Detailed numerical analysis of evaporation of a micrometer water droplet suspended on a glass filament

George, Oluwafemi Ayodele; Xiao, Jie; Rodrigo, Carles Safont; Mercadé‐Prieto, Ruben; Sempere, J.; Chen, Xiao

doi:10.1016/j.ces.2017.02.038

Cited by 31 publications

(19 citation statements)

References 40 publications

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“…Finally, it is important to point out that the suppression of surface tension forces adopted in this work could in principle affect the internal motion in the liquid phase, because of the different the tangential shear stress at the interface. However, our comparative analyses in this sense, not reported in this work, show that the results obtained with DropletSMOKE++ are in a reasonable agreement both with experimental [66,67] and numerical [36,68] works not based on the VOF methodology. These investigations are still preliminary, but indicate that even neglecting surface tension the internal circulation phenomenon can be quantitatively and qualitatively captured with a reasonable accuracy.…”

Section: Numerical Results and Discussionsupporting

confidence: 68%

DropletSMOKE++: A comprehensive multiphase CFD framework for the evaporation of multidimensional fuel droplets

Saufi¹,

Frassoldati²,

Faravelli³

et al. 2019

International Journal of Heat and Mass Transfer

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This paper aims at presenting the DropletSMOKE++ solver, a comprehensive multidimensional computational framework for the evaporation of fuel droplets, under the influence of a gravity field and an external fluid flow. The Volume Of Fluid (VOF) methodology is adopted to dynamically track the interface, coupled with the solution of energy and species equations. The evaporation rate is directly evaluated based on the vapor concentration gradient at the phase boundary, with no need of semi-empirical evaporation sub-models.The strong surface tension forces often prevent to model small droplets evaporation, because of the presence of parasitic currents. In this work we by-pass the problem, eliminating surface tension and introducing a centripetal force toward the center of the droplet. This expedient represents a major novelty of this work, which allows to numerically hang a droplet on a fiber in normal gravity conditions without modeling surface tension. Parasitic currents are completely suppressed, allowing to accurately model the evaporation process whatever the droplet size. DropletSMOKE++ shows an excellent agreement with the experimental data in a wide range of operating conditions, for various fuels and initial droplet diameters, both in natural and forced convection. The comparison with the same cases modeled in microgravity conditions highlights the impact of an external fluid flow on the evaporation mechanism, especially at high pressures.Non-ideal thermodynamics for phase-equilibrium is included to correctly capture evaporation rates at high pressures, otherwise not well predicted by an ideal gas assumption. Finally, the presence of flow circulation in the liquid phase is discussed, as well as its influence on the internal temperature field. DropletSMOKE++ will be released as an open-source code, open to contributions from the sci-

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Section: Numerical Results and Discussionsupporting

confidence: 68%

DropletSMOKE++: A comprehensive multiphase CFD framework for the evaporation of multidimensional fuel droplets

Saufi¹,

Frassoldati²,

Faravelli³

et al. 2019

International Journal of Heat and Mass Transfer

View full text Add to dashboard Cite

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“…Droplet surface evaporation into the air ambient can be included via utilizing diffusion-convection analogy, which can be written as 22 : Here: C v is the specific heat at constant volume, being airflow velocity, and D v is diffusion coefficient (m 2 s −1 ). The interfacial mass-flux at droplet fluid and air contact surface can be obtained through the adoption of the mass-conservation terms, which are 23 , 24 : Here: represents interfacial velocity, is outward unit vector being normal to droplet fluid-air interface, vapor phase is specified by v and liquid phase is by l .…”

Section: Numerical and Validation Studymentioning

confidence: 99%

On the mechanism of droplet rolling and spinning in inclined hydrophobic plates in wedge with different wetting states

Yilbaş

Yakubu

Abubakar

et al. 2021

Sci Rep

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A water droplet rolling and spinning in an inclined hydrophobic wedge with different wetting states of wedge plates is examined pertinent to self-cleaning applications. The droplet motion in the hydrophobic wedge is simulated in 3D space incorporating the experimental data. A high-speed recording system is used to store the motion of droplets in 3D space and a tracker program is utilized to quantify the recorded data in terms of droplet translational, rotational, spinning, and slipping velocities. The predictions of flow velocity in the droplet fluid are compared with those of experimental results. The findings revealed that velocity predictions agree with those of the experimental results. Tangential momentum generated, via droplet adhesion along the three-phase contact line on the hydrophobic plate surfaces, creates the spinning motion on the rolling droplet in the wedge. The flow field generated in the droplet fluid is considerably influenced by the shear rate created at the interface between the droplet fluid and hydrophobic plate surfaces. Besides, droplet wobbling under the influence of gravity contributes to the flow inside the rolling and spinning droplet. The parallel-sided droplet path is resulted for droplet emerging from the wedge over the dusty surface.

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“…Droplet evaporation into the ambient air can be incorporated in the simulations by adopting the diffusion-convection equation [26]:…”

Section: Data Availability Statementmentioning

confidence: 99%

Impacting Droplet Can Mitigate Dust from PDMS Micro-Post Array Surfaces

et al. 2021

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In this paper, the impact mechanisms of a water droplet on hydrophobized micro-post array surfaces are examined and the influence of micro-post arrays spacing on the droplet behavior in terms of spreading, retraction, and rebounding is investigated. Impacting droplet behavior was recorded using a high-speed facility and flow generated in the droplet fluid was simulated in 3D geometry accommodating conditions of the experiments. Micro-post arrays were initially formed lithographically on silicon wafer surfaces and, later, replicated by polydimethylsiloxane (PDMS). The replicated micro-post arrays surfaces were hydrophobized through coating by functionalized nano-silica particles. Hydrophobized surfaces result in a contact angle of 153° ± 3° with a hysteresis of 3° ± 1°. The predictions of the temporal behavior of droplet wetting diameter during spreading agree with the experimental data. Increasing micro-post arrays spacing reduces the maximum spreading diameter on the surface; in this case, droplet fluid penetrated micro-posts spacing creates a pinning effect while lowering droplet kinetic energy during the spreading cycle. Flow circulation results inside the droplet fluid in the edge region of the droplet during the spreading period; however, opposing flow occurs from the outer region towards the droplet center during the retraction cycle. This creates a stagnation zone in the central region of the droplet, which extends towards the droplet surface onset of droplet rebounding. Impacting droplet mitigates dust from hydrophobized micro-post array surfaces, and increasing droplet Weber number increases the area of dust mitigated from micro-post arrays surfaces.

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Detailed numerical analysis of evaporation of a micrometer water droplet suspended on a glass filament

Cited by 31 publications

References 40 publications

DropletSMOKE++: A comprehensive multiphase CFD framework for the evaporation of multidimensional fuel droplets

DropletSMOKE++: A comprehensive multiphase CFD framework for the evaporation of multidimensional fuel droplets

On the mechanism of droplet rolling and spinning in inclined hydrophobic plates in wedge with different wetting states

Impacting Droplet Can Mitigate Dust from PDMS Micro-Post Array Surfaces

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