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1
Erdős, Máté, Olav Galteland, Dick Bedeaux, Signe Kjelstrup, Othonas A. Moultos, and Thijs J. H. Vlugt. "Gibbs Ensemble Monte Carlo Simulation of Fluids in Confinement: Relation between the Differential and Integral Pressures." Nanomaterials 10, no. 2 (February 9, 2020): 293. http://dx.doi.org/10.3390/nano10020293.
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The accurate description of the behavior of fluids in nanoporous materials is of great importance for numerous industrial applications. Recently, a new approach was reported to calculate the pressure of nanoconfined fluids. In this approach, two different pressures are defined to take into account the smallness of the system: the so-called differential and the integral pressures. Here, the effect of several factors contributing to the confinement of fluids in nanopores are investigated using the definitions of the differential and integral pressures. Monte Carlo (MC) simulations are performed in a variation of the Gibbs ensemble to study the effect of the pore geometry, fluid-wall interactions, and differential pressure of the bulk fluid phase. It is shown that the differential and integral pressure are different for small pores and become equal as the pore size increases. The ratio of the driving forces for mass transport in the bulk and in the confined fluid is also studied. It is found that, for small pore sizes (i.e., < 5 σ fluid ), the ratio of the two driving forces considerably deviates from 1.
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Franta, M., J. Málek, and K. R. Rajagopal. "On steady flows of fluids with pressure– and shear–dependent viscosities." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 461, no. 2055 (March 8, 2005): 651–70. http://dx.doi.org/10.1098/rspa.2004.1360.
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There are many technologically important problems such as elastohydrodynamics which involve the flows of a fluid over a wide range of pressures. While the density of the fluid remains essentially constant during these flows whereby the fluid can be approximated as being incompressible, the viscosity varies significantly by several orders of magnitude. It is also possible that the viscosity of such fluids depends on the shear rate. Here we consider the flows of a class of incompressible fluids with viscosity that depends on the pressure and shear rate. We establish the existence of weak solutions for the steady flows of such fluids subjected to homogeneous Dirichlet boundary conditions and to specific body forces that are not necessarily assumed to be small. A novel aspect of the study is the manner in which we treat the pressure that allows us to establish its compactness, as well as that of the velocity gradient. The method draws upon the physics of the problem, namely that the notion of incompressibility is an idealization that is attained by letting the compressibility of the fluid to tend to zero.
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Skadsem, Hans Joakim, Amare Leulseged, and Eric Cayeux. "Measurement of Drilling Fluid Rheology and Modeling of Thixotropic Behavior." Applied Rheology 29, no. 1 (March 1, 2019): 1–11. http://dx.doi.org/10.1515/arh-2019-0001.
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Abstract Drilling fluids perform a number of important functions during a drilling operation, including that of lifting drilled cuttings to the surface and balancing formation pressures. Drilling fluids are usually designed to be structured fluids exhibiting shear thinning and yield stress behavior, and most drilling fluids also exhibit thixotropy. Accurate modeling of drilling fluid rheology is necessary for predicting friction pressure losses in the wellbore while circulating, the pump pressure needed to resume circulation after a static period, and how the fluid rheology evolves with time while in static or near-static conditions. Although modeling the flow of thixotropic fluids in realistic geometries is still a formidable future challenge to be solved, considerable insights can still be gained by studying the viscometric flows of such fluids. We report a detailed rheological characterization of a water-based drilling fluid and an invert emulsion oilbased drilling fluid. The micro structure responsible for thixotropy is different in these fluids which results in different thixotropic responses. Measurements are primarily focused at transient responses to step changes in shear rate, but cover also steady state flow curves and stress overshoots during start-up of flow. We analyze the shear rate step change measurements using a structural kinetics thixotropy model.
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Batzle, Michael, and Zhijing Wang. "Seismic properties of pore fluids." GEOPHYSICS 57, no. 11 (November 1992): 1396–408. http://dx.doi.org/10.1190/1.1443207.
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Pore fluids strongly influence the seismic properties of rocks. The densities, bulk moduli, velocities, and viscosities of common pore fluids are usually oversimplified in geophysics. We use a combination of thermodynamic relationships, empirical trends, and new and published data to examine the effects of pressure, temperature, and composition on these important seismic properties of hydrocarbon gases and oils and of brines. Estimates of in‐situ conditions and pore fluid composition yield more accurate values of these fluid properties than are typically assumed. Simplified expressions are developed to facilitate the use of realistic fluid properties in rock models. Pore fluids have properties that vary substantially, but systematically, with composition, pressure, and temperature. Gas and oil density and modulus, as well as oil viscosity, increase with molecular weight and pressure, and decrease with temperature. Gas viscosity has a similar behavior, except at higher temperatures and lower pressures, where the viscosity will increase slightly with increasing temperature. Large amounts of gas can go into solution in lighter oils and substantially lower the modulus and viscosity. Brine modulus, density, and viscosities increase with increasing salt content and pressure. Brine is peculiar because the modulus reaches a maximum at a temperature from 40 to 80°C. Far less gas can be absorbed by brines than by light oils. As a result, gas in solution in oils can drive their modulus so far below that of brines that seismic reflection bright spots may develop from the interface between oil saturated and brine saturated rocks.
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KRESS, BRIAN T., and DAVID C. MONTGOMERY. "Pressure determinations for incompressible fluids and magnetofluids." Journal of Plasma Physics 64, no. 4 (October 2000): 371–77. http://dx.doi.org/10.1017/s0022377800008825.
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Certain unresolved ambiguities surround pressure determinations for incompressible flows: both Navier–Stokes and magnetohydrodynamic (MHD). For uniform-density fluids with standard Newtonian viscous terms, taking the divergence of the equation of motion leaves a Poisson equation for the pressure to be solved. But Poisson equations require boundary conditions. For the case of rectangular periodic boundary conditions, pressures determined in this way are unambiguous. But in the presence of ‘no-slip’ rigid walls, the equation of motion can be used to infer both Dirichlet and Neumann boundary conditions on the pressure P, and thus amounts to an over-determination. This has occasionally been recognized as a problem, and numerical treatments of wallbounded shear flows usually have built in some relatively ad hoc dynamical recipe for dealing with it – often one that appears to ‘work’ satisfactorily. Here we consider a class of solenoidal velocity fields that vanish at no-slip walls, have all spatial derivatives, but are simple enough that explicit analytical solutions for P can be given. Satisfying the two boundary conditions separately gives two pressures, a ‘Neumann pressure’ and a ‘Dirichlet pressure’, which differ nontrivially at the initial instant, even before any dynamics are implemented. We compare the two pressures, and find that, in particular, they lead to different volume forces near the walls. This suggests a reconsideration of no-slip boundary conditions, in which the vanishing of the tangential velocity at a no-slip wall is replaced by a local wall-friction term in the equation of motion.
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Wang, Jin Feng, and Jin Gen Deng. "Fuzzy Ball Drilling Fluid for CBM in the Ordos Basin of China." Advanced Materials Research 651 (January 2013): 717–21. http://dx.doi.org/10.4028/www.scientific.net/amr.651.717.
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Fuzzy ball drilling fluids have been developed in order to effectively control lost circulation during CBM drilling. Depending upon fuzzy balls and colloids in fuzzy balls, the fuzzy ball drilling fluids changed their shapes and properties to completely plug underground heterogeneous seepage channels so as to strengthen the pressure bearing capacity of formations. This paper describes the available features of the fuzzy ball drilling fluid including efficient plugging, good carrying and suspension, formation damage control, compatible weighted by any weighted materials without auxiliary equipment. The fuzzy ball drilling fluids can finish drilling in low pressure natural gas zone, control CBM leakage; control the natural fractures, drilling in different pressures in the same open hole, combination with the air drilling mode, etc. during Ordos CBM drilling. The fuzzy ball drilling fluid will not affect down-hole motors and MWD. The fuzzy ball drilling fluid will be blend simply as conventional water based drilling fluids. The existing CBM drilling equipment can completely meet the fuzzy ball drilling mixing and it is maintained conveniently. The fuzzy ball drilling fluid is the efficient drilling fluid.
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Li, Zuo Chen, Zhi Heng Zhang, Liang Zhan, and Jia Rong Cai. "Fuzzy Ball Drilling Fluids for CBM in the Ordos Basin of China." Advanced Materials Research 602-604 (December 2012): 843–46. http://dx.doi.org/10.4028/www.scientific.net/amr.602-604.843.
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Fuzzy ball drilling fluids have been developed in order to effectively control lost circulation during CBM drilling. Depending upon fuzzy balls and colloids in fuzzy balls, the fuzzy ball drilling fluids changed their shapes and properties to completely plug underground heterogeneous seepage channels so as to strengthen the pressure bearing capacity of formations. This paper describes the available features of the fuzzy ball drilling fluid including efficient plugging, good carrying and suspension, formation damage control, compatible weighted by any weighted materials without auxiliary equipment. The fuzzy ball drilling fluids can finish drilling in low pressure natural gas zone, control CBM leakage; control the natural fractures, drilling in different pressures in the same open hole, combination with the air drilling mode, etc. during Ordos CBM drilling. The fuzzy ball drilling fluid will not affect down-hole motors and MWD. The fuzzy ball drilling fluid will be blend simply as conventional water based drilling fluids. The existing CBM drilling equipment can completely meet the fuzzy ball drilling mixing and it is maintained conveniently. The fuzzy ball drilling fluid is the efficient drilling fluid.
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Escobar, Freddy-Humberto, Angela-Patricia Zambrano, Diana-Vanessa Giraldo, and José-Humberto Cantillo. "Pressure and pressure derivative analysis for non-newtonian pseudoplastic fluids in double-porosity formations." CT&F - Ciencia, Tecnología y Futuro 4, no. 3 (May 24, 2011): 47–60. http://dx.doi.org/10.29047/01225383.238.
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Non-Newtonian fluids are often used during various drilling, workover and enhanced oil recovery processes. Most of the fracturing fluids injected into reservoir-bearing formations possess non-Newtonian nature and these fluids are often approximated by Newtonian fluid flow models. In the field of well testing, several analytical and numerical models taking into account Bingham, pseudoplastic and dilatant non-Newtonian behavior have been introduced in the literature to study their transient nature in porous media for a better reservoir characterization. Most of them deal with fracture wells and homogeneous formations and well test interpretation is conducted via the straight-line conventional analysis or type-curve matching. Only a few studies consider the pressure derivative analysis. However, there exists a need of a more practical and accurate way of characterizing such systems. So far, it does not exist any methodology to characterize heterogeneous formation bearing non-Newtonian fluids through of well test analysis. In this study, an interpretation methodology using the pressure and pressure derivative log-log plot is presented for non-Newtonian fluids in naturally fractured formations, so the dimensionless fracture storativity ratio, ω, and interporosity flow parameter, λ, are obtained from characteristics points found on such plot. The developed equations and correlations are successfully verified by their application only to synthetic well test data since no actual field data are available. A good match is found between the results provided by the proposed technique and the values used to generate the simulated data.
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Bushmin, S. A., Ye A. Vapnik, M. V. Ivanov, Yu M. Lebedeva, and E. V. Savva. "Fluids in High-Pressure Granulites." Petrology 28, no. 1 (January 2020): 17–46. http://dx.doi.org/10.1134/s0869591120010026.
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Todd, B. D., Denis J. Evans, and Peter J. Daivis. "Pressure tensor for inhomogeneous fluids." Physical Review E 52, no. 2 (August 1, 1995): 1627–38. http://dx.doi.org/10.1103/physreve.52.1627.
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Nagy, T. "Pressure shocks in radiating fluids." Acta Physica Hungarica 74, no. 3 (June 1994): 279–86. http://dx.doi.org/10.1007/bf03156307.
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Hanson, R. Brooks. "Hydrodynamics of magmatic and meteoric fluids in the vicinity of granitic intrusions." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 87, no. 1-2 (1996): 251–59. http://dx.doi.org/10.1017/s0263593300006660.
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ABSTRACT:Numerical models that account for fluid flow, magmatic and metamorphic fluid production, topography and thermal expansion of the fluid following emplacement of a granitic magma in the upper crust reveal controls on the distribution of magmatic fluids during the evolution of a hydrothermal system. Initially, fluid pressures are close to lithostatic in and near an intrusion, and internally generated magmatic and metamorphic fluids are expelled. Later, fluid pressures drop to hydrostatic values and meteoric fluids circulate throughout the system. High permeabilities and low rates of fluid production accelerate this transition. Fluid production in the magma and wallrocks is the dominant mechanism elevating fluid pressures to lithostatic values. For granitic intrusions, about three to five times as much magmatic fluid is produced as metamorphic fluid. Continuous fluid release from a granitic magma with a vertical dimensions of 10 km produces a dynamic permeability of up to several tens of microdarcies.Near the surface, topography associated with a typical volcano acts to maintain a shallow meteoric flow system and drive fluids laterally. The exponential decay with depth of the influence of topography on fluid pressures results in a persistent zone of mixing at a depth of 1-2 km between these meteoric fluids and magmatic fluids despite variations in the strength of the magmatic hydrothermal system. However, in shallow systems where fluid release is episodic, dramatic changes in the region of mixing are still possible because fluid pressure is sensitive to variations in the rates of fluid production. At depth, high rates of metamorphic fluid production in the wallrocks and low permeabilities (< 1 μD) produce elevated fluid pressures, which hinder the lateral flow of magmatic fluids. Together, these patterns are consistent with the distribution and evolution of skarns and hydrothermal ore deposits around granitic magmas.
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Isnikurniawan, Ahmad, Yasuhiro Fujita, Sachio Tanimoto, and Tatsuo Sawada. "Investigation of Cluster Formation in MR Fluid under Compression Using Ultrasonic Measurement." Materials Science Forum 792 (August 2014): 147–52. http://dx.doi.org/10.4028/www.scientific.net/msf.792.147.
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This paper reports measurement results of ultrasonic propagation velocity in MR fluid under compression. Experiments were conducted by applying different pressures in MR fluid at constant magnetic flux density. At low magnetic flux densities (100 and 200 mT), the ultrasonic propagation velocity in MR fluids changes when subjected to pressure. This change is related to cluster formation in MR fluid. The ultrasonic propagation velocity change is smaller when higher pressures are applied, indicating that cluster size in MR fluid becomes thinner under higher pressures. However, at higher magnetic flux densities (300 and 400 mT), ultrasonic propagation velocities under different pressures are nearly similar. These results indicate that at higher magnetic flux densities, pressures do not affect cluster formation in MR fluids.
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Xu, Zhengming, Kan Wu, Xianzhi Song, Gensheng Li, Zhaopeng Zhu, and Baojiang Sun. "A Unified Model To Predict Flowing Pressure and Temperature Distributions in Horizontal Wellbores for Different Energized Fracturing Fluids." SPE Journal 24, no. 02 (December 31, 2018): 834–56. http://dx.doi.org/10.2118/194195-pa.
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Summary Energized fracturing fluids, including foams, carbon dioxide (CO2), and nitrogen (N2), are widely used for multistage fracturing in horizontal wells. However, because density, rheology, and thermal properties are sensitive to temperature and pressure, it is important to understand the flow and thermal behaviors of energized fracturing fluids along the wellbore. In this study, a unified steady-state model is developed to simulate the flow and thermal behaviors of different energized fracturing fluids and to investigate the changes of fluid properties from the wellhead to the toe of the horizontal wellbore. The velocity and pressure are calculated using continuity and momentum equations. Temperature profiles of the whole wellbore/formation system are obtained by simultaneously solving energy equations of different thermal regions. Temperature, pressure, and energized-fluid properties are coupled in both depth and radial directions using an iteration scheme. This model is verified against field data from energized-fluid-injection operations. The relative average errors for pressure and temperature are less than 5%. The effects of injection pressure, mass-flow rate, annulus-fluid type, foam quality, and proppant volumetric concentration on pressure and temperature distributions are analyzed. Influence degrees of these operating parameters on the bottomhole pressure (BHP) for different energized fracturing fluids are calculated. The required injection parameters at the surface to achieve designed bottomhole treating parameters for different energized fracturing fluids are compared. The results of this study might help field operators to select the most-suitable energized fluid and further optimize energized-fluid-fracturing treatments.
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Fetecau, Constantin, Dumitru Vieru, Tehseen Abbas, and Rahmat Ellahi. "Analytical Solutions of Upper Convected Maxwell Fluid with Exponential Dependence of Viscosity under the Influence of Pressure." Mathematics 9, no. 4 (February 7, 2021): 334. http://dx.doi.org/10.3390/math9040334.
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Some unsteady motions of incompressible upper-convected Maxwell (UCM) fluids with exponential dependence of viscosity on the pressure are analytically studied. The fluid motion between two infinite horizontal parallel plates is generated by the lower plate, which applies time-dependent shear stresses to the fluid. Exact expressions, in terms of standard Bessel functions, are established both for the dimensionless velocity fields and the corresponding non-trivial shear stresses using the Laplace transform technique and suitable changes of the unknown function and the spatial variable in the transform domain. They represent the first exact solutions for unsteady motions of non-Newtonian fluids with pressure-dependent viscosity. The similar solutions corresponding to the flow of the same fluids due to an exponential shear stress on the boundary as well as the solutions of ordinary UCM fluids performing the same motions are obtained as limiting cases of present results. Furthermore, known solutions for unsteady motions of the incompressible Newtonian fluids with/without pressure-dependent viscosity induced by oscillatory or constant shear stresses on the boundary are also obtained as limiting cases. Finally, the influence of physical parameters on the fluid motion is graphically illustrated and discussed. It is found that fluids with pressure-dependent viscosity flow are slower when compared to ordinary fluids.
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Prokofiev, Vsevolod Yu, and Vladimir B. Naumov. "Physicochemical Parameters and Geochemical Features of Ore-Forming Fluids for Orogenic Gold Deposits Throughout Geological Time." Minerals 10, no. 1 (January 5, 2020): 50. http://dx.doi.org/10.3390/min10010050.
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This paper reviews data from numerous publications focused on the physicochemical parameters and chemical composition of ore-forming fluids from orogenic gold deposits formed during various geological epochs. The paper presents analysis of the distribution of the principal parameters of mineralizing fluids depending on the age of the mineralization. Some parameters of the fluids (their salinity and pressure) at orogenic gold deposits are demonstrated to systematically vary from older (median salinity 6.1 wt.%, median pressure 1680 bar) to younger (median salinity 3.6 wt.%, median pressure 1305 bar) deposits. The detected statistically significant differences between some parameters of mineralizing fluids at orogenic gold deposits are principally new information. The parameters at which mineralization of various age was formed are demonstrated to pertain to different depth levels of similar mineralization-forming systems. The fluid parameters of the most ancient deposits (which are mostly deeply eroded) correspond to the deepest levels of orogenic fluid systems. Hence, the detected differences in the salinity and pressure of the mineralizing fluids at orogenic deposits of different age reflect the vertical zoning of the mineralizing fluid systems.
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Han, Xuan Zhuo, Bao Kui Gao, Hong Qiang Zhang, Xing Qin, and Wei Wang. "Compressible Fluids Mitigation Effect Research in Deepwater Oil and Gas Well." Advanced Materials Research 734-737 (August 2013): 1165–70. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.1165.
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During well drilling and petroleum production in deepwater, wellhole temperature changes will cause annular pressure buildup (APB), which is of great danger to casing strings. Based on previous research results, this paper introduces the traditional bulk modulus elasticity calculation method of mixed gas and liquid into annulus fluids, to predict annular pressure buildup by thermal when gas mixture is used. Pressure mitigation effect of common used compressible fluid is investigated and compared with experiment results from references. Through engineering case, the changing rule of mixed fluid bulk modulus versus gas volume and impact of mixed fluid volume on annular pressure are calculated. It shows that bulk modulus obtained in this paper has small errors compared with simulation experiment. But the errors are acceptable in engineering environment. And so, annular pressures needed in a well can be predicted and controlled precisely by adjusting gas volume as shown in examples.
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Verweij, J. M., H. J. Simmelink, J. Underschultz, and N. Witmans. "Pressure and fluid dynamic characterisation of the Dutch subsurface." Netherlands Journal of Geosciences - Geologie en Mijnbouw 91, no. 4 (December 2012): 465–90. http://dx.doi.org/10.1017/s0016774600000342.
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AbstractThis paper presents and discusses the distribution of fluid and leak-off pressure data from the subsurface of onshore and offshore Netherlands in relation to causes of formation fluid overpressure and the permeability framework. The observed fluid pressure conditions demonstrate a clear regional difference between the southern and the north and north-eastern part of the study area. In the southern area, formation fluid pressures are close to normal and well below measured leak-off pressures. In the north, formation fluids are overpressured and may locally even approach the measured leak-off pressures. The regional differences in fluid overpressure can, in large part, be explained by differences in geologic framework and burial history. In the south, relatively low rates of sedimentary loading and the presence of relatively permeable sedimentary units have led to the currently observed normally pressured conditions. In the northern area, relatively rapid Neogene sediment loading plays an important role in explaining the observed overpressure distributions in Cenozoic mudstones, Cretaceous Chalk and Rijnland groups, and probably also in Jurassic units. The permeability framework of the northern and north-eastern area is significantly affected by Zechstein and Triassic salt deposits and structures. These units are characterised by very low permeability and severely restrict fluid flow and pressure dissipation. This has created hydraulically restricted compartments with high overpressures (for example overpressures exceeding 30 MPa in the Lower Germanic Trias Group in the Terschelling Basin and Dutch Central Graben).
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Dvorkin, Jack, and Amos Nur. "Filtration fronts in pressure compliant reservoirs." GEOPHYSICS 57, no. 8 (August 1992): 1089–92. http://dx.doi.org/10.1190/1.1443320.
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Hydrofracturing is believed to be the major mechanism responsible for the migration of crust fluids and for the transport of hydrocarbons from overpressured fluid compartments. In their analysis of the process of porosity reduction in the earth’s crust and crustal pore pressure generation, Walder and Nur (1984) point out that elevated pore pressure generated as a result of local porosity reduction may lead to brittle failure with partial relief of high pore pressure. Such episodic fracturing accompanied by crack healing, may be a common process throughout most of the crust. Hunt (1990) also speculates that the generation of oil and gas within the compartments plus the thermal expansion of pore fluids eventually causes fracturing of the top compartment seal during periods of basin sinking. Seal fracturing causes a pressure drop with compartment fluids rushing to the breakout point. Episodic cycles of resealing and breakout may occur in intervals of thousands of years in rapidly sinking basins such as the United States Gulf coast.
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Pucciarelli, Andrea, Sara Kassem, and Walter Ambrosini. "Overview of a Theory for Planning Similar Experiments with Different Fluids at Supercritical Pressure." Energies 14, no. 12 (June 21, 2021): 3695. http://dx.doi.org/10.3390/en14123695.
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The recent advancements achieved in the development of a fluid-to-fluid similarity theory for heat transfer with fluids at supercritical pressures are summarised. The prime mover for the development of the theory was the interest in the development of Supercritical Water nuclear Reactors (SCWRs) in the frame of research being developed worldwide; however, the theory is general and can be applied to any system involving fluids at a supercritical pressure. The steps involved in the development of the rationale at the basis of the theory are discussed and presented in a synthetic form, highlighting the relevance of the results achieved so far and separately published elsewhere, with the aim to provide a complete overview of the potential involved in the application of the theory. The adopted rationale, completely different from the ones in the previous literature on the subject, was based on a specific definition of similarity, aiming to achieve, as much as possible, similar distributions of enthalpies and fluid densities in a duct containing fluids at a supercritical pressure. This provides sufficient assurance that the complex phenomena governing heat transfer in the addressed conditions, which heavily depend on the changes in fluid density and in other thermophysical properties along and across the flow duct, are represented in sufficient similarity. The developed rationale can be used for planning possible counterpart experiments, with the aid of supporting computational fluid-dynamic (CFD) calculations, and it also clarifies the role of relevant dimensionless numbers in setting up semi-empirical correlations for heat transfer in these difficult conditions, experiencing normal, enhanced and deteriorated regimes. This paper is intended as a contribution to a common reflection on the results achieved so far in view of the assessment of a sufficient body of knowledge and understanding to base successful predictive capabilities for heat transfer with fluids at supercritical pressures.
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Hurtig, Nicole C., Artas A. Migdisov, and Anthony E. Williams-Jones. "Are Vapor-Like Fluids Viable Ore Fluids for Cu-Au-Mo Porphyry Ore Formation?" Economic Geology 116, no. 7 (November 1, 2021): 1599–624. http://dx.doi.org/10.5382/econgeo.4835.
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Abstract Ore formation in porphyry Cu-Au-(Mo) systems involves the exsolution of metal-bearing fluids from magmas and the transport of the metals in magmatic-hydrothermal plumes that are subject to pressure fluctuations. Deposition of ore minerals occurs as a result of cooling and decompression of the hydrothermal fluids in partly overlapping ore shells. In this study, we address the role of vapor-like fluids in porphyry ore formation through numerical simulations of metal transport using the Gibbs energy minimization software, GEM-Selektor. The thermodynamic properties of the hydrated gaseous metallic species necessary for modeling metal solubility in fluids of moderate density (100–300 kg/m3) were derived from the results of experiments that investigated the solubility of metals in aqueous HCl- and H2S-bearing vapors. Metal transport and precipitation were simulated numerically as a function of temperature, pressure, and fluid composition (S, Cl, and redox). The simulated metal concentrations and ratios are compared to those observed in vapor-like and intermediate-density fluid inclusions from porphyry ore deposits, as well as gas condensates from active volcanoes. The thermodynamically predicted solubility of Cu, Au, Ag, and Mo decreases during isothermal decompression. At elevated pressure, the simulated metal solubility is similar to the metal content measured in vapor-like and intermediate-density fluid inclusions from porphyry deposits (at ~200–1,800 bar). At ambient pressure, the metal solubility approaches the metal content measured in gas condensates from active volcanoes (at ~1 bar), which is several orders of magnitude lower than that in the high-pressure environment. During isochoric cooling, the simulated solubility of Cu, Ag, and Mo decreases, whereas that of Au reaches a maximum between 35 ppb and 2.6 ppm depending on fluid density and composition. Similar observations are made from a compilation of vapor-like and intermediate-density fluid inclusion data showing that Cu, Ag, and Mo contents decrease with decreasing pressure and temperature. Increasing the Cl concentration of the simulated fluid promotes the solubility of Cu, Ag, and Au chloride species. Molybdenum solubility is highest under oxidizing conditions and low S content, and gold solubility is elevated at intermediate redox conditions and elevated S content. The S content of the vapor-like fluid strongly affects metal ratios. Thus, there is a decrease in the Cu/Au ratio as the S content increases from 0.1 to 1 wt %, whereas the opposite is the case for the Mo/Ag ratio; at S contents of >1 wt %, the Mo/Ag ratio also decreases. In summary, thermodynamic calculations based on experiments involving gaseous metallic species predict that vapor-like fluids may transport and efficiently precipitate metals in concentrations sufficient to form porphyry ore deposits. Finally, the fluid composition and pressure-temperature evolution paths of vapor-like and intermediate-density fluids have a strong effect on metal solubility in porphyry systems and potentially exert an important control on their metal ratios and zoning.
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Singh, U. P., Amit Medhavi, R. S. Gupta, and Siddharth Shankar Bhatt. "Analysis of Peristaltic Transport of Non-Newtonian Fluids Through Nonuniform Tubes: Rabinowitsch Fluid Model." Zeitschrift für Naturforschung A 72, no. 7 (July 26, 2017): 601–8. http://dx.doi.org/10.1515/zna-2017-0033.
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AbstractPeristaltic transport is an important mechanism of physiological phenomenon and peristaltic pumps. With the advancement of medical science, it has been established that the physiological fluids do not behave like Newtonian fluids. Therefore, in order to understand the behaviour and properties of physiological fluids during peristalsis, selection of appropriate fluid model is of great importance. In the present investigation, properties of peristaltic transport through nonuniform tube have been studied for non-Newtonian fluids using Rabinowitsch fluid model. Theoretical analysis has been presented for long wavelength and low Reynolds number approximation. To analyse various properties of the flow, analytical expressions for velocity, pressure gradient, pressure rise, friction force, and temperature have been obtained. The numerical results for the same have been obtained to present the effect of various physical and flow parameters on fluid velocity, pressure rise, friction force, and temperature. Significant variation of these properties has been observed in the analysis for non-Newtonian nature of the fluid and nonuniformity of the tube.
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Drlička, R., V. Kročko, and M. Matúš. "Machinability improvement using high-pressure cooling in turning." Research in Agricultural Engineering 60, Special Issue (December 30, 2014): S70—S76. http://dx.doi.org/10.17221/38/2013-rae.
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Process fluids are used primarily for their cooling and lubricating effect in machining. Many ways to improve their performance have been proposed; the analysis of some of them is provided in the paper. The effect of high pressure cooling has been investigated with regard to chip formation and tool life. Standard and for high pressure application particularly designed indexable cutting inserts were used with fluid pressure 1.5 and 7.5 MPa. The pressure effect on tool life at different feed rates was observed as well. Not each cooling pressure value or machined material showed favourable chip formation. Tool life though has improved significantly while machining with a lower feed rate.
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ALHUSSAN, KHALED. "METHOD OF ENERGY TRANSFER." Modern Physics Letters B 19, no. 28n29 (December 20, 2005): 1663–66. http://dx.doi.org/10.1142/s0217984905010165.
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The aim of this paper is to show numerically the semi-ideal way of transferring energy in the non-steady supersonic mechanism. Energy can be transferred between two fluids in semi-ideal process if the two fluids are brought together for a direct contact. This paper shows the energy transfer between two fluids via the direct fluid-fluid interaction in a non-steady supersonic flow. This was shown by using two fluids one with higher energy than the other. Results including contour plots of static pressure, static temperature, and total pressure and velocity vectors show the structure of flow of the energy-transfer-mechanism in a supersonic flow.
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Escobar, Freddy-Humberto, Laura-Jimena Vega, and Luis-Fernando Bonilla. "Determination of well-drainage area for power-law fluids by transient pressure analysis." CT&F - Ciencia, Tecnología y Futuro 5, no. 1 (November 30, 2012): 45–56. http://dx.doi.org/10.29047/01225383.214.
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Since conventional oil is almost depleted, oil companies are focusing their efforts on exploiting heavy oil reserves. A modern and practical technique using the pressure and pressure derivative, log-log plot for estimating the well-drainage area in closed and constant-pressure reservoirs, drained by a vertical well is presented by considering a non-Newtonian flow model for describing the fluid behavior. Several synthetic examples were presented for demonstration and verification purposes.Such fluids as heavy oil, fracturing fluids, some fluids used for Enhanced Oil Recovery (EOR) and drilling muds can behave as either Power-law or Bingham, usually referred to as the non-Newtonian fluids. Currently, there is no way to estimate the well-drainage area from conventional well test analysis when a non-Newtonian fluid is dealt with; therefore, none of the commercial well test interpretation package can estimate this parameter (drainage area).
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Li, Song Jing, Jing Hui Peng, Sheng Zhuo Zhang, and Jacob M. Mchenya. "Depression of Self-Excited Pressure Oscillations and Noise in the Pilot Stage of a Hydraulic Jet-Pipe Servo-Valve Using Magnetic Fluids." Advanced Materials Research 378-379 (October 2011): 632–35. http://dx.doi.org/10.4028/www.scientific.net/amr.378-379.632.
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Magnetic fluid (MF) shows an increased saturation magnetization when exposed to a magnetic field. In order to improve the quality of servo-valve products by depressing and overcoming the self-excited high-frequency pressure oscillations and noise appearing in pilot stage of a hydraulic servo-valve, application of magnetic fluid in a hydraulic servo-valve is developed in this paper. Large damping can be introduced by the magnetic fluids into the servo-valve if magnetic fluids are filled into the working gaps of the hydraulic servo-valve torque motor. After the construction and working principle of a hydraulic servo-valve with magnetic fluids are introduced, the high-frequency pressure oscillation signals are tested and recorded when magnetic fluids are applied or not in the servo-valve. Experimental results are compared and analyzed by using FFT analysis method. It is shown that pressure oscillations of the servo-valve are depressed when magnetic fluids are applied.
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Yap, WW, D. Young, and V. Pathi. "Effects of gelatine and medium molecular weight starch as priming fluid in cardiopulmonary bypass - a randomised controlled trial." Perfusion 22, no. 1 (January 2007): 57–61. http://dx.doi.org/10.1177/0267659107077903.
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Perioperative volume replacement after cardiopulmonary bypass is complicated by post-bypass systemic inflammatory process. The aim of this study was to assess the effects of using two different colloid solutions as priming fluids in cardiopulmonary bypass. The study's primary end point was to measure the amount of fluid replacement needed during and post-cardiopulmonary bypass; blood loss, change in blood profile and intraocular pressure were secondary end points, used as measures of plasma oncotic pressures. Patients undergoing coronary artery bypass grafting were recruited. Both patients and surgeons were blinded to receive either Gelofusine® or Voluven® as priming fluids. At fixed intervals during cardiopulmonary bypass, the patients had their intraocular pressures measured. Intra and postoperative fluid replacement was in the form of 4.5% human albumin and the amount was recorded for each subject. The result did not show any significant differences in the amount of fluid needed to be replaced, in blood loss or in blood profile between the two groups. However, it showed an increase in intraocular pressure in both groups once cardiopulmonary bypass commenced. The average intraocular pressure was higher in the Gelofusine ® group compared to the Voluven® group. The significant increase in intraocular pressure measurements in the Gelofusine® group compared to the Voluven® group support the hypothesis that Voluven maintains the plasma oncotic pressure better and reduces fluid shift. Perfusion (2007) 22, 57—62.
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Apparao, Siddangouda, Trimbak Vaijanath Biradar, and Neminath Bhujappa Naduvinamani. "Non-Newtonian Effects of Second-Order Fluids on the Hydrodynamic Lubrication of Inclined Slider Bearings." International Scholarly Research Notices 2014 (October 23, 2014): 1–7. http://dx.doi.org/10.1155/2014/787304.
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Theoretical study of non-Newtonian effects of second-order fluids on the performance characteristics of inclined slider bearings is presented. An approximate method is used for the solution of the highly nonlinear momentum equations for the second-order fluids. The closed form expressions for the fluid film pressure, load carrying capacity, frictional force, coefficient of friction, and centre of pressure are obtained. The non-Newtonian second order fluid model increases the film pressure, load carrying capacity, and frictional force whereas the center of pressure slightly shifts towards exit region. Further, the frictional coefficient decreases with an increase in the bearing velocity as expected for an ideal fluid.
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Golinelli, Nicola, and Andrea Spaggiari. "Experimental validation of a novel magnetorheological damper with an internal pressure control." Journal of Intelligent Material Systems and Structures 28, no. 18 (February 1, 2017): 2489–99. http://dx.doi.org/10.1177/1045389x17689932.
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In the present article, we have investigated the behaviour of magnetorheological fluids under a hydrostatic pressure of up to 40 bar.We have designed, manufactured and tested a magnetorheological damper with a novel architecture, which provides the control of the internal pressure. The pressurewas regulated by means of an additional apparatus connected to the damper that acts on the fluid volume. The magnetorheological damper was tested under sinusoidal inputs and with several values for the magnetic field and internal pressure. The results show that the new architecture is able to work without a volume compensator and bear high pressures. On the one hand, the influence of the hydrostatic pressure on the yield stress of the magnetorheological fluids is not strong, probably because the ferromagnetic particles cannot arrange themselves into thicker columns. On the other hand, the benefits of the pressure on the behaviour of the magnetorheological damper are useful in terms of preventing cavitation.
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Kariotoglou, Petros, and Dimitris Psillos. "Teaching and Learning Pressure and Fluids." Fluids 4, no. 4 (November 25, 2019): 194. http://dx.doi.org/10.3390/fluids4040194.
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This essay is a synthesis of more than twenty years of research, already published, on teaching and learning fluids and pressure. We examine teaching fluids globally, i.e., the content to be taught and its transformations, students’ alternative conceptions and their remediation, the sequence of educational activities, being right for students’ understanding, as well as tasks for evaluating their conceptual evolution. Our samples are junior high school students and primary school student-teachers. This long-term study combines research and development concerning teaching and learning fluids and has evolved through iteratively based design application and reflective feedback related to empirical data. The results of our research include several publications.
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Gor, Gennady Y., Daniel W. Siderius, Vincent K. Shen, and Noam Bernstein. "Modulus–pressure equation for confined fluids." Journal of Chemical Physics 145, no. 16 (October 28, 2016): 164505. http://dx.doi.org/10.1063/1.4965916.
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Fründt, Jens, Artur Steiff, and Paul-Michael Weinspach. "Pressure relief with highly viscous fluids." Process Safety Progress 16, no. 1 (1997): 57–59. http://dx.doi.org/10.1002/prs.680160116.
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Shamaev, V. A., O. A. Kunitskaya, I. V. Grigorjev, I. N. Medvedev, D. A. Parinov, and S. S. Burmistrova. "Wood impregnation with fluids under pressure." Systems. Methods. Technologies, no. 4(40) (2018): 152–56. http://dx.doi.org/10.18324/2077-5415-2018-4-152-156.
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Vergne, PH. "Pressure viscosity behavior of various fluids." High Pressure Research 8, no. 1-3 (February 1992): 451–54. http://dx.doi.org/10.1080/08957959108260704.
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Mistura, L. "The pressure tensor in nonuniform fluids." Journal of Chemical Physics 83, no. 7 (October 1985): 3633–37. http://dx.doi.org/10.1063/1.449170.
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Kaminsky, R. D. "Predicting Single-Phase and Two-Phase Non-Newtonian Flow Behavior in Pipes." Journal of Energy Resources Technology 120, no. 1 (March 1, 1998): 2–7. http://dx.doi.org/10.1115/1.2795006.
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Improved and novel prediction methods are described for single-phase and two-phase flow of non-Newtonian fluids in pipes. Good predictions are achieved for pressure drop, liquid holdup fraction, and two-phase flow regime. The methods are applicable to any visco-inelastic non-Newtonian fluid and include the effect of surface roughness. The methods utilize a reference fluid for which validated models exist. For single-phase flow, the use of Newtonian and power-law reference fluids are illustrated. For two-phase flow, a Newtonian reference fluid is used. Focus is given to shear-thinning fluids. The approach is theoretically based and is expected to be more accurate for large, high-pressure pipelines than present correlation methods, which are all primarily based on low-pressure, small-diameter pipe experimental data.
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Yesilata, Bulent, Alparslan O¨ztekin, Sudhakar Neti, and Jacob Kazakia. "Pressure Measurements in Highly Viscous and Elastic Fluids." Journal of Fluids Engineering 122, no. 3 (May 9, 2000): 626–33. http://dx.doi.org/10.1115/1.1287927.
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Pressure measurements in flows of highly viscous and elastic fluids are of practical importance in polymer processing and rheology systems. Special problems arise during such pressure measurements. High fluid viscosity results in excessive dynamic response time (rise time) of the pressure measuring systems. This is true for systems that consist of manometers as well as pressure transducers attached to the base of a small hole at the wall. We model the dynamic response and examine related disturbing effects. These systematic errors in pressure measurements include hole-pressure effects, instabilities in cavity flow, and the time lag of the disturbance wave. We consider static and dynamic flow systems of a polymer solution (PIB/C14/PB Boger fluid) to study these problems and show that instantaneous pressure measurements in these systems can effectively be performed. [S0098-2202(00)02703-6]
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Mulargia, Francesco, and Andrea Bizzarri. "Fluid pressure waves trigger earthquakes." Geophysical Journal International 200, no. 3 (January 12, 2015): 1279–83. http://dx.doi.org/10.1093/gji/ggu469.
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Abstract Fluids—essentially meteoric water—are present everywhere in the Earth's crust, occasionally also with pressures higher than hydrostatic due to the tectonic strain imposed on impermeable undrained layers, to the impoundment of artificial lakes or to the forced injections required by oil and gas exploration and production. Experimental evidence suggests that such fluids flow along preferred paths of high diffusivity, provided by rock joints and faults. Studying the coupled poroelastic problem, we find that such flow is ruled by a nonlinear partial differential equation amenable to a Barenblatt-type solution, implying that it takes place in form of solitary pressure waves propagating at a velocity which decreases with time as v ∝ t [1/(n − 1) − 1] with n ≳ 7. According to Tresca-Von Mises criterion, these waves appear to play a major role in earthquake triggering, being also capable to account for aftershock delay without any further assumption. The measure of stress and fluid pressure inside active faults may therefore provide direct information about fault potential instability.
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Xie, Gang, Ming Yi Deng, Jun Lin Su, and Liang Chun Pu. "Study on Shale Gas Drilling Fluids Technology." Advanced Materials Research 868 (December 2013): 651–56. http://dx.doi.org/10.4028/www.scientific.net/amr.868.651.
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Via discussing the advantages and disadvantages of different types of oil-based drilling fluids, the main reason why oil-based drilling fluids are less used in our country is obtained that dont form a complete series of matching technology. The essence of wellbore instability caused by using water-based drilling fluids to drill shale is analyzed that the formation collapse pressure is greater than drilling fluids column pressure. The fundamental way of controlling borehole wall stability that use water-based drilling fluids to drill shale horizontal well was proposed that deeply researched the shale hydration mechanism, developed efficient blocking agent and inhibitors and established shale gas drilling fluid suppression system, which made water-based drilling fluids have excellent performance.
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Watanabe, Toshiaki, Hironori Maehara, and Shigeru Itoh. "Evaporating Cryogenic Fluids by Direct Contacting Normal Temperature Fluids." Materials Science Forum 673 (January 2011): 219–24. http://dx.doi.org/10.4028/www.scientific.net/msf.673.219.
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In recent years in Japan, the demand of cryogenic fluids like a LH2, LNG is increasing because of the advance of fuel cell device technology, hydrogen of engine, and stream of consciousness for environmental agreement. On the other hand, as for fisheries as well, the use of a source of energy that environment load is small has been being a pressing need. We paid attention to the effective use of cold heat of the liquid fuel which is a cryogenic fluid. That method is to use a cold heat which an cryogenic fluid has, without a heat exchanger. The mixture of the extreme low temperature fluid and the normal temperature fluid becomes the cause which causes pressure vessel and piping system crush due to explosive boiling and rapid freezing. Therefore, we carried out the experiments related to promotion of evaporating cryogenic fluids, in the contact directly of the room temperature fluids and cryogenic fluids.
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MUKHERJEE, BARUN K., and HIMANSHU K. SACHAN. "Fluids in coesite-bearing rocks of the Tso Morari Complex, NW Himalaya: evidence for entrapment during peak metamorphism and subsequent uplift." Geological Magazine 146, no. 6 (July 15, 2009): 876–89. http://dx.doi.org/10.1017/s0016756809990069.
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AbstractFluid inclusions trapped in coesite-bearing rocks provide important information on the fluid phases present during ultrahigh-pressure metamorphism. The subduction-related coesite-bearing eclogites of the Tso Morari Complex, Himalaya, contain five major types of fluids identified by microthermometry and Raman spectroscopy. These are: (1) high-salinity brine, (2) N2, (3) CH4, (4) CO2and (5) low-salinity aqueous fluids. These fluids were trapped during both deep subduction and exhumation processes. The coesite-bearing rocks are inferred to have been buried to a depth of >120 km, where they experienced ultrahigh-pressure metamorphism. The fluid–rock interaction provides direct evidence for fluid derivation during a deep subduction process as demonstrated by silica–carbonate assemblages in eclogite. High salinity brine, N2and CH4inclusions are remnants of prograde and peak metamorphic fluids, whereas CO2and low-salinity aqueous fluids appear to have been trapped late, during uplift. The high-salinity brine was possibly derived from subducted ancient metasedimentary rocks, whereas the N2and CH4fluids were likely generated through chemical breakdown of NH3-bearing K minerals and graphite. Alternatively, CH4might have been formed by a mixed fluid that was released from calcareous sediments during subduction or supplied through subducted oceanic metabasic rocks. High density CO2is associated with matrix minerals formed during granulite-facies overprinting of the ultrahigh-pressure eclogite. During retrogression to amphibolite-facies conditions, low-salinity fluids were introduced from external sources, probably the enclosing gneisses. This source enhances salinity differences as compared to primary saline inclusions. The subducting Indian lithosphere produced brines prior to achieving maximal depths of >120 km, where fluids were instead dominated by gaseous phases. Subsequently, the Indian lithosphere released CO2-rich fluids during fast exhumation and was then infiltrated by the low-salinity aqueous fluids near the surface through external sources. Elemental modelling may improve quantitative understanding of the complexity of fluids and their reactions.
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ROBERTSON, ROSALIND E., TIM CARROLL, and LINDSAY E. PEARCE. "Bacillus Spore Inactivation Differences after Combined Mild Temperature and High Pressure Processing Using Two Pressurizing Fluids." Journal of Food Protection 71, no. 6 (June 1, 2008): 1186–92. http://dx.doi.org/10.4315/0362-028x-71.6.1186.
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Spores of six species (28 strains) of dairy Bacillus isolates were added to sterile reconstituted skim milk and pressure processed (600 MPa for 60 s at 75°C) using either a water-based pressurizing fluid or silicon oil. Processing temperatures peaked at 88 and 90°C, respectively, for both fluids. For all strains, the log inactivation was consistently higher in the silicon oil than in the water-based fluid. This has potential implications for food safety assessment of combined pressure-temperature processes. High pressure processing causes mild heating during pressurization of both the target sample (i.e., spores) and the pressurizing fluid used for pressure delivery. Primarily, the adiabatic heat of compression of the fluids as well as other heat-transfer properties of the fluids and equipment determines the magnitude of this heating. Pressure cycles run with silicon oil were 7 to 15°C higher in temperature during pressurization than pressure cycles run with the water-based pressurizing fluid, due to the greater adiabatic heat of compression of silicon oil. At and around the target pressure, however, the temperatures of both pressurizing fluids were similar, and they both dropped at the same rate during the holding time at the target pressure. We propose that the increased spore inactivation in the silicon oil system can be attributed to additional heating of the spore preparation when pressurized in oil. This could be explained by the temperature difference between the silicon oil and the aqueous spore preparation established during the pressurization phase of the pressure cycle. These spore-inactivation differences have practical implications because it is common practice to develop inactivation kinetic data on small, jacketed laboratory systems pressurized in oil, with extensive heat loss. However, commercial deployment is invariably on large industrial systems pressurized in water, with limited heat loss. Such effects should be considered in food safety assessments of combined pressure-temperature processes.
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Fernández-Guillamón, Ana, Ángel Molina-García, Francisco Vera-García, and José A. Almendros-Ibáñez. "Organic Rankine Cycle Optimization Performance Analysis Based on Super-Heater Pressure: Comparison of Working Fluids." Energies 14, no. 9 (April 29, 2021): 2548. http://dx.doi.org/10.3390/en14092548.
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The organic Rankine cycle (ORC) is widely accepted to produce electricity from low-grade thermal heat sources. In fact, it is a developed technology for waste-heat to electricity conversions. In this paper, an ORC made up of super-heater, turbine, regenerator, condenser, pump, economizer and evaporator is considered. An optimization model to obtain the maximum performance of such ORC, depending on the super-heater pressure, is proposed and assessed, in order to find possible new working fluids that are less pollutant with similar behavior to those traditionally used. The different super-heater pressures under analysis lie in between the condenser pressure and 80% of the critical pressure of each working fluid, taking 100 values uniformly distributed. The system and optimization algorithm have been simulated in Matlab with the CoolProp library. Results show that the twelve working fluids can be categorized into four main groups, depending on the saturation pressure at ambient conditions (condenser pressure), observing that the fluids belonging to Group 1, which corresponds with the lower condensing pressure (around 100 kPa), provide the highest thermal efficiency, with values around η=23−25%. Moreover, it is also seen that R123 can be a good candidate to substitute R141B and R11; R114 can replace R236EA and R245FA; and both R1234ZE and R1234YF have similar behavior to R134A.
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Jackson, J. D. "Fluid flow and convective heat transfer to fluids at supercritical pressure." Nuclear Engineering and Design 264 (November 2013): 24–40. http://dx.doi.org/10.1016/j.nucengdes.2012.09.040.
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Revathi, D., and K. Saravanan. "Experimental studies on hydrodynamic aspects for mixing of non-Newtonian fluids in a Komax static mixer." Chemical Industry and Chemical Engineering Quarterly, no. 00 (2020): 9. http://dx.doi.org/10.2298/ciceq191017009r.
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Mixing is the degree of homogeneity of two or more phases and it plays a vital role in the quality of the final product. It is conventionally carried out by mechanical agitators or by static mixers. Static mixers are a series of geometric mixing elements fixed within a pipe, which use the energy of the flow stream to create mixing between two or more fluids or to inject metered liquid into a continuous process. The objective of this work is to predict hydrodynamic aspects of the static mixer designed. The mixing performance of Komax static mixer has been determined for the blending of non-Newtonian fluid streams with identical or different rheology by using experimental study. The energy needed for mixing comes from the force created by the liquid due to turbulence and the geometry of the static mixer. Pressure drop in static mixer depend strongly on geometric arrangement of the inserts, properties of fluids to be mixed and flow conditions. Hence pressure drop studies are carried out for different flow rates of fluids with different concentrations of two non-Newtonian fluids. Starch and xanthan gum solutions are used as working fluids. It is observed from the experimental results that the pressure drop per unit length increases as the fluid flow rate increases and the nature of fluid flow varies with the velocity of the fluids.
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Zhu, Qidi, Zhiqiang Sun, and Jiemin Zhou. "Performance analysis of organic Rankine cycles using different working fluids." Thermal Science 19, no. 1 (2015): 179–91. http://dx.doi.org/10.2298/tsci120318014z.
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Low-grade heat from renewable or waste energy sources can be effectively recovered to generate power by an organic Rankine cycle (ORC) in which the working fluid has an important impact on its performance. The thermodynamic processes of ORCs using different types of organic fluids were analyzed in this paper. The relationships between the ORC?s performance parameters (including evaporation pressure, condensing pressure, outlet temperature of hot fluid, net power, thermal efficiency, exergy efficiency, total cycle irreversible loss, and total heat-recovery efficiency) and the critical temperatures of organic fluids were established based on the property of the hot fluid through the evaporator in a specific working condition, and then were verified at varied evaporation temperatures and inlet temperatures of the hot fluid. Here we find that the performance parameters vary monotonically with the critical temperatures of organic fluids. The values of the performance parameters of the ORC using wet fluids are distributed more dispersedly with the critical temperatures, compared with those of using dry/isentropic fluids. The inlet temperature of the hot fluid affects the relative distribution of the exergy efficiency, whereas the evaporation temperature only has an impact on the performance parameters using wet fluid.
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Siddiqui, Abdul M., Maya K. Mitkova, and Ali R. Ansari. "On the Unsteady Flow of Two Incompressible Immiscible Second Grade Fluids between Two Parallel Plates." Advanced Materials Research 1016 (August 2014): 546–53. http://dx.doi.org/10.4028/www.scientific.net/amr.1016.546.
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Unsteady, pressure driven in the gap between two parallel plates flow of two non-Newtonian incompressible second grade fluids is considered. The governing equations are established for the particular two-layer flow and analytical solutions of the equations that satisfy the imposed boundary conditions are obtained. The velocity of each fluid is expressed as function of the material constants, time dependent pressure gradient and other characteristics of the fluids. As part of the solution, an expression for the interface velocity is derived. We analyze the shift of the velocity maximum from one to another fluid as a function of variety of values of fluids’ parameters.
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O’Hara, Stephen G. "Elastic‐wave attenuation in fluid‐saturated Berea sandstone." GEOPHYSICS 54, no. 6 (June 1989): 785–88. http://dx.doi.org/10.1190/1.1442707.
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In a previous publication (O’Hara, 1985), I presented detailed measurements on the attenuation of elastic waves in fluid‐saturated Berea sandstone. These measurements were used in a systematic empirical study of the frequency dependence of attenuation as a function of external pressure applied to the sandstone, pore fluid pressure, and the saturated sandstone temperature. Two pore fluids were used in the study: a brine solution and n-heptane. I measured the attenuation of the extensional and torsional rod modes of cylindrical specimens of the sandstone at identical conditions of pressure and temperature for each of the two fluids.
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Böke, Julia Sophie, Daniel Kraus, and Thomas Henkel. "Microfluidic Network Simulations Enable On-Demand Prediction of Control Parameters for Operating Lab-on-a-Chip-Devices." Processes 9, no. 8 (July 29, 2021): 1320. http://dx.doi.org/10.3390/pr9081320.
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Reliable operation of lab-on-a-chip systems depends on user-friendly, precise, and predictable fluid management tailored to particular sub-tasks of the microfluidic process protocol and their required sample fluids. Pressure-driven flow control, where the sample fluids are delivered to the chip from pressurized feed vessels, simplifies the fluid management even for multiple fluids. The achieved flow rates depend on the pressure settings, fluid properties, and pressure-throughput characteristics of the complete microfluidic system composed of the chip and the interconnecting tubing. The prediction of the required pressure settings for achieving given flow rates simplifies the control tasks and enables opportunities for automation. In our work, we utilize a fast-running, Kirchhoff-based microfluidic network simulation that solves the complete microfluidic system for in-line prediction of the required pressure settings within less than 200 ms. The appropriateness of and benefits from this approach are demonstrated as exemplary for creating multi-component laminar co-flow and the creation of droplets with variable composition. Image-based methods were combined with chemometric approaches for the readout and correlation of the created multi-component flow patterns with the predictions obtained from the solver.
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Wei, Ming Shan, Lei Shi, Chao Chen Ma, and Danish Syed Noman. "Simulations of Waste Heat Recovery System Using R123 and R245fa for Heavy-Duty Diesel Engines." Advanced Materials Research 805-806 (September 2013): 1827–35. http://dx.doi.org/10.4028/www.scientific.net/amr.805-806.1827.
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To improve fuel economy, an Organic Rankine Cycle (ORC) system is proposed to recover waste heat from heavy-duty diesel engines. R123 and R245fa were selected as working fluids. Extensive numerical simulations were conducted to find thermal efficiency of the system under different evaporation pressures, mass flow rates of working fluids and temperature of engine exhaust gases. Results show that the system thermal efficiency was increased with the increase in evaporation pressure for both R123 and R245fa. Efficiency of R123 system was found to be greater than that of R245fa system. For Rankine cycle with both R123 and R245fa, mass flow rate range varied with the evaporation pressure. Limited by evaporation rates and thermal decomposition of the working fluid, the range of mass flow rates in R245fa system was narrower than the R123 system. The thermal efficiency with different temperatures of engine exhaust gases was similar under the fixed evaporation pressure.