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Simulation of the Asphaltene Deposition Rate in Oil Wells under Different Multiphase Flow Condition

ENERGIES 2024年第1期17卷

作者： Wang, Xiaoming Dong, Pingchuan Zhang, Youheng Gao, Xiaodong Chen, Shun Tian, Ming Cui, Yongxing PetroChina Tarim Oilfield Co Korla 841000 Peoples R China China Univ Petr State Key Lab Petr Resources & Prospecting Beijing 102200 Peoples R China China Univ Petr Coll Petr Engn Beijing 102200 Peoples R China Sinopec Res Inst Petr Engn Beijing 100083 Peoples R China

As the wellbore pressure falls below the bubble point pressure, the light components in the oil phase are liberated, forming additional vapor, and the single-phase flow becomes a gas-liquid two-phase flow. However, most studies simplify the multiphase flow to a single-phase flow to study asphaltene deposition in wellbores. This assumption under multiphase conditions may lead to inaccurate prediction results and a substantial economic and operational burden for the oil and gas industry. Therefore, it is crucial to predict the deposition rate of asphaltene in a multiphase flow to assist in minimizing this issue. To do so, the volume of fluid coupling level-set (VOSET) model was used to obtain the flow pattern (bubble, slug, churn, and annular) in the current work. In the next step, the VOSET + k-epsilon turbulent + DPM models were used to simulate asphaltene deposition in a multiphase flow. Finally, the effects of different parameters, such as the gas superficial velocity, liquid superficial velocity, particle diameter, interfacial tension, viscosity, and average deposition rate, were investigated. The findings revealed that the maximum average deposition rate of asphaltene particles in a bubble flow is 1.35, 1.62, and 2 times that of a slug flow, churning flow, and annular mist flow, respectively. As the apparent velocity of the gas phase escalates from 0.5 m/s to 4 m/s, the average deposition rate experiences an increase of 82%. Similarly, when the apparent velocity of the liquid phase rises from 1 m/s to 5 m/s, the average deposition rate is amplified by a factor of 2.1. An increase in particle diameter from 50 mu m to 400 mu m results in a 27% increase in the average deposition rate. When the oil-gas interfacial tension is augmented from 0.02 n/m to 0.1 n/m, the average deposition rate witnesses an 18% increase. Furthermore, an increase in crude oil viscosity from 0.012 mPa center dot s to 0.06 mPa center dot s leads to a 34% increase in the average deposition rat

关键词： multiphase flow flow pattern VOSET model asphaltene deposition average deposition rate computational methods in fluid dynamics

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A library for wall-modelled large-eddy simulation based on OpenFOAM technology

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COMPUTER PHYSICS COMMUNICATIONS 2019年 239卷 204-224页

作者： Mukha, T. Rezaeiravesh, S. Liefvendahl, M. Uppsala Univ Dept Informat Technol Box 337 SE-75105 Uppsala Sweden Swedish Def Res Agcy FOI SE-16490 Stockholm Sweden

This work presents a feature-rich open-source library for wall-modelled large-eddy simulation (WMLES), which is a turbulence modelling approach that reduces the computational cost of standard (wall-resolved) LES by introducing special treatment of the inner region of turbulent boundary layers (TBLs). The library is based on OpenFOAM and enhances the general-purpose LES solvers provided by this software with state-of-the-art wall modelling capability. The included wall models belong to the class of wall-stress models that account for the under-resolved turbulent structures by predicting and enforcing the correct local value of the wall shear stress. A review of this approach is given, followed by a detailed description of the library, discussing its functionality and extensible design. The included wall-stress models are presented, based on both algebraic and ordinary differential equations. To demonstrate the capabilities of the library, it was used for WMLES of turbulent channel flow and the flow over a backward-facing step (BFS). For each flow, a systematic simulation campaign was performed, in order to find a combination of numerical schemes, grid resolution and wall model type that would yield a good predictive accuracy for both the mean velocity field in the outer layer of the TBLs and the mean wall shear stress. The best result, approximate to 1% error in the above quantities, was achieved for channel flow using a mildly dissipative second-order accurate scheme for the convective fluxes applied on an isotropic grid with 27 000 cells per delta(3)-cube, where delta is the channel half-height. In the case of flow over a BFS, this combination led to the best agreement with experimental data. An algebraic model based on Spalding's law of the wall was found to perform well for both flows. On the other hand, the tested more complicated models, which incorporate the pressure gradient in the wall shear stress prediction, led to less accurate results. (C) 2019 Elsevier

关键词： Wall modelling OpenFOAM Boundary layer turbulence Large-eddy simulations computational methods in fluid dynamics

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Enhanced schlieren imaging applied in heat and air jet visualizations: A wave propagation-based model 3

Enhanced schlieren imaging applied in heat and air jet visua...

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3rd International Conference on Photonics and Optical Engineering

作者： Oca, Gilbert M. Almoro, Percival F. Univ Philippines Diliman Natl Inst Phys Quezon City 1101 Philippines

ISBN: (数字)9781510627802

ISBN: (纸本)9781510627802

Refractive index variations caused by temperature or pressure gradients in transparent fluids are invisible to the naked eye. Schlieren effect reveals this variation using refraction and the knife-edge method. High contrast schlieren images are important in the analyses of fluid flow, gas density, shockwaves, heat transfer, flames, ballistics, leak detection and other applications. The neglect of physical or wave theory in schlieren technique leads to erroneous results in some circumstance. Specifically, a study had mathematically shown that illumination is fairly uniform over large part of the field but suddenly increases at the edge and is fairly appreciable for some way outside the actual physical boundary of the aperture. This bright edge is noticeable in all schlieren systems whereas a geometrical optics would lead to a uniformly illuminated field. Geometric ray-tracing codes are useful for optical design, but they cannot describe the key role of diffraction in the formation of schlieren image. In this study, a wave propagation-based model of the schlieren technique is proposed. Compared to the ray optics approach, the proposed model provides valuable insights and visualization of fluid flow dynamics Some predictions of the model will be confirmed through experimental demonstrations. Setup parameters are also optimized resulting in enhanced resolution of schlieren images.

关键词： Schlieren devices Reflection and refraction Wave optics Wave propagation Fourier optics computational methods in fluid dynamics

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Lattice Boltzmann simulations of gravity currents

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EUROPEAN JOURNAL OF MECHANICS B-fluidS 2018年 67卷 125-136页

作者： Ottolenghi, L. Prestininzi, P. Montessori, A. Adduce, C. La Rocca, M. Univ Roma Tre Dept Engn I-00146 Rome Italy

This paper is aimed at assessing the ability of the Lattice-Boltzmann Method (LBM) in reproducing the fundamental features of lock-exchange gravity currents. Both two- and three-dimensional numerical simulations are presented at different Reynolds numbers (1000 <= Re <= 30,000). Turbulence has been accounted for by implementing an equivalent Large Eddy Simulation (LES) model in the LBM framework. The advancement of the front position and the front velocity obtained by LBM numerical simulations are compared with laboratory experiments appositely performed with similar initial and boundary conditions and with previous results from literature, revealing that the dynamics of the gravity current as a whole is correctly reproduced. Lobes and clefts instabilities arising in three-dimensional simulations and the entrainment parameter are also analysed and comparisons with previous studies are presented. (C) 2017 Elsevier Masson SAS. All rights reserved.

关键词： Buoyancy-driven flows computational methods in fluid dynamics Lattice-Boltzmann method

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Combined effects of fluid type and particle shape on particles flow in microfluidic platforms

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MICROfluidICS AND NANOfluidICS 2019年第7期23卷 84-84页

作者： Basagaoglu, Hakan Blount, Justin Succi, Sauro Freitas, Christopher J. Southwest Res Inst Mech Engn Div San Antonio TX 78238 USA Edwards Aquifer Author San Antonio TX 78215 USA Southwest Res Inst Def Intelligence Solut Div San Antonio TX 78238 USA Fdn Ist Italiano Tecnol Ctr Life Nanosci Sapienza I-00165 Rome Italy Ist Applicaz Calcolo Via Taurini 19 I-00185 Rome Italy

Recent numerical analyses to optimize the design of microfluidic devices for more effective entrapment or segregation of surrogate circulating tumor cells (CTCs) from healthy cells have been reported in the literature without concurrently accommodating the non-Newtonian nature of the body fluid and the non-uniform geometric shapes of the CTCs. Through a series of two-dimensional proof-of-concept simulations with increased levels of complexity (e.g., number of particles, inline obstacles), we investigated the validity of the assumptions of the Newtonian fluid behavior for pseudoplastic fluids and the circular particle shape for different-shaped particles (DSPs) in the context of microfluidics-facilitated shape-based segregation of particles. Simulations with a single DSP revealed that even in the absence of internal geometric complexities of a microfluidics channel, the aforementioned assumptions led to 0.11-0.21W (W is the channel length) errors in lateral displacements of DSPs, up to 3-20% errors in their velocities, and 3-5% errors in their travel times. When these assumptions were applied in simulations involving multiple DSPs in inertial microfluidics with inline obstacles, errors in the lateral displacements of DSPs were as high as 0.78W and in their travel times up to 23%, which led to different (un)symmetric flow and segregation patterns of DSPs. Thus, the fluid type and particle shape should be included in numerical models and experiments to assess the performance of microfluidics for targeted cell (e.g., CTCs) harvesting.

关键词： computational methods in fluid dynamics Hydrodynamics Hydraulics Hydrostatics

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computational performance of SequenceL coding of the lattice Boltzmann method for multi-particle flow simulations

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COMPUTER PHYSICS COMMUNICATIONS 2017年 213卷 92-99页

作者： Basagaoglu, Hakan Blount, Justin Blount, Jarred Nelson, Bryant Succi, Sauro Westhart, Phil M. Harwell, John R. Southwest Res Inst Mech Engn Div San Antonio TX 78238 USA Southwest Res Inst Def Intelligence Solut Div San Antonio TX 78238 USA Texas Tech Univ Dept Comp Sci Lubbock TX 79409 USA Texas Multicore Technol Inc Austin TX 78728 USA CNR IAC Via Taurini 19 I-00185 Rome Italy Southwest Res Inst Intelligent Syst Div San Antonio TX 78238 USA

This paper reports, for the first time, the computational performance of SequenceL for mesoscale simulations of large numbers of particles in a microfluidic device via the lattice-Boltzmann method. The performance of SequenceL simulations was assessed against the optimized serial and parallelized (via OpenMP directives) FORTRAN90 simulations. At present, OpenMP directives were not included in interparticle and particle-wall repulsive (steric) interaction calculations due to difficulties that arose from inter-iteration dependencies between consecutive iterations of the do-loops. SequenceL simulations, on the other hand, relied on built-in automatic parallelism. Under these conditions, numerical simulations revealed that the parallelized FORTRAN90 outran the performance of SequenceL by a factor of 2.5 or more when the number of particles was 100 or less. SequenceL, however, outran the performance of the parallelized FORTRAN90 by a factor of 1.3 when the number of particles was 300. Our results show that when the number of particles increased by 30-fold, the computational time of SequenceL simulations increased linearly by a factor of 1.5, as compared to a 3.2-fold increase in serial and a 7.7-fold increase in parallelized FORTRAN90 simulations. Considering SequenceL's efficient built-in parallelism that led to a relatively small increase in computational time with increased number of particles, it could be a promising programming language for computationally-efficient mesoscale simulations of large numbers of particles in microfluidic experiments. (C) 2016 Elsevier B.V. All rights reserved.

关键词： computational methods in fluid dynamics Hydrodynamics Lattice-Boltzmann SequenceL

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Heavy oil slurry transportation through horizontal pipelines: Experiments and CFD simulations

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INTERNATIONAL JOURNAL OF MULTIPHASE FLOW 2017年 91卷 130-141页

作者： Zambrano, Hector Sigalotti, Leonardo Di G. Klapp, Jaime Pena-Polo, Franklin Bencomo, Alfonso Univ Cent Venezuela Fac Ingn Ciencias Ingn Apartado Postal 47750 Caracas 1041A Venezuela Univ Autonoma Metropolitana Azcapotzalco Dept Ciencias Basicas Area Fis Proc Irreversibles Av San Pablo 180 Mexico City 02200 DF Mexico IVIC Ctr Fis Apartado Postal 20632 Caracas 1020A Venezuela Inst Nacl Invest Nucl Dept Fis Carretera Mexico Toluca S-N Ocoyoacac 52750 Estado De Mexic Mexico Ctr Invest & Estudios Avanzados CINVESTAV IPN Dept Matemat ABACUS Ctr Matemat Aplicadas & Computo Alto Rendi Carretera Mexico Toluca Km 38-5 Ocoyoacac 52740 Estado De Mexic Mexico Univ Cent Venezuela Escuela Met & Ciencia Mat Fac Ingn Apartado Postal 47750 Caracas 1041A Venezuela

The pressure-driven slurry flow of heavy oil in a horizontal pipe is investigated experimentally and numerically for Reynolds numbers in the range 44-805, solid concentrations by weight between 1 and 12%, and mean slurry velocities of similar to 0.2-2.3 m s(-1). A three-dimensional, algebraic slip mixture (ASM) model is used as part of the CFD software FLUENT 6.3 to obtain the numerical solutions. The results for the pressure drop are compared with experimental data of slurry prepared with de-asphalted oil as the liquid phase and asphaltic residues as the solid phase with mean particle sizes of 500 gm. Based on the experimental measurements, the critical deposition velocity for these slurries was estimated to vary from 0.171 m s(-1) (for 1% solid concentration and mean slurry velocity of 0.22 m) to 0.66 m s(-1) (for 12% concentration and mean slurry velocity of 2.3 m s(-1)). However, for the full range of mean velocities tested, the flow of these highly viscous mixtures was found to be in a homogeneous regime. The numerically predicted pressure drops are in good agreement with the experimental data with relative deviations of similar to 0.8-13%. In contrast, errors of similar to 3-24% are obtained when comparing the experimental results with the Fanning friction factor correlation. While the temperature of the circulating slurry rises with the flow rate due to viscous heating and friction of the solid particles with the pipe walls, we find that at the moderate flow velocities and efflux concentrations considered the slurry morphology is not affected by the gradual dissolution of the solid particles (asphaltenes) into the liquid phase. Other important slurry flow characteristics, such as the mean slurry friction coefficient and slurry velocity distribution, are also analyzed, which predict the homogeneous, symmetric character of the flow. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： Multiphase flows Particle-laden flows Laminar flows Flow in pipes Pressure drop computational methods in fluid dynamics

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Enhanced computational performance of the lattice Boltzmann model for simulating micron- and submicron-size particle flows and non-Newtonian fluid flows

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COMPUTER PHYSICS COMMUNICATIONS 2017年 213卷 64-71页

作者： Basagaoglu, Hakan Harwell, John R. Hoa Nguyen Succi, Sauro Southwest Res Inst Mech Engn Div San Antonio TX 78238 USA Southwest Res Inst Def Intelligence Solut Div San Antonio TX 78238 USA Trinity Univ Dept Math San Antonio TX 78212 USA CNR IAC Via Taurini 19 I-00185 Rome Italy

Significant improvements in the computational performance of the lattice-Boltzmann (LB) model, coded in FORTRAN90, were achieved through application of enhancement techniques. Applied techniques include optimization of array memory layouts, data structure simplification, random number generation outside the simulation thread(s), code parallelization via OpenMP, and intra- and inter-timestep task pipelining. Effectiveness of these optimization techniques was measured on three benchmark problems: (i) transient flow of multiple particles in a Newtonian fluid in a heterogeneous fractured porous domain, (ii) thermal fluctuation of the fluid at the sub-micron scale and the resultant Brownian motion of a particle, and (iii) non-Newtonian fluid flow in a smooth-walled channel. Application of the aforementioned optimization techniques resulted in an average 21x performance improvement, which could significantly enhance practical uses of the LB models in diverse applications, focusing on the fate and transport of nano-size or micron-size particles in non-Newtonian fluids. (C) 2016 Elsevier B.V. All rights reserved.

关键词： computational methods in fluid dynamics Hydrodynamics Lattice-Boltzmann FORTRAN Optimization

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An improved lattice Boltzmann method for simulating advective-diffusive processes in fluids

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JOURNAL OF computational PHYSICS 2017年 332卷 363-375页

作者： Aursjo, Olav Jettestuen, Espen Vinningland, Jan Ludvig Hiorth, Aksel IRIS POB 8046 N-4068 Stavanger Norway Univ Oslo Dept Phys POB 1048 Blindern NO-0316 Oslo Norway Univ Stavanger Natl IOR Ctr Norway N-4036 Stavanger Norway

Lattice Boltzmann methods are widely used to simulate advective-diffusive processes in fluids. Lattice Bhatnagar-Gross-Krook methods presented in the literature mostly just exhibit first order spatial accuracy and introduce errors proportional to the velocity squared. Formulations proposed to alleviate this have only been partly successful and are valid only in certain specific situations. We present and demonstrate here, a formulation that produces no such second order errors. This formulation suggests that a subtle, but important, adjustment is all it takes to improve the accuracy of the method. The key to the improved accuracy of this new model is the non-standard definition of the concentration that relates to the distribution function describing the advection-diffusion in lattice Boltzmann. The main advantage of the algorithm comes to view when simulating situations where fluid density variations appear. The present formulation of the advection-diffusion algorithm will, by taking into account these fluid density variations, drastically reduce the errors produced compared to the standard formulations. We also show how a source term is included in this new formulation without it losing its second order spatial accuracy. (C) 2016 Elsevier Inc. All rights reserved.

关键词： computational methods in fluid dynamics Mixing Classical transport

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Mesoscopic modelling of microbubble in liquid with finite density ratio of gas to liquid

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EPL 2018年第2期122卷

作者： Pan, Dingyi Zhao, Gengyao Lin, Yuqing Shao, Xueming Zhejiang Univ Dept Engn Mech State Key Lab Fluid Power & Mechatron Syst Hangzhou 310027 Zhejiang Peoples R China Zhejiang Univ Dept Engn Mech Key Lab Soft Machines & Smart Devices Zhejiang Pr Hangzhou 310027 Zhejiang Peoples R China

A microbubble model is developed with the mesoscopic simulation tool, dissipative particle dynamics (DPD) and many-body dissipative particle dynamics (MDPD). Standard DPD particles are employed to represent bubble phase at low density, and MDPD particles are for the liquid phase. The microbubble can be stable in liquid, in contrast to the vacuum bubble model. Gas-liquid interface is well presented with density and pressure jumps. The density ratio of gas to liquid can be lower than 0.1 by increasing the cut-off radius of bubble particles. Oscillating behavior of the microbubble model is investigated and validated by comparing with the Rayleigh-Plesset equation. The current model shows correct dynamic response, and the fluctuating behavior is captured as well. The lower the density ratio of the microbubble model, the closer the oscillating frequency to that of continuum theory. Copyright (C) EPLA, 2018

关键词： Molecular dynamics and particle methods computational methods in fluid dynamics Gas-liquid and vacuum-liquid interfaces

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