Interplay of capillary and Marangoni flows in micropillar evaporation

Yuncu, Goksel
Akkus, Yigit
Dursunkaya, Zafer
The evaporation from a micropillar evaporator is a problem governed by various interfacial phenomena such as the capillarity-induced liquid flow, thin-film evaporation intensifying near the contact lines, and thermocapillarity-induced Marangoni flow. However, past research has not been able to assess the effect of Marangoni flow due to the missing coupling between cell-and device-level modeling. In this work, we develop a comprehensive model for the evaporation from a micropillar evaporator by coupling the liquid flow with the energy transfer in both liquid and solid domains at both cell-and device-levels. The model is successfully validated with previous experiments. When the Marangoni number is sufficiently high, the model identifies a sharp reduction in the evaporator temperature attributed to the thermocapillary convection creating circulations beneath the liquid-vapor interface, which results in the formation of periodic reverse surface flows on the interface. This temperature drop cannot be identified when thermocapillarity is switched off in the model and the model's prediction substantially deviates from experimental measurement. Therefore, the current study reveals a hitherto unexplored role of Marangoni flow in the evaporation of water from micropillar evaporators.


Comprehensive modeling of heat and mass transport in a micropillar evaporator
Yuncu, Göksel; Dursunkaya, Zafer; Akkuş, Yiğit; Department of Mechanical Engineering (2022-4-05)
Thin-film evaporation and the replenishing capillary liquid flow have paramount importance for various technological applications spanning from desalination to electronics cooling. With the developments enabling faster and cheaper yet more precise fabrication, evaporators with micropillar arrays have attracted substantial attention to sustain efficient evaporation fed by passive liquid transport. Although considerable effort has been devoted to designing optimized wicks, the full picture is still blurry due...
Modeling of fluid -vapor interface in the condensation zone of a grooved heat pipe
Alipour, Mobin; Dursunkaya, Zafer; Department of Mechanical Engineering (2017)
Condensation in grooved heat pipes involves several simultaneous phenomena including vapor-liquid boundaries whose shapes are unknown a priori, fluid flow due to capillary and dispersion pressure gradients and condensation over ultra thin films. In grooved heat pipes, the majority of condensation occurs on fin tops due to the thinner liquid film, having a lower thermal resistance, compared to inside the groove where the fluid is substantially thicker. Majority of the studies in the literature assume an appr...
Enhanced thermal conductivity of nanofluids: a state-of-the-art review
Özerinç, Sezer; Yazicioglu, Almila Guevenc (2010-02-01)
Adding small particles into a fluid in cooling and heating processes is one of the methods to increase the rate of heat transfer by convection between the fluid and the surface. In the past decade, a new class Of fluids called nanofluids, in which particles of size 1-100 nm with high thermal conductivity are Suspended in a conventional heat transfer base fluid, have been developed. It has been shown that nanofluids containing a small amount of metallic or nonmetallic particles, Such as Al2O3, CuO, Cu, SiO2,...
Deposition of CZTSe thin films and illumination effects on the device properties of Ag/n-Si/p-CZTSe/In heterostructure
Bayrakli, O.; Terlemezoğlu, Makbule; GULLU, H. H.; Parlak, Mehmet (2017-06-30)
Characterization of Cu2ZnSnSe4 (CZTSe) thin films deposited by thermal evaporation sequentially from the pure elemental sources and in-situ post annealing was carried out at 400 C under Se evaporation atmosphere. Another annealing process was applied in nitrogen atmosphere at 450 degrees C to get poly-crystalline monophase CZTSe film structure. XRD analysis together with Raman spectroscopy was used to determine the structural properties. Spectral optical absorption coefficient evaluated from transmission da...
Structural characteristics of thermally evaporated Cu0.5Ag0.5InSe2 thin films
Gullu, H. H.; Parlak, Mehmet (2016-05-01)
In this work, Cu0.5Ag0.5InSe2 (CAIS) thin film samples were prepared by thermal evaporation of Cu, Ag, InSe and Se evaporants sequentially on glass substrates. Following the deposition, annealing processes were applied at different temperatures. The as-grown and annealed CAIS samples were nearly stoichiometric in the detection limit of the compositional measurement. The x-ray diffraction (XRD) measurements revealed that they were in polycrystalline structure with a preferred orientation along the (112) dire...
Citation Formats
G. Yuncu, Y. Akkus, and Z. Dursunkaya, “Interplay of capillary and Marangoni flows in micropillar evaporation,” INTERNATIONAL JOURNAL OF THERMAL SCIENCES, vol. 184, pp. 0–0, 2023, Accessed: 00, 2023. [Online]. Available: