Heat transfer model for gas–liquid slug flows under constant flux

Walsh, Patrick; Walsh, Edmond J.; Muzychka, Y. S.

doi:10.1016/j.ijheatmasstransfer.2010.03.007

Cited by 85 publications

(49 citation statements)

References 30 publications

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“…Many experiments have been performed to measure the heat transfer enhancement in microchannels with droplets, slugs, or plugs [9]. Some experiments used cylindrical microtubes [10,11,12,13], while others used rectangular microchannels [14,15,16,17]. Their experimental results showed significant enhancement of heat transfer when comparing with single phase flow, and the Nusselt numbers are several times higher than the single phase counterpart.…”

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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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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“…Previous studies in this area by Horvath et al (1973), Walsh et al (2010), and Howard et al (2011) have shown slug length to be an important parameter, significantly influencing the resultant pressure drop, heat and mass transfer rates. Nonetheless, to the best of the authors' knowledge, there are only three models in the literature that account for the effects of slug length on pressure drop.…”

Section: Liquid-gas Pressure Drop Modelsmentioning

confidence: 97%

“…At the microscale, however, the dominance of surface forces over gravitational forces results in slug and droplet flow regimes being the most commonly encountered. Slug or Taylor flow regimes offer significantly enhanced levels of heat, (Walsh et al, 2010), and mass, (Ghaini et al, 2010), transfer over equivalent single phase flow systems. Consequently, they can be found in a diverse range of technologies including compact heat exchangers, (Muzychka et al, 2011), monolith catalysts, (Kreutzer et al, 2005b), and biomedical devices, (Gunther et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Review and extension of pressure drop models applied to Taylor flow regimes

Eain

Egan

Howard

et al. 2015

International Journal of Multiphase Flow

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a b s t r a c tThis paper investigates the pressure drop induced by both liquid-liquid and liquid-gas segmented Taylor flow regimes. A comprehensive experimental programme was completed using four different liquidliquid and three different liquid-gas combinations over dimensionless slug length, Reynolds and Capillary numbers that spanned several orders of magnitude. Comparisons between the liquid-liquid pressure drop data and the most referenced expressions in the literature highlighted their lack of robustness and demonstrated their inapplicability for use with most practical systems that incorporate liquid-liquid Taylor flow regimes. The experimental pressure drop values obtained for the liquid-gas flows agreed well with existing pressure drop correlations. Interpretation of the liquid-liquid data using liquid-gas models unearthed the existence of a threshold viscosity ratio. Above this threshold, experimental liquid-liquid data was found to agree well with existing liquid-gas models. Below this threshold, results showed that the dispersed slug velocity needed to be considered as the flows were subject to higher interfacial contributions and inertial effects. A modification is proposed to an existing liquid-gas pressure drop correlation. This proposed modification extends the applicability of the correlation to liquid-liquid flows, and furthermore extends the non-dimensional limits of the correlation.

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“…The residual values are calculated between the temperature profiles generated by the complete models (Equations (20) and (21)) and those estimated by the 2T simplified model (Equations (29) and (30)). The residual values are calculated as:…”

Section: Analytical Validation Of the Simplified Modelmentioning

confidence: 99%

“…Moreover, many experimental and theoretical works concerning the thermal effects and thermal characterisation of segmented liquid gas flows have been presented. [27][28][29] Most of these studies concern the cooling systems of miniaturised electronic devices, which are used to improve micro-heat exchangers.…”

Section: Introductionmentioning

confidence: 99%

Quantitative thermal analysis of heat transfer in liquid–liquid biphasic millifluidic droplet flows

Romano

Pradère

Toutain

et al. 2014

Quantitative InfraRed Thermography Journal

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. In this paper, infrared thermography is used to propose a simple quantitative approach toward understanding the thermal behaviour of a liquid-liquid biphasic millifluidic droplet flow under isoperibolic conditions. It is shown that due to the isoperibolic boundary condition, the thermal behaviour at the established periodic state can be managed according to different orders, i.e. either a continuous or fluctuating contribution. A complete analytical solution is proposed for the complex problem model, then a simplified model is proposed. Finally, a simple homogeneous equivalent thin body model approximation with a characteristic coefficient function of a biphasic flow mixing law is sufficient for describing the thermal behaviour of the media under isoperibolic conditions. From this theoretical validation, the experimental results concerning the behaviour of a biphasic oil and droplet flow are presented. An analytical representation law is proposed to quantitatively estimate and predict the thermal behaviour of the flow. Moreover, it is demonstrated that with this new method, the thermophysical properties of the phase can be estimated with a deviation less than 5% from that reported by the suppliers.

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Heat transfer model for gas–liquid slug flows under constant flux

Cited by 85 publications

References 30 publications

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

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

Review and extension of pressure drop models applied to Taylor flow regimes

Quantitative thermal analysis of heat transfer in liquid–liquid biphasic millifluidic droplet flows

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