Dispersion of Particles on Liquid Surfaces

2011 ◽  
Author(s):  
Shriram B. Pillapakkam ◽  
Pushpendra Singh
Keyword(s):  
Numerical Simulation ◽  
Particle Size ◽  
Vertical Motion ◽  
Liquid Interface ◽  
Water Interface ◽  
Small Particles ◽  
Air Water Interface ◽  
Large Velocity ◽  
Simulation Results ◽  
Air Liquid Interface

In a recent study we have shown that when small particles, e.g., flour, pollen, glass, etc., contact an air-liquid interface, they disperse rapidly as if they were in an explosion. The rapid dispersion is due to the fact that the capillary force pulls particles into the interface causing them to accelerate to a large velocity. The vertical motion of a particle during its adsorption causes a radially-outward lateral (secondary) flow on the interface that causes nearby particles to move away. We present direct numerical simulation results for the adsorption of particles and show that the inertia of a particle plays an important role in its motion in the direction normal to a fluid-liquid interface. Although the importance of inertia diminishes with decreasing particle size, on an air-water interface the inertia continues to be important even when the size is as small as a few nanometers.

Modeling of Particles Dispersion on Liquid Surfaces

2010 ◽  
Author(s):  
Sathishkumar Gurupatham ◽  
Bhavin Dalal ◽  
Sai Nudurupati ◽  
Ian S. Fischer ◽  
Pushpendra Singh ◽  
...  
Keyword(s):  
Particle Size ◽  
High Frequency ◽  
Liquid Surface ◽  
Maximum Velocity ◽  
Capillary Forces ◽  
Viscous Drag ◽  
Water Interface ◽  
Small Particles ◽  
Air Water Interface ◽  
Large Velocity

When small particles (e.g., flour, pollen, etc.) come in contact with a liquid surface, they immediately disperse. The dispersion can occur so quickly that it appears explosive, especially for small particles on the surface of mobile liquids like water. This explosive-like dispersion is the consequence of capillary forces pulling particles into the interface causing them to accelerate to a relatively large velocity. The maximum velocity increases with decreasing particle size; for nanometer-sized particles (e.g., viruses and proteins), the velocity on an air-water interface can be as large as 47 m/s. We also show that particles oscillate at a relatively-high frequency about their floating equilibrium before coming to stop under viscous drag. The observed dispersion is a result of strong repulsive hydrodynamic forces that arise because of these oscillations.

Blast Wave Mitigation from the Straight Tube by Using Water Part II - Numerical Simulation

2018 ◽  
Vol 910 ◽  
pp. 78-83 ◽  
Author(s):  
Yuta Sugiyama ◽  
Tomotaka Homae ◽  
Kunihiko Wakabayashi ◽  
Tomoharu Matsumura ◽  
Yoshio Nakayama
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Energy Transfer ◽  
Numerical Simulations ◽  
Blast Wave ◽  
Blast Waves ◽  
Straight Tube ◽  
Water Interface ◽  
Effect Of Water ◽  
Air Water Interface

This paper investigates explosions in a straight square tube in order to understand the mitigation effect of water on blast waves that emerge outside. Numerical simulations are used to assess the effect of water that is put inside the tube. The water reduces the peak overpressure outside, which agrees well with the experimental data. The increases in the kinetic and internal energies of the water are estimated, and the internal energy transfer at the air/water interface is shown to be an important factor in mitigating the blast wave in the present numerical method.

scholarly journals Synergistic action of TiO2 particles and surfactants on the foamability and stabilization of aqueous foams

RSC Advances ◽  
2017 ◽  
Vol 7 (71) ◽  
pp. 44972-44978 ◽  
Author(s):  
Huiying Cao ◽  
Xuan Zhang ◽  
Baiyong Ding ◽  
Long Wang ◽  
Naiyan Lu
Keyword(s):  
Synergistic Effect ◽  
Synergistic Action ◽  
Water Interface ◽  
New Materials ◽  
Small Particles ◽  
Tio2 Particles ◽  
Aqueous Foams ◽  
Air Water Interface

Small particles can be activated via a synergistic effect with surfactants and adsorbed to the air–water interface to generate and stabilize foams, which has been applied extensively to develop new materials and techniques.

Microresonator Concept for Mass Detection in Liquids

2011 ◽  
Author(s):  
Alejandro Allievi
Keyword(s):  
Analytical Model ◽  
Rotational Motion ◽  
Electrostatic Actuation ◽  
Liquid Interface ◽  
Point Mass ◽  
Liquid Interfaces ◽  
Mass Detection ◽  
Immiscible Liquids ◽  
Simulation Results ◽  
Air Liquid Interface

We evaluate enhanced mass detection possibilities with electrostatic actuation of a mechanical microoscillator positioned at a fluid-liquid interface. An analytical model is used to simulate the rotational motion of such configuration inside a microchannel either completely filled with two immiscible liquids, or partially filled forming an air-liquid interface. Simulation results show that improvements in sensitivity can be obtained through the use of fluid-liquid interfaces. For point mass detection, sensitivities of at least 9–15Hz/ng can be achieved using liquid-liquid interfaces. For air-liquid interfaces, it is conceivable to detect point masses in the order of tens of picograms.

Effect of Nickel-Modified SiC Particles on Compressive Damage of SiCp / 7075 Composites

2019 ◽  
Vol 944 ◽  
pp. 705-713
Author(s):  
Xiao Hong Wang ◽  
Qiao Gang Hu ◽  
Shi Yu Zhong ◽  
Teng Dang ◽  
Hai Lun Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Silicon Carbide ◽  
Particle Size ◽  
Nickel Plating ◽  
Compression Process ◽  
Thermal Compression ◽  
Simulation Results ◽  
Silicon Carbide Particles ◽  
Compressive Damage ◽  
Carbide Particles

The wettability between silicon carbide and aluminum is poor, silicon carbide is difficult to fuse or the distribution of silicon carbide is not uniform in the ingot when the SiCp / 7075 composite is prepared by melt casting.The surface modification of SiCp by nickel plating can significantly reduce the wetting angle of SiC/Al and improve the distribution uniformity of silicon carbide in SiCp / 7075. In this thesis, the thermal compression process 6.5% SiCp / 7075 reinforced by nickel-plated modified silicon carbide is simulated by DEFOEM-3D software.The influence of the shape and particle size of nickel-plated modified silicon carbide on its compressive damage has been highlighted, and the deformation characteristics of the SiC/Ni/Al interface layer in the thermal compression process have been discussed. The numerical simulation results show that the 6.5% SiCp / 7075 reinforced by spherical nickel-plated modified silicon carbide particles with a particle size of 15 μm has the smallest compression damage value of 0.0426, at this point the compression temperature is 400°C, the compression ratio is 15, and the compression rate is 0.03s-1. the hot compression test of 6.5% SiCp / 7075 reinforced by spherical nickel-plated modified silicon carbide particles with a particle size of 15 μm was performed by using the same compression parameters as the numerical simulation. After hot pressing, the sample had a smooth surface with few obvious cracks, which was consistent with the numerical simulation results. Key words: nickel-plating modification; silicon carbide particles; compressive damage; grain size; grain morphology

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