Numerical simulation of unsteady mass transfer by the level set method

Wang, Jianfeng; Lü, Ping; Wang, Zhihui; Yang, Chao; Mao, Zai‐Sha

doi:10.1016/j.ces.2008.03.018

Cited by 50 publications

(21 citation statements)

References 18 publications

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“…Bigger diameter and greater deformation of drops in the MIBK-acetic acid-water system cause larger numerical and experimental errors of mass-transfer coefficients than those in the water-succinic acid-butanol system. 40 Another important reason is that the present axisymmetric simulation captured only the Marangoni effect in form of toroidal roll cells, which are easier to be triggered than the hexagonal convection structure contributing to enhanced interphase mass transfer according to Bragard et al 7 and Mao et al 41 Probably, the higher predicted velocities in numerical simulations also result in higher convective intensity, especially in the initial rising stage of the drop, contributing somewhat to higher mass-transfer rate.…”

Section: Mass-transfer Coefficientmentioning

confidence: 89%

Numerical simulation of the Marangoni effect on transient mass transfer from single moving deformable drops

Wang

Lü

et al. 2011

AIChE Journal

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A level set approach was adopted in numerical simulation of interphase mass transfer from a deformable drop moving in a continuous immiscible liquid, and the simulation results on Marangoni effect were presented with respect to three experimental runs in the methyl isobutyl ketone-acetic acid-water system. Experiments showed that when the solute concentration was sufficiently high, the Marangoni effect would occur with the interphase mass transfer enhanced. Numerical results indicated that the masstransfer coefficient with Marangoni effect was larger than that without Marangoni effect and stronger Marangoni effect made the drop deform more easily. The predictions were qualitatively in accord with the experimental data. Numerical simulation revealed well the transient flow structure of Marangoni effect. V

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Section: Mass-transfer Coefficientmentioning

confidence: 89%

Numerical simulation of the Marangoni effect on transient mass transfer from single moving deformable drops

Wang

Lü

et al. 2011

AIChE Journal

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“…The procedure of numerical solution has been presented previously by Wang et al in detail [21]. The field of relative velocity around the bubble is presented in Fig.…”

Section: Viscosity Distribution Around a Bubblementioning

confidence: 99%

Numerical simulation of a bubble rising in shear-thinning fluids

Zhang

Yang

Mao

2010

Journal of Non-Newtonian Fluid Mechanics

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a b s t r a c tThe motion of a single bubble rising freely in quiescent non-Newtonian viscous fluids was investigated experimentally and computationally. The non-Newtonian effects in the flow of viscous inelastic fluids are modeled by the Carreau rheological model. An improved level set approach for computing the incompressible two-phase flow with deformable free interface is used. The control volume formulation with the SIMPLEC algorithm incorporated is used to solve the governing equations on a staggered Eulerian grid. The simulation results demonstrate that the algorithm is robust for shear-thinning liquids with large density ( 1 / g up to 103 ) and high viscosity (Á 1 /Á g up to 10 4 ). The comparison of the experimental measurements of terminal bubble shape and velocity with the computational results is satisfactory. It is shown that the local change in viscosity around a bubble greatly depends on the bubble shape and the zero-shear viscosity of non-Newtonian shear-thinning liquids. The shear-rate distribution and velocity fields are used to elucidate the formation of a region of large viscosity at the rear of a bubble as a result of the rather stagnant flow behind the bubble. The numerical results provide the basis for further investigations, such as the numerical simulation of viscoelastic fluids.

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“…Since then, the thermocapillary migration of a bubble has been studied extensively by a series of theoretical analyses [3][4][5][6], numerical simulations [7][8][9][10] and experimental investigations [11]. In the mean time, several numerical techniques for treating the two-phase flow, such as the front-tracking method [12,13] and the level-set method [14], have also been developed, which may provide effective techniques to directly investigate thermocapillary migration processes of bubbles or droplets [15][16][17][18], interfacial mass transfer [19,20] and interfacial flows with soluble surfactants [21,22].…”

Section: Introductionmentioning

confidence: 99%

Thermocapillary migration of a planar droplet at moderate and large Marangoni numbers

2011

Acta Mech

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Thermocapillary migration of a planar non-deformable droplet in flow fields with two uniform temperature gradients at moderate and large Marangoni numbers is studied numerically by using the front-tracking method. It is observed that the thermocapillary motion of planar droplets in the uniform temperature gradients is steady at moderate Marangoni numbers, but unsteady at large Marangoni numbers. The instantaneous migration velocity at a fixed migration distance decreases with increasing Marangoni numbers. The simulation results of the thermocapillary droplet migration at large Marangoni numbers are found in qualitative agreement with those of experimental investigations. Moreover, the results concerned with steady and unsteady migration processes are further confirmed by comparing the variations of temperature fields inside and outside the droplet. It is evident that at large Marangoni numbers the weak transport of thermal energy from outside of the droplet into inside cannot satisfy the condition of a steady migration process, which implies that the advection around the droplet is a more significant mechanism for heat transfer across/around the droplet at large Ma numbers. Furthermore, from the condition of overall steady-state energy balance in the flow domain, the thermal flux across its surface is studied for a steady thermocapillary droplet migration in a flow field with uniform temperature gradient. By using the asymptotic expansion method, a non-conservative integral thermal flux across the surface is identified in the steady thermocapillary droplet migration at large Marangoni numbers. This non-conservative flux may well result from the invalid assumption of a quasi-steady state, which indicates that the thermocapillary droplet migration at large Marangoni numbers cannot reach a steady state and is thus an unsteady process.

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Numerical simulation of unsteady mass transfer by the level set method

Cited by 50 publications

References 18 publications

Numerical simulation of the Marangoni effect on transient mass transfer from single moving deformable drops

Numerical simulation of the Marangoni effect on transient mass transfer from single moving deformable drops

Numerical simulation of a bubble rising in shear-thinning fluids

Thermocapillary migration of a planar droplet at moderate and large Marangoni numbers

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