Experimental investigation on thermocapillary drop migration at large Marangoni number in reduced gravity

Xie, Junhua; Lin, Hai; Zhang, Pu; Liu, Fang; Hu, Wenrui

doi:10.1016/j.jcis.2004.12.023

Cited by 43 publications

(57 citation statements)

References 11 publications

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“…Both the theoretical analysis and numerical simulation are based on the assumptions of quasi-steady state and non-deformation of the droplet. However, the experimental results of Hadland et al [11] and Xie et al [28] were not in qualitative agreement with the above theoretical and numerical results, and it was shown that the droplet migration speed non-dimensionalized by the YGB velocity decreased as Ma number increased. The experiment investigation was completed in several ranges of large Ma numbers, where the droplet migration was in an accelerating state and did not reach a steady one.…”

Section: Introductionmentioning

confidence: 77%

“…In the following calculations, we adopt the silicone oil of nominal viscosity 5cst and the FC-75 Fluorinert liquid, i.e., the working media in the space experiment [28], as the continuous phase fluid and the droplet, respectively. The physical parameters of the continuous fluid and the droplet at temperature 25 • C are given in Table 1.…”

Section: Results and Analysismentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 77%

Section: Results and Analysismentioning

confidence: 99%

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

2011

Acta Mech

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“…On the fourth Shen-Zhou spaceship, Xie et al carried out experiments with larger values of Re 1 ͑up to 300͒ and Ma 1 ͑up to 5500͒. 11 There are also lots of numerical studies on this subject. Szymczyk and Siekmann 12 first calculated the steady migration of bubbles.…”

Section: Introductionmentioning

confidence: 99%

Thermocapillary migration of nondeformable drops

Yin

Gao

et al. 2008

Physics of Fluids

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In this paper, we present a numerical study on the thermocapillary migration of drops. The NavierStokes equations coupled with the energy conservation equation are solved by the finite-difference front-tracking scheme. The axisymmetric model is adopted in our simulations, and the drops are assumed to be perfectly spherical and nondeformable. The benchmark simulation starts from the classical initial condition with a uniform temperature gradient. The detailed discussions and physical explanations of migration phenomena are presented for the different values of ͑1͒ the Marangoni numbers and Reynolds numbers of continuous phases and drops and ͑2͒ the ratios of drop densities and specific heats to those of continuous phases. It is found that fairly large Marangoni numbers may lead to fluctuations in drop velocities at the beginning part of simulations. Finally, we also discuss the influence of initial conditions on the thermocapillary migrations.

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“…Based on the years of ground-based research of the drop or bubble migration by means of matched-density and the facility of drop shaft [30,31] , the space experiment of drop thermocapillary migration at large Ma was performed on board the space ship Shen Zhou (SZ-4) of China in 2002 [32] . The experimental apparatus consisted of a test cell unit including drop injection system, optical diagnostics and illumination system, a recorder for data and video image recording, a controller unit and a power supply, as shown in Figure 5.…”

Section: Experiments Of Drop Marangoni Migrationmentioning

confidence: 99%

Space experimental studies of microgravity fluid science in China

Long

Kang

et al. 2009

Chin. Sci. Bull.

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Microgravity fluid physics is an important part of microgravity sciences, which consists of simple fluids of many new systems, gas-liquid two-phase flow and heat transfer, and complex fluid mechanics. In addition to the importance of itself in sciences and applications, microgravity fluid physics closely relates to microgravity combustion, space biotechnology and space materials science, and promotes the developments of interdisciplinary fields. Many space microgravity experiments have been performed on board the recoverable satellites and space ships of China and pushed the rapid development of microgravity sciences in China. In the present paper, space experimental studies and the main results of the microgravity fluid science in China in the last 10 years or so are introduced briefly. microgravity fluid physics, microgravity gas-liquid two-phase flow, microgravity complex fluid, microgravity combustion, space biotechnologyThe technologies of rockets and satellites require the study of the fluid management problem in the storage tanks, and such problems of microgravity engineering in the microgravity environment have been studied in China during the development of space technology [1] . Studies on microgravity sciences in China were started in the late 1980s, when the scientists completed some space experiments on board the Chinese recoverable satellites by the promotion of the National HighTechnology Research Program of China. Main research subjects were the scientific experiments of materials science, in charged by the experts of the Institute of Semiconductor of the Chinese Academy of Sciences (CAS) and the Lanzhou Institute of Physics [2][3][4] , and experiments of space biology, in charged by the experts of life sciences in the CAS [5][6][7] . Some nice results were obtained, although resources of space experiments on board the recoverable satellite were relatively limited in the preliminary period.Microgravity fluid physics is an import part of microgravity sciences, and requires relatively complicated experimental facility in general, mostly the optical diagnostic instrumentations. Theoretical and experimental studies of the microgravity fluid physics on the ground were started relatively early in China [8] ; the scientists of China and Japan jointly completed the microgravity experiments of the thermocapillary convection in floating half zone [9] and drop Marangoni migration [10] using the JAMIC drop shift in Hokkaido and the MGLAB drop shift in Toki respectively before the foundation of the Beijing Drop Tower, and the experimental results were nice. China's first space experiment of fluid physics was completed 10 years later after the initiation of one of the materials science. The experiments of Marangoni convection and thermocapillary convection in two immiscible liquid layers were performed on board the SJ-5

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Experimental investigation on thermocapillary drop migration at large Marangoni number in reduced gravity

Cited by 43 publications

References 11 publications

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

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

Thermocapillary migration of nondeformable drops

Space experimental studies of microgravity fluid science in China

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