Single-phase heat transfer of multi-droplet impact on liquid film

Liang, Gangtao; Zhang, Tianyu; Chen, Liuzhu; Chen, Yang; Shen, Shengqiang

doi:10.1016/j.ijheatmasstransfer.2018.11.145

Cited by 39 publications

(9 citation statements)

References 11 publications

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“…In the joint region, temperatures for ethanol and butanol are abnormally higher than the undisturbed region without impact. This result has some similarities with the heat transfer “blind spot” reported in a previous study . The abnormal phenomenon can be attributed to much lower thermal conductivities for ethanol and butanol than water and a local relatively thick liquid layer in the joint region, that is, heat released from the heating surface is more difficult to be rejected.…”

Section: Resultssupporting

confidence: 86%

Parametric Effects on Interface Evolution and Heat Transfer in Droplet Impact on Flowing Liquid Film

Liang

Chen

Wang

et al. 2019

Ind. Eng. Chem. Res.

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Interfacial phenomena and heat transfer associated with single droplet impact on a flowing liquid film are studied with three-dimensional simulations. Shearinduced sheet-film contact is detected successfully, governed by both flowing film and droplet velocities. Crown splashing at the downstream position is suppressed significantly, while cooling performance in the downstream crater is poorer than in the upstream crater because of slippage of the impact region along the streamwise direction. Increasing impact velocity and decreasing film thickness result in a very low wall temperature and high heat transfer coefficient because of enhanced convective heat transfer, but the increase in film velocity compromises cooling of the heating surface. Parametric effects of droplet impacting velocity, film thickness, and thermophysical properties on crown upstream and downstream heights in impact on the flowing film are virtually the same as those on the static film, but the unique parameter of film velocity in the former poses a negative effect on crown heights.

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Section: Resultssupporting

confidence: 86%

Parametric Effects on Interface Evolution and Heat Transfer in Droplet Impact on Flowing Liquid Film

Liang

Chen

Wang

et al. 2019

Ind. Eng. Chem. Res.

Self Cite

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“…this causes the enhanced convective heat transfer and enhanced synergy of velocity field and heat flow field inside the residual film [46]. It is interesting to note that this process is similar in mechanism to the sharp decrease in surface temperature during the nucleation during boiling.…”

Section: Droplet Impact On Liquid Filmmentioning

confidence: 84%

“…In this case, for a certain droplet size and velocity (We number), its impact leads to the formation of a so-called residual film [45]. In turn, this causes the enhanced convective heat transfer and enhanced synergy of velocity field and heat flow field inside the residual film [46]. It is interesting to note that this process is similar in mechanism to the sharp decrease in surface temperature during the nucleation during boiling.…”

Section: Droplet Impact On Liquid Filmmentioning

confidence: 99%

The Simultaneous Analysis of Droplets’ Impacts and Heat Transfer during Water Spray Cooling Using a Transparent Heater

Serdyukov

Miskiv

Surtaev

2021

Water

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This paper demonstrates the advantages and prospects of transparent design of the heating surface for the simultaneous study of the hydrodynamic and thermal characteristics of spray cooling. It was shown that the high-speed recording from the reverse side of such heater allows to identify individual droplets before their impact on the forming liquid film, which makes it possible to measure their sizes with high spatial resolution. In addition, such format enables one to estimate the number of droplets falling onto the impact surface and to study the features of the interface evolution during the droplets’ impacts. In particular, the experiments showed various possible scenarios for this interaction, such as the formation of small-scale capillary waves during impacts of small droplets, as well as the appearance of “craters” and splashing crowns in the case of large ones. Moreover, the unsteady temperature field during spray cooling in regimes without boiling was investigated using high-speed infrared thermography. Based on the obtained data, the intensity of heat transfer during spray cooling for various liquid flow rates and heat fluxes was analyzed. It was shown that, for the studied regimes, the heat transfer coefficient weakly depends on the heat flux density and is primarily determined by the flow rate. In addition, the comparison of the processes of spray cooling and nucleate boiling was made, and an analogy was shown in the mechanisms that determine their intensity of heat transfer.

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“…With the increase in eccentric distance, the liquid gathers more at the right rim of the liquid film (eccentric side) with the trailing droplet spread. After impact, the flow inside liquid film experiences downward-radial-upward redirections [15]. For an eccentric impact, it is more difficult for the liquid at eccentric side to flow upward and then retract.…”

Section: Effect Of the Eccentric Distancementioning

confidence: 99%

“…The influences of the liquid film thickness, droplet diameter and vertical droplet spacing on average heat flux are little [14]. Recently, Liang et al [15] discovered the cooling of the surface is determined by the contacting of the trailing droplet with surface, rather than the mixing of heated liquid film and impacting droplets. The decrease in vertical droplet spacing promotes the temperature uniformity on the liquid crown walls [16].…”

Section: Introductionmentioning

confidence: 99%

Effect of Eccentric Distance on Successive Dual-droplet Impacting a Super-hydrophobic Tube

et al. 2021

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Droplet impact is a common but significant phenomenon in industry. The CLSVOF (coupled level set and volume-of-fluid) method is used to numerically study the successive dual-droplet impacting a super-hydrophobic tube. For the impact velocity of 1.0 m/s, the effect of the eccentric distance on dynamic characteristics is analysed, the corresponding eccentric distances are 0.5, 1.0 and 2.0, respectively. In addition, the break-up during rebound is analysed with velocity field and pressure nephogram. Results show that, the eccentric distance hinders the spread during the initial period of spreading. With the increase in eccentric distance, more liquid gathers at the eccentric side and the liquid film might rebound easily without break-up under the same impact velocity. The break-up during rebound mainly depends on the local airflow and pressure difference. The high-pressure zone near the solid-liquid interface moves towards the eccentric side with the increase in eccentric distance.

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Single-phase heat transfer of multi-droplet impact on liquid film

Cited by 39 publications

References 11 publications

Parametric Effects on Interface Evolution and Heat Transfer in Droplet Impact on Flowing Liquid Film

Parametric Effects on Interface Evolution and Heat Transfer in Droplet Impact on Flowing Liquid Film

The Simultaneous Analysis of Droplets’ Impacts and Heat Transfer during Water Spray Cooling Using a Transparent Heater

Effect of Eccentric Distance on Successive Dual-droplet Impacting a Super-hydrophobic Tube

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