Investigation on droplet oscillatory behavior after free binary collision and coalescence

doi:10.11949/0438-1157.20191460

Abstract

Abstract:

Toluene and ultrapure water were used as the research object of the multiphase system. The high-speed camera test was used to analyze the oscillation behavior of binary droplets after free collision and coalescence. The experimental results show that the oscillation process of toluene droplets after coalescence has obvious periodicity and damping attenuation mechanism, and the Reynolds number, Weber number of droplets are the key dimensionless parameters affecting the process. There is a positive correlation between the inertial force and the oscillation period, while the viscous force dominates the damping attenuation mechanism of the oscillation process. It indicates that the damping coefficient increases with the increasing viscous force. At the same time, the collisional coalescence of droplets is relatively independent of its subsequent oscillation process, which means the collisional coalescence process has no obvious effect on the oscillation behavior of the droplet. In addition, the experimental and theoretical comparison show that the experimental results of the oscillation period are slightly higher than the theoretical values. In general, the standard deviations of the relative errors between experiment and calculation are 44.9% and 14.9% for the damping coefficient and oscillation period, respectively.

Key words: multiphase flow, fluid mechanics, free collision, coalescence, droplet oscillation

摘要：

以甲苯、超纯水为多相系统研究对象，采用高速摄像机测试分析了二元液滴自由碰撞聚并后的振荡行为特性。实验结果表明，聚并后甲苯液滴振荡过程存在明显的周期性与阻尼衰减机制，液滴Reynolds数、Weber数是影响聚并后液滴振荡周期、阻尼系数的关键无量纲参数。液滴惯性力与振荡周期呈正相关性，而液滴黏性力则主导了振荡过程的阻尼衰减机制，振荡阻尼系数随黏性力的增加而增加，同时，液滴碰撞聚并作用与其后续振荡过程相对独立，即碰撞聚并过程对液滴振荡行为特性无明显影响。此外，液滴振荡过程特性参数的实验与理论计算对比结果显示，振荡周期实验结果相较于理论值略微偏高，振荡周期、阻尼系数实验与计算值相对误差的标准差分别为14.9%和44.9%。

关键词: 多相流, 流体力学, 自由碰撞, 聚结, 液滴振荡

CLC Number:

TQ 021.1

Rui LI, Yiren ZHANG, Hang CHEN, Guimin LU, Jianguo YU. Investigation on droplet oscillatory behavior after free binary collision and coalescence[J]. CIESC Journal, 2020, 71(4): 1482-1490.

李睿, 张以任, 陈杭, 路贵民, 于建国. 二元液滴自由碰撞聚并后的振荡行为研究[J]. 化工学报, 2020, 71(4): 1482-1490.

Figures/Tables 14

Table 1 Physical properties of toluene-water

物性参数	T = 15℃		T = 25℃		T = 35℃
物性参数	水	甲苯	水	甲苯	水	甲苯
密度ρ /(kg·m^-3)	999.10	871.78	997.06	862.19	994.04	852.85
黏度μ /(kg·m^-1·s^-1)	11.4×10^-4	5.52×10^-4	8.95×10^-4	5.60×10^-4	7.27×10^-4	5.03×10^-4
界面张力σ /(N·m^-1)	3.80×10^-2		3.61×10^-2		3.51×10^-2

Fig.1 Experimental device

Fig.2 Free binary droplets collision, coalescence and its oscillatory behavior

Fig.3 Fitting results of experimental data and theoretical model

Fig.4 Effect of droplet equivalent diameter on damping coefficient

Fig.5 Effect of droplet equivalent diameter on oscillation period

Fig.6 Effect of binary droplets relative velocity on damping coefficients

Fig.7 Effect of binary droplets relative velocity on oscillation periods

Fig.8 Effect of droplets dimensionless number after coalescence on damping coefficients

Fig.9 Effect of droplets dimensionless number after coalescence on oscillation period

Fig.10 Comparison of experimental and theoretical damping coefficients

Fig.11 Comparison of experimental and theoretical frequence

Fig.12 Effect of droplets ratio of Reynolds number on deviation of damping coefficient

Fig.13 Effect of droplets ratio of Reynolds number on deviation of oscillation frequency

References 34

1	Kumar S, Ramkrishna D. On the solution of population balance equations by discretization(Ⅰ): A fixed pivot technique[J]. Chem. Eng. Sci., 1996, 51: 1311-1332.
2	Marchisio D, Fox R. Solution of population balance equations using the direct quadrature method of moments[J]. Journal of Aerosol Science, 2005, 36: 43-73.
3	Attarakih M, Hlawitschka M, Abu-Khader M. CFD-population balance modeling and simulation of coupled hydrodynamics and mass transfer in liquid extraction columns[J]. Appl. Math. Model, 2015, 39: 5105-5120.
4	王凯, 易诗婷, 周倩倩, 等. 微通道内纳米颗粒对液滴聚并的影响规律[J]. 化工学报, 2016, 67(2): 469-475.
	Wang K, Yi S T, Zhou Q Q, et al. Effect of nano-particles on droplet coalescence in microchannel device[J]. CIESC Journal, 2016, 67(2): 469-475.
5	Coulaloglou C A, Tavlarides L L. Description of interaction processes in agitated liquid-liquid dispersions[J]. Chem. Eng. Sci., 1977, 32: 1289-1297.
6	Coulaloglou C A. Dispersed phase interactions in an agitated flow vessel[D]. Chicago: Illinois Institute of Technology, 1975.
7	Coulaloglou C A, Tavlarides L L. Drop size distributions and coalescence frequencies of liquid-liquid dispersions in flow vessels[J]. AIChE Journal, 1976, 22: 289-297.
8	Luo H, Svendsen H F. Theoretical model for drop and bubble breakup in turbulent dispersions[J]. AIChE Journal, 1996, 42: 1225-1233.
9	Prince M J, Blanch H W. Bubble coalescence and break-up in air-sparged bubble columns[J]. AIChE Journal, 1990, 36: 1485-1499.
10	Sovova H. Breakage and coalescence of drops in a batch stirred vessel(Ⅱ): Comparison of model and experiments[J]. Chem. Eng. Sci., 1981, 36: 1567-1573.
11	Lee C H. Bubble breakup and coalescence in turbulent gas-liquid dispersions[J]. Chemical Engineering Communications, 1987, 59: 65-84.
12	Tsouris C, Tavlarides L L. Breakage and coalescence models for drops in turbulent dispersions[J]. AIChE Journal, 1994, 40: 395-406.
13	Lehr F, Mewes D. A transport equation for the interfacial area density applied to bubble columns[J]. Chem. Eng. Sci., 1999, 56: 1159-1166.
14	Venneker B C H. Population balance modeling of aerated stirred vessels based on CFD[J]. AIChE Journal, 2002, 48: 673-685.
15	Howarth W J. Coalescence of drops in a turbulent flow field[J]. Chem. Eng. Sci., 1964, 19: 33-38.
16	Park J Y, Blair L M. The effect of coalescence on drop size distribution in an agitated liquid-liquid dispersion[J]. Chem. Eng. Sci., 1975, 30: 1057-1064.
17	Kuboi R. Collision and coalescence of dispersed drops in turbulent liquid flow[J]. Journal of Chemical Engineering of Japan, 1972, 5: 423-424.
18	Lehr F. Bubble-size distributions and flow fields in bubble columns[J]. AIChE Journal, 2002, 48: 2426-2443.
19	Doubliez L. The drainage and rupture of a non-foaming liquid film formed upon bubble impact with a free surface[J]. International Journal of Multiphase Flow, 1991, 17: 783-803.
20	Das P K, Kumar R. Coalescence of drops in stirred dispersion: a white noise model for coalescence[J]. Chem. Eng. Sci., 1987, 42: 213-220.
21	魏超, 罗和安, 王良芥. 两流体颗粒间最小液膜厚度的靠近-减薄耦合模型[J]. 化工学报, 2004, 55(5): 732-736.
	Wei C, Luo H A, Wang L J. Model of minimum thickness of liquid film between two fluid particles by coupling of approaching and thinning[J]. Journal of Chemical Industry and Engineering(China), 2004, 55(5): 732-736.
22	Liao Y, Lucas D. A literature review on mechanisms and models for the coalescence process of fluid particles[J]. Chem. Eng. Sci., 2010, 65: 2851-2864.
23	Liao Y, Lucas D. A literature review of theoretical models for drop and bubble breakup in turbulent dispersions[J]. Chem. Eng. Sci., 2009, 64: 3389-3406.
24	李少伟, 景山, 张琦, 等. 萃取柱内液-液两相流CFD-PBM模拟研究进展[J]. 过程工程学报, 2012, 12(4): 702-711.
	Li S W, Jing S, Zhang Q, et al. Advances in simulation of liquid-liquid two-phase flow in extraction columns with CFD-PBM[J]. The Chinese Journal of Process Engineering, 2012, 12(4): 702-711.
25	Ata S, Pughb R J, Jamesona G J. The influence of interfacial ageing and temperature on the coalescence of oil droplets in water[J]. Colloids and Surfaces A: Physicochem. Eng. Aspects, 2011, 374: 96-101.
26	Stover R L, Tobias C W, Denn M M. Bubble coalescence dynamics[J]. AIChE Journal, 1997, 43: 2385-2392.
27	Yesenia S M, Ghislain B, Ata S. Analysis of bubble coalescence dynamics and postrupture oscillation of capillary-held bubbles in water[J]. Ind. Eng. Chem. Res., 2017, 56:14781-14792.
28	Bournival G, Ata S, Karakashev S I. An investigation of bubble coalescence and post-rupture oscillation in non-ionic surfactant solutions using high-speed cinematography[J]. Colloid Interface Science, 2014, 414: 50-58.
29	Miller C A, Scriven L E. The oscillations of a fluid droplet immersed in another fluid[J]. Journal of Fluid Mechanics, 1968, 32: 417-435.
30	Lu H L, Apfel R E. Shape oscillations of drops in the presence of surfactants[J]. Journal of Fluid Mechanics, 1991, 222: 351-368.
31	Green D W, Perry R H. Perry s Chemical Engineers Handbook[M]. 8th ed. New York: The McGraw-Hill Companies, 2008:50-176.
32	Ata S. The detachment of particles from coalescing bubble pairs[J]. Colloid Interface Sci., 2009, 338: 558-565.
33	Tsamopoulos J A, Brown R A. Nonlinear oscillations of inviscid drops and bubbles[J]. Journal of Fluid Mechanics, 1983, 127: 519-537.
34	Abi C N, Vejražka J, Masbernat O. Shape oscillations of an oil drop rising in water: effect of surface contamination[J]. Journal of Fluid Mechanics, 2012, 702: 533-542.

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