Stable cluster of identical water droplets formed under the infrared irradiation: Experimental study and theoretical modeling

Dombrovsky, Leonid A.; Fedorets, Alexander A.; Levashov, V. Yu.; Kryukov, A. P.; Bormashenko, Edward; Nosonovsky, Michael

doi:10.1016/j.ijheatmasstransfer.2020.120255

Cited by 26 publications

(15 citation statements)

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“…the evaporation model has shown a good agreement with the experimental data [53]. This model has been also successfully employed in recently published studies [23,26]. Note that the thickness of the Knudsen layer is on the order of the mean free path of gas molecules (about 0.2 µm under ambient conditions), and the model is applicable for droplets of larger radii.…”

Section: Modeling Of Evaporation Of Microdropletssupporting

confidence: 63%

“…First, we assume that the temperature difference within the droplet is negligible, which is justified for small droplet. Following [23], consider the characteristic time scale, τ rel,t , of the thermal equilibration of small water droplets. This time scale may be roughly estimated from the equation Fo = α w τ rel,t /a 2 = 1, where α w = k w /(ρ w c w ) is the thermal diffusivity of water and Fo is the Fourier number.…”

Section: Modeling Of Evaporation Of Microdropletsmentioning

confidence: 99%

“…Suspended droplets are driven towards the center. However, they do not coalesce, because there is also a repulsion force between the droplets, which is also aerodynamic in nature [23]. Consequently, droplets approach each other and settle (while levitating all at same height forming a monolayer) at a certain equilibrium distance from each other, where the drag towards the center is equilibrated by aerodynamic repulsion (Figure 6b).…”

Section: A Promising Technology For Tracing Submicron Scaled Particlementioning

confidence: 99%

“…Consequently, a typical life span of a droplet cluster is on the order of a minute. However, by irradiating and heating the droplets with the infrared radiation, the condensational growth can be suppressed [18,23]. It has been recently demonstrated in [23] that completely equilibrium small clusters containing several identical droplets can be produced and these clusters are stable during the extended periods of time sufficient for the laboratory biological study.…”

Section: A Promising Technology For Tracing Submicron Scaled Particlementioning

confidence: 99%

“…the milestones of this study include stabilization of the cluster managing the cluster parameters that is important for the laboratory observations of biochemical processes in single droplets. In addition to [15,17], we refer to several basic publications [18][19][20][21][22][23] related to cluster management as applied to the observation of processes in the droplets. the droplets levitate at a height comparable with their radii, where the vertical component of the drag force is equilibrated by their own weight [24].…”

Section: Introductionmentioning

confidence: 99%

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Modeling Evaporation of Water Droplets as Applied to Survival of Airborne Viruses

et al. 2020

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Many viruses, such as coronaviruses, tend to spread airborne inside water microdroplets. Evaporation of the microdroplets may result in a reduction of their contagiousness. However, the evaporation of small droplets is a complex process involving mass and heat transfer, diffusion, convection and solar radiation absorption. Virological studies indicate that airborne virus survival is very sensitive to air humidity and temperature. We employ a model of droplet evaporation with the account for the Knudsen layer. This model suggests that evaporation is sensitive to both temperature and the relative humidity (RH) of the ambient air. We also discuss various mechanisms such as the effect of solar irradiation, the dynamic relaxation of moving droplets in ambient air and the gravitational sedimentation of the droplets. The maximum estimate for the spectral radiative flux in the case of cloudless sky showed that the radiation contribution to evaporation of single water droplets is insignificant. We conclude that at small and even at moderately high levels of RH, microdroplets evaporate within dozens of seconds with the convective heat flux from the air being the dominant mechanism in every case. The numerical results obtained in the paper are in good qualitative agreement with both the published laboratory experiments and seasonal nature of many viral infections. Sophisticated experimental techniques may be needed for in situ observation of interaction of viruses with organic particles and living cells within microdroplets. The novel controlled droplet cluster technology is suggested as a promising candidate for such experimental methodology.

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Section: Modeling Of Evaporation Of Microdropletssupporting

confidence: 63%

Section: Modeling Of Evaporation Of Microdropletsmentioning

confidence: 99%

Section: A Promising Technology For Tracing Submicron Scaled Particlementioning

confidence: 99%