra, S. and Mostaghimi, J., Capillary Effects during Droplet Impact on A Solid Surface. Phys. Fluids, 1996. 8(3), pp. 650-659. 8.Mao, T., Kuhn, D. C. S., and Tran, H., Spread and Rebound of Liquid Droplets upon Impact on Falt Surfaces. AlChE J, 1997. 43(9), pp. 2169-2179. 9.Zhang, X. and Basaran, O. A., Dynamic Surface Tension Effects in Impact of a Drop with a Solid Surface. J.Colloid Interface Sci, 1997. 187, pp. 166-178. 10.Thoroddsen, S. T. and Sakakibara, J., Evolution Of The Fingering Pattern Of An Impacting Drop. Phys. Fluid, 1998. 10, pp. 1359-1374. 11.Gu, Y. and Li, D., Liquid Drop Spreading On Solid Surfaces At Low Impact Speeds. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2000. 163, pp. 239-245. 12.Sikalo, S., Marengo, M., and Tropea, C., Analysis Of Impact Of Droplets On Horizontal Surfaces. Exp. Fluids, 2002. 25, pp. 503-510. 13.Sikalo, S., Wilhelm, H., Roisman, l., Jakirlic, S. and Tropea, C., Dynamic Contact Angle of Spreading Droplets:Experiments and Simulations. Phys Fluids, 2005. 17, pp. 062103. 14.Son, Y., Kim, C., Yang, D. H. and Ahn, D. J., Spreading of An Inkjet Droplet On A Solid Surface with A Controlled Contact Angle at Low Weber and Reynolds Numbers. Langmuir, 2008. 24, pp. 2900-2907. 15.Brackbill, J. U., Kothe, D. B. and Zemach, C., A Continuum Method for Modeling Surface Tension. Computational Phys, 1992. 100, pp. 335-354. 16. Harlow, F. and Welch, E., Numerical Calculation of Time-Dependent Viscous Incompressible Flow of Fluid with a Free Surface. Phys Fluids, 1965. 8, pp. 2182. 17. Hirt, C. W., Nichols, B. D. and Romero, N. C., SOLA-A numerical solution algorithm for transient fluid flow. LA-5852 technical report 1975. 18.宋詠程, 液滴掉落現象之數值模擬. 中原大學土木工程學系碩士論文, 2003. 19. Zhao, D. H., Shen, H. W., Lai, J. S. and Tabios, G. Q., Approximate Riemann Solvers in FVM for 2D Hydraulic Shock Wave Modeling. Hydraulic Engineering, 1996. 122, pp. 692-702. 20.王耀增, 撞擊在乾表面上的液滴特性之實驗探討. 國立中興大學機械工程學系碩士論文, 2008.
摘要: 
本研究是採用計算流體力學模擬軟體Fluent 6.3中的流體體積法(Volume of Fluid)模型,探討純水及含有不同重量百分比濃度的(水-甘油)液滴以相同的撞擊速度撞擊在乾玻璃表面時,從流場、壓力分佈,以及能量的觀點來瞭解液滴撞擊後的運動行為。研究中,無因次參數韋伯數(We)在81.05~119.20之間變化,雷諾數(Re)則在3.76~4180範圍內。
模擬結果發現: (1)在撞擊前期,液滴之動能、位能皆快速降低,減少之能量一部份存於變形液滴的表面能;另一部份則用來克服黏滯阻力,因此在變形過程中表面能、消耗能均呈現快速增加。達平衡階段時,能量以表面能為主;黏滯係數越小(雷諾數越大)者,其存留總能量百分比越大。(2)在撞擊初期,純水液滴的表面能呈單調增加的變化,最後趨於定值;然而,含有甘油50%~ 100%者,其表面能則呈現先減少,待達到最小值後,表面能會再度增加的變化。隨著含甘油百分比增加(低雷諾數者),達到最小表面能之時間變長,且其所擁有的最小表面能較小。(3)撞擊過程中,表面能量先減後增之趨勢應和變形液滴擴張速率的急劇變化有關。

This study investigates the temporal evolutions of various kinds of energy for an impinging droplet of various compositions onto dry surface by way of Fluent (CFD software). The Weber number ranges from 81.05 to 119.20 and Reynolds numbers are from 3.76 to 4180.
Simulation results show that: (1) immediately after impingement, the kinetic energy and potential energy decrease quickly and monotonously. Most part of it is stored as surface energy; the other part is dissipated to overcome the viscous drag force. During the spreading process, the surface and dissipation energy increase substantially. During the equilibrium stage, the stored surface energy becomes dominant. For droplets with high Reynolds numbers, high percentage of energy is stored as the surface energy. (2) During the impacting process, the surface energy increases monotonously for water droplet. However the surface energy first experience a decrease until a local minimum of the surface energy is reached; and then increases substantially. The higher the weight percentage of the glycerin, the smaller value the local minimum; and the longer the time elapse to reach the local minimum . (3) Formation of the local minimum of the surface energy may be caused by significant deceleration of the spreading speed within the corresponding time interval.
URI: http://hdl.handle.net/11455/2229
其他識別: U0005-1108200910535600
Appears in Collections:機械工程學系所

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