Contact between a gas bubble and a solid surface and froth flotation

1970 ◽  
Vol 1 ◽  
pp. 112 ◽  
Author(s):  
A. Scheludko ◽  
Sl. Tschaljowska ◽  
A. Fabrikant
Keyword(s):  
Solid Surface ◽  
Froth Flotation ◽  
Gas Bubble

Film Size During Bubble Collision With a Solid Surface

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Travis S. Emery ◽  
Satish G. Kandlikar
Keyword(s):  
Solid Surface ◽  
Froth Flotation ◽  
Bond Number ◽  
Film Drainage ◽  
Drainage Rate ◽  
Archimedes Number ◽  
Experimental Parameters ◽  
Bubble Collision ◽  
The Impact ◽  
The Relationship

The impact and bounce of a bubble with a solid surface is of significant interest to many industrial processes such as froth flotation and biomedical engineering. During the impact, a liquid film becomes trapped between the bubble and the solid surface. The pressure buildup in this film leads to the generation of a film force. The drainage rate of this film plays a crucial role in dictating the bouncing process and is known to be a function of the radial film size. However, radial film size is not an easily attained experimental measurement and requires advanced instrumentation to capture. The bouncing process has been characterized using nondimensional numbers that are representative of the bubble collision and film drainage phenomena. These are: Bond number (Bo), Archimedes number (Ar), Froude number (Fr), and the ratio of film force to buoyancy force (FF/FB). These numbers are used to define a predictive function for film radius. Experimentally validated numerical modeling has been implemented to determine the relationship between the four nondimensional numbers, and a quasi-static model is employed to relate the film force to the radial film size. Comparison of our experimental results is in agreement with the predicted film size within ±20%. From these results, the radial film size during bubble impact with a solid surface may be predicted using the easily measurable experimental parameters of bubble size, bubble impact velocity, and the liquid properties.

The drainage of a thin aqueous film between a solid surface and an approaching gas bubble

1991 ◽  
Vol 52 ◽  
pp. 163-174 ◽  
Author(s):  
Leonard R. Fisher ◽  
Emma E. Mitchell ◽  
David Hewitt ◽  
John Ralston ◽  
Joe Wolfe
Keyword(s):  
Solid Surface ◽  
Gas Bubble

Gravitational Settling of Glass Fibers on an Air Bubble

2015 ◽  
Author(s):  
Gregory Lecrivain ◽  
Giacomo Petrucci ◽  
Uwe Hampel ◽  
Ryoichi Yamamoto
Keyword(s):  
Froth Flotation ◽  
Bubble Surface ◽  
Liquid Interface ◽  
Particle Orientation ◽  
Water Tank ◽  
Gas Bubble ◽  
Mining Operations ◽  
Air Bubble ◽  
Froth Layer ◽  
Attachment Mechanism

Froth flotation is a separation process in which air bubbles are introduced in a water tank to separate the valuable commodities from the valueless material. Based on their relative affinity to water the valuable particles attach to the bubble surface and are carried to the top of the flotation tank to form the froth layer. The resulting froth layer is eventually collected to produce the concentrate. Froth flotation has been used for more than a century in mining operations to separate valuable materials such as rare earth metals from excavated ores. More recently, froth flotation has been employed for the treatment of contaminated water. In the present study, the effect of the particle elongation on the attachment mechanism is investigated in great detail. Using an in-house optical micro-bubble sensor the attachment of micron glass fibres on the surface of a stationary air bubble immersed in stagnant water is investigated. The attachment mechanism is here defined as three successive events: the approach of the particle near the bubble upstream pole, the collision of the solid particle with the gas-liquid interface and the particle sliding on the gas bubble surface. The translational particle velocities together with the particle orientation during entire attachment process are measured and compared with a theoretical model. For the first time the existence of two types of attachment is shown. Upon collision near the upstream pole of the gas bubble the major axis of the fibre aligns with the local bubble surface. If collision occurs at least 30° further downstream the contact is likely to take a punctual form, i.e. the head of the fibre is in contact with the gas-liquid interface.

The disposition of gas–oil mixtures trapped under ice

1980 ◽  
Vol 58 (8) ◽  
pp. 1183-1190
Author(s):  
D. R. Topham
Keyword(s):  
Solid Surface ◽  
Oil And Gas ◽  
Sessile Drop ◽  
Stable Solution ◽  
Crude Oils ◽  
Drop Formation ◽  
Gas Bubble ◽  
Gas Oil ◽  
Oil Mixtures

A number of stable configurations which can be formed from mixtures of oil and gas trapped in water under a solid surface is examined. In particular, the problem of a lens of oil lying within a sessile bubble of gas is solved, and two forms of stable solution are found; a discrete lens of oil lying in the bottom of the gas bubble and a double sessile drop formation with the oil completely enclosing the gas. A comparison of the energies of the formation indicates the ranges of oil properties where each configuration is likely to be found. The results are applied to the specific case of crude oils trapped under ice and an appropriate existence diagram constructed.

Microwave resonance method for measuring microliter volumes of free moisture in aviation fuels

2020 ◽  
pp. 49-56
Author(s):  
Vitaly V. Volkov ◽  
Michael A. Suslin ◽  
Jamil U. Dumbolov
Keyword(s):  
Solid Surface ◽  
Free Water ◽  
Resonance Method ◽  
Cavity Resonator ◽  
Maximum Error ◽  
Aviation Fuel ◽  
Fuel Quality ◽  
Microwave Resonance ◽  
Free Moisture ◽  
Microwave Losses

One of the conditions for ensuring the safety of air transport operation is the quality of aviation fuel refueled in aircraft. Fuel quality control is a multi-parameter task that includes monitoring the free moisture content. Regulatory documents establish the content of free water no more than 0.0015% by weight. It is developed a direct electrometric microwave resonance method for controlling free moisture in aviation fuels, which consists in changing the shape of the water drops by pressing them on a solid surface inside a cylindrical cavity resonator. This can dramatically increase dielectric losses. Analytical and experimental analysis of the proposed method is carried out. The control range from 0,5 to 30 μl of absolute volume of moisture in aviation fuels with a maximum error of not morethan 25 % is justified. The sensitivity of the proposed method for monitoring microwave losses in free moisture drops transformed into a thin layer by pressing is an order of magnitude greater than the sensitivity of the method for monitoring microwave losses in moisture drops on a solid surface in a resonator. The proposed method can be used as a basis for the development of devices for monitoring the free moisture of aviation fuels in the conditions of the airfield and laboratory. The direction of development of the method is shown.

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