Experimental study of the effects of contact deformation on drop coalescence scenario

Wei Cunju; Li Yingjie; Wang Luhai; Yang Jiming

doi:10.11729/syltlx20160146

Volume 31 Issue 3

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Wei Cunju, Li Yingjie, Wang Luhai, et al. Experimental study of the effects of contact deformation on drop coalescence scenario[J]. Journal of Experiments in Fluid Mechanics, 2017, 31(3): 88-93. doi: 10.11729/syltlx20160146

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Experimental study of the effects of contact deformation on drop coalescence scenario

doi: 10.11729/syltlx20160146

1.
Department of Modern Mechanics, University of Science and Technology of China, Hefei 230027, China
2.
China Institute of Water Resources and Hydropower Research, Beijing 100038, China

Received Date: 2016-09-23
Rev Recd Date: 2016-12-27
Publish Date: 2017-06-25

Abstract

Abstract

The evolution of cross section of the liquid bridge during drop coalescence is captured with a new type of experimental setup which contains the generation of large drops, top-view observation and high-speed shadowgraph. The optical results support the previous findings obtained with electrical measurements in the initial stage of the coalescence. Thanks to the unique advantages of the top-view observation, the shape and position of the liquid bridge connecting the drops is clearly demonstrated in this paper. Two coalescence scenarios with different approaching speed of the drops, v_a, are distinguished as the center scenario and the off-center scenario based on the location of the starting point of coalescence. The critical speed, v_cross, which divides the scenarios, is noticed and measured with the present device. It is found that the approaching speed has little influence on the coalescence process in the center scenario when v <v_cross. On the contrary, the onset of coalescence switches to the edge of the contacting film formed by the approaching drops and the off-center scenario appears consequently when v> v_cross.
- drop coalescence,
- drop collision,
- drop deformation

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References(21)

References

[1]	陈晓东, 胡国庆.微流控器件中的多相流动[J].力学进展, 2015, 45: 55-110. http://www.cnki.com.cn/Article/CJFDTOTAL-LXJZ201500003.htm Chen X D, Hu G Q. Multiphase flow in microfluidic devices[J]. Advances in Mechanics, 2015, 45: 55-110. http://www.cnki.com.cn/Article/CJFDTOTAL-LXJZ201500003.htm
[2]	申峰, 李易, 刘赵淼, 等.基于微流控技术的微液滴融合研究进展[J].分析化学, 2015, 43(12): 1942-1954. doi: 10.11895/j.issn.0253-3820.100509 Shen F, Li Y, Liu Z M, et al. Advances in micro-droplets coalescence using microfluidics[J]. Chinese Journal of Analytical Chemistry, 2015, 43(12): 1942-1954. doi: 10.11895/j.issn.0253-3820.100509
[3]	Sprittles J E, Shikhmurzaev Y D. Coalescence of liquid drops: different models versus experiment[J]. Physics of Fluids, 2012, 24(12): 122105. doi: 10.1063/1.4773067
[4]	Sprittles J E, Shikhmurzaev Y D. Dynamics of liquid drops coalescing in the inertial regime[J]. Phys Rev E Stat Nonlin Soft Matter Phys, 2014, 89(6): 063008. doi: 10.1103/PhysRevE.89.063008
[5]	Sprittles J E, Shikhmurzaev Y D. The coalescence of liquid drops in a viscous fluid: interface formation model[J]. Journal of Fluid Mechanics, 2014, 751: 480-499. doi: 10.1017/jfm.2014.313
[6]	Sprittles J E, Shikhmurzaev Y D. A parametric study of the coalescence of liquid drops in a viscous gas[J]. Journal of Fluid Mechanics, 2014, 753: 279-306. doi: 10.1017/jfm.2014.362
[7]	Thoroddsen S, Etoh T, Takehara K. High-speed imaging of drops and bubbles[J]. Annu Rev Fluid Mech, 2008, 40: 257-85. doi: 10.1146/annurev.fluid.40.111406.102215
[8]	Kavehpour H P. Coalescence of drops[J]. Annual Review of Fluid Mechanics, 2015, 47(1): 245-268. doi: 10.1146/annurev-fluid-010814-014720
[9]	Baroudi L, Nagel S R, Morris J F, et al. Dynamics of viscous coalescing droplets in a saturated vapor phase[J]. Physics of Fluids, 2015, 27(12): 121702. doi: 10.1063/1.4936942
[10]	Pothier J C, Lewis L J. Molecular-dynamics study of the viscous to inertial crossover in nanodroplet coalescence[J]. Physical Review B, 2012, 85(11): 115447. doi: 10.1103/PhysRevB.85.115447
[11]	刘栋. 液滴碰撞及其融合过程的数值模拟研究[D]. 北京: 清华大学, 2013. Liu D. Numerical simulations on collision and coalescence of binary droplets[D]. Beijing: Tsinghua University, 2013.
[12]	Tang C, Zhang P, Law C K. Bouncing, coalescence, and separation in head-on collision of unequal-size droplets[J]. Physics of Fluids, 2012, 24(2): 022101. doi: 10.1063/1.3679165
[13]	Paulsen J D, Burton J C, Nagel S R. Viscous to inertial crossover in liquid drop coalescence[J]. Phys Rev Lett, 2011, 106(11): 114501. doi: 10.1103/PhysRevLett.106.114501
[14]	Paulsen J D, Burton J C, Nagel S R, et al. The inexorable resistance of inertia determines the initial regime of drop coalescence[J]. Proc Natl Acad Sci U S A, 2012, 109(18): 6857-6861. doi: 10.1073/pnas.1120775109
[15]	Paulsen J D. Approach and coalescence of liquid drops in air[J]. Phys Rev E Stat Nonlin Soft Matter Phys, 2013, 88(6): 063010. doi: 10.1103/PhysRevE.88.063010
[16]	Paulsen J D, Carmigniani R, Kannan A, et al. Coalescence of bubbles and drops in an outer fluid[J]. Nat Commun, 2014, 5: 3182. http://www.oalib.com/paper/3582125
[17]	Wang L, Zhang G, Wu H, et al. Note: a top-view optical approach for observing the coalescence of liquid drops[J]. Rev Sci Instrum, 2016, 87(2): 026103. doi: 10.1063/1.4941778
[18]	王鲁海. 复杂管流条件下涡轮流量计响应规律及多相影响研究[D]. 合肥: 中国科学技术大学, 2016. Wang L H. The response characteristics of flowmeter in complex and multiphase flow conditions[D]. Hefei: University of Science and Technology of China, 2016.
[19]	Fezzaa K, Wang Y. Ultrafast x-ray phase-contrast imaging of the initial coalescence phase of two water droplets[J]. Phys Rev Lett, 2008, 100(10): 104501. doi: 10.1103/PhysRevLett.100.104501
[20]	Zhang P, Law C K. An analysis of head-on droplet collision with large deformation in gaseous medium[J]. Physics of Fluids, 2011, 23(4): 042102. doi: 10.1063/1.3580754
[21]	Case S C. Coalescence of low-viscosity fluids in air[J]. Phys Rev E Stat Nonlin Soft Matter Phys, 2009, 79(2): 026307. doi: 10.1103/PhysRevE.79.026307