Academic literature on the topic 'Porous materials Fluid dynamics Computer simulation'
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Journal articles on the topic "Porous materials Fluid dynamics Computer simulation"
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Bultreys, T., S. Van Offenwert, W. Goethals, M. N. Boone, J. Aelterman, and V. Cnudde. "X-ray tomographic micro-particle velocimetry in porous media." Physics of Fluids 34, no. 4 (April 2022): 042008. http://dx.doi.org/10.1063/5.0088000.
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Fluid flow through intricate confining geometries often exhibits complex behaviors, certainly in porous materials, e.g., in groundwater flows or the operation of filtration devices and porous catalysts. However, it has remained extremely challenging to measure 3D flow fields in such micrometer-scale geometries. Here, we introduce a new 3D velocimetry approach for optically opaque porous materials, based on time-resolved x-ray micro-computed tomography (CT). We imaged the movement of x-ray tracing micro-particles in creeping flows through the pores of a sandpack and a porous filter, using laboratory-based CT at frame rates of tens of seconds and voxel sizes of 12 μm. For both experiments, fully three-dimensional velocity fields were determined based on thousands of individual particle trajectories, showing a good match to computational fluid dynamics simulations. Error analysis was performed by investigating a realistic simulation of the experiments. The method has the potential to measure complex, unsteady 3D flows in porous media and other intricate microscopic geometries. This could cause a breakthrough in the study of fluid dynamics in a range of scientific and industrial application fields.
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Tiribocchi, A., M. Lauricella, A. Montessori, S. Melchionna, and S. Succi. "Disordered interfaces in soft fluids with suspended colloids." International Journal of Modern Physics C 30, no. 10 (October 2019): 1941004. http://dx.doi.org/10.1142/s0129183119410043.
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Computer simulations of bi-continuous two-phase fluids with interspersed dumbbells show that, unlike rigid colloids, soft dumbbells do not lead to arrested coarsening. However, they significantly alter the curvature dynamics of the fluid–fluid interface, whose probability density distributions are shown to exhibit (i) a universal spontaneous transition (observed even in the absence of colloids) from an initial broad-shape distribution towards a highly localized one and (ii) super-diffusive dynamics with long-range effects. Both features may prove useful for the design of novel families of soft porous materials.
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Krakowska, Paulina, and Paweł Madejski. "Research on Fluid Flow and Permeability in Low Porous Rock Sample Using Laboratory and Computational Techniques." Energies 12, no. 24 (December 9, 2019): 4684. http://dx.doi.org/10.3390/en12244684.
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The paper presents results of fluid flow simulation in tight rock being potentially gas-bearing formation. Core samples are under careful investigation because of the high cost of production from the well. Numerical simulations allow determining absolute permeability based on computed X-ray tomography images of the rock sample. Computational fluid dynamics (CFD) give the opportunity to use the partial slip Maxwell model for permeability calculations. A detailed 3D geometrical model of the pore space was the input data. These 3D models of the pore space were extracted from the rock sample using highly specialized software poROSE (poROus materials examination SoftwarE, AGH University of Science and Technology, Kraków, Poland), which is the product of close cooperation of petroleum science and industry. The changes in mass flow depended on the pressure difference, and the tangential momentum accommodation coefficient was delivered and used in further quantitative analysis. The results of fluid flow simulations were combined with laboratory measurement results using a gas permeameter. It appeared that for the established parameters and proper fluid flow model (partial slip model, Tangential Momentum Accommodation Coefficient (TMAC), volumetric flow rate values), the obtained absolute permeability was similar to the permeability from the core test analysis.
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Bliyeva, Dana, Dossan Baigereyev, and Kholmatzhon Imomnazarov. "Computer Simulation of the Seismic Wave Propagation in Poroelastic Medium." Symmetry 14, no. 8 (July 25, 2022): 1516. http://dx.doi.org/10.3390/sym14081516.
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This article presents an algorithm for the numerical solution of an initial-boundary value problem for a symmetric t-hyperbolic system of partial differential equations. This problem is based on continual filtration model, which describes the propagation of seismic waves in a poroelastic medium saturated with a fluid characterized by such physical parameters as the propagation velocities of longitudinal P- (fast and slow) and transverse S-waves, the density of the medium materials, and porosity. The system of linearized equations of saturated porous media is formulated in terms of physical variables of the velocity–stress tensor of the porous matrix and the velocity–pressure of the saturating fluid in the absence of energy dissipation. The solution is implemented numerically using an explicit finite difference upwind scheme built on a staggered grid to avoid the appearance of oscillations in the solution functions. The program code implementing parallel computing is developed in the high-performance Julia programming language. The possibility of using the approach is demonstrated by the example of solving the problem of propagation of seismic waves from a source located in the formation. Computational experiments based on real data from oil reservoirs have been implemented, and dynamic visualization of solutions consistent with the first waves arrival times has been obtained.
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Xing, Z. B., Xingchao Han, Hanbing Ke, Q. G. Zhang, Zhiping Zhang, Huijin Xu, and Fuqiang Wang. "Multi-phase lattice Boltzmann (LB) simulation for convective transport of nanofluids in porous structures with phase interactions." International Journal of Numerical Methods for Heat & Fluid Flow 31, no. 8 (March 22, 2021): 2754–88. http://dx.doi.org/10.1108/hff-07-2020-0481.
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Purpose A combination of highly conductive porous media and nanofluids is an efficient way for improving thermal performance of relevant applications. For precisely predicting the flow and thermal transport of nanofluids in porous media, the purpose of this paper is to explore the inter-phase coupling numerical methods. Design/methodology/approach Based on the lattice Boltzmann (LB) method, this study combines the convective flow, non-equilibrium thermal transport and phase interactions of nanofluids in porous matrix and proposes a new multi-phase LB model. The micro-scale momentum and heat interactions are especially analyzed for nanoparticles, base fluid and solid matrix. A set of three-phase LB equations for the flow/thermal coupling of base fluid, nanoparticles and solid matrix is established. Findings Distributions of nanoparticles, velocities for nanoparticles and the base fluid, temperatures for three phases and interaction forces are analyzed in detail. Influences of parameters on the nanofluid convection in the porous matrix are examined. Thermal resistance of nanofluid convective transport in porous structures are comprehensively discussed with the models of multi-phases. Results show that the Rayleigh number and the Darcy number have significant influences on the convective characteristics. The result with the three-phase model is mildly larger than that with the local thermal non-equilibrium model. Originality/value This paper first creates the multi-phase theoretical model for the complex coupling process of nanofluids in porous structures, which is useful for researchers and technicians in fields of thermal science and computational fluid dynamics.
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Tsao, Wen-Huai, Ying-Chuan Chen, Christopher E. Kees, and Lance Manuel. "The Effect of Porous Media on Wave-Induced Sloshing in a Floating Tank." Applied Sciences 12, no. 11 (May 31, 2022): 5587. http://dx.doi.org/10.3390/app12115587.
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Placing porous media in a water tank can change the dynamic characteristics of the sloshing fluid. Its extra damping effect can mitigate sloshing and, thereby, protect the integrity of a liquefied natural gas tank. In addition, the out-of-phase sloshing force enables the water tank to serve as a dynamic vibration absorber for floating structures in the ocean environment. The influence of porous media on wave-induced sloshing fluid in a floating tank and the associated interaction with the substructure in the ambient wave field are the focus of this study. The numerical coupling algorithm includes the potential-based Eulerian–Lagrangian method for fluid simulation and the Newmark time-integration method for rigid-body dynamics. An equivalent mechanical model for the sloshing fluid in a rectangular tank subject to pitch motion is proposed and validated. In this approach, the degrees of freedom modeling of the sloshing fluid can be reduced so the numerical computation is fast and inexpensive. The results of the linear mechanical model and the nonlinear Eulerian–Lagrangian method are correlated. The dynamic interaction between the sloshing fluid and floating body is characterized. The effectiveness of the added porous media in controlling the vibration and mitigating the sloshing response is confirmed through frequency response analysis.
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Singh, Jitendra Kumar, Gauri Shenker Seth, and Saikh Ghousia Begum. "Unsteady MHD natural convection flow of a rotating viscoelastic fluid over an infinite vertical porous plate due to oscillating free-stream." Multidiscipline Modeling in Materials and Structures 14, no. 2 (June 4, 2018): 236–60. http://dx.doi.org/10.1108/mmms-06-2017-0054.
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Purpose The purpose of this paper is to present an analytical study on an unsteady magnetohydrodynamic (MHD) boundary layer flow of a rotating viscoelastic fluid over an infinite vertical porous plate embedded in a uniform porous medium with oscillating free-stream taking Hall and ion-slip currents into account. The unsteady MHD flow in the rotating fluid system is generated due to the buoyancy forces arising from temperature and concentration differences in the field of gravity and oscillatory movement of the free-stream. Design/methodology/approach The resulting partial differential equations governing the fluid motion are solved analytically using the regular perturbation method by assuming a very small viscoelastic parameter. In order to note the influences of various system parameters and to discuss the important flow features, the numerical results for fluid velocity, temperature and species concentration are computed and depicted graphically vs boundary layer parameter whereas skin friction, Nusselt number and Sherwood number at the plate are computed and presented in tabular form. Findings An interesting observation is recorded that there occurs a reversal flow in the secondary flow direction due to the movement of the free stream. It is also noted that a decrease in the suction parameter gives a rise in momentum, thermal and concentration boundary layer thicknesses. Originality/value Very little research work is reported in the literature on non-Newtonian fluid dynamics where unsteady flow in the system arises due to time-dependent movement of the plate. The motive of the present analytical study is to analyse the influences of Hall and ion-slip currents on unsteady MHD natural convection flow of a rotating viscoelastic fluid (non-Newtonian fluid) over an infinite vertical porous plate embedded in a uniform porous medium with oscillating free-stream.
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Huang, Wei, Sima Didari, Yan Wang, and Tequila A. L. Harris. "Generalized periodic surface model and its application in designing fibrous porous media." Engineering Computations 32, no. 1 (March 2, 2015): 7–36. http://dx.doi.org/10.1108/ec-03-2013-0085.
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Purpose – Fibrous porous media have a wide variety of applications in insulation, filtration, acoustics, sensing, and actuation. To design such materials, computational modeling methods are needed to engineer the properties systematically. There is a lack of efficient approaches to build and modify those complex structures in computers. The paper aims to discuss these issues. Design/methodology/approach – In this paper, the authors generalize a previously developed periodic surface (PS) model so that the detailed shapes of fibers in porous media can be modeled. Because of its periodic and implicit nature, the generalized PS model is able to efficiently construct the three-dimensional representative volume element (RVE) of randomly distributed fibers. A physics-based empirical force field method is also developed to model the fiber bending and deformation. Findings – Integrated with computational fluid dynamics (CFD) analysis tools, the proposed approach enables simulation-based design of fibrous porous media. Research limitations/implications – In the future, the authors will investigate robust approaches to export meshes of PS models directly to CFD simulation tools and develop geometric modeling methods for composite materials that include both fibers and resin. Originality/value – The proposed geometric modeling method with implicit surfaces to represent fibers is unique in its capability of modeling bent and deformed fibers in a RVE and supporting design parameter-based modification for global configuration change for the purpose of macroscopic transport property analysis.
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Yamada, Toru, Jinliang Yuan, and Bengt Ake Sunden. "Application of many-body dissipative particle dynamics to determine liquid characteristics." International Journal of Numerical Methods for Heat & Fluid Flow 25, no. 7 (September 7, 2015): 1619–37. http://dx.doi.org/10.1108/hff-09-2014-0293.
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Purpose – The purpose of this paper is to find out the applicability of the many-body dissipative particle dynamics (MDPD) method for various real fluids by specifically focusing on the effects of the MDPD parameters on the MDPD fluid properties. Design/methodology/approach – In this study, the MDPD method based on van der Waals (vdw) equation of state is employed. The simulations are conducted by using LAMMPS with some modifications of the original package to include the many-body features in the simulation. The simulations are investigated in a three-dimensional Cartesian box solution domain in which MDPD particles are distributed. In order to evaluate the MDPD liquid characteristics for a stationary liquid film, self-diffusivity, viscosity, Schmidt number (Sc) and surface tension, are estimated for different MDPD parameters. The parameters are carefully selected based on previous studies. A set of single-droplet simulations is also performed to analyze the droplet characteristics and its behavior on a solid-wall. Besides, the relationship between the characteristic length in the DPD simulations and scaling parameters for the stationary liquid-film case is discussed by employing the Ohnesorge number. Findings – The results show that the liquid properties in the MDPD simulations can be widely ranged by varying the MDPD parameters. The values are highly influenced by the many-body feature in the conservative force which is not included in the original DPD method. It is also found that the wetting ability of the MDPD fluid on solid walls can be easily controlled by changing a many-body parameter. The characteristic length between the MDPD reduced unit and real unit is related for the stationary liquid-film case by employing the Ohnesorge number. Originality/value – The present parametric study shows that the liquid properties in the MDPD method can vary by carefully controlling the MDPD parameters, which demonstrates the high-potential applicability of the method for various real fluids. This will contribute to research areas in multi-phase transport phenomena at nano and sub-micron scales in, for example, fuel cells, batteries and other engineering devices involving porous media.
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Azadbakhti, Reza, Farzad Pourfattah, Abolfazl Ahmadi, Omid Ali Akbari, and Davood Toghraie. "Eulerian–Eulerian multi-phase RPI modeling of turbulent forced convective of boiling flow inside the tube with porous medium." International Journal of Numerical Methods for Heat & Fluid Flow 30, no. 5 (July 17, 2019): 2739–57. http://dx.doi.org/10.1108/hff-03-2019-0194.
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Purpose The purpose of this study is simulation the flow boiling inside a tube in the turbulent flow regime for investigating the effect of using a porous medium in the boiling procedure. Design/methodology/approach To ensure the accuracy of the obtained numerical results, the presented results have been compared with the experimental results, and proper coincidence has been achieved. In this study, the phase change phenomenon of boiling has been modeled by using the Eulerian–Eulerian multi-phase Rensselaer Polytechnic Institute (RPI) wall boiling model. Findings The obtained results indicate using a porous medium in boiling process is very effective in a way that by using a porous medium inside the tub, the location of changing the liquid to the vapor and the creation of bubbles, changes. By increasing the thermal conductivity of porous medium, the onset of phase changing postpones, which causes the enhancement of heat transfer from the wall to the fluid. Generally, it can be said that using a porous medium in boiling flows, especially in flow with high Reynolds numbers, has a positive effect on heat transfer enhancement. Also, the obtained results revealed that by increasing Reynolds number, the created vapor phase along the tube decreases and by increasing Reynolds number, the Nusselt number enhances. Originality/value In present research, by using the computational fluid dynamics, the effect of using a porous medium in the forced boiling of water flow inside a tube has been investigated. The fluid boiling inside the tube has been simulated by using the multi-phase Eulerian RPI wall boiling model, and the effect of thermal conductivity of a porous medium and the Reynolds number on the flow properties, heat transfer and boiling procedure have been investigated.
Dissertations / Theses on the topic "Porous materials Fluid dynamics Computer simulation"
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Awad, Mohammad Ali. "An investigation of flux-limiting and non-linear solution techniques for efficient simulation of transport in porous media." Thesis, Queensland University of Technology, 2000. https://eprints.qut.edu.au/37057/1/37057_Awad_2000.pdf.
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This thesis presents a comprehensive analysis of efficient computational techniques for simulating transport in porous media. The equations that govern the flow of liquids in porous media are ubiquitous in science and engineering. For example, the governing equations find application in fields as diverse as drying, ground water flow, contamination and petroleum reservoir engineering. Typically, the conservation laws that are encountered are highly non-linear and have steep fronts that require resolution in time. It is one of the aims of this work to analyse the use of higher order spatial weighting schemes and temporal methods for reducing numerical dispersion. Another important ingredient in the development of an efficient simulator is the treatment of the non-linear system that results from the discrete analogue of the conservation law. In this work, a vertex-centered finite volume method has been used for discretising a representative conservation law in one-dimension and three non-linear iterative methods, an inexact full Newton method, the modified Shamanskii method (referred as the Definitive method), and the globally convergent Newton method ( with line searching) will be scrutinised. The globally convergent Newton method will converge to a solution from almost any any starting point, or it will fail to do so in a well defined manner. The size of the Newton step used in this scheme is controlled to ensure that a sufficient decrease in the non-linear residual has been achieved before the new iterate is computed. In this sense, one can view the solution procedure as a minimisation of the sum of the squares of the coordinate functions. Two case studies have been chosen to highlight the performance of the chosen numerical techniques. At first, the focus will be on the accuracy and efficiency of the spatial weighting methods for a linear advection-dispersion equation and then, a two-phase flow problem will be analysed to gauge the performance of the non-linear solvers. In both cases, comparisons with exact solutions will be provided. One of the outcomes of this work highlights that flux limiting techniques, when used in conjunction with Crank Nicolson temporal weighting, are far more accurate and efficient than solution methods that use a first order upstream strategy. Furthermore, the flux limiter with the sensor based on the ratio of fluxes, when used in combination with the Definitive non-linear solution technique produced an efficient and accurate computational model for two-phase flow.
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Lavarda, Jairo Vinícius. "Convecção natural de fluidos de lei de potência e de Bingham em cavidade fechada preenchida com meio heterogêneo." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1306.
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CAPESVários estudos numéricos investigaram cavidades fechadas sob o efeito da convecção natural preenchidas com fluidos newtonianos generalizados (FNG) nos últimos anos pelas aplicações diretas em trocadores de calor compactos, no resfriamento de sistemas eletrônicos e na engenharia de polímeros. Neste trabalho é realizada a investigação numérica do processo de convecção natural de fluidos de lei de Potência e de Bingham em cavidades fechadas, aquecidas lateralmente e preenchidas com meios heterogêneos e bloco centrado. O meio heterogêneo é constituído de blocos sólidos, quadrados, desconectados e condutores de calor. Como parâmetros são utilizados a faixa de Rayleigh de 104 à 107, índice de potência n de 0, 6 à 1, 6, número de Bingham de 0, 5 até Bimax , sendo investigado da influência do número de Prandtl para cada modelo de fluido. Nas cavidades com meio heterogêneo são utilizadas as quantidades de blocos de 9, 16, 36 e 64, mantendo-se a razão entre a condutividade térmica do sólido e do fluido κ = 1. Para as cavidades com bloco centrado, são utilizados os tamanhos adimensionais de 0, 1 à 0, 9 com κ = 0, 1; 1 e 10. A modelagem matemática é realizada pelas equações de balanço de massa, de quantidade de movimento e de energia. As simulações são conduzidas no programa comercial ANSYS FLUENT R . Inicialmente são resolvidos problemas com fluidos newtonianos em cavidade limpa, seguida de cavidade preenchida com meio heterogêneo e posteriormente bloco centrado para validação da metodologia de solução. Na segunda etapa é realizada o estudo com os modelos de fluidos de lei de Potência e de Bingham seguindo a mesma sequência. Os resultados são apresentados na forma de linhas de corrente, isotermas e pelo número de Nusselt médio na parede quente. De maneira geral, a transferência de calor na cavidade é regida pelo número de Rayleigh, tamanho e condutividade térmica dos blocos, pelo índice de potência para o modelo de lei de Potência e do número de Bingham para o modelo de Bingham. O número de Prandtl tem grande influência nos dois modelos de fluidos. O meio heterogêneo reduz a transferência de calor na cavidade quando interfere na camada limite térmica para ambos os fluidos, sendo feita uma previsão analítica para o fluido de lei de Potência. Para bloco centrado, a interferência na camada limite com fluido de lei de Potência também foi prevista analiticamente. A transferência de calor aumentou com bloco de baixa condutividade térmica e pouca interferência e com bloco de alta condutividade térmica e grande interferência, para ambos os fluidos.
Many studies have been carried out in square enclosures with generalized Newtonian fluids with natural convection in past few years for directly applications in compact heat exchangers, cooling of electronics systems and polymeric engineering. The natural convection in square enclosures with differently heated sidewalls, filled with power-law and Bingham fluids in addition with heterogeneous medium and centered block are analyzed in this study. The heterogeneous medium are solid, square, disconnected and conducting blocks. The parameters used are the Rayleigh number in the range 104 - 107 , power index n range of 0, 6 - 1, 6, Bingham number range of 0, 5 - Bimax , being the influence of Prandtl number investigated for each fluid model. The number of blocks for heterogeneous medium are 9, 16, 36 and 64, keeping constant solid to fluid conductive ratio, κ = 1. For enclosures with centered block are used the nondimensional block size from 0, 1 to 0, 9, with solid to fluid conductive ratio in range κ = 0, 1; 1 and 10. Mathematical modeling is done by mass, momentum and energy balance equations. The solution of equations have been numerically solved in ANSYS FLUENT R software. Firstly, numerical solutions for validation with Newtonian fluids in clean enclosures are conducted, followed by enclosures with heterogeneous medium and centered block. Subsequently, numerical solutions of power-law and Bingham fluids with same enclosures configurations are conducted. The results are reported in the form of streamlines, isotherms and average Nusselt number at hot wall. In general, the heat transfer process in enclosure is governed by Rayleigh number, size and thermal conductivity of the blocks, power index n for power-law fluid and Bingham number for Bingham fluid. Both fluid models are very sensitive with Prandtl number changes. Heterogeneous medium decrease heat transfer in enclosure when affects thermal boundary layer for both fluid models. One analytical prediction was made for power-law fluid. An increase in heat transfer occurs with low thermal conductivity block and few interference and with high thermal conductivity block and great interference, for both fluids.
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Barter, Wiliam Hale. "Numerical simulation of three-dimensional unsaturated flow in a heterogeneous porous medium." Thesis, The University of Arizona, 1995. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0054_m_sip1_w.pdf&type=application/pdf.
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Holladay, Seth R. "Optimized Simulation of Granular Materials." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3856.
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Visual effects for film and animation often require simulated granular materials, such as sand, wheat, or dirt, to meet a director's needs. Simulating granular materials can be time consuming, in both computation and labor, as these particulate materials have complex behavior and an enormous amount of small-scale detail. Furthermore, a single cubic meter of granular material, where each grain is a cubic millimeter, would contain a billion granules, and simulating all such interacting granules would take an impractical amount of time for productions. This calls for a simplified model for granular materials that retains high surface detail and granular behavior yet requires significantly less computational time. Our proposed method simulates a minimal number of individual granules while retaining particulate detail on the surface by supporting surface particles with simplified interior granular models. We introduce a multi-state model where, depending on the material state of the interior granules, we replace interior granules with a simplified simulation model for the state they are in and automate the transitions between those states. The majority of simulation time can thus be focused on visible portions of the material, reducing the time spent on non-visible portions, while maintaining the appearance and behavior of the mass as a whole.
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Khan, Irfan. "Direct numerical simulation and analysis of saturated deformable porous media." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34664.
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Existing numerical techniques for modeling saturated deformable porous media are based on
homogenization techniques and thus are incapable of performing micro-mechanical investigations, such as the effect of micro-structure on the deformational characteristics of the media. In this research work, a numerical scheme is developed based on the parallelized hybrid lattice-Boltzmann finite-element method, that is capable of performing micro-mechanical investigations through direct numerical
simulations.
The method has been used to simulate compression of model saturated porous media made of
spheres and cylinders in regular arrangements. Through these simulations it is found that in the limit of small Reynolds number, Capillary number and strain, the deformational behaviour of a real porous media can be recovered through model porous media when the parameters porosity, permeability and bulk compressive modulus are matched between the two media.
This finding motivated research in using model porous geometries to represent more complex
real porous geometries in order to perform investigations of deformation on the latter. An attempt has been made to apply this technique to the complex geometries of ªfeltº, (a fibrous mat used in paper industries). These investigations lead to new understanding on the effect of fiber diameter on the bulk properties of a fibrous media and subsequently on the deformational behaviour of the media. Further the method has been used to investigate the constitutive relationships in deformable porous media.
Particularly the relationship between permeability and porosity during the deformation of the media is investigated. Results show the need of geometry specific investigations.
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Konduri, Suchitra. "Computational investigations of molecular transport processes in nanotubular and nanocomposite materials." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28281.
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Thesis (M. S.)--Chemical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Nair, Sankar; Committee Member: Koros, William; Committee Member: Ludovice, Peter; Committee Member: Meredith, Carson; Committee Member: Thio, Yonathan; Committee Member: Zhou, Min.
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Abbasi, Baharanchi Ahmadreza. "Development of a Two-Fluid Drag Law for Clustered Particles Using Direct Numerical Simulation and Validation through Experiments." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2489.
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This dissertation focused on development and utilization of numerical and experimental approaches to improve the CFD modeling of fluidization flow of cohesive micron size particles. The specific objectives of this research were: (1) Developing a cluster prediction mechanism applicable to Two-Fluid Modeling (TFM) of gas-solid systems (2) Developing more accurate drag models for Two-Fluid Modeling (TFM) of gas-solid fluidization flow with the presence of cohesive interparticle forces (3) using the developed model to explore the improvement of accuracy of TFM in simulation of fluidization flow of cohesive powders (4) Understanding the causes and influential factor which led to improvements and quantification of improvements (5) Gathering data from a fast fluidization flow and use these data for benchmark validations. Simulation results with two developed cluster-aware drag models showed that cluster prediction could effectively influence the results in both the first and second cluster-aware models. It was proven that improvement of accuracy of TFM modeling using three versions of the first hybrid model was significant and the best improvements were obtained by using the smallest values of the switch parameter which led to capturing the smallest chances of cluster prediction. In the case of the second hybrid model, dependence of critical model parameter on only Reynolds number led to the fact that improvement of accuracy was significant only in dense section of the fluidized bed. This finding may suggest that a more sophisticated particle resolved DNS model, which can span wide range of solid volume fraction, can be used in the formulation of the cluster-aware drag model. The results of experiment suing high speed imaging indicated the presence of particle clusters in the fluidization flow of FCC inside the riser of FIU-CFB facility. In addition, pressure data was successfully captured along the fluidization column of the facility and used as benchmark validation data for the second hybrid model developed in the present dissertation. It was shown the second hybrid model could predict the pressure data in the dense section of the fluidization column with better accuracy.
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Tavares, Renato Normandia. "Simulação numérica da convecção mista em cavidade preenchida com meio poroso heterogêneo e homogêneo." Universidade Tecnológica Federal do Paraná, 2016. http://repositorio.utfpr.edu.br/jspui/handle/1/1657.
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No presente trabalho é apresentada a modelagem e solução numérica da convecção mista em cavidade aquecida por baixo com o topo deslizante, preenchida com meio poroso heterogêneo e homogêneo. Na abordagem heterogênea, o domínio do sólido é representado por blocos condutores de calor igualmente espaçados; a fase fluido circunda os blocos, limitada pelas paredes da cavidade. A abordagem homogênea ou poro-contínua é caracterizada através da porosidade e da permeabilidade da cavidade. As equações de conservação da massa, quantidade de movimento e energia são obtidas, adimensionalizadas e generalizadas de modo a representarem tanto o modelo contínuo quanto o poro-contínuo. A solução numérica é obtida através do método dos volumes finitos. As equações são discretizadas via esquema QUICK e é utilizado o algoritmo SIMPLE para o acoplamento pressão - velocidade. Visando o regime laminar, os parâmetros do escoamento são mantidos no intervalo de 102≤Re≤103 e 103≤Ra≤106 tanto para a abordagem heterogênea, quanto para a homogênea. Nas configurações testadas para o modelo contínuo, 9, 16, 36 e 64 blocos são considerados para cada combinação de Re e Ra e a porosidade microscópica é mantida constante φ=0,64 . No modelo poro-contínuo o número de Darcy (Da) é definido em função do número de blocos da cavidade heterogênea e da porosidade φ. Resultados numéricos do estudo comparativo entre a abordagem microscópica e a macroscópica são apresentados. Como resultado, correlações para o Nusselt médio para os modelos contínuo e poro-contínuo são obtidas em função do Ra modificado para cada Re.In this work is presented mixed convection heat transfer inside a lid-driven cavity heated from below and filled with heterogeneous and homogeneous porous medium. In the heterogeneous approach, the solid domain is represented by heat conductive equally spaced blocks; the fluid phase surrounds the blocks being limited by the cavity walls. The homogeneous or pore-continuum approach is characterized by the cavity porosity and permeability. Generalized mass, momentum and energy conservation equations are obtained in dimensionless form to represent both the continuum and the pore-continuum models. The numerical solution is obtained via the finite volume method. QUICK interpolation scheme is set for numerical treatment of the advection terms and SIMPLE algorithm is applied for pressure-velocity coupling. Aiming the laminar regime, the flow parameters are kept in the range of 102≤Re≤103 and 103≤Ra≤106 for both the heterogeneous and homogeneous approaches. In the tested configurations for the continuous model, 9, 16, 36, and 64 blocks are considered for each combination of Re and Ra being the microscopic porosity set as constant φ=0,64 . For the pore-continuum model the Darcy number (Da) is set according to the number of blocks in the heterogeneous cavity and the φ. Numerical results of the comparative study between the microscopic and macroscopic approaches are presented. As a result, average Nusselt number equations for the continuum and the pore continuum models as a function of Ra and Re are obtained.
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Sandlin, Matthew. "An experimental and numerical study of granular hopper flows." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50318.
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In a proposed design for a concentrated solar power tower, sand is irradiated by
solar energy and transfers its energy to another fluid stream by means of a finned tube
heat exchanger. To maximize heat transfer and minimize potential damage to the heat
exchanger, it is desired to have a very uniform flow through the heat exchanger.
However, performing full scale flow tests can be expensive, impractical, and depending
upon the specific quantities of interest, unsuitable for revealing the details of what it
happening inside of the flow stream.
Thus, the discrete element method has been used to simulate and study particulate
flows. In this project, the flow of small glass beads through a square pyramid shaped
hopper and a wedge shaped hopper were studied at the lab scale. These flows were also
simulated using computers running two versions of discrete element modeling software –
EDEM and LIGGGHTS. The simulated results were compared against the lab scale flows
and against each other. They show that, in general, the discrete element method can be
used to simulate lab scale particulate flows as long as certain material properties are well
known, especially the friction properties of the material. The potential for increasing the
accuracy of the simulations, such as using better material property data, non-uniform
particle size distributions, and non-spherical particle shapes, as well as simulating heat
transfer within a granular flow are also discussed.
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Yazzan, Kountar Saddam. "Numerical simulation of dynamic spontaneous imbibition with variable inlet saturation and interfacial coupling effects using Bentsen's transport equation." 2010. http://hdl.handle.net/10048/834.
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Thesis (M.Sc.)--University of Alberta, 2010.Title from PDF file main screen (viewed on Apr. 13, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Petroleum Engineering, Department of Civil and Environmental Engineering, University of Alberta. Includes bibliographical references.
Books on the topic "Porous materials Fluid dynamics Computer simulation"
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Kraus, Johannes, Mary F. Wheeler, Bastian Peter, and Robert Scheichl. Simulation of flow in porous media: Applications in energy and environment. Berlin: Walter de Gruyter GmbH & Co., KG, 2013.
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Lappala, E. G. Documentation of computer program VS2D to solve the equations of fluid flow in variably saturated porous media. Denver, Colo: Dept. of the Interior, U.S. Geological Survey, 1987.
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Eisfeld, Bernhard. Management and Minimisation of Uncertainties and Errors in Numerical Aerodynamics: Results of the German collaborative project MUNA. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013.
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B, Sagar, U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research. Division of Regulatory Applications., Analytic and Computational Research, Inc., and Center for Nuclear Waste Regulatory Analyses (Southwest Research Institute), eds. PORFLOW: A multifluid multiphase model for simulating flow, heat transfer, and mass transport in fractured porous media : user's manual, version 2.41. Washington, DC: Division of Regulatory Applications, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1993.
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Pena, Gonçalo, José A. Ferreira, Sílvia Barbeiro, and Mary F. Wheeler. Modelling and Simulation in Fluid Dynamics in Porous Media. Springer London, Limited, 2012.
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Pena, Gonçalo, José A. Ferreira, Sílvia Barbeiro, and Mary F. Wheeler. Modelling and Simulation in Fluid Dynamics in Porous Media. Springer New York, 2015.
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Simulation of Flow in Porous Media: Applications in Energy and Environment (Radon Series on Computational and Applied Mathematics Book 12). De Gruyter, 2013.
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A method for the modelling of porous and solid wind tunnel walls in computational fluid dynamics codes. [Moffett Field, Calif.]: National Aeronautics and Space Administration, Ames Research Center, 1993.
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Center, Ames Research, ed. A method for the modelling of porous and solid wind tunnel walls in computational fluid dynamics codes. [Moffett Field, Calif.]: National Aeronautics and Space Administration, Ames Research Center, 1993.
Find full textBook chapters on the topic "Porous materials Fluid dynamics Computer simulation"
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Shilko, Evgeny V., Alexey Yu Smolin, Andrey V. Dimaki, and Galina M. Eremina. "Particle-Based Approach for Simulation of Nonlinear Material Behavior in Contact Zones." In Springer Tracts in Mechanical Engineering, 67–89. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-60124-9_4.
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AbstractMethods of particles are now recognized as an effective tool for numerical modeling of dynamic mechanical and coupled processes in solids and liquids. This chapter is devoted to a brief review of recent advances in the development of the popular particle-based discrete element method (DEM). DEM is conventionally considered as a highly specialized technique for modeling the flow of granular media and the fracture of brittle materials at micro- and mesoscopic scales. However, in the last decade, great progress has been made in the development of the formalism of this method. It is largely associated with the works of the scientific group of Professor S. G. Psakhie. The most important achievement of this group is a generalized formulation of the method of homogeneously deformable discrete elements. In the chapter, we describe keystones of this implementation of DEM and a universal approach that allows one to apply various rheological models of materials (including coupled models of porous fluid-saturated solids) to a discrete element. The new formalism makes possible qualitative expansion of the scope of application of the particle-based discrete element technique to materials with various rheological properties and to the range of considered scales form microscopic to macroscopic. The capabilities of this method are especially in demand in the study of the features of contact interaction of materials. To demonstrate these capabilities, we briefly review two recent applications concerning (a) the effect of adhesive interaction on the regime of wear of surface asperities under tangential contact of bodies and (b) the nonmonotonic dependence of the stress concentration in the neck of the human femur on the dynamics of hip joint contact loading.
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Feng, Z., P. Gu, M. Zheng, X. Yan, and D. W. Bao. "Environmental Data-Driven Performance-Based Topological Optimisation for Morphology Evolution of Artificial Taihu Stone." In Proceedings of the 2021 DigitalFUTURES, 117–28. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-5983-6_11.
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AbstractTaihu stone is the most famous one among the top four stones in China. It is formed by the water's erosion in Taihu Lake for hundreds or even thousands of years. It has become a common ornamental stone in classical Chinese gardens because of its porous and intricate forms. At the same time, it has become a cultural symbol through thousands of years of history in China; later, people researched its spatial aesthetics; there are also some studies on its structural properties. For example, it has been found that the opening of Taihu stone caves has a steady-state effect which people develop its value in the theory of Poros City, Porosity in Architecture and some cultural symbols based on the original ornamental value of Taihu stone. This paper introduces a hybrid generative design method that integrates the Computational Fluid Dynamics (CFD) and Bi-directional Evolutionary Structural Optimization (BESO) techniques. Computational Fluid Dynamics (CFD) simulation enables architects and engineers to predict and optimise the performance of buildings and environment in the early stage of the design and topology optimisation techniques BESO has been widely used in structural design to evolve a structure from the full design domain towards an optimum by gradually removing inefficient material and adding materials simultaneously. This research aims to design the artificial Taihu stone based on the environmental data-driven performance feedback using the topological optimisation method. As traditional and historical ornament craftwork in China, the new artificial Taihu stone stimulates thinking about the new value and unique significance of the cultural symbol of Taihu stone in modern society. It proposes possibilities and reflections on exploring the related fields of Porosity in Architecture and Poros City from the perspective of structure.
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Barraza-Jiménez, Diana, Sandra Iliana Torres-Herrera, Patricia Ponce Peña, Carlos Omar Ríos-Orozco, Adolfo Padilla Mendiola, Elva Marcela Coria Quiñones, Raúl Armando Olvera Corral, Sayda Dinorah Coria Quiñones, and Manuel Alberto Flores-Hidalgo. "A CFD Porous Materials Model to Test Soil Enriched with Nanostructured Zeolite Using ANSYS-Fluent(™)." In Computational Fluid Dynamics [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.100487.
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Soil health is a great concern worldwide due to the huge variety of pollutants and human activities that may cause damage. There are different ways to remediate and make a better use of soil and a choice may be using zeolite in activities like gardening, farming, environment amending, among others. In this work is proposed a model to simulate how mixing zeolite with soil may be beneficial in different ways, we are especially interested in interactions of mixed soil-zeolite with water. This model is based in different flow regimes where water interacts with two layers formed by nanostructured zeolite and soil in a vertical arrangement. The analysis is approached as a bi-layer porous material model resolved by using the mathematical model implemented in ANSYS-Fluent. Such model uses a multi-fluid granular model to describe the flow behavior of a fluid–solid mixture where all the available interphase exchange coefficient models are empirically based. Despite the great capabilities of numerical simulation tools, it is known that at present time, the literature lacks a generalized formulation specific to resolve this kind of phenomena where a porous media is analyzed. This model is developed to obtain a systematic methodology to test nanomaterials with porous features produced in our laboratory which is the next step for near future work within our research group.
Conference papers on the topic "Porous materials Fluid dynamics Computer simulation"
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Flueckiger, Scott, Zhen Yang, and Suresh V. Garimella. "Thermocline Energy Storage in the Solar One Power Plant: An Experimentally Validated Thermomechanical Investigation." In ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/es2011-54578.
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The growing interest in large-scale solar power production has led to a renewed exploration of thermal storage technologies. In a thermocline storage system, heat transfer fluid (HTF) from the collection field is simultaneously stored at both excited and dead thermal states inside a single tank. A granulated porous medium included in the tank provides thermal mass for storage and reduces the amount of HTF volume required. While the thermocline offers a low-cost storage option, thermal ratcheting of the tank wall (generated by filler material reorientation from continuous thermal cycling) poses a significant design concern. A comprehensive simulation of the 170 MWht thermocline tank used in conjunction with the Solar One pilot plant is performed with a multi-dimensional two-temperature computational fluid dynamics model. In operation from 1982 to 1986, this tank was subject to extensive instrumentation, including multiple strain gages along the tank wall to monitor hoop stress. Temperature profiles along the wall material are extracted from the simulation results to compute hoop stress via finite element models and compared with the original gage data. While the strain gages experienced large uncertainty, the stresses computed from the simulation agree reasonably well with the experimental measurements. The maximum predicted hoop stress agrees to within 6.8% of the maximum stress recorded by the most reliable strain gages.
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Charpentier, I., and N. Jakse. "Efficient parallel algorithms for molecular dynamics simulation involving three-body potential: application to the Axilrod-Teller fluid at constant pressure." In International Workshop on New Approaches to High Tech Materials: Nondestructive Testing and Computer Simulations in Materials Scienc, edited by Alexander I. Melker. SPIE, 1998. http://dx.doi.org/10.1117/12.299607.
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Kolev, Nikolay Ivanov. "SKYTHIA: A Universal Multi-Phase Flow Analyzer." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-31285.
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SKYTHIA is a computer code for computational simulation of transient multi-phase flows based on three multi-component velocity fields in a porous structure that may change its geometry in time. The foundation of the computer code SKYTHIA allows applications for mathematical simulation of a variety of processes. From • two-phase gas-plasma multi-component hydrogen detonation in pipe-network with dissociation of the gases, • through condensation water-steam shock waves in complex pipe networks, • gas solution and dissolution in liquids, dissolved gas release from water in pipe network and gas-slug formation and transport, • pressure wave propagation, piping force computation and risk analysis in conventional island of 1700 MWe power plant including detailed models of the high pressure turbine, • diesel injection problems, • particles sedimentation in water, • turbulent mixing and transport in a nuclear power plant sump, • termite injection by high pressure steam-hydrogen mixture into air environment, melt-water interaction in postulated SWR 1000 severe accidents, alumina melt jet dropped into a subcooled water, Urania melt jet dropped in water, • void formation in existing-, • or future boiling water reactors, • void fraction and velocity distribution in nuclear reactors with different thermal powers, • modern steam generator simulation, thermal coupling of multi-phase non-equilibrium three fluid non-homogeneous non-equilibrium flow inside the primary piping systems to complete 3D multi-phase non-equilibrium three fluid non-homogeneous non-equilibrium flow inside secondary systems with cyclones and dryers, • volume fraction of steam in family of steam generators with different power, • water velocities and void fraction in flooding reservoir for primary emergency condenser being operating on the secondary site as boiler; thermal coupling of multi-phase non-equilibrium three fluid non-homogeneous flow inside the primary piping systems to complete 3D multi-phase non-equilibrium three fluid non-homogeneous flow inside secondary systems, • complete system for moisture separation of typical PWR, dynamic performance: multi-phase non-equilibrium three fluid non-homogeneous flow inside the secondary moisture separation system, • local volume fractions of oxide and sodium liquid as a function of (r, z) in the vertical plane for a fast breeder reactor during melt water interaction; energetic interaction of molten reactor material with liquid sodium in argon environment, • modern pre-heater (condenser) simulation, thermal coupling of single phase flow inside the primary piping systems to complete 3D multi-phase non-equilibrium three fluid non-homogeneous non-equilibrium condensing flow inside secondary systems, etc. All this applications demonstrate the capability of single model architecture to handle different material systems, different intensities of interactions, and large variety of the spatial and temporal scales of the simulated processes. This paper gives brief information about the basic principles used to build SKYTHIA, part of the validation procedure and illustrations of some very complex process simulations.
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Rakhsha, Milad, Conlain Kelly, Nic Olsen, Radu Serban, and Dan Negrut. "Multibody Dynamics vs. Fluid Dynamics: Similarities and Differences." In ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/detc2019-97999.
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Abstract In large, rigid multibody dynamics problems with friction and contact, encountered for instance in granular flows, one can witness distinctly different system-level dynamics. This contribution concentrates on the case of fluid-like behavior of large multibody dynamics systems such as granular materials, when the system experiences large strains. The results reported herein draw on computer simulation; on the one hand, we solve the Newton-Euler equations of motion, which govern the evolution of multibody dynamics system featuring frictional contact. On the other hand, we solve the Navier-Stokes equations which describe the time evolution of fluids. To demonstrate the similarities and differences between the multibody and fluid dynamics we consider three problems modeled and solved using different methods; (i) a compressibility test; (ii) the classical dam break problem, and (iii) the dam break simulation with an obstacle. These experiments provide insights into conditions under which on can expect similar characteristics from multibody and fluid dynamics systems governed by manifestly different equations of motion and solved by vastly different numerical solution methods. The models and simulation platform used are publicly available and part of an open source code called Chrono. Both the multibody and fluid dynamics simulations are carried out using GPU computing.
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Deza, Mirka, and Francine Battaglia. "Effects of Increasing Inlet Velocities and Side Port Air Injection on a Biomass Fluidizing Bed." In ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-31106.
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Fluidized beds are being used in practice to gasify biomass to create producer gas, a flammable gas that can be used for process heating. However, recent literature has identified the need to better understand and characterize biomass fluidization hydrodynamics, and computational fluid dynamics (CFD) is one approach in this effort. Previous work by the authors considered the validity of using two-dimensional versus three-dimensional simulations to model a cold-flow fluidizing biomass bed configured with a single side port air injection. The side port is introduced to inject air and promote mixing within the bed. Comparisons with experiments indicated that three-dimensional simulations were necessary to capture the fluidization behavior for the more complex geometry. This paper considers the effects of increasing fluidization air flow and side port air flow on the homogeneity of the bed material in a 10.2 cm diameter fluidized bed. Two air injection ports diametrically opposed to each other are also considered to determine their effects on fluidization hydrodynamics. Whenever possible, the simulations are compared to experimental data of time-averaged local gas holdup obtained using X-ray computed tomography. This study will show that increasing the fluidization and side port air flows contribute to a more homogeneous bed. Furthermore, the introduction of two side ports results in a more symmetric gas-solid distribution.
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Yang, Xiaofan, and Z. Charlie Zheng. "Continuum/Nano-Scale Simulation of Surface Diffusion Process in Flow." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62960.
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Fluid transport with diffusion through micro-/nano-channels is found in many natural phenomena and industrial processes, including fluid transport or diffusion through nano-materials, molecular/atomistic transfer across nuclear pores or in the MEMS devices among other applications. Those nano-pores can be treated as nano-channels in the thin layers of the membranes. The transport phenomena of fluid in such small confined channels, usually in the size of ten molecular diameters or less, differs significantly from its bulk behaviors and cannot be described with continuum theory. In this case, molecular dynamics (MD) simulation, rather than continuum methods, is better suited to study the phenomena. The surface diffusion, related to both the fluid and solid material properties and the flow rate, can be used as a parameter for estimating the adsorbing capacity of a porous nano-material. The transport of fluids through porous materials occurs mainly by diffusion. In this study, a molecular-continuum hybrid scheme is used for the study of the diffusion in a representative Couette flow problem. By varying the velocity of the moving-solid wall, we investigated the effect of the shearing condition on the mass flux going through the pores. The relationship of the physical mechanisms and the transport phenomena (e.g. Fick’s law) were then linked among the different length scales. Activated carbon with its high surface area has been emerging as a promising candidate for an adsorbent due to not only its stable thermodynamic and mechanical properties but also its homogenous and isotropic porous distribution and relatively even pore size. In this study, we focus on the characteristics of the permeation and the adsorption process between different gases and the carbon substrate under various shearing conditions. The investigation of the diffusion process of fluids through the pores of the nano-materials has become an interesting topic in recent decades. This investigation has been divided into two major areas: 1) the diffusivity estimation and 2) the transient diffusion rate. We apply a continuum/MD hybrid scheme to a model problem of various gases transport through a carbon substrate with several pores in a channel flow under different shear rates. Instead of inserting and deleting particles from the control volumes used in the DCV-GCMD method, we keep the number of particles in the simulation system constant. The interactions between fluid/fluid, fluid/solid and solid/solid are all assumed to be under Lennard-Jones potentials. In the modeled Couette flow, the two solid walls are constructed with nano-pores that allow fluids to go through the substrate to study the transient diffusion rate (flux). Before simulating the fluid transport through the nano-pores, we need to validate the natural diffusion properties of the bulk fluid. To do this, a system (as a cube) consisting of pure liquid argon molecules is used to perform the pure MD simulation. The radial distribution function (RDF) is used as the parameter to verify the natural diffusion of the liquid argon fluid in the bulk flow, which is a structural correlation. It describes the spherically averaged local organization around any given molecule. Figure 1 shows a good comparison of the radial distribution functions between the MD prediction and the experimental measurement of Eisenstein and Gingrich (1942). By comparing our calculation to Wu et al. (2008) under similar circumstances, we found that the average (from 8 pores) and corrected mass flux J · (RTh) is linearly proportional to the average pressure gradient along the pore. And the slope of this relationship is the transport diffusivity, which is 4.6 × 10−7m2/s under 273K and 4.9 × 10−7m2/s under 300K. This indicates that the current simulation follows the Fick’s law exactly. Similarly, for other gases, the same linear relationships can also be obtained. These calculations are listed in Table 1 that shows the transport diffusivity increases with temperature. The mass fluxes of three gases at various pore widths are calculated as shown in Fig. 2. Generally, with larger pores, the mass fluxes increase. However, among three gases, the increase of H2 is much faster than the other two gases because of hydrogen’s smaller molecular size. In another word, smaller molecules as H2 have faster diffusion rates during the adsorption process.
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Wang, Yaou, Allen R. Miller, and K. Kabiri-Bamoradian. "Non-Newtonian Behavior Computer Aided Simulation of Metal Matrix Aluminum Alloy." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-86401.
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This work is a case study of non-Newtonian behavior of metal matrix composite materials used in the metal casting process. The casting alloys considered are composed of an aluminum alloy matrix reinforced with a relative high fraction of ceramic particles. The composite material exhibits non-Newtonian behavior with viscosity dependent on shear rate, volume fraction of suspended solid particles, phase change and solid fraction of primary metal during solidification. Computer aided simulation method, computational fluid dynamics (CFD), is used in this work to analyze the effect of non-Newtonian behavior on the flow pattern of the composite material during casting mold filling process. The result of this work is expected to describe an approach suitable for die design analysis and operation parameters optimization in the metal matrix alloy casting process.
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Shafik, Mahmoud, and Anne Lechevretel. "Computer Simulation and Modelling of Passive Humidification Device Cavity for Intensive Care Patient Medical Applications." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36505.
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This paper presents the research that has been undertaken into the passive humidification device cavity airflow structures and patterns. This was aiming to improve the device airflow, Heat and Moisture Exchange (HME) materials performance, for a greater patient care. However the objectives were to assist in understanding the optimal cavity structural geometries, generating improved airflow patterns over target HME material structures and consequently leading to improved heat and moisture exchange properties. Airflow studies of the device have been undertaken using the Computational Fluid Dynamics (CFD) interface of the ANSYS. The CFD package enables analysis of fluid flow and heat transfer. This paper presents the results of the CFD simulations carried out on different passive humidification device cavity designs and materials arrangements. An optimised design leading to enhanced airflow structures and patterns, heat and moisture properties of the device is also presented in this paper.
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Fontalvo, Victor, Danny Illera, Humberto Gómez, and Marco Sanjuan. "CFD Multiphysics Modeling and Performance Evaluation of PEM Fuel Cells." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-72160.
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Computational Fluid Dynamics (CFD) models allows the three-dimensional simulation of the complex electrochemical, fluid dynamics, and thermodynamic phenomena related to the temperature and pressure distribution in the channels and the porous media than occurs inside the fuel. This work presents a CFD Multiphysics simulation of a PEM Fuel Cell under different operational conditions in their inlet streams. The simulation was done by using COMSOL Multiphysics® software, and it takes into account the mass transfer of gases in the channels, the porous media and the electrochemistry from reactions in a 5 cm2 active area. From the electrochemical perspective, the relationship between the charge transfer and the overpotentials are taken into account by kinetic expressions. In addition, the ohm’s law is applied in conjunction with the charge transfer to describe the conduction of current in the electrodes and electrolytes. Gas diffusion layers (GDL) along with the catalyst layers are modeled as porous media restricting the electrochemical reaction. As the result of different simulation scenarios representing different operational conditions, the characteristic Polarization Curve of the fuel cell, the dependence between the voltage in the cell, and the demanded current by the load are obtained. A reduction in the electrical potential was evidenced due to the reaction activation potential, the ohmic losses due to the electrical resistance of the materials and the concentration losses as a result of deficiencies in the diffusion of the reactants through the porous medium. Currents distributions and water content are analyzed in order to understand the role of temperature, load, and humidity over the fuel cell performance.
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Carter, James, Timothy Harrigan, and S. K. Punwani. "Computer Simulation and Validation of Fire Hazards in Fuel Tanks." In ASME/IEEE 2007 Joint Rail Conference and Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/jrc/ice2007-40085.
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Flammable materials such as gasoline, ethanol, and diesel fuel are commonly transported in bulk via rail. In many cases, pockets of vapor can be generated inside the tank that can present a hazard if spilled during a collision or other catastrophic accident. Vapor conditions above the Lower Explosive Limit (LEL) if exposed to an external ignition source can result in an explosion or fire. Alternately, residual vapors within a tank present an explosion hazard if not properly vented or inerted prior to maintenance activities. This paper summarizes a generalized study of hazards associated with flammable liquids using computation fluid dynamics (CFD) to predict vapor conditions within a tank or following a spill. The analysis was verified in laboratory testing using scaled tank geometries. A demonstration case was developed using diesel fuel in a locomotive fuel tank. Typical road locomotives carry 3000–5000 gal of diesel fuel during normal operation. As the locomotive consumes fuel, large volumes are available for vapor generation within the tank. In a post-collision scenario, under ambient temperatures over the flash point of the fuel, the vapor that vents to the atmosphere presents a significant fire hazard. Further, flammable mists can be generated by the sprays that develop due to fuel leaks from a moving train. Studies of accident cases over a 10 year period indicated that a fire occurred in 80% of the accidents in which fuel was spilled. A CFD analysis was applied to the geometry associated with a locomotive fuel tank. The analysis models the two phase flow using the “volume of fluid” formalism in Fluent, and using a user defined diesel fuel evaporation algorithm. The tank and environmental parameters included fuel volume, fuel temperature, and air flow within the tank, and critical values of vapor content, temperature and velocity were plotted. The analysis predicted ignition of the external vapor cloud at temperatures relevant to a spill in a summer environment in the southwest, and propagation of the flame into the fuel tank. Laboratory testing confirmed the analysis: Once ignited, a flame propagated into the tank, causing an explosion and fire. The analysis methods developed can be applied to a variety of geometries and fluids, providing a basis for full scale testing. The overall intent of the analysis is to aid in the development of fire mitigation approaches for fuel and flammable material transport that would be practical for railroad use.