Capillary Penetration of Liquid Droplets into Porous Materials

Denesuk, M.; Smith, Gabriella; Zelinski, Brian J.J.; Kreidl, Norbert J.; Uhlmann, D. R.

doi:10.1006/jcis.1993.1235

Cited by 160 publications

(181 citation statements)

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“…The accelerated growth for more viscous binders, anticipated from the torque curves which indicated lower L/S ratios in order to achieve optimum liquid requirement, can be explained by the longer penetration time (as defined by Denesuk et al [19]) of the more viscous binders in the granules that form a film on the surface leading to successful coalescence between granules. This observation is further confirmed by Fig.…”

Section: /9mentioning

confidence: 92%

Wet granulation in laboratory scale high shear mixers: Effect of binder properties

2011

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a b s t r a c t Keywords:High shear mixer granulator Torque curves Work of adhesion Viscosity Scale-up The effect of binder properties on torque curves, granule growth kinetics, wet mass consistency and dry granule strength has been investigated in this study. Granulation runs have been performed on a fine cohesive microcrystalline cellulose powder (Avicel 105, d 50 = 20 μm) in two types of laboratory high shear mixers: a MiPro high shear mixer using a 1.9 L bowl and a 6 L Diosna high shear mixer. Binders used included ultra-pure water and solutions of varying concentrations of PVP and HPMC allowing us to cover different values for parameters like viscosity and work of adhesion. Torque curves recorded during granulation are found to allow good control of the process. Optimum liquid requirement for granulation has been found to vary with binder type and decrease with increasing viscosity while granule growth kinetics has been found to be to be related to the work of adhesion for low viscosity binders. Granule strength has been evaluated for wet granules by the means of wet mass consistency measurements on a mixer torque rheometer and for dried granules by means of uniaxial compression tests on a Texture Analyser mechanical testing machine. For low viscosity binders both wet mass consistency and dry granule strength have been found to depend on the work of adhesion. For high viscosity binders higher wet mass consistencies but lower dry granule strengths have been observed. Granulating on the larger 6 L scale has shown that constant impeller tip speed offers good agreement in terms of mean granule size however granule size distribution seems to be scale dependant.

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Section: /9mentioning

confidence: 92%

Wet granulation in laboratory scale high shear mixers: Effect of binder properties

2011

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“…Denesuk et al [14,15] studied the spreading and permeation processes on a porous substrate with parallel vertical holes using a simple hydrodynamic model. The process was divided into three stages based on the variety of dominant forces.…”

Section: Introductionmentioning

confidence: 99%

“…The others [14,15,20,21,24,25] studied the spreading and permeating integrally. The separate and competitive mechanisms of the spreading and permeation processes are still unclear, which motivates the present study.…”

Section: Introductionmentioning

confidence: 99%

Droplet spreading and permeating on the hybrid-wettability porous substrates: a lattice Boltzmann method study

Wenkai

et al. 2016

Open Physics

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Abstract:The spreading and permeation of droplets on porous substrates is a fundamental process in a variety of applications, such as coating, dyeing, and printing. The spreading and permeating usually occur synchronously but play different roles in the practical applications. The mechanisms of the competition between spreading and permeation is significant but still unclear. A lattice Boltzmann method is used to study the spreading and permeation of droplets on hybrid-wettability porous substrates, with different wettability on the surface and the inside pores. The competition between the spreading and the permeation processes is studied in this work from the effects of the substrate and the fluid properties, including the substrate wettability, the porous parameters, as well as the fluid surface tension and viscosity. The results show that increasing the surface wettability and the porosity contact angle both inhibit the spreading and the permeation processes. When the inside porosity contact angle is larger than 90 ∘ (hydrophobic), the permeation process does not occur. The droplets suspend on substrates with Cassie state. The droplets are more easily to permeate into substrates with a small inside porosity contact angle (hydrophilic), as well as large pore sizes. Otherwise, the droplets are more easily to spread on substrate surfaces with small surface contact angle (hydrophilic) and smaller pore sizes. The competition between droplet spreading and permeation is also related to the fluid properties. The permeation process is enhanced by increasing of surface

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“…Denesuk [38] developed an analytical model for droplet suction into porous media, treating the individual pores as vertical cylinders into which liquid penetrates. The model was developed for two limiting cases -a fixed contact line with varying contact angle, and a fixed contact angle with varying contact area -but did not provide any insight into when these regimes might occur.…”

Section: Dynamic Contact Angle Measurementsmentioning

confidence: 99%

Metal functionalization of carbon nanotubes for enhanced sintered powder wicks

Kousalya

Weibel

Garimella

et al. 2013

International Journal of Heat and Mass Transfer

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Phase change cooling schemes involving passive heat spreading devices, such as heat pipes and vapor chambers, are widely adopted for thermal management of high heat-flux technologies. In this study, carbon nanotubes (CNTs) are fabricated on a 200 μm thick sintered copper powder wick layer using a microwave plasma enhanced chemical vapor deposition technique. A physical vapor deposition process is used to coat the CNTs with a varying thickness of copper to promote surface wetting with the working fluid, water. Thermal performance of the bare sintered copper powder sample (without CNTs) and the copper-functionalized CNT-coated sintered copper powder wick samples is compared using an experimental facility that simulates the capillary fluid feeding conditions of a vapor chamber. A notable reduction in the boiling incipience superheat is observed for the nanostructured samples. Additionally, nanostructured samples having a thicker copper coating provided a considerable increase in dryout heat flux, supporting heat fluxes up to 457 W/cm 2 from a 5 mm × 5 mm heat input area, while maintaining lower surface superheat temperatures compared to a bare sintered powder sample; this enhancement is attributed primarily to the improved surface wettability. Dynamic contact angle measurements are conducted to quantitatively compare the surface wetting trends for varying copper coating thicknesses and confirm the increase in hydrophilicity with increasing coating thickness.

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Capillary Penetration of Liquid Droplets into Porous Materials

Cited by 160 publications

References 0 publications

Wet granulation in laboratory scale high shear mixers: Effect of binder properties

Wet granulation in laboratory scale high shear mixers: Effect of binder properties

Droplet spreading and permeating on the hybrid-wettability porous substrates: a lattice Boltzmann method study

Metal functionalization of carbon nanotubes for enhanced sintered powder wicks

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