Liquid fluid displacement

Several experimental arrangements are used to measure and analyze the wetting of liquids on solid surfaces. Typical geometries are a spreading drop on a solid surface, liquid-fluid displacement through a capillary tube, steady immersion or withdrawal of fibers, plates or tapes from a pool of liquid, and the rotation of a horizontal cylinder in a liquid (Fig. 7.12). 

Flow patterns of immiscible liquid/fluid displacement in a capillary tube... 

A bstract Liquid flow as disturbed by the presence of a fluid interface of definite shape was studied during immiscible liquid/fluid displacement in a capillary tube. Microscopic cinematography with tracer method has been used to obtain flow patterns on both sides of the moving interface. The effect of the curvature of the interface on the distribution of velocity components was investigated. The experimental results obtained for flat liquid/fluid interfaces were compared with those calculated from an approximate solution of the flow equation by Kafka and Dussan V. 

Key words Liquid/fluid displacement, capillary flow, flow pattern, shape of the interface... 

Miscible fluid displacement is a process in which a fluid, which is miscible with oil at reservoir temperature and pressure conditions, is injected into a reservoir to displace oil. The miscible fluid (an oil-soluble gas or liquid) allows trapped oil to dissolve in it, and the oil is therefore mobilised. 

Fluid-Displacement Pumps In addition to pumps that depend on the mechanical ac tion of pistons, plungers, or impellers to move the liquid, other devices for this purpose employ displacement by a secondary fluid. This group includes air lifts and acid eggs. 

The mixer discussed below is part ofa ferrofluidic microsystem [159], Ferrofluids can be used for fluid displacement by magnetic action using an external permanent magnet source. Ferrofluids are superparamagnetic liquids. 

The simulation results are shown in Fig. 13.34 for the Newtonian, Amoco Polybutene (PB) H-100 of weight average molecular weight Mw = 103 and a constant viscosity up to 10s 1 of 19Pa s. The fluid flow in the liquid being displaced by the gas bubble is viewed from a Lagrangian perpective, where the bubble is stationary and the tube wall is... 

In density determination the volume of fluid, displaced by a known weight of powder, is determined. Since weight can be measured accurately, the problem is that of accurate determination of volume. With pyknometers (or density bottles) the fluid is a liquid, usually water with surfactant, unless the powder is water miscible. With gas pyknometers the fluid is usually dry air or helium. 

Table II shows the effect of chain length compatibility on oil recovery, fluid displacement efficiency, breakthrough time and effective gas mobility in porous media. For gas/liquid systems (e.g. Foams), a maximum in fluid displacement efficiency, a...

The apparent particle density (or if the particles have no closed pores, also the true particle density) can be measured by fluid displacement methods, i.e. pyknometry, which are in common use in industry today. The displacement can be measured with either liquids or gases and there are, therefore, two groups of techniques and instruments available, as follows. 

More accurate density measurements may be made by instruments that take advantage of the principle of Archimedes, where the apparent weight of an object immersed in a fluid is diminished by that of the fluid displaced. In the simplest version of this experiment, a sinker of known mass and volume is immersed in the fluid while suspended by a wire from an analytical balance. More sophisticated versions may use a magnet to suspend the sinker or measure the difference between two sinkers of similar mass and surface area but different volume. With care and good control of temperature and pressure, such instruments can achieve uncertainties of 0.02% or lower for both vapor and liquid densities. 

Archimedes principle The weight of the liquid displaced by a floating body is equal to the weight of the body. The principle was not in fact stated by Archimedes, though it has some connection with his discoveries. The principle is often stated in the form when a body is (partially or totally) immersed in a fluid, the upthrust on the body is equal to the weight of fluid displaced. 

Surfactants play an important role in the formation and stability of foams. Investigators have determined foam stability by measuring the half-life (e.g. t 2) the foam. Half-life is the time required to reduce foam voLume to half of its initial value. It has been demonstrated that the foam stability (i.e.half-life) decreased with increasing temperature, whereas the foaminess of the surfactant solution increased with temperature. It is likely that these properties of foam depend on the molecular structure and concentration of the surfactant at the gas/liquid interface. Comparison of the results of static foam stability with that of the dynamic behavior of foam in porous media revealed that the foam stability is not required for efficient fluid displacement or a decrease in the effective air mc >ility in a porous medium. Moreover, the ability of the surfactants to produce in-situ foam was one of the important factors in the displacement of the fluid in a porous medium. 

Because the measurement of a contact angle must involve some movement of the wetting line, it is possible, or even probable, that the act of spreading of the hquid will displace certain surface equilibria that will not be reestablished over the time frame of the experiment. For example, the displacement of a second fluid may result in the estabhshment of a nonequilibrium situation in terms of the adsorption of the various components at the solid-liquid, solid-fluid 2, and liquid-fluid 2 interfaces. Time will be required for adsorption equilibrium to be attained, and it may not be attained during the time of the contact angle measurement if the transport and adsorption-desorption phenomena involved are slow. The kinetic effect may be especially significant for solutions containing surfactants, polymers, or other dissolved adsorbates. 

Any of the three particle densities defined above should not be confused with bulk density of materials, which includes the voids between the particles in the volume measured. The different values of particle density can be also expressed in a dimensionless form, as relative density, or specific gravity, which is simply the ratio of the density of the particle to the density of water. It is easy to determine the mass of particles accurately but difficult to evaluate their volume because they have irregular shapes and voids between them. The apparent particle density, or if the particles have no closed pores also the true density, can be measured by fluid displacement methods, that is, pycnometry, which are in common use in industry. The displacement can be carried out using either a liquid or a gas, with the gas employed normally being air. Thus, the two known techniques to determine true or apparent density, when applicable, are liquid pycnometry and air pycnometry. 

The Archimedes theorem explains that all bodies immersed in an ideal fluid encounter a vertical thrust force oriented toward the top, called the buoyancy force, and equal as absolute value to the weight of the volume of the fluid displaced. This force is called the buoyancy force, denoted b and expressed in newtons (N). Actually, for a solid material, S, having a volume Vsin m immersed in a fluid (i.e., gas or liquid), F, with a mass density, Pp in kg.m the buoyancy force acting on the solid body can be written as follows ... 

This shows clearly that kinetic retardation is effective, as it should be, in the diffuse boundary region, where the fluid is compressible. The scaling of the lubrication approximation remains consistent only if the relaxation time r in Eq. (101) is of 0(6). With this scaling, the speed of the vapor-liquid interface displacement is of 0(5 ), i.c. of the same order of magnitude as the vertical velocity. 

Wettability refers to the interactions when a liquid / is brought into contact with a solid surface s initially surrounded by a gas (or the saturated liquid vapor V atmosphere) or another liquid [10]. These interactions can result in spreading without limits of the liquid over the surface displacing the other fluid, or the spreading process might come to an end if the equilibrium state is reached, which is characterized by a contact angle 6 between the liquid fluid and liquid-solid interfaces. This phenomenon is often described by a sessile drop resting on a solid surface (Fig. 1). 

The flow of a long bubble in a capillary is a classical problem in fluid mechanics. Bubbles have been used as tracers in capillaries filled with liquid in order to determine liquid velocity. This application led to the discovery that when a wetting viscous liquid is displaced by a gas bubble in a capillary a liquid film is deposited on the wall. Initial experimental findings that the thickness of the film was proportional to Ca / were confirmed and extended to Ca= 10 [3]. In his pioneering approach, Brether-ton [1] assumed creeping flow in the liquid and used lubrication theory for the region of the film between the end of the spherical bubble cap and the flat film behind it to calculate the thickness of the film, the pressure drop and... 

Raimondi, P., Gardner, G. H. F. and Petrick, C. B. Effect of Pore Structure and Molecular Diffusion on the Mixing of Miscible Liquids Flowing in Porous Media , Preprint 43 presented at AIChE-SPE Joint Symposium on Fundamental Concepts of Miscible Fluid Displacement, San Francisco, Calif. (Dec. 6-9, 1959). 

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