Effects of superheat and temperature-dependent thermophysical properties on evaporating thin liquid films in microchannels

Zhao, Junjie; Duan, Yuan-Yuan; Wang, Xiaodong; Wang, Bu‐Xuan

doi:10.1016/j.ijheatmasstransfer.2010.10.026

Cited by 52 publications

(66 citation statements)

References 30 publications

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“…In the present work the thickness of non evaporation region is considered d 0 ¼ 3 nm as boundary conditions. The specified boundary condition (12-b) is obtained using the shooting method to satisfy the boundary condition at far field of the intrinsic meniscus region [27,34]. Since the thickness of thin film at x ¼ 0 is field region the disjoining pressure is sufficiently small and the meniscus radius approaches the constant value [27].…”

Section: Modelingmentioning

confidence: 99%

Experimental and numerical investigation of a shaped microchannel evaporator for a micro Rankine cycle application

Azarkish

Arslan

Behzadmehr

et al. 2015

International Journal of Thermal Sciences

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Section: Modelingmentioning

confidence: 99%

Experimental and numerical investigation of a shaped microchannel evaporator for a micro Rankine cycle application

Azarkish

Arslan

Behzadmehr

et al. 2015

International Journal of Thermal Sciences

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“…The effect of an increasing channel width, was an increased thin-film length (Qu et al 2002;Zhao et al, 2011). Du and Zhao (2012) attempted to quantify the effects of using altered evaporation models.…”

Section: Varying Thermophysical Properties Slip Boundary Conditionmentioning

confidence: 99%

Numerical Investigation of an Evaporating Thin Film on a Heated Surface

Ball¹,

Polansky²,

Kaya³

2013

Frontiers in Heat and Mass Transfer

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The fluid flow and heat transfer in an evaporating extended meniscus are numerically studied. Continuity, momentum, energy equations and the Kelvin-Clapeyron model are used to develop a third order, non-linear ordinary differential equation which governs the evaporating thin film. It is shown that the numerical results strongly depend on the choice of the accommodation coefficient and Hamaker constant as well as the initial perturbations. Therefore, in the absence of experimentally verified values, the numerical solutions should be considered as qualitative at best. It is found that the numerical results produce negative liquid pressures under certain specific conditions. This result may suggest that the thin film can be in an unstable state of tension; however, this finding remains speculative without experimental validation. Although similar thin-film models proved to be very useful in gaining qualitative insight into the characteristics of evaporating thin films, the results shown in this study indicate that careful experimental investigations are needed to verify the mathematical models.

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“…Because of the geometric symmetry, only one side of the meniscus is considered and the following assumptions are introduced: (1) quasi-steady two-dimensional laminar flow with both the liquid and vapor being incompressible; (2) a pure fluid with the fluid thermophysical properties correlated as polynomial functions of temperature as in our previous studies [11]; (3) gravitational forces and the vapor recoil pressure are neglected; (4) atomically smooth solid surfaces are assumed to be either hydrophilic or hydrophobic; (5) a constant wall temperature, T w , of 344 K and a bulk vapor temperature, T v , varying from 324 to 343 K; (6) combined temperature and velocity slip only occur in the thin-film region; and (7) a two-layer model is used with a liquid-film layer of thickness δ over a nanolayer of thickness l * . The liquid film does not feel the presence of the wall directly due to the nanolayer [14].…”

Section: Thin-film Evaporation Modelmentioning

confidence: 99%

“…(16) with the velocity profiles (u l and u v ). The analytical expressions for u l , u v , dP l /dx, and dP v /dx are given in Zhao et al [11]. The pressure difference between the liquid and vapor at the liquid-vapor interface can be expressed by the augmented Young-Laplace equation…”

Section: Thin-film Evaporation Modelmentioning

confidence: 99%

“…Most studies of thin liquid film evaporation [9][10][11][12][13][14] have assumed that there is no temperature slip at the wall and the effect of the Kapitza resistance is negligible, so T w = T w . Atomistic simulations by Freund [15] showed that the Kapitza resistance at the solidliquid boundary is negligible at macroscopic scales but important for evaporating thin meniscus films.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Near-Wall Liquid Layering, Velocity Slip, and Solid–Liquid Interfacial Thermal Resistance for Thin-Film Evaporation in Microchannels

Zhao

Huang

Min

et al. 2011

Nanoscale and Microscale Thermophysical Engineering

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Heat transfer and liquid flow near solid-liquid interfaces for evaporating thin films in microchannels were investigated based on the augmented Young-Laplace equation and kinetic theory. A wall-affected nanolayer was used to correlate the Kapitza resistance with the liquid layering and velocity slip for both hydrophilic and hydrophobic surfaces. This nanolayer physical model was developed to show the combined effects of the solid-liquid interfacial temperature slip and the velocity slip on the thin-film evaporation. The resultsshow that the liquid velocity slip elongates the thin-film region and enhances the evaporation. A minimum slip length exists for the extremely wetting case. The Kapitza resistance and nanolayer disordering for hydrophobic surfaces tend to reduce the thin liquid film superheat and overall heat transfer, leading to a larger U-shaped temperature drop. The nanolayer ordering enhances the thin-film evaporation but cannot entirely counteract the Kapitza resistance.

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Effects of superheat and temperature-dependent thermophysical properties on evaporating thin liquid films in microchannels

Cited by 52 publications

References 30 publications

Experimental and numerical investigation of a shaped microchannel evaporator for a micro Rankine cycle application

Experimental and numerical investigation of a shaped microchannel evaporator for a micro Rankine cycle application

Numerical Investigation of an Evaporating Thin Film on a Heated Surface

Near-Wall Liquid Layering, Velocity Slip, and Solid–Liquid Interfacial Thermal Resistance for Thin-Film Evaporation in Microchannels

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