Active control of the freezing process of a ferrofluid droplet with magnetic fields

Zhang, Hui; Zhao, Yugang; Fang, Wenzhen; Zhang, Chaoyang; Zhu, Fangqi; Jin, Liwen; Yang, Chun

doi:10.1016/j.applthermaleng.2020.115444

Cited by 13 publications

(6 citation statements)

References 66 publications

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“…In the literature [21][22][23][24][25][26], some researchers use impinging drops on a supercooled substrate to mimic the scene in which icing occurs upon collisions of pendent drops when an aircraft passes through clouds at a relatively high altitude. The effects of surface chemistry and topography [27][28][29][30], drop size and impinging velocity Crystals 2021, 11, 691 2 of 11 in terms of Weber number [31,32], and system alignments [33][34][35][36][37][38] have been studied extensively to reveal the freezing mechanism and evaluate the anti-icing performance of each proposed anti-/de-icing method. Whereas these studies only focus on the spreading and freezing of impinging drops themselves, little attention is paid to the transport and phase change of the accompanying water vapor, which originates from the liquid-gas interface of the impinging drops and diffuses to the surroundings under a concentration gradient [39,40].…”

Section: Introductionmentioning

confidence: 99%

Ice Coverage Induced by Depositing a Water Drop onto the Supercooled Substrate at Extreme Low Vapor Pressure

et al. 2021

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Icing/snowing/frosting is ubiquitous in nature and industrial processes, and the accretion of ice mostly leads to catastrophic consequences. The existing understanding of icing is still limited, particularly for aircraft icing, where direct observation of the freezing dynamics is inaccessible. In this work, we investigate experimentally the impact and freezing of a water drop onto the supercooled substrate at extremely low vapor pressure, to mimic an aircraft passing through clouds at a relatively high altitude, engendering icing upon collisions with pendant drops. Special attention is focused on the ice coverage induced by an impinging drop, from the perimeter pointing outward along the radial direction. We observed two freezing regimes: (I) spread-recoil-freeze at the substrate temperature of Ts = −15.4 ± 0.2 °C and (II) spread (incomplete)-freeze at the substrate temperature of Ts = −22.1 ± 0.2 °C. The ice coverage is approximately one order of magnitude larger than the frozen drop itself, and counterintuitively, larger supercooling yields smaller ice coverage in the range of interest. We attribute the variation of ice coverage to the kinetics of vapor diffusion in the two regimes. This fundamental understanding benefits the design of new anti-icing technologies for aircraft.

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Section: Introductionmentioning

confidence: 99%

Ice Coverage Induced by Depositing a Water Drop onto the Supercooled Substrate at Extreme Low Vapor Pressure

et al. 2021

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“…96 The magnetic lift or squeezing conditions influence the time it takes for the droplet to freeze. 97 Inclusion of Lorentz forces (the combined force experienced by a point charge because of electric and magnetic fields) can also enhance the rate of flow or discharge, whereas nanoparticles decrease the discharge time. 98,99 Although a magnetic field leads to quicker in fluids that are non-electrically conductive as well as in electrically conductive ferrofluid, the ferrohydrodynamics and magnetohydrodynamics have a greater effect on electrically conductive ferrofluid, leading to shorter solidification time.…”

Section: Nanoparticle-enhanced Pcm Solidificationmentioning

confidence: 99%

Nano-engineered pathways for advanced thermal energy storage systems

Alagumalai¹,

Yang

Ding

et al. 2022

Cell Reports Physical Science

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Section: Ferromagnetism In Liquid Dropletsmentioning

confidence: 99%

Manipulating Dispersions of Magnetic Nanoparticles

2021

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Dispersions of magnetic nanoparticles (MNPs) can exhibit paramagnetic ferrofluid or ferromagnetic liquid behavior. By modifying the surface functionality of MNPs, ferrofluids have been used to fabricate novel magnetically actuated devices. If the surfacefunctionalized MNPs interact with complementary ligands at a fluid−fluid interface, MNP surfactants form and in situ assemble at the interface. When jammed interfacially, MNP surfactants give rise to ferromagnetic behavior of the liquid (droplet), which is endowed with permanent magnetic dipoles while maintaining all of the characteristics of a fluid system. Here, we give a brief overview of the developments in the dispersion of MNPs in liquids from ferrofluids to ferromagnetic liquid droplets, their responses to external fields, and the manipulation of these responses for end uses. The reversible room-temperature para-to-ferro transformation of magnetic liquids is highlighted. We discuss challenges in the synthesis and characterization of these unusual liquids along with potential technological applications.

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Active control of the freezing process of a ferrofluid droplet with magnetic fields

Cited by 13 publications

References 66 publications

Ice Coverage Induced by Depositing a Water Drop onto the Supercooled Substrate at Extreme Low Vapor Pressure

Ice Coverage Induced by Depositing a Water Drop onto the Supercooled Substrate at Extreme Low Vapor Pressure

Nano-engineered pathways for advanced thermal energy storage systems

Manipulating Dispersions of Magnetic Nanoparticles

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