Competing thermal and solutal advection decelerates droplet evaporation on heated surfaces

Kaushal, Abhishek; Jaiswal, Vivek; Mehandia, Vishwajeet; Dhar, Purbarun

doi:10.1016/j.euromechflu.2021.10.003

Cited by 12 publications

(2 citation statements)

References 67 publications

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“…Unlike DI water droplets, the nanobubble-dispersed fluid droplets interestingly exhibit CCR (constant contact radius) mode (see columns three through five of the NB fluid droplets in Figure ) with no shift of its triple line during boiling. This behavior is analogous to the constant contact radius mode observed in the evaporation of droplets. − On further magnification of Figure (second row and columns three through five in the top row of Figure ), it is readily evident that the nanobubble fluid droplets are in CCR mode via the change in their contact angle (red, yellow, and green droplet curvature profiles in the inset of Figure ) without losing their pinning effect. The CCR mode lasted for ∼245 ms for 87 million and 104 million bubbles/mL.…”

Section: Resultssupporting

confidence: 55%

Augmenting the Leidenfrost Temperature of Droplets via Nanobubble Dispersion

et al. 2022

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Droplets may rebound/levitate when deposited over a hot substrate (beyond a critical temperature) due to the formation of a stable vapor microcushion between the droplet and the substrate. This is known as the Leidenfrost phenomenon. In this article, we experimentally allow droplets to impact the hot surface with a certain velocity, and the temperature at which droplets show the onset of rebound with minimal spraying is known as the dynamic Leidenfrost temperature (T DL ). Here we propose and validate a novel paradigm of augmenting the T DL by employing droplets with stable nanobubbles dispersed in the fluid. In this first-of-itskind report, we show that the T DL can be delayed significantly by the aid of nanobubble-dispersed droplets. We explore the influence of the impact Weber number (We), the Ohnesorge number (Oh), and the role of nanobubble concentration on the T DL . At a fixed impact velocity, the T DL was noted to increase with the increase in nanobubble concentration and decrease with an increase in impact velocity for a particular nanobubble concentration. Finally, we elucidated the overall boiling behaviors of nanobubble-dispersed fluid droplets with the substrate temperature in the range of 150− 400 °C against varied impact We through a detailed phase map. These findings may be useful for further exploration of the use of nanobubble-dispersed fluids in high heat flux and high-temperature-related problems and devices.

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Section: Resultssupporting

confidence: 55%

Augmenting the Leidenfrost Temperature of Droplets via Nanobubble Dispersion

et al. 2022

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“…TM is observed in many phenomena of practical importance, such as in combustion, , in weld pools, , in bubble and drop migration dynamics, − in the evaporation kinetics of droplets, − and in liquid films, − etc. TM finds relevance in thermo-fluid dynamics aspects of many industrial processes such as producing thin metal foils; surface patterning, coating, or painting using liquid films; lubrication and lubricant migration behavior; etc.…”

Section: Introductionmentioning

confidence: 99%

Marangoni Flows in a Bilayer Liquid Microfilm Interface on Wave-Contoured Hot Substrates

Agrawal,

Das,

Dhar

2023

Langmuir

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This study explores the thermal Marangoni hydrodynamics in an immiscible, binary-liquid thin-film system, which is open to the gas phase at the top and rests on a heated substrate with wavy topology. The sinusoidal contour of the heated (constant-temperature) substrate results in temperature gradients along the liquid–liquid and liquid–gas interfaces, causing fluctuations in the interfacial tension, ultimately leading to Marangoni hydrodynamics in the liquid–liquid films. This type of flow is notable in liquid film coatings on patterned surfaces, which are widely used in MEMS/NEMS applications (Weinstein, S. J.; Palmer, H. J. Liquid Film Coating: Scientific Principles and Their Technological Implications; 1997, pp 19–62; Palacio, M.; Bhushan, B. Adv. Mater. 2008, 20, 1194–1198) and biological cell sorting operations (Witek, M. A.; Freed, I. M.; Soper, S. A. Anal. Chem. 2019, 92, 105–131). We solve the coupled Navier–Stokes and energy equations by the perturbation technique to obtain approximate analytical solutions and an understanding of the thermal and hydrodynamic transport in the system domain. Our study explores the parametric influence of the relative thermal conductivity of the liquid layers (k), film thickness ratio (r), and the system’s Biot number (Bi) on these transport phenomena. While the strength of the thermal Marangoni effect that is generated reduces with an increase in the relative thermal conductivity (k), the impact of r depends on the k value. We observe that for k > 1 the intensity of Marangoni flow increases with r; however, the opposite holds for k < 1. Furthermore, larger values of Bi induce higher resistance to the vertical conduction from the wavy substrate compared to the convection resistance offered at the top surface, destructively interfering with the ability of the patterned substrate to generate interfacial temperature fluctuations and hence weakening the Marangoni flow.

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Analysis of mixed prostate specific antigen and Tween-20 sessile droplets for the reduction in interfacial PSA adsorption

Rathaur¹,

Panda²

2023

Chemical Engineering Journal Advances

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Competing thermal and solutal advection decelerates droplet evaporation on heated surfaces

Cited by 12 publications

References 67 publications

Augmenting the Leidenfrost Temperature of Droplets via Nanobubble Dispersion

Augmenting the Leidenfrost Temperature of Droplets via Nanobubble Dispersion

Marangoni Flows in a Bilayer Liquid Microfilm Interface on Wave-Contoured Hot Substrates

Analysis of mixed prostate specific antigen and Tween-20 sessile droplets for the reduction in interfacial PSA adsorption

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