Artykuły w czasopismach: „Gas-fine flow”

1

Mase, Nobuyuki, Takuya Iio, Kohei Nagai, Tomoki Kozuka, Akhtar Mst Sammi, Kohei Sato i Tetsuo Narumi. "Fine-Bubble–Slug-Flow Hydrogenation of Multiple Bonds and Phenols". Synlett 31, nr 19 (21.10.2020): 1919–24. http://dx.doi.org/10.1055/s-0040-1705948.

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AbstractWe describe a promising method for the continuous hydrogenation of alkenes or alkynes by using a newly developed fine-bubble generator. The fine-bubble-containing slug-flow system was up to 1.4 times more efficient than a conventional slug-flow method. When applied in the hydrogenation of phenols to the corresponding cyclohexanones, the fine bubble–slug-flow method suppressed over-reduction. As this method does not require the use of excess gas, it is expected to be widely applicable in improving the efficiency of gas-mediated flow reactions.

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MASUDA, Hiroaki, Shuji MATSUSAKA, Satoshi AKIBA i Hiroaki SHIMOMURA. "Electrification of Fine Particles in Gas-Solids Pipe Flow." Journal of the Society of Powder Technology, Japan 34, nr 2 (1997): 91–96. http://dx.doi.org/10.4164/sptj.34.91.

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Chlebnikovas, Aleksandras, i Pranas Baltrėnas. "Research of the Aerodynamic Parameters in a Special Cyclone with Secondary Inlets". Mokslas - Lietuvos ateitis 9, nr 4 (11.09.2017): 400–405. http://dx.doi.org/10.3846/mla.2017.1065.

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Special cyclone – gas treatment device which can be applied to remove the fine particulate matter bigger than 2 micrometres from aggressive gas flow at a temperature of 50–145 °C and a relative humidity of more than 95% and can be achieved the cleaning efficiency over 90%. Cyclone work is based on centrifugal forces and the resulting additional filtration process operation. Cyclone structure equipped with primary and secondary gas flow inflows through which gas dispersed flow is supplied parallel to all channels of the cyclone. Analysed modified multi-channel cyclone can be effectively treated from fine particulate matter, during the cleaning of aggressive gas flow an adhesion/cohesion phenomena could be reduced. Research of aerodynamic parameters it’s the first step of studies to determine the optimal case, at the average gas flow velocity in cyclone channels were 8, 12 and 16 m/s, the gas flow dynamics dependencies into cyclone were determined.

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GILBERTSON, M. A., i I. EAMES. "Segregation patterns in gas-fluidized systems". Journal of Fluid Mechanics 433 (25.04.2001): 347–56. http://dx.doi.org/10.1017/s0022112001003950.

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The formation of segregation patterns in initially homogeneous, fluidized, binary mixtures of particles has been studied. The adjustment of the bed depends on the proportions of fine and coarse particles in the mixture and the gas flow rate relative to the minimum fluidization velocities of the two components. The particles are immobile until the gas flow rate is sufficiently large to fluidize the mixture of particles. When the gas flow rate exceeds this critical value, alternating vertical bands of coarse and fine particles form. At a second critical gas velocity this pattern breaks down and the more familiar pattern of a mixed horizontal band on top of a layer of coarse particles forms. A phase diagram, constructed from experimental observations, shows the conditions for which each of these regimes exists. Its structure is explained in terms of the fluidization and consequent mobility of the mixture components. When horizontal bands are present, the thickness of the lower layer of coarse particles decreases with increasing gas flow rate depending on the proportion of fine particles in the bed. This, and its development, can be understood by analogy with the sedimentation of particles through a turbulent fluid. The experiments imply that the efficiency of mixing by the bubbles in the fluidized bed is very much less than that expected from gas bubbles in a liquid.

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YAMAOKA, Hideyuki. "Flow Characteristics of Gas and Fine Particles in Packed Bed". Tetsu-to-Hagane 72, nr 3 (1986): 403–10. http://dx.doi.org/10.2355/tetsutohagane1955.72.3_403.

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Masuda, Hiroaki, Shuji Matsusaka, Satoshi Akiba i Hiroaki Shimomura. "Electrification of Fine Particles in Gas-Solids Pipe Flow [Translated]†". KONA Powder and Particle Journal 16 (1998): 216–22. http://dx.doi.org/10.14356/kona.1998024.

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Kuznetsov, G. V., P. A. Kuibin i P. A. Strizhak. "Motion of fine-spray liquid droplets in hot gas flow". Thermophysics and Aeromechanics 21, nr 5 (październik 2014): 609–16. http://dx.doi.org/10.1134/s0869864314050096.

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Guo, Falei. "Gas flow and mixing behavior in fine-powder fluidized bed". AIChE Journal 33, nr 11 (listopad 1987): 1895–98. http://dx.doi.org/10.1002/aic.690331117.

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IWAMA, SABURO, i KAZUHIRO MIHAMA. "GROWTH OF In-Sb FINE PARTICLES BY FLOWING-GAS EVAPORATION TECHNIQUE". Surface Review and Letters 03, nr 01 (luty 1996): 49–53. http://dx.doi.org/10.1142/s0218625x96000127.

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Fine particles of the In-Sb system were prepared by the FGE technique (flowing-gas evaporation technique). The characteristic of the technique is that the formation of the vapor zone and particle growth zone along the flow of inert gas can be controlled by the inert-gas species and the flow velocity. From single-source evaporations, In fine islands grown on the amorphous carbon in the metal vapor zone showed a fiber structure with [111] and [001] fiber axes. In the particle growth zone In fine particles were formed, showing very frequently a characteristic contrast in them due to a lattice defect. Sb fine particles showed amorphous structure. These results may be attributed to the enhanced quenching effect of the FGE technique, already observed in the ordinary gas-evaporation technique. By coevaporation of In and Sb, granular film grew in the metal vapor zone, and fine particles were formed in the particle growth zone. The crystal structure was assigned to be the zincblende type including the wurtzite type of intermetallic compound InSb.

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Bikkulov, Rustem Ya, Andrey V. Dmitriev, Vadim E. Zinurov i Guzel R. Badretdinova. "Separation of Fine Particles from Gas in Paint-Spraying Booths". MATEC Web of Conferences 346 (2021): 03070. http://dx.doi.org/10.1051/matecconf/202134603070.

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Nowadays, at production facilities with paint-spraying booths that use paint and varnish materials to cover the surfaces of product, the problem of gas flow contamination with finely dispersed solid particles of dust and rubbish, which negatively affect the quality of products, is increasingly being raised. In order to minimize the content of solid particles in the gas flow, coarse and fine filters are installed in the paint-spraying booths, which prevent dust particles from entering the surface of products. However, the existing purification devices have a number of disadvantages that affect the efficiency of collecting finely dispersed particles from the gas flow with a size of 0.5-5 microns. The authors of article developed a square separator to increase the efficiency of collecting finely dispersed particles from gas flows in the paint-spraying booths. The installation of proposed separation device in the paint-spraying booths affects not only the quality of collecting solid particles, but also increases the service life of fine and coarse filters In the course of numerical studies, the results of impact of structural and technological parameters, namely, the impact of inlet rate and scale of separation device on the efficiency of collecting solid particles from the gas flow, were obtained.

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Kustov, Maksym, Andriy Melnichenko, Oleksii Basmanov i Olexandr Tarasenko. "Modeling of Gas Sorption Process by Dispersed Liquid Flow". Materials Science Forum 1068 (19.08.2022): 239–47. http://dx.doi.org/10.4028/p-jdydlo.

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A mathematical model of the process of gas propagation in the atmosphere and its sorption by fine flow has been developed. The use of the finite difference method in modeling allows to obtain numerical solutions of the spatial distribution of gas concentration during its deposition by a jet of arbitrary intensity and shape. The proposed method of mathematical description of the process of sorption of hazardous gases allows you to choose an arbitrary number and spatial location of nodal points that satisfy the Courant-Friedrichs-Levy condition. The developed model allows to predict the intensity of gas sorption in technological processes and in the elimination of the consequences of emergencies. The use of the developed model will increase the efficiency of emergency management and choose effective methods of sorption of hazardous gases in the atmosphere. The results of numerical calculations confirmed the efficiency of the developed model and theoretically demonstrated the effectiveness of using water curtains for the sorption of ammonia from the atmosphere. According to the simulation results, it is established that the use of fine spray jets can significantly reduce the distance of distribution of hazardous gas.

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Zinurov, V. E., R. Ja Bikkulov, A. V. Dmitriev, O. S. Dmitrieva i A. N. Nikolaev. "Determination of the design velocity of the gas flow in coarse and fine filters with varying degrees of contamination in the paint booths". Power engineering: research, equipment, technology 24, nr 5 (8.12.2022): 3–12. http://dx.doi.org/10.30724/1998-9903-2022-24-5-3-12.

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OBJECT. Determination of the design velocity of the gas flow in coarse and fine filters with varying degrees of contamination. METHODS. We carried experimental studies out to solve the problem. To exclude errors during the studies caused by marriage or other reasons, 3 samples of each of the coarse and fine filters (clean and used) were used. To determine the design speed, an experimental installation was assembled, presented in the work, which included an air duct, an air injection fan, a nozzle for measuring excess pressure in front of the filter under study, an air vent hole, filter samples, a ventilation grate and measuring instruments – a differential pressure gauge testo 510i and an anemometer testo 405i. RESULTS. The article describes the relevance of the topic, analyzes the change in the pressure drop in the duct when using spent and clean coarse and fine filters. They showed that an increase in their operational life is possible with the use of a multi-vortex separator, which can be installed as a preliminary stage of purification. CONCLUSION. The estimated gas flow velocity when using coarse filters is only 2 m/s. The estimated gas flow velocity when using fine filters is only 0.5 m/s. A comparison of the difference in the pressure drop in the duct when using coarse and fine (spent and clean) filters shows that coarse filters are more susceptible to dusty flow, i.e. the bulk of particles in the dusty flow at an enterprise with paint chambers are relatively large particles. Hydraulic resistance increases by 1.58 times.

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13

Jung, Jongwon, Hongsig Kang, Shuang Cindy Cao, Riyadh I. Al-Raoush, Khalid Alshibli i Joo Yong Lee. "Effects of Fine-Grained Particles’ Migration and Clogging in Porous Media on Gas Production from Hydrate-Bearing Sediments". Geofluids 2019 (23.05.2019): 1–11. http://dx.doi.org/10.1155/2019/5061216.

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The migration of fine particles in porous media has been studied for different applications, including gas production from hydrate-bearing sediments. The clogging behavior of fine particles is affected by fine particle-pore throat size ratio, fine particle concentration, ionic concentration of fluids, and single/multiphase fluid flow. While previous studies presented valuable results, the data are not enough to cover a broad range of particle types and sizes and pore throat size in natural hydrate-bearing sediments. This paper presents a novel micromodel to investigate the effects of fine particle-pore throat size ratio, fine concentration, ionic concentration of fluid, and single/multiphase fluid flow on clogging or bridging in porous media. The results show that (1) the concentration of fine particles required to form clogging and/or bridging in pores decreased with the decrease in fine particle-pore throat size ratio, (2) the effects of ionic concentration of fluid on clogging behaviors depend on the types of fine particles, and (3) fine particles prefer to accumulate along the deionized water- (DW-) CO2 interface and migrate together, which in turn easily causes clogging in pores. As a result, multiphase fluid flow during gas production from hydrate-bearing sediments could easily develop clogging in pore throats, where the relative permeability of DW-CO2 in porous media decreases. Accordingly, the relatively permeability of porous media should be evaluated by considering the clogging behavior of fines.

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Druitt, T. H., G. Avard, G. Bruni, P. Lettieri i F. Maez. "Gas retention in fine-grained pyroclastic flow materials at high temperatures". Bulletin of Volcanology 69, nr 8 (24.02.2007): 881–901. http://dx.doi.org/10.1007/s00445-007-0116-7.

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Gan, J. Q., Z. Y. Zhou i A. B. Yu. "Micromechanical analysis of flow behaviour of fine ellipsoids in gas fluidization". Chemical Engineering Science 163 (maj 2017): 11–26. http://dx.doi.org/10.1016/j.ces.2017.01.020.

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McMullan, W. A. "Large Eddy simulation of tracer gas dispersion in a cavity". Fluid Dynamics Research 54, nr 1 (14.01.2022): 015502. http://dx.doi.org/10.1088/1873-7005/ac421b.

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Abstract This paper assesses the prediction of inert tracer gas dispersion within a cavity of height (H) 1.0 m, and unity aspect ratio, using large Eddy simulation (LES). The flow Reynolds number was 67 000, based on the freestream velocity and cavity height. The flow upstream of the cavity was laminar, producing a cavity shear layer which underwent a transition to turbulence over the cavity. Three distinct meshes are used, with grid spacings of H / 100 (coarse), H / 200 (intermediate), and H / 400 (fine) respectively. The Smagorinsky, WALE, and Germano-Lilly subgrid-scale models are used on each grid to quantify the effects of subgrid-scale modelling on the simulated flow. Coarsening the grid led to small changes in the predicted velocity field, and to substantial over-prediction of the tracer gas concentration statistics. Quantitative metric analysis of the tracer gas statistics showed that the coarse grid simulations yielded results outside of acceptable tolerances, while the intermediate and fine grids produced acceptable output. Interrogation of the fluid dynamics present in each simulation showed that the evolution of the cavity shear layer is heavily influenced by the grid and subgrid scale model. On the coarse and intermediate grids the development of the shear layer is delayed, inhibiting the entrainment and mixing of the tracer gas into the shear layer, reducing the removal of the tracer gas from the cavity. On the fine grid, the shear layer developed more rapidly, resulting in enhanced removal of the tracer gas from the cavity. Concentration probability density functions showed that the fine grid simulations accurately predicted the range, and the most probable value, of the tracer gas concentration towards both walls of the cavity. The results presented in this paper show that the WALE and Germano-Lilly models may be advantageous over the standard Smagorinsky model for simulations of pollutant dispersion in the urban environment.

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Hidaka, Nobuyuki, Toshitatsu Matsumoto, Katsuki Kusakabe i Shigeharu Morooka. "Flow of Fine Particles Entrained by Upward Gas Flow in Packed Beds of Coarse Particles." JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 32, nr 2 (1999): 197–203. http://dx.doi.org/10.1252/jcej.32.197.

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Alpeissov, Yessenbay, Ruslan Iskakov, Sultanbek Issenov i Аru Ukenova. "Obtaining a formula describing the interaction of fine particles with an expanding gas flow in a fluid layer". Eastern-European Journal of Enterprise Technologies 2, nr 1 (116) (28.04.2022): 87–97. http://dx.doi.org/10.15587/1729-4061.2022.255258.

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The interaction of fine particles with an expanding gas flow under fluidization conditions is considered. The objects of study are finely dispersed materials, their single particles, gas flow in a fluidized layer. The study used the laws of dynamics and hydrodynamics, the classical laws of mechanics, as well as mathematical methods for the analytical solution of equations. It is emphasized that when a particle moves upwards in a gas jet, three forces act on it: the resistance force Fc, the gravity force P, and the Archimedes force A. As a result, the motion of a fine particle in an expanding gas flow is described taking into account the law of dynamics. During the study, an analytical equation was obtained to determine the velocity of a particle during its rise and fall in a gas jet. During the study, an analytical equation was obtained to find the height of the particle ascent depending on the gas flow rate for given geometric parameters of the gas flow. The obtained formulas can be used in the process of studying the process of convective drying of finely dispersed materials for various design parameters of the dryer. In practice, as a rule, there are various empirical formulas that describe such interactions of particles for specific parameters, which make it difficult to generalize them. In this work, the correctness of the assumed conditions necessary for the analytical solution of the differential equation of particle motion is proved. As a result, formulas were obtained that make it possible to determine the velocity of a particle in a gas jet and the height of its rise depending on the gas flow rate. On the basis of these formulas, graphic dependences of the gas velocity in the jet on the height Vg=f(Z), as well as the dependences of the height of the particle rise hm on the air flow rate in the jet L at different jet expansion angles α=15°; α=20°; α=30° are plotted. It was found that with an increase in the height Z in an expanding jet, the gas velocity in the jet Vg decreases, with an increase in the air flow rate in the jet L, the height of the particle rise hm increases. These formulas are the basis for further consideration of the movement of particles in a fluidized layer in the process of convective drying of fine materials for its intensification of the drying process

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Sengupta, Madhumita, i Gary Mavko. "Impact of flow‐simulation parameters on saturation scales and seismic velocity". GEOPHYSICS 68, nr 4 (lipiec 2003): 1267–80. http://dx.doi.org/10.1190/1.1598119.

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Scales of fluid saturation below seismic resolution introduce uncertainties in the interpretation of seismic velocity. A “coarse‐scale” or “patchy” distribution always has a higher effective seismic velocity than a “fine‐scale” or “uniform” distribution. We present a multidisciplinary study which links rock physics and seismic modeling with reservoir engineering, and provides strategies to reduce uncertainties in saturation scales. In our study, we performed fine‐scale flow simulations that helped us to understand which reservoir parameters control the subseismic‐resolution fluid distribution. Our studies show that when gas is injected into oil reservoirs, gravitational forces induce the formation of subresolution gas caps, which lead to patchy saturation at seismic scales. We also learned that the uniform saturation model is appropriate for most waterflooding into oil and for primary production scenarios where gas comes out of solution. Fluid density contrasts, mobility ratios, and residual oil saturations are some parameters that are crucial in constraining saturation scales.

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XIE, M. L., J. Z. LIN i H. C. ZHOU. "TEMPORAL STABILITY OF A PARTICLE-LADEN BLASIUS BOUNDARY LAYER". Modern Physics Letters B 23, nr 02 (20.01.2009): 203–16. http://dx.doi.org/10.1142/s0217984909017844.

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The temporal instability of incompressible particle-laden Blasius boundary layer is investigated numerically using perturbation method and finite difference. The stability characteristics are calculated for varying Stokes' numbers and particle concentrations. The results, some of which agree with the calculations of earlier authors, show that the addition of fine particles tends to destabilize the flow while addition of the coarse particles has a stabilizing action. There is critical value for the effect of Stokes' number, and the value is about 1. The stabilizing effect of particles depends monotonously on the particle concentration, the critical Reynolds' number is directly proportional to the concentration in the range of stabilizing area, and vice versa for small Stokes' number. The most damped mode occurs when Stokes' number is of order 10 for different particle concentrations. The difference of perturbation velocity between the particle-laden flow and the clean gas flow is insignificant for fine particles, while the difference for coarse particles is obvious. For fine particles laden flow, the viscosity is reduced relatively because of the addition of particles, and the critical Reynolds' number is smaller than that of clean gas. For coarse particles, the interaction between particles and clean gas is remarkable because of the difference of perturbation velocity, and then the viscous dissipation tends to stabilize the flow.

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NOZAWA, Kentarou, Masakata SHIMIZU i Shin-ichi INABA. "In-flight Reduction of Fine Ores in a Hot Reducing Gas Flow". Tetsu-to-Hagane 79, nr 4 (1993): 443–48. http://dx.doi.org/10.2355/tetsutohagane1955.79.4_443.

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Ishii, K., M. Kobayashi, T. Ohba i T. Hara. "Preparation of Cu Films Containing Co Fine Particles by Gas-Flow Sputtering." Journal of the Magnetics Society of Japan 20, nr 2 (1996): 401–4. http://dx.doi.org/10.3379/jmsjmag.20.401.

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Pikulev, A. A. "Heat-transfer coefficient of a fine heated wire in a gas flow". Technical Physics 48, nr 6 (czerwiec 2003): 693–96. http://dx.doi.org/10.1134/1.1583820.

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Levdansky, V. V., J. Smolik i P. Moravec. "Influence of surface phenomena on free-molecule gas flow in fine channels". International Communications in Heat and Mass Transfer 34, nr 7 (sierpień 2007): 796–800. http://dx.doi.org/10.1016/j.icheatmasstransfer.2007.03.018.

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Hatano, Hiroyuki, Hiromitsu Matsuda i Hisashi Kono. "Microscopic observation of gas-solid two-phase flow with adhesive fine particles." KAGAKU KOGAKU RONBUNSHU 16, nr 4 (1990): 841–43. http://dx.doi.org/10.1252/kakoronbunshu.16.841.

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Benyahia, Sofiane. "Fine-grid simulations of gas-solids flow in a circulating fluidized bed". AIChE Journal 58, nr 11 (11.05.2012): 3589–92. http://dx.doi.org/10.1002/aic.13826.

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Qiao, Juncheng, Xianzheng Zhao, Jianhui Zeng, Guomeng Han, Shu Jiang, Sen Feng i Xiao Feng. "The Impacts of Nano-Micrometer Pore Structure on the Gas Migration and Accumulation in Tight Sandstone Gas Reservoirs". Energies 12, nr 21 (28.10.2019): 4102. http://dx.doi.org/10.3390/en12214102.

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The uncertainties between reservoir quality and gas migration and accumulation in tight sandstone gas reservoirs are intrinsically attributed to complex microscopic pore structures. Integrated analysis including the physical simulation experiment of gas migration and accumulation, X-ray computed tomography (X-CT), and casting thin section (CTS) were conducted on core plug samples collected from the Upper Paleozoic Permian Lower Shihezi and Shanxi tight sandstone of the Daniudi area in the Ordos Basin to investigate the impacts of pore structure on the gas migration and accumulation. Physical simulation suggested that the gas flows in migration in tight sandstone reservoirs were characterized by deviated-Darcy linear flow and non-linear flow regimes. Minimum and stable migration pressure square gradients determined by application of apparent permeability were employed as key parameters to describe gas flow. Pore structure characterization revealed that the tight sandstone reservoir was characterized by wide pore and throat size distributions and poor pore-throat connectivity. The pore–throat combinations could be divided into three types, including the macropore and coarse throat dominant reservoir, full-pore and full-throat form, and meso-small pore and fine throat dominant form. Comparative analyses indicated that pore and throat radii determined the gas flow regimes by controlling the minimum and stable migration pressure gradients. Gas accumulation capacity was dominated by the connected effective porosity, and the gas accumulation process was controlled by the cumulative effective porosity contribution from macropores to micropores. Variations in pore structures resulted in differences in gas migration and accumulation of tight sandstone reservoirs. The macropore and coarse throat-dominant and the full-pore and full-throat reservoirs exhibited greater gas migration and accumulation potentials than the small pore and fine throat dominate form.

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Chlebnikovas, Aleksandras, i Artūras Kilikevičius. "Study on Gas Flow Parameters and Fractional Removal Efficiency of Ultrafine Particulate Matter in Newly Developed Electro Cyclone-Filter". Atmosphere 14, nr 3 (9.03.2023): 527. http://dx.doi.org/10.3390/atmos14030527.

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The treatment of polluted industrial flow remains a relevant topic for the purpose of sustainable development and improvement of the general state of the environment. The removal of particulate matter, and especially their fine and ultra-fine fractions, from the gas flow, is an urgent task, but it poses many challenges and demands for purification technology. This paper presents the results of the first stage of the research using a newly developed cleaning device operating by a complex principle, which consists of a new generation two-stage centrifugal filtration device and an electro-filter. The rate of air flow was varied from 0.3 to 1.16 m/s at the inlet and corresponds to an air flow yield of 53 m3/h to 205 m3/h. The maximum pressure drop at an air flow of 255 m3/h is 26 Pa. Research has shown that the efficiency of removing ultra-fine particulate matter is up to 99.7% for particles 0.3–0.5 µm in size at 200 m3/h of the air flow rate.

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Yan, Pengfei, Deping Wang i Biao Yan. "Ultrasonic gas alloy atomization under near-zero aspiration pressure". International Journal of Modern Physics B 29, nr 10n11 (23.04.2015): 1540034. http://dx.doi.org/10.1142/s0217979215400342.

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In this paper, ultrasonic gas atomization (USGA) of Zn – Al under near-zero aspiration pressure was discussed. The protrusion length of delivery tube was modified to adjust the aspiration pressure. Under near-zero aspiration pressure, melt filming was observed by camera and more fine powders were produced. While under larger subambient aspiration pressure, melt filming was unavailable, corresponding to less fine powders. The results suggest that the position of the wake near the delivery tube can be optimized under near-zero aspiration. Less protrusion of delivery tube reduces the energy loss in gas flow deflection. Both facilitate to produce finer powders.

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Sharapov, Rinat. "Determination of the air separator circulation path parameters". E3S Web of Conferences 281 (2021): 01003. http://dx.doi.org/10.1051/e3sconf/202128101003.

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The article discusses the separation process efficiency issue of the fine powders in an air separator. The aerodynamic scheme of the air separator is proposed and the schemes of the gas-material flow through the elements of the separator gas-material path are considered. The equations of the gas-material flow motion through the separator gas-material path elements are proposed. The calculation of the air separator various operating modes is proposed. The results of an approximate graphical-analytical calculation of the gas-material path of the proposed aerodynamic scheme for the air separator are presented. A high convergence of theoretical positions with the performed experiments is shown.

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Nekrasov, S. G., i N. A. Pashnina. "The profiling effect on the characteristics of gas flow in fine vibrating clearances". Journal of Friction and Wear 31, nr 3 (czerwiec 2010): 171–79. http://dx.doi.org/10.3103/s1068366610030037.

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Mason, David J., i Avi Levy. "A model for non-suspension gas–solids flow of fine powders in pipes". International Journal of Multiphase Flow 27, nr 3 (marzec 2001): 415–35. http://dx.doi.org/10.1016/s0301-9322(00)00033-1.

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Yonezawa, Tetsu, Hiroki Tsukamoto, Yingqiong Yong, Mai Thanh Nguyen i Masaki Matsubara. "Low temperature sintering process of copper fine particles under nitrogen gas flow with Cu2+-alkanolamine metallacycle compounds for electrically conductive layer formation". RSC Advances 6, nr 15 (2016): 12048–52. http://dx.doi.org/10.1039/c5ra25058g.

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Edrisi, A. R. R., i S. I. I. Kam. "A New Foam Model in Pipes for Drilling and Fracturing Applications". SPE Journal 19, nr 04 (26.08.2013): 576–85. http://dx.doi.org/10.2118/162709-pa.

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Summary A series of recent experimental studies revealed that foam flow can be represented by two distinct flow regimes in general—low-quality regime, showing stable plug-flow pattern, and high-quality regime, showing unstable slug-flow pattern. This study, for the first time, presents how to develop a comprehensive foam model that can handle a variety of bubble-size distributions and both stable and unstable flow patterns with a two-flow-regime concept. Building an improved foam model on the basis of such a new concept can potentially help to better design and optimize many foam-associated processes including tight-gas and shale-gas foam fracturing, foam underbalanced drilling, foam liquid unloading, and cuttings transport. Analyzing the experimental data of surfactant foams and polymer-added foams shows that (i) in the low-quality regime, foam rheology is governed by bubble slippage at the wall with no significant change in its fine foam texture and (ii) in the high-quality regime, foam rheology is governed by the relative size of free-gas segment to fine-textured foam-slug segment. With these governing mechanisms, this improved foam model successfully reproduces foam-flow characteristics as observed in the experiments, including almost-horizontal pressure contours in the low-quality regime and inclined pressure contours in the high-quality regime. Although the model is built with a power-law fluid model, the same procedure can be applied for Bingham-plastic or yield-power-law fluids.

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Yuan, Yingzhong, Wende Yan, Fengbo Chen, Jiqiang Li, Qianhua Xiao i Xiaoliang Huang. "Numerical Simulation for Shale Gas Flow in Complex Fracture System of Fractured Horizontal Well". International Journal of Nonlinear Sciences and Numerical Simulation 19, nr 3-4 (26.06.2018): 367–77. http://dx.doi.org/10.1515/ijnsns-2017-0135.

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AbstractComplex fracture systems including natural fractures and hydraulic fractures exist in shale gas reservoir with fractured horizontal well development. The flow of shale gas is a multi-scale flow process from microscopic nanometer pores to macroscopic large fractures. Due to the complexity of seepage mechanism and fracture parameters, it is difficult to realize fine numerical simulation for fractured horizontal wells in shale gas reservoirs. Mechanisms of adsorption–desorption on the surface of shale pores, slippage and Knudsen diffusion in the nanometer pores, Darcy and non-Darcy seepage in the matrix block and fractures are considered comprehensively in this paper. Through fine description of the complex fracture systems after horizontal well fracturing in shale gas reservoir, the problems of conventional corner point grids which are inflexible, directional, difficult to geometrically discretize arbitrarily oriented fractures are overcome. Discrete fracture network model based on unstructured perpendicular bisection grids is built in the numerical simulation. The results indicate that the discrete fracture network model can accurately describe fracture parameters including length, azimuth and density, and that the influences of fracture parameters on development effect of fractured horizontal well can be finely simulated. Cumulative production rate of shale gas is positively related to fracture half-length, fracture segments and fracture conductivity. When total fracture length is constant, fracturing effect is better if single fracture half-length or penetration ratio is relatively large and fracturing segments are moderate. Research results provide theoretical support for optimal design of fractured horizontal well in shale gas reservoir.

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Achiles, Ana, i Vádila Guerra. "Performance of a cyclone scrubber on removal of fine particulate matter". Chemical Industry and Chemical Engineering Quarterly 26, nr 1 (2020): 31–40. http://dx.doi.org/10.2298/ciceq181220022a.

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Cyclones are not classified as effective devices for removing fine particles, while high efficiency wet scrubbers usually have high operational costs. In order to achieve better performance, the aim of this study is to evaluate, for the first time, a cyclone scrubber design based on the dimensions of a Stairmand cyclone separator with the inclusion of liquid injection nozzles located in different positions to improve the separation of fine particles. Given the lack of studies considering the effect of liquid injection and other operational conditions in the removal performance of a cyclone scrubber with Stairmand dimensions, the present paper provides a complete evaluation of these effects for the separation of sugar cane bagasse ash from air. The parameters investigated were inlet gas velocity, liquid injection position, liquid-to-gas flow ratio and droplet size distribution. The cyclone scrubber performance was evaluated considering collection efficiency and pressure drop. Overall efficiency of almost 99% and low-pressure drop was achieved by employing a liquid-to-gas flow ratio of 0.43 L/m? for the collection of ash from the combustion of sugar cane bagasse. Grade efficiencies revealed that injecting droplets into cyclones significantly improved the removal of fine particles with an aerodynamic diameter less than 2.5 ?m.

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Asmuin, Nor Zelawati. "Design for Two-Fluid Fine Nozzle with 50% Fill Ratio". Applied Mechanics and Materials 773-774 (lipiec 2015): 387–92. http://dx.doi.org/10.4028/www.scientific.net/amm.773-774.387.

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Sufficient air insert by reduced liquid in flashing propellants are required to produce fine droplet size with symmetrical spray in an aerosol atomiser without swirling design. It is called novel matched valve-actuator with two-fluid fine nozzle. Two-fluid fine nozzle design is an arrangement between air-assist atomiser insert, air blast and effervescent atomiser insert. However, 50% fill ratio and 9bar on pressure can with a currently acceptable become “Benchmark Objective” in this research. The results shows a few measurement with the same volume flow rate and variable flow rate of two fluids atomiser which have been taken in the experimental. 50 ml/min for liquid flow rate and 150ml/min flow rate of insert gas could reduce droplet size less than 70μm SMD by modifying the insert to promote greater cone angle and droplet size distribution with differences on quantity of air, liquid supply and the atomising velocity. Validation of two-fluid fine nozzle results is also recommended to be carried out and compared with the experiment results which related to turbulence kinetic energy with the atomiser insert and droplet size. Further researches are concentrating on modelling droplet breakup downstream of the atomiser insert.Keywordaerosol atomiser, two-fluid fine nozzle, fill ratio, droplet size.

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Hanam, E. S., D. R. Sofia, S. Y. Azhary, C. Panatarani i I. M. Joni. "Effect of Gas Sources on the Oxygen Transfer Efficiency Produced by Fine Bubbles Generator". Journal of Physics: Conference Series 2376, nr 1 (1.11.2022): 012004. http://dx.doi.org/10.1088/1742-6596/2376/1/012004.

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Abstract Fine bubbles (micro to nanometer-sized) have rapidly gained popularity in academia and industry due to their unique properties, such as their high surface area, stability, and longevity. In this study, the performance of oxygen transfer rate efficiency in fine bubbles with high purity oxygen and atmospheric air was analyzed. In this study, the developed fine bubbles generator with power requirement 300 watt was used to evaluate the production of fine bubbles and oxygen transfer efficiency at two type gas sources i.e., ambient air and high-purity oxygen in the small bench aqueous media (5 L water tank). The fine bubbles generator was set up at the pressure in 50 psi and gas flow rate at 0.3 L/min to produce fine bubbles in water medium. The effect of water recirculation process in the bubbles production was measured using particles size analyzer (PSA), zeta potential and dissolved oxygen (DO) meter to measure temperature and dissolved oxygen on the water. Dissolved Oxygen (DO) measurement shows the saturation value of oxygen concentration in water, for high purity oxygen is 30 mg/L higher than air which has a value of 8.64 mg/L. This causes the efficiency of gas transfer in high-purity oxygen to reach 72.09% higher than ambient air at 35.39%. The particle size distribution shows that the mean size of bubbles after 10 minutes recirculation was 465.5 nm and 599.9 nm correspondingly for ambient air and oxygen gas source. High purity oxygen also affect to the zeta potential value tends to be more negative than in ambient air. The type of high-purity oxygen gas can increase the efficiency of the oxygen transfer rate so that the gas containing high-purity oxygen increases the volumetric oxygen transfer rate coefficient which is 2 times higher than using ambient air.

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NODA, Naoki. "Gas Flow Control for the Improvement of Fine Particle Collection Efficiency on Electrostatic Precipitator". Hosokawa Powder Technology Foundation ANNUAL REPORT 24 (2016): 79–84. http://dx.doi.org/10.14356/hptf.14113.

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Shvab, A. V., Sh R. Sadretdinov i V. N. Brendakov. "Effects of gas flow and turbulent diffusion on the centrifugal classification of fine particles". Journal of Applied Mechanics and Technical Physics 53, nr 2 (marzec 2012): 173–81. http://dx.doi.org/10.1134/s0021894412020046.

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Yang, Xuliang, Yuemin Zhao i Zhenfu Luo. "Dry Cleaning of Fine Coal Based on Gas-Solid Two-Phase Flow: A Review". Chemical Engineering & Technology 40, nr 3 (9.02.2017): 439–49. http://dx.doi.org/10.1002/ceat.201600265.

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Sharma, Jyotsna, R. Gordon Moore i Sudarshan A. Mehta. "Effect of Methane Co-Injection in SAGD--Analytical and Simulation Study". SPE Journal 17, nr 03 (29.08.2012): 687–704. http://dx.doi.org/10.2118/148917-pa.

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Summary Steam-assisted gravity drainage (SAGD) is a commercially viable recovery method for oil sands of Athabasca used where other methods have been unsuccessful. In one variation of SAGD, a small amount of a noncondensable gas is added to the injected steam to maintain pressure in the chamber while using the energy in place, reducing steam consumption and providing thermal insulation from overburden heat losses. The role of gas during steam-gas co-injection processes, in terms of its effects on chamber development, bitumen flow rates, and heat losses, is not fully understood, and therefore is the main focus of this work. A new analytical model for gas injection in SAGD is derived, taking into account the three-phase flow of gas, oil, and water in the reservoir. The analytical theory is used to predict the fluid flow rates as well as phase mobility, relative permeability, and saturation profiles in the mobile oil region. The theoretical results are replicated by fine-grid numerical simulations. Methane was used as the noncondensable gas for the purpose of this study because it is the main solution gas in most reservoirs. It is, however, believed that the findings of this study are equally applicable to other noncondensable gases such as nitrogen, air, helium, and others. Fine-grid numerical simulations were performed to gain a visual understanding of gas distribution in a SAGD chamber and its effect on in-situ steam quality, overburden heat losses, phase saturations, and fluid-flow rates. The simulation results support the predictions of the mathematical theory. The results of the analytical and numerical study reveal that methane co-injection with steam is in general unfavorable in a SAGD operation. The injected methane tends to accumulate at the steam condensation front, which lowers the heat transfer rate of steam to the adjacent oil, resulting in lower oil production rates and slower growth of the chamber.

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Lv, Tai, i Pei Ye He. "Numerical Simulation of Vibration of Induced Draft Fan behind Desulfurization Tower Caused by Dust Accumulation". Applied Mechanics and Materials 675-677 (październik 2014): 619–22. http://dx.doi.org/10.4028/www.scientific.net/amm.675-677.619.

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For a reduction ofthe volume and cost of equipment, some thermal power plants have no gas heater in their desulfurization systems. Because of desulfurized gas with high humidity, residual dust, and limestone slurry, induced draft fan (IDF) is often subject to vibration caused by dust accumulation while operating, resulting in occasional shut-down for dust cleaning. To solve this problem, fine sand was added to jet nozzle in the circumstance of severe dust accumulation, to enhance cleaning effect in this study. The Fluent software was used to simulate the static pressure distribution on non-working surfaces of the IDF blades with different sand flows. Results showed that the addition of fine sand could enhance the static pressure on non-working surfaces. The optimum ratio of nozzle flow to sand flow was concluded. This was of great significance for IDF on low load to prevent dust accumulation vibration and to keep safe and stable operation.

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Chlebnikovas, Aleksandras, Dainius Paliulis, Kristina Kilikevičienė i Artūras Kilikevičius. "Experimental Research of Gaseous Emissions Impact on the Performance of New-Design Cylindrical Multi-Channel Cyclone with Adjustable Half-Rings". Sustainability 14, nr 2 (13.01.2022): 902. http://dx.doi.org/10.3390/su14020902.

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Cyclones are widely used for separating particles from gas in energy production objects. The efficiency of conventional centrifugal air cleaning devices ranges from 85 to 90%, but the weakness of many cyclones is the low collection efficiency of particles less than 10 μm in diameter. The novelty of this work is the research of the channel-type treatment device, with few levels adapted for precipitation of fine particulate matter, acting by a centrifugal and filtration principle. Many factors have an impact on cyclone efficiency—humidity, temperature, gas (air) composition, airflow velocity and etc. Many scientists evaluated only the effect of origin and size of PM on cyclone efficiency. The effect of gas (air) composition and temperature, and humidity on the multi-channel cyclone-separator efficiency still demands contributions. Complex theoretical and experimental research on air flow parameters and the efficiency of a cylindrical eight-channel system with adjustable half-rings for removing fine-dispersive particles (<20 μm) was carried out. The impact of air humidity and temperature on air flow, and gaseous smoke components on the removal of wood ashes was analyzed. The dusty gas flow was regulated. During the experiment, the average velocity of the cyclone was 16 m/s, and the temperature was 20–50 °C. The current paper presents experimental research results of wood ash removal in an eight-channel cyclone and theoretical methodology for the calculation of airflow parameters and cyclone effectiveness.

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Okamoto, Yasuhiro, Yoshiyuki Uno i Hiroshi Suzuki. "Effect of Nozzle Shape on Micro-Cutting Performance of Thin Metal Sheet by Pulsed Nd: YAG Laser". International Journal of Automation Technology 4, nr 6 (5.11.2010): 510–17. http://dx.doi.org/10.20965/ijat.2010.p0510.

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In precision laser cutting, the generation of dross can be reduced by using a high-pressure assist gas flow. However, our previous work made it clear that, for a conventional convergent nozzle, the pressure of assist gas on a workpiece is reduced to less than half of the cylinder gas pressure because of the generation of Mach Shock Disk. Furthermore, the removal of material from the micro-kerf becomes difficult since the fluidity of molten material is low in the narrow kerf. Therefore, nozzle shapes were investigated to improve the removal of material from the micro-kerf, and their effect on the fine cutting of a thin metal plate using a pulsed Nd: YAG laser was also discussed. The height of dross could be reduced by using a Laval throat nozzle with an initial expansion zone compared with that for a straight throat nozzle. The pressure on the workpiece was greater, and the straightness of the assist gas flow was excellent when the Laval throat nozzle with the initial expansion zone was used. Moreover, it was confirmed that the molten material could be effectively removed from the micro-kerf even at a middle cylinder gas pressure of around 600 kPa. Therefore, the Laval throat nozzle with the initial expansion zone can be used for fine cutting owing to its reduction of dross.

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Gildfind, David E., Chris M. James, Pierpaolo Toniato i Richard G. Morgan. "Performance considerations for expansion tube operation with a shock-heated secondary driver". Journal of Fluid Mechanics 777 (20.07.2015): 364–407. http://dx.doi.org/10.1017/jfm.2015.349.

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A shock-heated secondary driver is a modification typically applied to an expansion tube which involves placing a volume of helium between the primary diaphragm and the test gas. This modification is normally used to either increase the driven shock strength through the test gas for high-enthalpy conditions, or to prevent transmission of primary driver flow disturbances to the test gas for low-enthalpy conditions. In comparison to the basic expansion tube, a secondary driver provides an additional configuration parameter, adds mechanical and operational complexity, and its effect on downstream flow processes is not trivial. This paper reports on a study examining operation of a shock-heated secondary driver across the entire operating envelope of a free-piston-driven expansion tube, using air as the test gas. For high-enthalpy conditions it is confirmed that the secondary driver can provide a performance increase, and it is further shown how this device can be used to fine tune the flow condition even when the free-piston driver configuration is held constant. For low-enthalpy flow conditions, wave processes through the driven tube are too closely coupled, and the secondary driver no longer significantly influences the magnitude of the final test gas flow properties. It is found that these secondary driver operating characteristics depend principally on the initial density ratio between the secondary driver helium gas and the downstream test gas.

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Wang, Guangyu, i Yangwei Liu. "A grid-adaptive simulation model for turbulent flow predictions". Physics of Fluids 34, nr 7 (lipiec 2022): 075125. http://dx.doi.org/10.1063/5.0090485.

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Hybrid Reynolds-averaged Navier–Stokes (RANS) and large eddy simulation (LES) methods, abbreviated as hybrid RANS-LES, have been rapidly developed and increasingly used for predicting complex turbulent flows. In this study, a new high-fidelity hybrid RANS-LES strategy that modifies the turbulent viscosity equation using the ratio of grid length scale to turbulent integral length scale based on the Kolmogorov energy spectrum, termed the grid-adaptive simulation (GAS) model, is proposed to achieve high accuracy for turbulent flows using different grid resolutions. Using the shear-stress transport (SST) k–ω model as the baseline turbulence model, the GAS-SST model is validated by predicting three typical turbulent flows with coarse and fine meshes, including periodic hill flow, circular cylinder flow, and simplified tip leakage flow. As a reference, the scale-adaptive simulation (SAS) and delayed detached-eddy simulation (DDES) models are also employed to predict the above three turbulent flows. Solutions of GAS-SST, SAS-SST, and DDES-SST are compared against the high-fidelity data from the experiments or LES solutions. Detailed comparisons show that the GAS-SST model could achieve high accuracy with different grid resolutions for all three validation cases, which means that the GAS model has strong grid-adaptive ability. The results predicted by the GAS-SST model using coarse meshes are usually much more in agreement with the high-fidelity data than those predicted by SAS-SST and DDES-SST models. The GAS model demonstrates the potential to address the accuracy and computational efficiency requirements for predicting turbulent flows.

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Guan, Dawei, Aoxing Qu, Zifei Wang, Xin Lv, Qingping Li, Shudong Leng, Bo Xiao i in. "Fluid flow-induced fine particle migration and its effects on gas and water production behavior from gas hydrate reservoir". Applied Energy 331 (luty 2023): 120327. http://dx.doi.org/10.1016/j.apenergy.2022.120327.

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Zhou, Hui, i Hamdi A. Tchelepi. "Operator-Based Multiscale Method for Compressible Flow". SPE Journal 13, nr 02 (1.06.2008): 267–73. http://dx.doi.org/10.2118/106254-pa.

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Summary Multiscale methods have been developed for accurate and efficient numerical solution of flow problems in large-scale heterogeneous reservoirs. A scalable and extendible Operator-Based Multiscale Method (OBMM) is described here. OBMM is cast as a general algebraic framework. It is natural and convenient to incorporate more physics in OBMM for multiscale computation. In OBMM, two operators are constructed: prolongation and restriction. The prolongation operator is constructed by assembling the multiscale basis functions. The specific form of the restriction operator depends on the coarse-scale discretization formulation (e.g., finitevolume or finite-element). The coarse-scale pressure equation is obtained algebraically by applying the prolongation and restriction operators to the fine-scale flow equations. Solving the coarse-scale equation results in a high-quality coarse-scale pressure. The finescale pressure can be reconstructed by applying the prolongation operator to the coarse-scale pressure. A conservative fine-scale velocity field is then reconstructed to solve the transport (saturation) equation. We describe the OBMM approach for multiscale modeling of compressible multiphase flow. We show that extension from incompressible to compressible flows is straightforward. No special treatment for compressibility is required. The efficiency of multiscale formulations over standard fine-scale methods is retained by OBMM. The accuracy of OBMM is demonstrated using several numerical examples including a challenging depletion problem in a strongly heterogeneous permeability field (SPE 10). Introduction The accuracy of simulating subsurface flow relies strongly on the detailed geologic description of the porous formation. Formation properties such as porosity and permeability typically vary over many scales. As a result, it is not unusual for a detailed geologic description to require 107-108 grid cells. However, this level of resolution is far beyond the computational capability of state-of-the-art reservoir simulators (106 grid cells). Moreover, in many applications, large numbers of reservoir simulations are performed (e.g., history matching, sensitivity analysis and stochastic simulation). Thus, it is necessary to have an efficient and accurate computational method to study these highly detailed models. Multiscale formulations are very promising due to their ability to resolve fine-scale information accurately without direct solution of the global fine-scale equations. Recently, there has been increasing interest in multiscale methods. Hou and Wu (1997) proposed a multiscale finite-element method (MsFEM) that captures the fine-scale information by constructing special basis functions within each element. However, the reconstructed fine-scale velocity is not conservative. Later, Chen and Hou (2003) proposed a conservative mixed finite-element multiscale method. Another multiscale mixed finite element method was presented by Arbogast (2002) and Arbogast and Bryant (2002). Numerical Green functions were used to resolve the fine-scale information, which are then coupled with coarse-scale operators to obtain the global solution. Aarnes (2004) proposed a modified mixed finite-element method, which constructs special basis functions sensitive to the nature of the elliptic problem. Chen et al. (2003) developed a local-global upscaling method by extracting local boundary conditions from a global solution, and then constructing coarse-scale system from local solutions. All these methods considered incompressible flow in heterogeneous porous media where the pressure equation is elliptic. A multiscale finite-volume method (MsFVM) was proposed by Jenny et al. (2003, 2004, 2006) for heterogeneous elliptic problems. They employed two sets of basis functions--dual and primal. The dual basis functions are identical to those of Hou and Wu (1997), while the primal basis functions are obtained by solving local elliptic problems with Neumann boundary conditions calculated from the dual basis functions. Existing multiscale methods (Aarnes 2004; Arbogast 2002; Chen and Hou 2003; Hou and Wu 1997; Jenny et al. 2003) deal with the incompressible flow problem only. However, compressibility will be significant if a gas phase is present. Gas has a large compressibility, which is a strong function of pressure. Therefore, there can be significant spatial compressibility variations in the reservoir, and this is a challenge for multiscale modeling. Very recently, Lunati and Jenny (2006) considered compressible multiphase flow in the framework of MsFVM. They proposed three models to account for the effects of compressibility. Using those models, compressibility effects were represented in the coarse-scale equations and the reconstructed fine-scale fluxes according to the magnitude of compressibility. Motivated to construct a flexible algebraic multiscale framework that can deal with compressible multiphase flow in highly detailed heterogeneous models, we developed an operator-based multiscale method (OBMM). The OBMM algorithm is composed of four steps:constructing the prolongation and restriction operators,assembling and solving the coarse-scale pressure equations,reconstructing the fine-scale pressure and velocity fields, andsolving the fine-scale transport equations. OBMM is a general algebraic multiscale framework for compressible multiphase flow. This algebraic framework can also be extended naturally from structured to unstructured grid. Moreover, the OBMM approach may be used to employ multiscale solution strategies in existing simulators with a relatively small investment.

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Karimi-Fard, M., i L. J. J. Durlofsky. "Accurate Resolution of Near-Well Effects in Upscaled Models Using Flow-Based Unstructured Local Grid Refinement". SPE Journal 17, nr 04 (29.11.2012): 1084–95. http://dx.doi.org/10.2118/141675-pa.

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Summary We present a new approach for representing wells in coarse-scale reservoir simulation models. The technique is based on an expanded well model concept which provides a systematic procedure for the construction of the near-well grid. The method proceeds by first defining an underlying fine-scale model, in which the well and any key near-well features such as hydraulic fractures are fully resolved using an unstructured grid. In the (coarse) simulation model, the geometry of the grid in the expanded well region, and the associated "radial" transmissibilities, are determined from the solution of a fine-scale, single-phase, well-driven flow problem. The coarse-scale transmissibilities outside of the well region are computed using existing local upscaling techniques or by applying a new global upscaling procedure. Thus, through use of near-well flow-based gridding and generalized local grid refinement, this methodology efficiently incorporates the advantages of highly-resolved unstructured grid representations of wells into coarse models. The overall model provided by this technique is compatible with any reservoir simulator that allows general unstructured cell-to-cell connections (model capabilities, in terms of flow physics, are defined by the simulator). The expanded well modeling approach is applied to challenging 3D problems involving injection and production in a low-permeability heterogeneous reservoir, tight-gas production by a hydraulically-fractured well, and production in a gas-condensate reservoir. In the first two cases, where it is possible to simulate the fine-grid unstructured model, results using the expanded well model closely match the reference solutions, while standard approaches lead to significant error. In the gas-condensate example, which involves a nine-component compositional model, the reference solution is not computed, but the solution using the expanded well model is shown to be physically reasonable while standard coarse-grid solutions show large variation under grid refinement.

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