Heat Transfer, Phase Change, and Thermocapillary Flow in Films of Molten Metal on a Substrate

Ajaev, Vladimir S.; Willis, David A.

doi:10.1080/10407780600619535

Cited by 12 publications

(6 citation statements)

References 22 publications

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“…There are situations when the surface tension of an initially flat film is highly non-uniform, e.g., due to rapid localized heating or addition of surfactants. The models of film dynamics under these conditions are discussed by, e.g., Jensen and Grotberg (1992) and Ajaev and Willis (2006) and are beyond the scope of the present review. Our objective is to focus on situations when film breakup is a result of intrinsic instability rather than imposed surface tension gradients.…”

Section: Introductionmentioning

confidence: 99%

Instability and Rupture of Thin Liquid Films on Solid Substrates

Ajaev

2013

Interfac Phenom Heat Transfer

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Studies of rupture of thin liquid films on solid surfaces are important for modeling of multiphase flows in microfluidic devices, heat exchange systems, mining industry, and for biomedical applications such as dynamics of the tear film in the eye. In the present study we review theoretical work on film rupture and discuss its comparison with some recent experiments. Conditions for the break-up of thin liquid films by London-van der Waals dispersion forces, electrostatic effects, and thermocapillary instability are discussed.

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Section: Introductionmentioning

confidence: 99%

Instability and Rupture of Thin Liquid Films on Solid Substrates

Ajaev

2013

Interfac Phenom Heat Transfer

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“…Understanding the stability and morphological evolution of thin liquid films is vital for a variety of applications such as processing of foam networks (Ashby et al 2000;Banhart 2001), pulsed laser micromachining (Ajaev & Willis 2006) and liquid multilayers (Fisher & Golovin 2005). For example, in a foam, there are sections of crowded gas bubbles separated by uniform, thin, liquid lamella.…”

Section: Introductionmentioning

confidence: 99%

Oscillatory instability and rupture in a thin melt film on its crystal subject to freezing and melting

Beerman

Brush

2007

J. Fluid Mech.

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Lubrication theory is used to derive a coupled pair of strongly nonlinear partial differential equations governing the evolution of interfaces separating a thin film of a pure melt from its crystalline phase and from a gas. The free melt–gas (MG) interface deforms in response to the local state of stress and the crystal–melt (CM) interface can deform by freezing and melting only. A linear stability analysis of a static, uniform film subject to the effects of MG interface capillary forces, thermocapillary forces, the latent heat of fusion, van der Waals attraction, heat transfer and solidification volume change effects, reveals stationary and oscillatory instabilities. The effect of a temperature gradient (by increasing the gas phase temperature) is to stabilize a film. As the temperature gradient is reduced, the onset of instability is oscillatory and is at a unique, finite wavenumber. Instability is oscillatory for all marginally stable, non-isothermal cases. Crystals with higher density than the melt are more stable, whereas crystals with lower density are less stable in the presence of an applied temperature gradient. Fully nonlinear numerical solutions show that oscillatory instabilities lead to rupture by growth of standing or travelling waves. Rupture times and the number of oscillations to rupture increase as the temperature gradient is increased. For stationary linearly unstable initial conditions, the CM interface retreats by melting away from the tip region of the encroaching MG interface due to a rise in the heat flux there as the film thins and nears rupture. Larger amplitude disturbances increase the maximum allowable temperature for instability, at a given wavenumber, and decrease the time to rupture at fixed temperature and wavenumber.

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“…Models for this configuration have also incorporated evaporative mass transfer effects due to the high-energy flux. The thin film approximation is still applicable, and a non-linear equation for the film thickness has been derived [13]. Experimental work has shown that the interface can undergo instabilities that lead to droplet and ring formations that may be exploited for circuit fabrication [14].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Crystal-Melt Surface Energy on the Stability of Ultra-Thin Melt Films

Beerman¹,

Brush

2008

Math. Model. Nat. Phenom.

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Abstract. The stability and evolution of very thin, single component, metallic-melt films is studied by analysis of coupled strongly nonlinear equations for gas-melt (GM) and crystalmelt (CM) interfaces, derived using the lubrication approximation. The crystal-melt interface is deformable by freezing and melting, and there is a thermal gradient applied across the film. Linear analysis reveals that there is a maximum applied far-field temperature in the gas, beyond which there is no film instability. Instabilities observed in the absence of CM surface energy are oscillatory for all marginally stable states. The effect of the CM surface energy is to expand the parameter range over which a film is unstable. The new range of instabilities are of longer wavelength and are stationary, compared to the range found in the absence of CM surface energy. Numerical analysis illustrates how perturbations grow to rupture by standing waves. With CM surface energy, an initially longer (stationary) wavelength perturbation has a relatively slow growth rate, but it can trigger the appearance of much faster growing shorter wavelength (oscillatory) instabilities, leading to an accelerated film rupture process.

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Heat Transfer, Phase Change, and Thermocapillary Flow in Films of Molten Metal on a Substrate

Cited by 12 publications

References 22 publications

Instability and Rupture of Thin Liquid Films on Solid Substrates

Instability and Rupture of Thin Liquid Films on Solid Substrates

Oscillatory instability and rupture in a thin melt film on its crystal subject to freezing and melting

The Effect of Crystal-Melt Surface Energy on the Stability of Ultra-Thin Melt Films

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