影响纳米流体液滴蒸发沉积图案的关键因素分析
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摘要
目前关于液滴蒸发后沉积图案的研究主要集中于描述其物理现象的变化,但是对于蒸发过程中导致沉积图案形成的受力分析少有研究。影响纳米流体液滴蒸发沉积图案的主要因素是与液滴接触的底板温度和纳米颗粒的质量浓度。本文选用4种不同温度(30℃、47℃、64℃和81℃)的玻璃载玻片作为底板,采用粒径为20nm的3种质量分数(0.05%、0.1%和0.2%)的Al_2O_3-H_2O纳米溶液来研究纳米流体液滴在固体表面上蒸发后沉积图案的形成机理。实验结果表明,随着溶液质量分数的增加和底板温度的升高,咖啡圈效应越来越明显,且内环结构也逐渐清晰可见。其中咖啡圈效应由底板温度和溶液质量分数共同影响。溶液质量分数和底板温度都与马兰戈尼(Marangoni)效应呈正相关性,但由停滞点和Marangoni效应产生的内环结构,受底板温度的影响更大。
At present, research on deposition patterns after droplet evaporation mainly focuses on describing changes in physical phenomena. However, little research has been done on the force analysis that leads to the formation of deposition patterns during evaporation. The key factors affecting the deposition pattern of the nanofluid droplet are the substrate temperature and the mass fraction of the nanoparticle in the nanofluid droplet. Based on glass film with four different temperatures(30℃, 47℃,64℃ and 81℃), the evaporation of aluminum oxide-water mixed liquid drops were studied by using 0.05%, 0.1% and 0.2% mass fraction of aluminum oxide and pure water, and they were used to study the formation mechanism of the deposition pattern of the nanodroplets after evaporation on the solid surface.Results of aluminum oxide-water mixed liquid's deposition pattern showed that as the mass fraction of the solution increases and the temperature of the substrate increases, the coffee ring effect becomes more and more obvious and the inner ring structure is gradually visible. In addition, the coffee ring effect is affected by the temperature of the bottom plate and the mass fraction of the solution. Although both the mass fraction of the solution and the temperature of the bottom plate are positively correlated with the Marangoni effect, the inner ring structure produced by the stagnation point and the Marangoni effect is more affected by the temperature of the bottom plate.
At present, research on deposition patterns after droplet evaporation mainly focuses on describing changes in physical phenomena. However, little research has been done on the force analysis that leads to the formation of deposition patterns during evaporation. The key factors affecting the deposition pattern of the nanofluid droplet are the substrate temperature and the mass fraction of the nanoparticle in the nanofluid droplet. Based on glass film with four different temperatures(30℃, 47℃,64℃ and 81℃), the evaporation of aluminum oxide-water mixed liquid drops were studied by using 0.05%, 0.1% and 0.2% mass fraction of aluminum oxide and pure water, and they were used to study the formation mechanism of the deposition pattern of the nanodroplets after evaporation on the solid surface.Results of aluminum oxide-water mixed liquid's deposition pattern showed that as the mass fraction of the solution increases and the temperature of the substrate increases, the coffee ring effect becomes more and more obvious and the inner ring structure is gradually visible. In addition, the coffee ring effect is affected by the temperature of the bottom plate and the mass fraction of the solution. Although both the mass fraction of the solution and the temperature of the bottom plate are positively correlated with the Marangoni effect, the inner ring structure produced by the stagnation point and the Marangoni effect is more affected by the temperature of the bottom plate.
引文
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[19]梁功有,曾忠,张永祥,等.两球形颗粒间横向毛细力的格子Boltzmann研究[J].应用数学和力学, 2013, 34(5):445-453.LIANG G Y, ZENG Z, ZHANG Y X, et al. Lateral capillary forces between two spherical particles:a lattice Boltzmann study[J]. Applied Mathematics and Mechanics, 2013, 34(5):445-453.
[20] ZHU D S, WU S Y, WANG N. Surface tension and viscosity of aluminum oxide nanofluids[C]//American Institute of Physics Conference Series., American Institute of Physics, 2010:460-464.
[21]蔡碧昊.底板热属性对纳米流体液滴蒸发的影响[D].天津:天津商业大学, 2014.CAI B H. Influence of thermal properties of substrate on the evaporation of nanofluid sessile droplets[D]. Tianjin:Tianjin University of Commerce, 2014.
[22] XU X, LUO J. Marangoni flow in an evaporating water droplet[J].Applied Physics Letters, 2007, 91(12):3972.
[23] DEEGAN R D, BAKAJIN O, DUPONT T F, et al. Contact line deposits in an evaporating drop[J]. Phys. Rev. E, 2000, 62(1 Pt B):756-765.
[24] SCHAFFER E, WONG P Z. Contact line dynamics near the pinning threshold:a capillary rise and fall experiment[J]. Physical Review E:Statistical Physics Plasmas Fluids&Related Interdisciplinary Topics,2000, 61(5A):5257.
[25] BRUTIN D. Droplet Wetting and Evaporation[M]. France:Elsevier,2015, 464.
[26] PARSA M, HARMAND S, SEFIANE K, et al. Effect of substrate temperature on pattern formation of nanoparticles from volatile drops[J]. Langmuir, 2015, 31(11):3354-67.
[27] STILL T, YUNKER P J, YODH A G. Surfactant-induced marangoni eddies alter the coffee-rings of evaporating colloidal drops.[J].Langmuir, 2012, 28(11):4984-4988.
[28] WEON B M, JE J H. Capillary force repels coffee-ring effect[J].Physical Review E:Statistical Nonlinear&Soft Matter Physics, 2010,82(1 Pt 2):015305.
[29] BUFFONE C, SEFIANE K. Investigation of thermocapillary convective patterns and their role in the enhancement of evaporation from pores[J]. International Journal of Multiphase Flow, 2004, 30(9):1071-1091.
[2]罗昊.基于微纳米结构表面的浸润性及液滴蒸发行为的研究[D].西安:西北大学, 2016.LUO H. Wetting and evaporation dynamics on micro/nano structured surfaces[D]. Xi’an:Northwest University, 2016.
[3] ZHONG X, CRIVOI A, DUAN F. Sessile nanofluid droplet drying[J].Adv. Colloid Interface Sci., 2015, 217(3):13-30.
[4] ZHANG Y, QIAN Y, LIU Z, et al. Surface wrinkling and cracking dynamics in the drying of colloidal droplets[J]. Eur. Phys. J. E:Soft Matter, 2014, 37(9):1-7.
[5] DEEGAN R D, BAKAJIN O, DUPONT T F. Capillary flow as the cause of ring stains from dried liquids[J]. Nature, 1997, 389(6653):827-829.
[6] MAMPALLIL D, ERAL H B. A review on suppression and utilization of the coffee-ring effect.[J]. Adv. Colloid Interface Sci., 2018, 252:38-54.
[7] CONN J J, DUFFY B R, PRITCHAR D, et al. Fluid-dynamical model for antisurfactants[J]. Physical Review E, 2016, 93(4):043121.
[8] ZUO W, RAO Z J, WU G X, et al. Influence of surfactants on deposition coverage areas and evaporation time of pesticide droplets on cabbage leaves[J]. Journal of Southwest University, 2011, 33(9):1-5.
[9] MOON Y J, KANG H, SANG H L, et al. Effect of contact angle and drop spacing on the bulging frequency of inkjet-printed silver lines on FC-coated glass[J]. Journal of Mechanical Science&Technology,2014, 28(4):1441-1448.
[10] ASKOUNIS A, TAKATA Y, SEFIANE K, et al."Biodrop"evaporation and ring-stain deposits:the significance of DNA length[J]. Langmuir the ACS Journal of Surfaces&Colloids, 2016, 32(17):4361-4369.
[11] SHABALIN V N, SHATOKHINA S N, DUTOV V V, et al. Method of diagnosing complicated urolithiasis and prognosticating urolithiasis:EP0504409[P]. 1996.
[12] CHOI S U S. Enhancing thermal conductivity of fluids with nanoparticles[J]. Asme. Fed., 1995, 231(1):99-105.
[13] WASAN D T, NIKOLOV A D. Spreading of nanofluids on solids[J].Nature, 2003, 423(6936):156-9.
[14] ASKOUNIS A, OREJON D, KOUTSOS V, et al. Nanoparticle deposits near the contact line of pinned volatile droplets:size and shape revealed by atomic force microscopy[J]. Soft Matter, 2011, 7(9):4152-4155.
[15] LIM S, ZHANG H, WU P, et al. The dynamic spreading of nanofluids on solid surfaces—Role of the nanofilm structural disjoining pressure[J]. J. Colloid Interface Sci., 2016, 470(9):22-30.
[16] TAYLOR J R.误差分析导论[M].王中宇,译. 2版.北京:高等教育出版社, 2015:308.TAYLOR J R. An introduction to error analysis[M]. WANG Z Y, trans.2nd ed. Beijing:Higher Education Press, 2015:308.
[17]马晓燕.纳米流体液滴蒸发过程及颗粒沉积图案的研究[D].天津:天津商业大学, 2016.MA X Y. Evaporating process of nanofluid sessile droplet and deposition patterns of nanoparticles[D]. Tianjin:Tianjin University of Commerce, 2016.
[18]李芹芹.纳米流体液滴蒸发过程温度分布及沉积图案研究[D].天津:天津商业大学, 2018.LI Q Q. Study on temperature distribution and deposition pattern of nanofluid droplet evaporation process[D]. Tianjin:Tianjin University of Commerce, 2018.
[19]梁功有,曾忠,张永祥,等.两球形颗粒间横向毛细力的格子Boltzmann研究[J].应用数学和力学, 2013, 34(5):445-453.LIANG G Y, ZENG Z, ZHANG Y X, et al. Lateral capillary forces between two spherical particles:a lattice Boltzmann study[J]. Applied Mathematics and Mechanics, 2013, 34(5):445-453.
[20] ZHU D S, WU S Y, WANG N. Surface tension and viscosity of aluminum oxide nanofluids[C]//American Institute of Physics Conference Series., American Institute of Physics, 2010:460-464.
[21]蔡碧昊.底板热属性对纳米流体液滴蒸发的影响[D].天津:天津商业大学, 2014.CAI B H. Influence of thermal properties of substrate on the evaporation of nanofluid sessile droplets[D]. Tianjin:Tianjin University of Commerce, 2014.
[22] XU X, LUO J. Marangoni flow in an evaporating water droplet[J].Applied Physics Letters, 2007, 91(12):3972.
[23] DEEGAN R D, BAKAJIN O, DUPONT T F, et al. Contact line deposits in an evaporating drop[J]. Phys. Rev. E, 2000, 62(1 Pt B):756-765.
[24] SCHAFFER E, WONG P Z. Contact line dynamics near the pinning threshold:a capillary rise and fall experiment[J]. Physical Review E:Statistical Physics Plasmas Fluids&Related Interdisciplinary Topics,2000, 61(5A):5257.
[25] BRUTIN D. Droplet Wetting and Evaporation[M]. France:Elsevier,2015, 464.
[26] PARSA M, HARMAND S, SEFIANE K, et al. Effect of substrate temperature on pattern formation of nanoparticles from volatile drops[J]. Langmuir, 2015, 31(11):3354-67.
[27] STILL T, YUNKER P J, YODH A G. Surfactant-induced marangoni eddies alter the coffee-rings of evaporating colloidal drops.[J].Langmuir, 2012, 28(11):4984-4988.
[28] WEON B M, JE J H. Capillary force repels coffee-ring effect[J].Physical Review E:Statistical Nonlinear&Soft Matter Physics, 2010,82(1 Pt 2):015305.
[29] BUFFONE C, SEFIANE K. Investigation of thermocapillary convective patterns and their role in the enhancement of evaporation from pores[J]. International Journal of Multiphase Flow, 2004, 30(9):1071-1091.