Numerical simulation of gas–liquid two-phase flow and convective heat transfer in a micro tube

Fukagata, Koji; Kasagi, Nobuhide; Ua-arayaporn, Poychat; Himeno, Takehiro

doi:10.1016/j.ijheatfluidflow.2006.04.010

Cited by 94 publications

(53 citation statements)

References 24 publications

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“…The numerical studies on non-evaporating or condensing flow has been studied in larger amount compared to studies of phase changing Taylor bubble flow. Fukagata et al [74] carried out a numerical study on the flow and heat transfer characteristics of a bubble flow train without phase change using level set method. They were able to obtain qualitative agreement with experimental results regarding wall temperature and found higher local Nusselt numbers beneath the bubble compared to single-phase flow.…”

Section: Literature Reviewmentioning

confidence: 99%

Direct numerical simulation of incompressible multiphase flow with phase change

Lee

Riaz

Aute

2017

Journal of Computational Physics

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Phase change problems arise in many practical applications such as air-conditioning and refrigeration, thermal energy storage systems and thermal management of electronic devices.The physical phenomenon in such applications are complex and are often difficult to be studied in detail with the help of only experimental techniques. The efforts to improve computational techniques for analyzing two-phase flow problems with phase change are therefore gaining momentum.The development of numerical methods for multiphase flow has been motivated generally by the need to account more accurately for (a) large topological changes such as phase breakup and merging, (b) sharp representation of the interface and its discontinuous properties and (c) accurate and mass conserving motion of the interface. In addition to these considerations, numerical simulation of multiphase flow with phase change introduces additional challenges related to discontinuities in the velocity and the temperature fields. Moreover, the velocity field is no longer divergence free. For phase change problems, the focus of developmental efforts has thus been on numerically attaining a proper conservation of energy across the interface in addition to the accurate treatment of fluxes of mass and momentum conservation as well as the associated interface advection.Among the initial efforts related to the simulation of bubble growth in film boiling applications the work in [1] was based on the interface tracking method using a moving unstructured mesh. That study considered moderate interfacial deformations. A similar problem was subsequently studied using moving, boundary fitted grids Among the front capturing methods, sharp interface methods have been found to be particularly effective both for implementing sharp jumps and for resolving the interfacial velocity field. However, sharp velocity jumps render the solution susceptible to erroneous oscillations in pressure and also lead to spurious interface velocities. To implement phase change, the work in [16] employed point mass source terms derived from a physical basis for the evaporating mass flux. To avoid numerical instability, the authors smeared the mass source by solving a pseudo time-step diffusion equation. This measure however led to mass conservation issues due to non-symmetric integration over the distributed mass source region. The problem of spurious pressure oscillations related to point mass sources was also investigated by [17]. Although their method is based on the VOF, the large pressure peaks associated with sharp mass source was observed to be similar to that for the interface tracking method.Such spurious fluctuation in pressure are essentially undesirable because the effect is globally transmitted in incompressible flow. Hence, the pressure field formation due to phase change need to be implemented with greater accuracy than is reported in current literature.The accuracy of interface advection in the presence of interfacial mass flux (mass flux conservation) has been discussed in [14,18]. ...

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Section: Literature Reviewmentioning

confidence: 99%

Direct numerical simulation of incompressible multiphase flow with phase change

Lee

Riaz

Aute

2017

Journal of Computational Physics

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“…Various interface tracking/capturing techniques have been employed to simulate the heat transfer in droplets, slugs, and plugs, such as the volume of fluid method [19], the level set method [20,21], and the phase field method [22]. Regarding the geometries of microchannels, most simulations were performed with cylindrical microcapillaries [18,20,22,21,23,19] or two dimensional (2D) microchannels [8], where the three dimensional (3D) effect on the flow and on the heat transfer process cannot be considered. However, in most microchannel heat exchangers, the microchannels usually have rectangular or other non-circular cross sections [14,15,16,17].…”

Section: Introductionmentioning

confidence: 99%

Three dimensional features of convective heat transfer in droplet-based microchannel heat sinks

Che

Wong

Nguyen

et al. 2015

International Journal of Heat and Mass Transfer

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Convective heat transfer in droplet-based microchannel heat sinks can be enhanced by the recirculating vortices due to the presence of interfaces. In rectangular microchannels, the three dimensional structures of the vortices and the 'gutters' (i.e., the space between the curved droplet interface and the corner of the microchannel) can significantly affect the heat transfer process. Numerical simulations of the heat transfer process are performed to study the three dimensional features in droplet-based microchannel heat sinks. The finite volume method and the level set method are employed to simulate the flow dynamics, the evolution of the interface, and the heat transfer. The results show that the 'gutters' can hinder the heat transfer process because of its parallel flow, whereas the recirculating flow in droplets and in slug regions between successive droplets can enhance the heat transfer by advecting hot fluid towards the center of the droplets/slugs and advecting fresh fluid towards the wall of the channel. The effects of the length of droplets, the aspect ratio of the channel cross sections, and the Peclet number are analyzed.

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“…A similar strategy combined with a continuum surface force (CSF) model for modeling surface tension effects was applied in simulating Taylor flows in horizontal microchannels [3]. Fukagata et al [7] numerically studied Taylor flows with a focus on heat transfer in a two-dimensional and axisymmetric tube using a LS method. A phase-field method was applied by He et al [8] in revealing the bubble shape, superficial velocities of gas and liquid in a two-dimensional and axisymmetric channel for gas-liquid two-phase flows.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on Single Flowing Liquid and Supercritical CO2 Drop in Microchannel: Thin Film, Flow Fields, and Interfacial Profile

et al. 2018

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Abstract:Taylor segments, as a common feature in two-or multi-phase microflows, are a strong flow pattern candidate for applications when enhanced heat or mass transfer is particularly considered. A thin film that separates these segments from touching the solid channel and the flow fields near and inside the segment are two key factors that influence (either restricting or improving) the performance of heat and mass transfer. In this numerical study, a computational fluid dynamics (CFD) method and dense carbon dioxide (CO 2 ) and water are applied and used as a fluid pair, respectively. One single flowing liquid or supercritical CO 2 drop enclosed by water is traced in fixed frames of a long straight microchannel. The thin film, flow fields near and within single CO 2 drop, and interfacial distributions of CO 2 subjected to diffusion and local convections are focused on and discussed. The computed thin film is generally characterized by a thickness of 1.3~2.2% of the channel width (150 µm). Flow vortexes are formed within the hydrodynamic capsular drop. The interfacial distribution profile of CO 2 drop is controlled by local convections near the interface and the interphase diffusion, the extent of which is subject to the drop size and drop speed as well.

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Numerical simulation of gas–liquid two-phase flow and convective heat transfer in a micro tube

Cited by 94 publications

References 24 publications

Direct numerical simulation of incompressible multiphase flow with phase change

Direct numerical simulation of incompressible multiphase flow with phase change

Three dimensional features of convective heat transfer in droplet-based microchannel heat sinks

Numerical Study on Single Flowing Liquid and Supercritical CO2 Drop in Microchannel: Thin Film, Flow Fields, and Interfacial Profile

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