Fluid systems


Thermal Properties and Temperature related Behavior of Rock/fluid Systems  [c.386]

A2.5.3 ANALYTIC TREATMENT OF CRITICAL PHENOMENA IN FLUID SYSTEMS. THE VAN DER WAALS EQUATION  [c.616]

A third exponent y, usually called the susceptibility exponent from its application to the magnetic susceptibility x in magnetic systems, governs what m pure-fluid systems is the isothennal compressibility k, and what in mixtures is the osmotic compressibility, and detennines how fast these quantities diverge as the critical point is approached (i.e. as > 1).  [c.639]

The exponents apply not only to solid systems (e.g. order-disorder phenomena and simple magnetic systems), but also to fluid systems, regardless of the number of components. (As we have seen in section A2.5.6.4 it is necessary in multicomponent systems to choose carefully the variable to which the exponent is appropriate.)  [c.652]

If these assumptions are satisfied then the ideas developed earlier about the mean free path can be used to provide qualitative but useful estimates of the transport properties of a dilute gas. While many varied and complicated processes can take place in fluid systems, such as turbulent flow, pattern fonnation, and so on, the principles on which these flows are analysed are remarkably simple. The description of both simple and complicated flows m fluids is based on five hydrodynamic equations, die Navier-Stokes equations. These equations, in trim, are based upon the mechanical laws of conservation of particles, momentum and energy in a fluid, together with a set of phenomenological equations, such as Fourier s law of themial conduction and Newton s law of fluid friction. When these phenomenological laws are used in combination with the conservation equations, one obtains the Navier-Stokes equations. Our goal here is to derive the phenomenological laws from elementary mean free path considerations, and to obtain estimates of the associated transport coefficients. Flere we will consider themial conduction and viscous flow as examples.  [c.671]

Measurement by Electromagnetic Effects. The magnetic flow meter is a device that measures the potential developed when an electrically conductive flow moves through an imposed magnetic field. The voltage developed is proportional to the volumetric flow rate of the fluid and the magnetic field strength. The process fluid sees only an empty pipe so that the device has a very low pressure drop. The device is useful for the measurement of slurries and other fluid systems where an accumulation of another phase could interfere with flow measurement by other devices. The meter must be installed in a section of pipe that is much less conductive than the fluid. This limits its appHcabiHty in many industrial situations.  [c.110]

Teflon PEA can be fabricated into high temperature electrical insulation and components and materials for mechanical parts requiring long flex life. Teflon PEA 350 is used as liner for chemical process equipment, specialty tubing, and molded articles for a variety of appHcations. Teflon PEA 340 is a general-purpose resin for tubing, shapes, primary insulation, wire and cable jacketing, injection- and blow-molded components, and compression-molded articles. Teflon PEA 440 HP is a chemically modified form of PEA-340 with enhanced purity and improved thermal stabiHty while processing. This resin is suitable in semiconductor manufacturing, fluid handling systems for industry or life sciences, and instmmentation for precise measurements of fluid systems.  [c.377]

Siace 1980 over 1000 patents have been issued for drilling fluid systems and materials ia the United States alone. A 1994 listing of products from 117 supphers offers ca 3000 trade names (6). This array of trade name products actually represents less than 100 separate chemical types that may be purchased iadividuaHy or as a blend. Moreover, some of these materials are for completion and workover fluids. These differ from drilling fluids ia that completion fluids are used after the well has been drilled and prior to the initia tion of production whereas workover fluids are used duting remedial work on older wells.  [c.174]

The disposal of waste drilling fluids and drill cuttings in the United States has long been regulated either by local authorities, the individual states, or by the federal government. These regulations continue to change. The offshore disposal of both diesel and mineral oil drilling fluids and associated cuttings has always been prohibited in U.S. waters. However discharge of mineral oil mud cuttings has been permitted in the North Sea and elsewhere as long as the oil content of the cuttings was below some regulatory limit. The regulatory oil-on-cuttings limit in some sectors of the North Sea is, as of this writing, being lowered significantly. There is a definite move toward alternative fluid systems, many of which ate used in U.S. offshore areas.  [c.184]

The difference between homogeneous and heterogeneous flow is due to the deposition velocity, below which soHd particles start to separate from the slurry and build up in the pipeline, and is related to the degree of turbulence and the particle fall rate. Homogeneous slurries behave more like single-fluid systems deposition velocity is primarily a property of heterogeneous slurries. Deposition velocity increases with increasing particle density, soHds concentration, particle size, and pipeline diameter. In the transport of heterogeneous slurries, turbulent flow is an important requirement to prevent soHds from building up in the pipeline. Slurries may be classified according to particle size, eg, coUoidal (<1 / m), stmctured (1—50 pm), and finely dispersed (50—150 pm, mostly produced by grinding). A polydispersed stmctured category, often encountered with products of technological processes and produced by dispersion and grinding, is also defined and described as containing a broader ranger of particles, eg, from finer particles to coarser particles, and sometimes lumps (26). A maximum flow velocity to minimize pipe wall erosion must be determined.  [c.48]

Although fluid systems containing particulates introduce sampling difficulties, these systems do conform to one rule of good sampling. They are in motion. For example, powders should be sampled from a moving stream rather than when at rest. Also the whole of the stream should be sampled, not just a part of it. For gas systems, whole stream sampling is usually not possible for Hquids, it can only be done from the outfall of a pipe. A third rule in sampling is that small quantities should be taken frequentiy rather than large quantities taken infrequentiy. The ideal place to sample is where the sample is weU-mixed.  [c.298]

One common situation, the required pumping for the transport of fluid systems with a high concentration of suspended soUds, eg, those exceeding 10 vol %, exemplifies the interplay of the phenomena just mentioned in conjunction with coUoidal behavior. The pumping operation is needed for many processes. Extmsion in the polymer industry, the processing of gelatinous foods and cosmetic items, the fabrication of various high performance materials in the ceramic and metaUurgical industries, the preparation and handling of pigment slurries in the paint industry, and the treatment of waste by-products in the minerals and water industries are a few examples in which the transport behavior of coUoids is very important. The prediction and control of suspension rheology, especiaUy the thixotropic and dilatant tendencies, is primarily important for these and other uses. These rheological properties depend, in turn, on the specific interactions among the coUoidal particles, the dispersing medium, and the solute additives, ie, salts, surfactants, and polymers. Wetting, electrical double-layer, and van der Waals forces nearly always effect the interactions that determine the coUoidal behavior of a given system.  [c.394]

Cussler, Diffusion Mass Transfer in Fluid Systems, Cambridge, 1984.  [c.553]

Types of Heat-Tracing Systems Industrial heat-tracing systems are generally fluid systems or electrical systems. In fluid systems, a pipe or tube called the tracer is attached to the pipe being traced, and a warm fluid is put through it. The tracer is placed under the insulation. Steam is by far the most common fluid used in the tracer, although ethylene glycol and more exotic heat-transfer fluids are used. In electrical systems, an electrical heating cable is placed against the pipe under the insulation.  [c.1011]

When the problem is to disrupt Ughtly bonded clusters or agglomerates, a new aspect of fine grinding enters. This may be iUustrated by the breakdown of pigments to incorporate them in liquid vehicles in the making of paints, and the disruption of biological cells to release soluble produces. Purees, food pastes, pulps, and the like are processed by this type of mill. Dispersion is also associated with the formation of emulsions which are basically two-fluid systems. Syrups, sauces, milk, ointments, creams, lotions, and asphalt and water-paint emulsions are in this categoiy.  [c.1863]

A criterion for the namre of flow, either laminar or mrbulent flow in fluid systems is the value of the Reynolds number. This number, Rg is defined by the equation  [c.58]

Steam traeing is the most eommon type of industrial pipe traeing. In 1960, over 95 pereent of industrial traeing systems were steam traeed. By 1995, improvements in eleetrie heating teehnology inereased the eleetrie share to 30 to 40 pereent, but steam traeing is still the most eommon system. Fluid systems other than steam are rather uneommon and aeeount for less than 5% of traeing systems.  [c.461]

More specifically, data bases are now available which are designed as aids to plastics material selection. One estimate in 1993 was that there were 300-400 systems in the field.Systems vary as to whether they are limited to the products of a particular company, to a particular area of activity and to the depth of coverage over a broad area.  [c.894]

Mathematical models of fluid systems  [c.27]

Like thermal systems, it is eonvenient to eonsider fluid systems as being analogous to eleetrieal systems. There is one important differenee however, and this is that the relationship between pressure and flow-rate for a liquid under turbulent flow eondi-tions is nonlinear. In order to represent sueh systems using linear differential equations it beeomes neeessary to linearize the system equations.  [c.27]

Core flood systems  [c.210]

Evans, L.B., 1989. Simulation with respect to solid-fluid systems. Computers and Chemical Engineering, 13, 343.  [c.305]

Very recently, the scientific interests of several leading theoretical laboratories have turned to studies of quenched-annealed fluids. To the best of our knowledge, there has not been a comprehensive review of the theoretical studies of quenched-annealed fluid systems. Our intention in this chapter is to fill, at least partially, an existing vacuum. Evidently, it is impossible to discuss the state of the art in this rapidly developing area in every detail in a single paper with restricted dimensions. We will omit, for example, the discussion of the fundamentals of the replica method for lattice systems, referring the reader to a monograph [1].  [c.293]

Let us proeeed now with some original results from our laboratory [47] that illustrate possibilities of the applieation of the ROZ theory for partly quenehed fluid systems.  [c.307]

The Zion PRA data base includes generic, plant-specific, and combined "updated" component failure data, maintenance frequencies for oomponents, initiating event data, human error rates, and component operability, test and service hour data. A nine-page component failure data table specifies mean values and 60% confidence interval error factors for generic data and updated mean values and variances for particular component types and failure modes. Most of the component failure rates were applicable to all systems, but exceptions are noted in some cases. Tables with maintenance frequency mean and variance values for selected components tables with initiating event occurrence probability mean, median, and 90% confidence bound values and fluid systems unavailability values are among the Zion PRA Data Base tables with features. A series of graphs shows the distribution of probability density versus occurrences per year for each initiating event for example, loss of Reactor Cooling System flow, core power excursion, and turbine trip. A System Description and Analysis Summary section provides brief descriptions of the safety systems essential to core damage prevention.  [c.124]

By definition, a supercritical fluid exists when both the temperature and pressure of the system exceed the critical values, and P. The critical parameters of some fluids are listed in Table 12-1 [11]. Supercritical fluids have physical properties that position them between liquids and gases. Like gases, supercritical fluids are highly compressible, and properties of the fluid including density and viscosity can be manipulated by changes in pressure and temperature. Under the conditions used for most chromatographic separations, solute diffusion coefficients are often an order of magnitude higher in supercritical fluids than in traditional liquids, and viscosities are lower than those of liquids [12]. Supercritical fluids can be comprised of a single component, but binary and ternary fluid systems are also possible. At temperatures  [c.300]

We discuss classical non-ideal liquids before treating solids. The strongly interacting fluid systems of interest are hard spheres characterized by their harsh repulsions, atoms and molecules with dispersion interactions responsible for the liquid-vapour transitions of the rare gases, ionic systems including strong and weak electrolytes, simple and not quite so simple polar fluids like water. The solid phase systems discussed are ferroniagnets and alloys.  [c.437]

The speeifie examples ehosen in this seetion, to illustrate the dynamies in eondensed phases for the variety of system-speeifie situations outlined above, eorrespond to long-wavelengdi and low-frequeney phenomena. In sueh eases, eonservation laws and broken syimnetry play important roles in the dynamies, and a maeroseopie hydrodynamie deseription is either adequate or is amenable to an appropriate generalization. There are otiier examples where short-wavelengdi and/or high-frequeney behaviour is evident. If this is the ease, one would require a more mieroseopie deseription. For fluid systems whieh are the foeus of this seetion, sueh deseriptions may involve a kinetie theory of dense fluids or generalized hydrodynamies whieh may be linear or may involve nonlinear mode eoupling. Sueh mieroseopie deseriptions are not eonsidered in this seetion.  [c.717]

The adsorption of sulfide collectors on sulfide minerals can best be described by electrochemical reactions whereia the mineral, the collector, or both are known to undergo redox reactions (30). This process is unique to sulfide mineral systems. Most sulfides exhibit metallic properties and undergo electrochemical reactions that are much like corrosion reactions exhibited by metals. Redox reactions are not relevant ia aoasulfide mineral flotatioa systems. Ia these latter systems, the adsorptioa is geaeraHy a chemisorption, surface chemical reactioa, or a physisorptioa, ie, electrostatic attractioa betweea oppositely charged mineral surface and collector, and is often a combination of these processes (30). Surface charge on the minerals, as approximated by zeta potentials, is therefore important ia aoasulfide systems. Because surface charge oa oxides and siUcates is strongly dependent on pH, the adsorption mechanism for a given collector, the choice of a collector, and the flotation selectivity are all iafluenced strongly by pH.  [c.412]

These methods of size enlargement depend on heat transfer to accomplish particle bonding. Heat may be transferred to the particle agglomerates, as in the drying of a concentrated slurry or paste, the fusion of a mass of fines, or chemical reaction between particles at elevated temperatures. Alternatively, heat may be removed from the material to cause agglomeration by chilling, as in the sohdification—crystallization of a melt or concentrated suspension. Heat transfer may be direct from a heat-transfer fluid or indirect across a heat-transfer surface. As a consequence, heat transfer and drying equipment used is quite varied and includes packed-bed systems of particulates and aggregates, dispersed particle—fluid systems, and heating and cooling on moving surfaces. An equally wide variety of preagglomeration equipment is used to preform powders and pastes into agglomerates suitable for drying, firing, or chilling. Included are balling devices and pellet mills as described above and extmders using rollers, bars, or wiper blades to force plastic pastes through perforated plates or grids to preform the paste into rods and other shapes (75).  [c.118]

A number of theoretical models have been proposed to describe the phase behavior of polymer—supercritical fluid systems, eg, the SAET and LEHB equations of state, and mean-field lattice gas models (67—69). Many examples of polymer—supercritical fluid systems are discussed ia the Hterature (1,3).  [c.225]

Gas AntisolventRecrystallizations. A limitation to the RESS process can be the low solubihty in the supercritical fluid. This is especially evident in polymer—supercritical fluid systems. In a novel process, sometimes termed gas antisolvent (GAS), a compressed fluid such as CO2 can be rapidly added to a solution of a crystalline soHd dissolved in an organic solvent (114). Carbon dioxide and most organic solvents exhibit full miscibility, whereas in this case the soHd solutes had limited solubihty in CO2. Thus, CO2 acts as an antisolvent to precipitate soHd crystals. Using C02 s adjustable solvent strength, the particle size and size distribution of final crystals may be finely controlled. Examples of GAS studies include the formation of monodisperse particles (<1 fiva) of a difficult-to-comminute explosive (114) recrystallization of -carotene and acetaminophen (86) salt nucleation and growth in supercritical water (115) and a study of the molecular thermodynamics of the GAS crystallization process (21).  [c.228]

Photochromic compounds that can be thermally faded have also been used in engineering studies to visuali2e flows in dynamic fluid systems (44,45).  [c.165]

U.S. Patent 4,349,415 (September 28, 1979), R. P. DeEUippi and E. Vivian (to Critical Fluid Systems, Inc.).  [c.419]

In its general sense, multiphase flow is not currently solvable by computational fluid dynamics. However, in certain cases reasonable solutions are possible. These include well-separated flows where the phases are confined to relatively well-defined regions separated by one or a few interfaces and flows in which a second phase appears as discrete particles of known size and shape whose motion may be approximately computed with drag coefficient formulations, or rigorously computed with refined meshes applying boundary conditions at the particle surface. Two-fluid modeling, in which the phases are treated as overlapping continua, with each phase occupying a volume fraction that is a continuous function of position (and time) is a useful approximation which is becoming available in commercial software. See Elghobashi and Abou-Arab (I. Physics Fluids, 26, 931-938 [1983]) for a /c— model for two-fluid systems.  [c.673]

Close-Clearance Stirrers For some pseiidoplastic fluid systems stagnant fluid may be found next to the -essel walls in parts remote from propeller or turbine impellers. In such cases, an anchor impeller maybe used (Fig, 18-6), The fluid flow is principally circular or helical (see Fig, 18-7) in the direction of rotation of the anchor. Whether substantial axial or radial fluid motion also occurs depends on the fluid iscosity and the design of the upper blade-supporting spokes. Anchor agitators are used particularly to obtain irnpro ed heat transfer in high-consistency fluids,  [c.1627]

Chapman and Holland Liquid Mixing and Processing in Stirred Tonhs, Reinhold, New York, 1966) review heat transfer to low-viscosity fluids in agitated vessels. Uhl [ Mechanically Aided Heat Transfer, in Uhl and Gray (eds.). Mixing Theory and Practice, vol. 1, Academic, New York, 1966, chap. V] surveys heat transfer to low- and high-viscosity agitated fluid systems. This review includes scraped-waU units and heat transfer on the jacket and coil side for agitated vessels.  [c.1642]

Industrial heat-traeing systems are generally fluid systems or eleetrieal systems. In fluid systems, a pipe or tube ealled the traeer is attaehed to the pipe being traeed, and a warm fluid is put through it. The traeer is plaeed under the insulation. Steam is by far the most eommon fluid used in the traeer, although ethylene glyeol and more exotie heat-transfer fluids are used. In eleetrieal systems, an eleetrieal heating eable is plaeed against the pipe under the insulation.  [c.461]

The chemical bonds between molecules are highly directional in many liquids. Water is one of the good examples of this class of hquids [93]. The formation of directional bonds can be generated in the statistical mechanics of fluids by the introduction of short-range, orientation-dependent, attractive forces into the Hamiltonian. Different types of molecular clusters can be formed (dimers, trimers, chains, fragments of a network of bonds, or an entire network), dependent on the nature of these short-range forces and mechanism of their saturation. The theory developed by Wertheim [8-11] provides effective tools to investigate thermodynamics and structural properties of this class of fluid systems. In fact, careful examination of the mechanism of saturation of the orientation-dependent forces had permitted Wertheim to formulate his theory. Extension of the theory of Wertheim to seemingly simpler models with spherically symmetric association, due to the efforts of Kalyuzhnyi and Stell [94], appeared later than the original theory.  [c.192]

Our final focus in this review is on charged quenched-annealed fluid systems. Very recently Bratko, Chakraborty and Chandler have addressed this problem [34-36]. A set of grand canonical computer simulation results for infinitely diluted electrolyte adsorbed in an electroneutral matrix of ions has been presented and an attempt to describe them at the level of  [c.296]

However, we also need to discuss how the attractive interactions between species can be included in the theory of partly quenched systems. These interactions comprise an intrinsic feature of realistic models for partially quenched fluid systems. In particular, the model for adsorption of methane in xerosilica gel of Kaminsky and Monson [41] is characterized by very strong attraction between matrix obstacles and fluid species. Besides, the fluid particles attract each other via the Lennard-Lones potential. Both types of attraction (the fluid-matrix and fluid-fluid) must be included to gain profound insight into the phase transitions in partly quenched media. The approach of Ford and Glandt to obtain the chemical potential utilizing  [c.304]

In conclusion, we have presented fundamental relations and reviewed some recent developments in the theory of quenched-annealed or partly quenched fluid systems. Theoretical developments presented in this study are focused on the problem of adsorption of fluids and mixtures in a rigidly fixed system of interconnecting micropores. In contrast to previous studies of fluids confined in pores of idealized geometry, such as slit-like, cyUndrical, or spherical, a microporous media considered in this work results from, for example, quenching of a system of particles. These can be either spherical or non-spherical in shape. Moreover, a disordered rigidly fixed matrix can be prepared of from chains or polymerizing monomers that may form branched and network-like structures. Most important, is that the matrix provides a disordered medium of interconnecting space for adsorption of a fluid. A highly non-trivial structure can be formed by considering a system of freely overlapping spherical particles, so-called random matrix [17-20]. Adsorption of fluids and mixtures into a system of interconnecting pores has many specific features that are not observed for an individual pore.  [c.341]


See pages that mention the term Fluid systems : [c.640]    [c.312]    [c.1013]    [c.987]    [c.307]    [c.854]   
Advanced control engineering (2001) -- [ c.27 ]