Numerical investigation into the evaporation dynamics of drop-on-drop collisions over heated wetting surfaces

Guggilla, Ganesh; Pattamatta, Arvind; Narayanaswamy, Ramesh

doi:10.1016/j.ijheatmasstransfer.2018.03.029

Cited by 26 publications

(10 citation statements)

References 34 publications

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“…This is because of the reduction in surface mean temperature as a result of initial droplet (sessile) interaction with the surface. Also, the previous work using numerical modelling [53] revealed that there is rapid decline in heat transfer rate due to the increased film thickness during the drop-on-drop impingement.…”

Section: Spread Hydrodynamicsmentioning

confidence: 96%

“…m e m single (12) m e and m single are the cumulative evaporated mass and pre-impacting droplet mass. A similar approach was applied to the drop-on-drop impingement over a hot surface by Guggilla et al [53] as shown in Figure 33. In this case, the maximum spread factor is derived as…”

Section: Analytical Modelling 441 Maximum Spreadmentioning

confidence: 99%

“…The discrepancy with the spread factor prediction is due to the boiling phenomena reported Moreover, in the previous studies of Batzdorf [61], the values a = 8/3 and b = 4/3, are adopted for FC-72 droplet collision over chromium surface and obtained a good approximation for the cases studied. Later on, Guggilla et al [53] extended the study to drop-on-drop impact of FC-72 and the values of the same order, a = 8/3 and b = 3.4 are utilized to estimate the quantities. With these observations, it is determined that the analytical models are efficient in capturing the spread and heat transfer dynamics for the given constants a and b , and these values are sensitive to the nature of the liquid, surface, and boiling regimes (wall superheat).…”

Section: Input Heat Transfermentioning

confidence: 99%

“…Minamikawa et al [52] numerically studied successive impact of two drops on a heated wall and found that the morphology in film boiling regime is strongly dependent on vertical spacing between the drops. Guggilla et al [53] used a phase-change numerical model and studied the drop-on-drop impact over heated surfaces in film evaporation regime. The effect of non-dimensional numbers on evaporation dynamics of drop-on-drop collision and theoretical model to evaluate the numerical findings was developed.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

An experimental investigation into the spread and heat transfer dynamics of a train of two concentric impinging droplets over a heated surface

Guggilla

Narayanaswamy

Pattamatta

2020

Experimental Thermal and Fluid Science

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Section: Spread Hydrodynamicsmentioning

confidence: 96%

Section: Analytical Modelling 441 Maximum Spreadmentioning

confidence: 99%

Section: Input Heat Transfermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An experimental investigation into the spread and heat transfer dynamics of a train of two concentric impinging droplets over a heated surface

Guggilla

Narayanaswamy

Pattamatta

2020

Experimental Thermal and Fluid Science

Self Cite

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“…As highlighted before the drop-on-drop impact scenario is also encountered during spray cooling applications. Guggilla et al 35 performed a simulation of drop-on-drop impact (FC-72 as a working fluid) on a heated hydrophilic substrate (θ ∼ 35°) to estimate the heat transfer during such interactions. The spread factor is found to be large with drop-on-drop impact compared to a single droplet impacting a substrate.…”

Section: Dropletsmentioning

confidence: 99%

Drop-on-Drop Impact Dynamics on a Superhydrophobic Surface

Jaiswal

Khandekar

2021

Langmuir

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Investigation of multiple droplet interactions is vital due to its importance in various applications, including sprays. In this context, the interaction of a sessile droplet (droplet #1) interaction with an oncoming droplet (droplet #2), in a vertically aligned, dropon-drop configuration, on a superhydrophobic surface is investigated, both experimentally and computationally. Three droplet impact regimes, with low We number of the impacting droplet (i.e., We droplet #2 ∼ 1.0) is observed, viz., gentle merging, late merging, and droplet bounce-off without merging. Complementary simulation of the gentle merging regime shows that a very high-pressure gradient is generated between the neck and the bulk region immediately after the contact, which acts as a driving force for the subsequent rapid evolution of the droplet shape. With a larger We number (We droplet #2 ∼ 8.2 and 14.8), there is always a unique outcome of the impact experiments. The two droplets merge, spread, recede, and bounce-off; there are multiple instances of rebound of the combined droplet mass from the surface. The estimated shear stress emanating during the impact and subsequent dynamics is large enough to cause deterioration of chemically coated superhydrophobic surfaces. The difference in the shape of moving droplet #2 at the instance of impact for We droplet #2 ∼ 1, as compared to We droplet #2 ∼ 8.2 and 14.8 is also highlighted. Important time scales during coalescence and beyond are the inertial-capillary time scale (∼16 ms) and viscous-capillary time scale (∼8 s). We also highlight the role of the droplet #1 deposition boundary condition, influence of the We number of droplet #2, and substrate wettability on drop-on-drop interactions, which has direct relevance to the transport mechanisms happening in various engineering applications like spraying pesticides, spray cooling, and rain interactions, etc.

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Crater radius analysis after dual droplets successive oblique impact on liquid film

Bao,

Zhao,

Gong

et al. 2024

Surface & Interface Analysis

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Droplet impact is a common occurrence in nature, agriculture, and industry. The research on the multi‐droplet impact is fundamental to understanding the tangled nature of reality. This paper numerically studies the successive oblique impact of dual droplets on the liquid film by building an effective three‐dimensional model. The leading and trailing droplets are set to pass a certain impact point with the same velocity. The main contribution of this paper is the investigation of the effects of Weber number, liquid film thickness, impact angle, and impact time interval on the interface morphology evolution after the droplet impact. Results show that splash pattern conversion of the primary or secondary crown occurs with the change of these factors. Besides, the variations of the maximum crater radius in upstream, lateral, and downstream directions with time are quantitatively analyzed. The crater radius analysis is carried out from three perspectives, the variation during the single droplet impact, the change during the dual droplets impact, and the comparison between them. It is found that the crater of dual droplets impact exhibits shape distortion in the deformation period and appears a marked dimensional increase in the secondary expansion period.

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Numerical investigation into the evaporation dynamics of drop-on-drop collisions over heated wetting surfaces

Cited by 26 publications

References 34 publications

An experimental investigation into the spread and heat transfer dynamics of a train of two concentric impinging droplets over a heated surface

An experimental investigation into the spread and heat transfer dynamics of a train of two concentric impinging droplets over a heated surface

Drop-on-Drop Impact Dynamics on a Superhydrophobic Surface

Crater radius analysis after dual droplets successive oblique impact on liquid film

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