Journal articles on the topic 'CFD process model'
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Ta, C. T., J. Beckley, and A. Eades. "A multiphase CFD model of DAF process." Water Science and Technology 43, no. 8 (April 1, 2001): 153–57. http://dx.doi.org/10.2166/wst.2001.0488.
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A Eulerian-Eulerian multiphase CFD model is employed for the air/water flow. A 3D structure grid is used to incorporate the air nozzle and tank geometry. The fixed frictionless wall boundary approximating the free surface acts as a sink to allow the air bubbles to escape. The air/water volume fraction in the flotation tank is evaluated to determine the effective air/water fluid density. The floc particle is then introduced and is tracked in the air/water fluid using a disperse Lagrangean model. Fate of these flocs depends on their sizes and density. Flocs therefore can either escape through the top water surface, settles in the main tank or breakthrough under the outlet weir. The CFD model is developed for a full scale DAF tank to predict the flow dynamic, particle removal and settled solid profile. The general flow pattern is compared with flow visualisation using the underwater camera. Comparison of average fluid velocities is carried out using acoustic Doppler velocimetry ADV measurement.
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Słupik, Łukasz, Adam Fic, Zbigniew Buliński, Andrzej J. Nowak, Ludwik Kosyrczyk, and Grzegorz Łabojko. "CFD model of the coal carbonization process." Fuel 150 (June 2015): 415–24. http://dx.doi.org/10.1016/j.fuel.2015.02.044.
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Agonafer, D., and A. Vimba. "Solid Model Based Preprocessor to CFD Code for Applications to Electronic Cooling Systems." Journal of Electronic Packaging 119, no. 2 (June 1, 1997): 138–43. http://dx.doi.org/10.1115/1.2792220.
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The use of a solid model based Computer Aided Design (CAD) tool as a preprocessor to a finite control-volume based Computational Fluid Dynamics (CFD) code is presented. Preprocessing includes geometry description, grid generation, definition of material properties, application of boundary conditions, and definition of solution control parameters. The CAD based preprocessor, as opposed to traditional finite control-volume preprocessors, provides the above capabilities in a powerful graphic environment. Using a solid model based CAD tool, work is reduced, and visualization is enhanced employing the capabilities of the three-dimensional solid modeler. In addition, a technique which categorizes control volumes into groups comprising the solid and fluid portions of the problem domain is presented. At the completion of preprocessing, a model appropriate as input to a CFD code is generated. This model is then solved using the CFD program. The process is shown in a tutorial form by considering a two-dimensional turbulent flow problem in an electronic card on board package. Although the methodology shown in this paper focuses on specific CFD and Solid Model programs, the concept can readily be applied to other CFD and/or Solid Model programs.
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Boroń, Sylwia, and Tomasz Wdowiak. "Numerical representation of extinguishing gas discharge process." MATEC Web of Conferences 247 (2018): 00043. http://dx.doi.org/10.1051/matecconf/201824700043.
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The aim of the work was to provide the analysis of the use of computational fluid dynamics (CFD) for modeling the stage of extinguishing gas discharge to a compartment, which is not taking into account in standard models. The CFD techniques may let to predict gas parameters in dependence of various conditions in a protected area. The investigations were carried out with software ANSYS Fluent 18.2, using Realizable k-ε model and SIMPLE algorithm. The numerical model was validated using experimental data. The subject of the study were standard and newly proposed inert gases. The results showed that adequate selection of input parameter let to simulate the gas discharge stage with high accuracy. The numerical results have a good agreement with the experimental results. The conclusions provide recommendations for the gas discharge prediction based on CFD technique.
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Nastac, L., F. R. Dax, and W. Hanusiak. "Methodology for modeling the EB-PVD coating process." Journal de Physique IV 120 (December 2004): 307–14. http://dx.doi.org/10.1051/jp4:2004120035.
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This paper presents a methodology for modeling and analyzing the Electron Beam-Physical Vapor Deposition (EB-PVD) coating process. The Knudsen (Kn) number for the current processing conditions is near but smaller than 0.1 so the continuum approach (based on Navier-Stokes equations) is still valid though the dilute gas regime is considered. The methodology developed in this work is applied to optimization of the evaporation and deposition rates and patterns of metal vapors on ceramic substrates. The methodology is based on the numerical solution of evaporation, fluid flow, species transfer, heat transfer, and a deposition/condensation kinetics model. The models developed for the analysis of the coating process include an ingot EB-melting/evaporation model, a computational fluid dynamics (CFD)-vapor distribution/plume dynamics model (chamber model), and a coating-kinetics model. Numerical simulations at the macro-level were conducted using CFD software. The results from the ingot EB-melting/evaporation model are used as input data in the CFD-vapor distribution model. The coating-kinetics model uses as input, data pressure, temperature, and concentration of Ti-6Al-4V (Ti-6-4) vapors computed with the CFD model. To account for the rarefied gas regime (where Knudsen number [Kn] could be larger than 0.1), appropriate low-pressure “boundary slip conditions” with momentum and thermal accommodation coefficients as a function of Kn were used. Numerical results for temperature and Ti-6-4 vapor concentration profiles in the chamber are presented. Experiments conducted at FMW Composite Systems Inc. are also presented.
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Wachowicz, Jan, Jacek Marian Łączny, Sebastian Iwaszenko, Tomasz Janoszek, and Magdalena Cempa-Balewicz. "Modelling of Underground Coal Gasification Process Using CFD Methods / Modelowanie Procesu Podziemnego Zgazowania Węgla Kamiennego Z Zastosowaniem Metod CFD." Archives of Mining Sciences 60, no. 3 (September 1, 2015): 663–76. http://dx.doi.org/10.1515/amsc-2015-0043.
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Abstract The results of model studies involving numerical simulation of underground coal gasification process are presented. For the purpose of the study, the software of computational fluid dynamics (CFD) was selected for simulation of underground coal gasification. Based on the review of the literature, it was decided that ANSYS-Fluent will be used as software for the performance of model studies. The ANSYS- -Fluent software was used for numerical calculations in order to identify the distribution of changes in the concentration of syngas components as a function of duration of coal gasification process. The nature of the calculations was predictive. A geometric model has been developed based on construction data of the georeactor used during the researches in Experimental Mine “Barbara” and Coal Mine “Wieczorek” and it was prepared by generating a numerical grid. Data concerning the georeactor power supply method and the parameters maintained during the process used to define the numerical model. Some part of data was supplemented based on the literature sources. The main assumption was to base the simulation of the georeactor operation on a mathematical models describing reactive fluid flow. Components of the process gas and the gasification agent move along the gasification channel and simulate physicochemical phenomena associated with the transfer of mass and energy as well as chemical reactions (together with the energy effect). Chemical reactions of the gasification process are based on a kinetic equation which determines the course of a particular type of equation of chemical coal gasification. The interaction of gas with the surrounding coal layer has also been described as a part of the model. The description concerned the transport of thermal energy. The coal seam and the mass rock are treated as a homogeneous body. Modelling studies assumed the coal gasification process is carried out with the participation of separately oxygen and air as a gasification agent, under the specific conditions of the georeactor operations within the time interval of 100 hours and 305 hours. The results of the numerical solution have been compared with the results of experimental results under in-situ conditions.
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Wang, Gang, Shou Mei Xiong, and Yi Ming Rong. "CFD-Based Multicomponent Model for Solidification of Casting Process." Advanced Materials Research 189-193 (February 2011): 1656–59. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.1656.
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The solidification model is vital to the simulation of casting process with mushy zoned involved. The author has built a multicomponent model for solidification which is derived from the principles of fluid dynamics. The model has been realized on the commercial CFD package, in which the solid and liquid of metal are united in one frame. In this model the flow behavior of solid is constrained by increasing the viscosity, the latent heat and the buoyancy are also considered, and the key point is the effect of solid fraction on the flow in the mushy zone. The details of flow can be captured even in the mushy zone by using this model.
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Xu, Qing, Yu-Xing Li, Xiao-Ning Li, Jia-Bin Wang, Fan Yang, Yi Yang, and Tian-Ling Ren. "Simulation of SiO2 etching in an inductively coupled CF4 plasma." Modern Physics Letters B 31, no. 06 (February 28, 2017): 1750042. http://dx.doi.org/10.1142/s0217984917500427.
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Plasma etching technology is an indispensable processing method in the manufacturing process of semiconductor devices. Because of the high fluorine/carbon ratio of CF4, the CF4 gas is often used for etching SiO2. A commercial software ESI-CFD is used to simulate the process of plasma etching with an inductively coupled plasma model. For the simulation part, CFD-ACE is used to simulate the chamber, and CFD-TOPO is used to simulate the surface of the sample. The effects of chamber pressure, bias voltage and ICP power on the reactant particles were investigated, and the etching profiles of SiO2 were obtained. Simulation can be used to predict the effects of reaction conditions on the density, energy and angular distributions of reactant particles, which can play a good role in guiding the etching process.
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CHO, SU K., and VAMSHI M. KORIVI. "PORT DESIGN OPTIMIZATION USING CFD ANALYSIS." Journal of Advanced Manufacturing Systems 03, no. 01 (June 2004): 21–32. http://dx.doi.org/10.1142/s0219686704000375.
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Shape of ports that are part of an engine cylinder head is vital to engine performance and emissions. The advance of CFD (Computation Fluid Dynamics) analysis technology helps designers run the simulation to improve the port design and to provide the better model for a flow bench test. This paper presents the automation of design optimization process integrating CAD modeling, mesh generation and CFD simulation.
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Janoszek, Tomasz, Krzysztof Stańczyk, and Adam Smoliński. "Modelling Test of Autothermal Gasification Process Using CFD." Archives of Mining Sciences 62, no. 2 (June 27, 2017): 253–68. http://dx.doi.org/10.1515/amsc-2017-0019.
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AbstractThere are many complex physical and chemical processes, which take place among the most notable are the chemical reactions, mass and energy transport, and phase transitions. The process itself takes place in a block of coal, which properties are variable and not always easy to determine in the whole volume. The complexity of the phenomena results in the need for a construction of a complex model in order to study the process on the basis of simulation. In the present study attempts to develop a numerical model of the fixed bed coal gasification process in homogeneous solid block with a given geometry were mode. On the basis of analysis and description of the underground coal gasification simulated in the ex-situ experiment, a numerical model of the coal gasification process was developed. The model was implemented with the use of computational fluid dynamic CFD methods. Simulations were conducted using commercial numerical CFD code and the results were verified with the experimental data.
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Schmid, Michal. "Windshield Defrost Simplified CFD Model." Production Engineering Archives 25, no. 25 (December 1, 2019): 8–11. http://dx.doi.org/10.30657/pea.2019.25.02.
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Abstract The windshield defrost system, in general, is a vehicle safety feature. Thus, its restricted by variety of directives. However, the OMEs’ benchmark targets could be even more demanding as the deicing process is in addition also part of passengers comfort. From vehicle design point of view the wind-shield defrost system is typically connected to HVAC unit (Heating, Ventilation and Air Conditioning). In the technical solution the windshield is heated via hot air convection. Nevertheless, other methods are becoming more and more popular, like directly heated glass by hot wire ohmic heating (heated glasses). The defrost CFD model should predict the ice layer thickness in time and space and in environmental conditions defined according to appropriate directives and technical solution. The accurate and fast modelling technique is essential part of a vehicle development, especially nowadays, where the optimization techniques area widely used and requires hundreds of simulations runs. Modelling requests are even increasing with modern pure electric vehicles (EVs), were the thermal and energy management is more demanding compared to the classical internal combustion engine (ICE) vehicles. The aim of the work is to verify possibility to model the ice layer thickness with simplified approach, which could be beneficial from computational time burden.
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Lee, Minhyung, Gwanyong Park, Hyangin Jang, and Changmin Kim. "Development of Building CFD Model Design Process Based on BIM." Applied Sciences 11, no. 3 (January 29, 2021): 1252. http://dx.doi.org/10.3390/app11031252.
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This paper proposes the design process of optimized building Computational Fluid Dynamics (CFD) model based on Building Information Modelling (BIM). The proposed method consists of five-step processes: BIM data extraction, geometry simplification, grid optimization, attribute data matching, and finally, exporting a CFD case folder for OpenFOAM. Validation is performed to evaluate the improvement of the grid model and the accuracy of the simulation result. Validation is conducted for four indoor ventilation models. The number of grids increased or decreased, according to the optimization method, but did not change significantly. On the other hand, the maximum non-orthogonality improved by up to 20.78%, according to the optimization function. This proves that it is sufficiently effective in improving the grid quality. The accuracy of the proposed method is evaluated by relative error rate with the ANSYS simulation result. The error rates for flow and temperature are evaluated. The relative error rate is less than 5% under all conditions. Therefore, the accuracy of the proposed method is verified.
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McBride, D., M. Cross, and J. E. Gebhardt. "Heap leach modeling employing CFD technology: A ‘process’ heap model." Minerals Engineering 33 (June 2012): 72–79. http://dx.doi.org/10.1016/j.mineng.2011.10.003.
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Sheng, Dong-Yuan. "Synthesis of a CFD Benchmark Exercise: Examining Fluid Flow and Residence-Time Distribution in a Water Model of Tundish." Materials 14, no. 18 (September 21, 2021): 5453. http://dx.doi.org/10.3390/ma14185453.
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Computational Fluid Dynamics (CFD) has become an indispensable tool that can potentially predict many phenomena of practical interest in the tundish. Model verification and validation (V&V) are essential parts of a CFD model development process if the models are to be used with sufficient confidence in real industrial tundish applications. The crucial aspects of CFD simulations in the tundish are addressed in this study, such as the selection of the turbulence models, meshing, boundary conditions, and selection of discretization schemes. A series of CFD benchmarking exercises are presented serving as selected examples of appropriate modelling strategies. A tundish database, initiated by German Steel Institute VDEH working group “Fluid Mechanics and Fluid Simulation”, was revisited with the aim of establishing a comprehensive set of best practice guidelines (BPG) in CFD simulations for tundish applications. These CFD benchmark exercises yield important results for the sensible application of CFD models and contribute to further improving the reliability of CFD applications in metallurgical reactors.
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Lai, Y. H., Y. Gao, Y. Zhang, and J. X. Wang. "A Study of CFD Models for Investigating the Water Beam Assisted Form Error In-Process Optical Measurement." Key Engineering Materials 437 (May 2010): 472–76. http://dx.doi.org/10.4028/www.scientific.net/kem.437.472.
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The opaque coolant used in the removal machining processes has an inaccessibility problem for the form error in-process optical measurement. The water beam assisted approach should be one of the possible solutions for the problem. In this project, we propose to study the measurement process using the computational approach for better understanding of the process and for validating the models and settings. The experimental results and the Computational Fluid Dynamics (CFD) results are found close to each other. This gives us confidence in using the proposed CFD models and settings. The proposed new transparent window definition is suitable. The models and settings established include geometric model, mesh adaption model, domain settings, coolant concentration representation, expressions, boundary conditions, and CFX solver settings. The developed CFD models and settings will be useful in our further studies of the form error measurement method.
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Zhu, Guoming (George), and Xiang Chen. "Model-Based Engine Control." Mechanical Engineering 137, no. 12 (December 1, 2015): S2—S6. http://dx.doi.org/10.1115/1.2015-dec-6.
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Abstract This article focuses on control-oriented engine modeling and model-based engine control techniques. The engine modeling research is centered on the engine combustion process. Multi-zone, three dimensional computational fluid dynamics (CFD) models, with detailed chemical kinetics are able to precisely describe the thermodynamics, fluid and flow dynamics, heat transfer, and pollutant formation of the combustion process. The simplified one-dimensional combustion models have also been implemented into commercial codes such as GT-Power and Wave. However, these high fidelity models cannot be used for model-based control since they are too complicated to be used for real-time computing. Crank-resolved engine air handling system modeling is also important for describing the in-cylinder charge-mixing process. Therefore, for model-based control and real-time hardware-in-the-loop simulations, it is necessary to have a crank-resolved engine model with its complexity intermediate between the time-based mean-value and one-dimensional CFD models.
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Lin, Chen-Jiann, Tseng-Hsiang Tse, Liu-Cheng Che, and Liang-Ming Tsai. "Computer aided design and analysis on distributors in DAC columns." MATEC Web of Conferences 185 (2018): 00024. http://dx.doi.org/10.1051/matecconf/201818500024.
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Dynamic axial compression (DAC) columns are key elements in simulated moving bed, which is a chromatography process in drug industry and chemical engineering. In this study, rules for designing distributors are proposed based on mass conservation and validated by experiments, the computer aided design (CAD) and the computational fluid dynamics (CFD). Experimental works are conducted to choose feasible numerical parameters for simulations. In CFD, the transient laminar flow fields are governed by the momentum and species transport equations with Darcy's law to model the porous zone in the packed bed. Results show that CFD combined with CAD solid modelling is a good approach to explore detailed flow fields in DAC columns and carry out parameter analysis for innovative designs. For further testing and evaluation, a new model of compound distributor is designed, 3D printed and processed in factory for practical applications in preparative chromatography.
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Lebedev, Artem, Daria Lovskaya, and Natalia Menshutina. "Experimental Investigation and CFD Modeling of Supercritical Adsorption Process." Polymers 12, no. 9 (August 29, 2020): 1957. http://dx.doi.org/10.3390/polym12091957.
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The kinetics of the supercritical adsorption process was experimentally studied by the example of ”ibuprofen-silica aerogel” composition obtainment at various parameters: Pressure 120–200 bar and temperature 40–60 °C. Computational Fluid Dynamics (CFD) model of the supercritical adsorption process in a high-pressure apparatus based on the provisions of continuum mechanics is proposed. Using supercritical adsorption process kinetics experimental data, the dependences of the effective diffusion coefficient of active substance in the aerogel, and the maximum amount of the adsorbed active substance into the aerogel on temperature and pressure are revealed. Adequacy of the proposed model is confirmed. The proposed mathematical model allows predicting the behavior of system (fields of velocity, temperature, pressure, composition, density, etc.) at each point of the studied medium. It makes possible to predict mass transport rate of the active substance inside the porous body depending on the geometry of the apparatus, structure of flow, temperature, and pressure.
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Li, Ya Dong, Gang Xie, Lin Tian, Zhan Liang Yu, Yan Cui, and Yan Qing Hou. "Model on Titanium Tetrachloride Gas Phase Oxidation Process." Materials Science Forum 833 (November 2015): 56–60. http://dx.doi.org/10.4028/www.scientific.net/msf.833.56.
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Titanium tetrachloride (TiCl4) oxidation is the most important stage in the titanium dioxide production. High temperature, fast reaction and strong oxidation and strong corrosive atmosphere have increased a lot of difficulty to measuring and testing in oxidation reactor. Computational fluid dynamics (CFD) simulation is one of the most valid methods to investigate TiCl4 gas phase oxidation. In this paper, the achievements and progress about fluid dynamics simulations of titanium tetrachloride gas phase oxidation are described. The further research directions and new perspectives in this field are presented.
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HIRAI, Takuma, Shin-ichi TSUDA, and Naoki TANI. "J051055 A Validation of Multi-process Cavitation Model." Proceedings of Mechanical Engineering Congress, Japan 2012 (2012): _J051055–1—_J051055–5. http://dx.doi.org/10.1299/jsmemecj.2012._j051055-1.
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Freeman, David J., and Sally Wilkinson. "A New Wave in CFD." Mechanical Engineering 120, no. 06 (June 1, 1998): 64–67. http://dx.doi.org/10.1115/1.1998-jun-2.
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The convergence of virtual reality, parallel processing, and Internet access is enabling computational-fluid-dynamics (CFD) codes to model complex problems in the process and petroleum industries. Improved user interfaces are making it easier for non-specialists to use CFD to investigate the conditions under which flammable or poisonous gases, to investigate the conditions under which flammable or poisonous gases, for example, might build up around an oil platform. CFD rests on the sure foundation of the scientific laws that deal with mass, momentum, and energy. Engineers used CFD in the design of a coal-fired furnace whose burners produce a swirling flow, enhancing the efficiency of the combustion process. CFD codes simulate the processes in four key stages: ignition, laminar-flame propagation, turbulence generation, and turbulence-controlled combustion. The ignition process is usually represented by the sudden temperature increase of a small body of gas, such as in a single computational cell. Most CFD codes seeking to simulate explosions use variants of one of these models.
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Aguirre-Mendoza, Andres M., Sebastián Oyuela, Héctor G. Espinoza-Román, Oscar E. Coronado-Hernández, Vicente S. Fuertes-Miquel, and Duban A. Paternina-Verona. "2D CFD Modeling of Rapid Water Filling with Air Valves Using OpenFOAM." Water 13, no. 21 (November 4, 2021): 3104. http://dx.doi.org/10.3390/w13213104.
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The rapid filling process in pressurized pipelines has been extensively studied using mathematical models. On the other hand, the application of computational fluid dynamics models has emerged during the last decade, which considers the development of CFD models that simulate the filling of pipes with entrapped air, and without air expulsion. Currently, studies of CFD models representing rapid filling in pipes with entrapped air and with air expulsion are scarce in the literature. In this paper, a two-dimensional model is developed using OpenFOAM software to evaluate the hydraulic performance of the rapid filling process in a hydraulic installation with an air valve, considering different air pocket sizes and pressure impulsion by means of a hydro-pneumatic tank. The two-dimensional CFD model captures the pressure evolution in the air pocket very well with respect to experimental and mathematical model results, and produces improved results with respect to existing mathematical models.
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Vu, Anh Ngoc, and Tung Nguyen Minh Huynh. "An automated analysis process for vertical axis wind turbine." Science and Technology Development Journal 18, no. 4 (December 30, 2015): 145–52. http://dx.doi.org/10.32508/stdj.v18i4.1000.
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This paper presents an automated process for analyzing the performance of vertical axis wind turbine (VAWT). The details of this process will be demonstrated, which include the airfoil geometry representation using CST method, a hybrid meshing process combining structured grids and unstructured grids, CFD calculation process and processing data results to calculate the power coefficient of VAWT. These processes are designed as separate modules. CFD methods used in this research is RANS 2D using Realizable k turbulence model. Meshing process will be done on the GAMBIT software, the CFD calculations are done on commercial ANSYS FLUENT software and these processes are controlled by mathematical software MATLAB. The formulas used to calculate the power coefficient will be also introduced in this paper.
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Lvov, Vladislav, and Leonid Chitalov. "Semi-Autogenous Wet Grinding Modeling with CFD-DEM." Minerals 11, no. 5 (May 1, 2021): 485. http://dx.doi.org/10.3390/min11050485.
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The paper highlights the features of constructing a model of a wet semi-autogenous grinding mill based on the discrete element method and computational fluid dynamics. The model was built using Rocky DEM (v. 4.4.2, ESSS, Brazil) and Ansys Fluent (v. 2020 R2, Ansys, Inc., United States) software. A list of assumptions and boundary conditions necessary for modeling the process of wet semi-autogenous grinding by the finite element method is presented. The created model makes it possible to determine the energy-coarseness ratios of the semi-autogenous grinding (SAG) process under given conditions. To create the model in Rocky DEM the following models were used: The Linear Spring Rolling Limit rolling model, the Hysteretic Linear Spring model of the normal interaction forces and the Linear Spring Coulomb Limit for tangential forces. When constructing multiphase in Ansys Fluent, the Euler model was used with the primary phase in the form of a pulp with a given viscosity and density, and secondary phases in the form of air, crushing bodies and ore particles. The resistance of the solid phase to air and water was described by the Schiller–Naumann model, and viscosity by the realizable k-epsilon model with a dispersed multiphase turbulence model. The results of the work methods for material interaction coefficients determination were developed. A method for calculating the efficiency of the semi-autogenous grinding process based on the results of numerical simulation by the discrete element method is proposed.
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Rahman, Ahmad, Kano, and Mustafa. "Model Development and Exergy Analysis of a Microreactor for the Steam Methane Reforming Process in a CFD Environment." Entropy 21, no. 4 (April 15, 2019): 399. http://dx.doi.org/10.3390/e21040399.
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Steam methane reforming (SMR) is a dominant technology for hydrogen production. For the highly energy-efficient operation, robust energy analysis is crucial. In particular, exergy analysis has received the attention of researchers due to its advantage over the conventional energy analysis. In this work, an exergy analysis based on the computational fluid dynamics (CFD)-based method was applied to a monolith microreactor of SMR. Initially, a CFD model of SMR was developed using literature data. Then, the design and operating conditions of the microreactor were optimized based on the developed CFD model to achieve higher conversion efficiency and shorter length. Exergy analysis of the optimized microreactor was performed using the custom field function (CFF) integrated with the CFD environment. The optimized catalytic monolith microreactor of SMR achieved higher conversion efficiency at a smaller consumption of energy, catalyst, and material of construction than the reactor reported in the literature. The exergy analysis algorithm helped in evaluating length-wise profiles of all three types of exergy, namely, physical exergy, chemical exergy, and mixing exergy, in the microreactor.
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Ambrutis, Andrius, and Mantas Povilaitis. "Development of a CFD-Suitable Deep Neural Network Model for Laminar Burning Velocity." Applied Sciences 12, no. 15 (July 25, 2022): 7460. http://dx.doi.org/10.3390/app12157460.
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Hydrogen is a valued resource for today’s industry. As a fuel, it produces large amounts of energy and creates water during the process, unlike most other polluting energy sources. However, the safe use of hydrogen requires reliable tools able to accurately predict combustion. This study presents the implementation of a deep neural network of laminar burning velocity of hydrogen into an open-source CFD solver flameFoam. DNN was developed based on a previously created larger DNN, which was too large for CFD applications since the calculations took around 40 times longer compared to the Malet correlation. Therefore, based on the original model, a faster, but still accurate, DNN was developed and implemented into flameFoam starting with version 0.10. The paper presents the adaptation of the original DNN into a CFD-applicable version and the initial test results of the CFD–DNN simulation.
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Deng, Ming Hua, Zhu Gao, and Da Wei Mao. "3D Numerical Simulation of the Process of Draining into a Lock." Advanced Materials Research 838-841 (November 2013): 1667–70. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.1667.
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In some textbooks, the Steady-flow Integral Method (SIM) was used to compute the full time of Draining into a Ship Lock, although this method is simple, it only provides a coarse estimation and somehow misleads the students due to approximating the unsteady problem as a steady one and ignoring the inertia effect. The more complex CFD-based model, FLUENT, was used to compensate these shortcomings, the Volume of Fluid (VOF) method was utilized to calculate the free-surface, and the turbulence closure was obtained by the realizable k-ε turbulence model. The values of draining time derived from the two different methods have the same order of magnitude. By CFD, a more precise estimation of the draining time and abundant details about the draining process were obtained. In practical engineering, the geometry of a lock is far more complex than here, the SIM is hard to satisfy the demands for a optimal design, while the CFD method is a nice choice for this purpose.
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Tutak, Magdalena, Jarosław Brodny, Antoni John, Janos Száva, Sorin Vlase, and Maria Luminita Scutaru. "CFD Model Studies of Dust Dispersion in Driven Dog Headings." Mathematics 10, no. 20 (October 14, 2022): 3798. http://dx.doi.org/10.3390/math10203798.
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Dust is one of the most burdensome hazards found in the environment. It is composed of crushed solids that pose a threat to the health and life of people, machines and machine components. At high concentration levels, it can reduce visibility. All of these negative phenomena occur during the process of underground mining, where dust hazards are common. The negative impact of dust on the efficacy of the mining process prompts research in this area. The following study presents a method developed for model studies of dust dispersion in driven dog headings. This issue is immensely important due to the fact that these dog headings belong to a group of unidirectional excavations (including tunnelling). This paper presents the results of model studies on dust dispersion in driven dog headings. The main focus is on the analysis of the distribution of dust concentration along a dog heading during the mining process. In order to achieve this goal, a model test method based on the finite volume method, which is included in the group of CFD methods, was developed. Analyses were carried out for two different values of dust emission from the face of the excavation for the transient state. The results made it possible to determine areas with the highest potential for dust concentration. The size and location of these areas are mainly dependent on the amount of dust emissions during the mining process. The results can support the process of managing dust prevention and protection of workers during the mining excavation process.
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Patirnac, I., R. G. Ripeanu, and I. N. Ramadan. "Theoretical and experimental studies on the cut zone generated by AWJ process." FME Transactions 49, no. 4 (2021): 997–1004. http://dx.doi.org/10.5937/fme2104997p.
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The aim of this paper is to make a theoretical and experimental study to evaluate the water jet influence on a metallic material used in oilfield manufacturing, using AWJ process. It was investigated how the scattering of the jet has influenced the width of the kerf and neighboring area. The metallic material is P275NL2 which is a low temperature quality steel alloy specially used in petrochemical industry. The experimental tests were made on the waterjet cutting machine model YCWJ-380-1520 using preestablish working conditions. Theoretical investigations were performed using CFD simulation with planar 2D fluid flow on the geometrical model. Graphical correlation was performed between theoretical outcomes given by CFD simulation and experimental results on the regarded material, overlapping on the theoretical searching for the cutting velocity and the hardening velocity limits nearby the kerf.
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Tobo, Yohannis Mitiku, Jan Bartacek, and Ingmar Nopens. "Linking CFD and Kinetic Models in Anaerobic Digestion Using a Compartmental Model Approach." Processes 8, no. 6 (June 17, 2020): 703. http://dx.doi.org/10.3390/pr8060703.
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Understanding mixing behavior and its impact on conversion processes is essential for the operational stability and conversion efficiency of anaerobic digestion (AD). Mathematical modelling is a powerful tool to achieve this. Direct linkage of Computational Fluid Dynamics (CFD) and the kinetic model is, however, computationally expensive, given the stiffness of the kinetic model. Therefore, this paper proposes a compartmental model (CM) approach, which is derived from a converged CFD solution to understand the performance of AD under non-ideal mixing conditions and with spatial variation of substrates, biomass, pH, and specific biogas and methane production. To quantify the effect of non-uniformity on the reactor performance, the CM implements the Anaerobic Digestion Model 1 (ADM1) in each compartment. It is demonstrated that the performance and spatial variation of the biochemical process in a CM are significantly different from a continuously stirred tank reactor (CSTR) assumption. Hence, the assumption of complete mixed conditions needs attention concerning the AD performance prediction and biochemical process non-uniformities.
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Janoszek, Tomasz, and Wojciech Masny. "CFD Simulations of Allothermal Steam Gasification Process for Hydrogen Production." Energies 14, no. 6 (March 10, 2021): 1532. http://dx.doi.org/10.3390/en14061532.
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The article presents an experimental laboratory setup used for the empirical determination of the gasification of coal samples in the form of solid rock, cut out in the form of a cylinder. An experimental laboratory set enabled a series of experiments carried out at 700 °C with steam as the gasification agent. The samples were prepared from the coal seam, the use of which can be planned in future underground and ground gasification experiments. The result of the conducted coal gasification process, using steam as the gasification agent, was the syngas, including hydrogen (H2) with a concentration between 46% and 58%, carbon dioxide (CO2) with a concentration between 13% and 17%, carbon monoxide (CO) with a concentration between 7% and 11.5%, and methane(CH4) with a concentration between 9.6% and 20.1%.The results from the ex-situ experiments were compared with the results of numerical simulations using computational fluid dynamics (CFD) methods. A three-dimensional numerical model for the coal gasification process was developed using Ansys-Fluent software to simulate an ex-situ allothermal coal gasification experiment using low-moisture content hard coal under atmospheric conditions. In the numerical model, the mass exchange (flow of the gasification agent), the turbulence description model, heat exchange, the method of simulating the chemical reactions, and the method of mapping the porosity medium were included. Using the construction data of an experimental laboratory set, a numerical model was developed and its discretization (development of a numerical grid, based on which calculations are made) was carried out. Tip on the reactor, supply method, and parameters maintained during the gasification process were used to define the numerical model in the Ansys-Fluent code. A part of the data were supplemented on the basis of literature sources. Where necessary, the literature parameters were converted to the conditions corresponding to the experiment, which were carried out. After performing the calculations, the obtained results were compared with the available experimental data. The experimental and the simulated results were in good agreement, showing a similar tendency.
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Farivar, Foad, Hu Zhang, Zhao F. Tian, and Anshul Gupte. "CFD-DEM -DDM Model for Spray Coating Process in a Wurster Coater." Journal of Pharmaceutical Sciences 109, no. 12 (December 2020): 3678–89. http://dx.doi.org/10.1016/j.xphs.2020.09.032.
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Zhang, Chao, and Matthew Janeway. "Optimization of Turbine Blade Aerodynamic Designs Using CFD and Neural Network Models." International Journal of Turbomachinery, Propulsion and Power 7, no. 3 (June 30, 2022): 20. http://dx.doi.org/10.3390/ijtpp7030020.
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Optimization methods have been widely applied to the aerodynamic design of gas turbine blades. While applying optimization to high-fidelity computational fluid dynamics (CFD) simulations has proven capable of improving engineering design performance, a challenge has been overcoming the prolonged run-time due to the computationally expensive CFD runs. Reduced-order models and, more recently, machine learning methods have been increasingly used in gas turbine studies to predict performance metrics and operational characteristics, model turbulence, and optimize designs. The application of machine learning methods allows for utilizing existing knowledge and datasets from different sources, such as previous experiments, CFD, low-fidelity simulations, 1D or system-level studies. The present study investigates inserting a machine learning model that utilizes such data into a high-fidelity CFD driven optimization process, and hence effectively reduces the number of required evaluations of the CFD model. Artificial Neural Network (ANN) models were trained on data from over three thousand two-dimensional (2D) CFD analyses of turbine blade cross-sections. The trained ANN models were then used as surrogates in a nested optimization process alongside a full three-dimensional Navier–Stokes CFD simulation. The much lower evaluation cost of the ANN model allows for tens of thousands of design evaluations to guide the search of the best blade profiles to be used in the more expensive, high-fidelity CFD runs, improving the progress of the optimization while reducing the required computation time. It is estimated that the current workflow achieves a five-fold reduction in computational time in comparison to an optimization process that is based on three-dimensional (3D) CFD simulations alone. The methodology is demonstrated on the NASA/General Electric Energy Efficient Engine (E3) high pressure turbine blade and found Pareto front designs with improved blade efficiency and power over the baseline. Quantitative analysis of the optimization data reveals that some design parameters in the present study are more influential than others, such as the lean angle and tip scaling factor. Examining the optimized designs also provides insight into the physics, showing that the optimized designs have a lower amount of pressure drop near the trailing edge, but have an earlier onset of pressure drop on the suction side surface when compared to the baseline design, contributing to the observed improvements in efficiency and power.
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Blejchař, Tomáš, Jaroslav Konvička, Bernd von der Heide, Rostislav Malý, and Miloš Maier. "High Temperature Modification of SNCR Technology and its Impact on NOx Removal Process." EPJ Web of Conferences 180 (2018): 02009. http://dx.doi.org/10.1051/epjconf/201818002009.
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SNCR (Selective non-catalytic reduction) Technology is currently being used to reach the emission limit for nitrogen oxides at fossil fuel fired power plant and/or heating plant and optimum temperature for SNCR process is in range 850 - 1050°C. Modified SNCR technology is able to reach reduction 60% of nitrogen oxides at temperature up to 1250°C. So the technology can also be installed where the flue gas temperature is too high in combustion chamber. Modified SNCR was tested using generally known SNCR chemistry implemented in CFD (Computation fluid dynamics) code. CFD model was focused on detail simulation of reagent injection and influence of flue gas temperature. Than CFD simulation was compared with operating data of boiler where the modified SNCR technology is installed. By comparing the experiment results with the model, the effect on nitrous oxides removal process and temperature of flue gas at the injection region.
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Wang, Yi Fei, Zhong De Shan, Hao Qin Yang, Yong Xin Ren, and Ling Han Meng. "Research on Thermal Inkjet Technology Based on CFD." Materials Science Forum 1032 (May 2021): 101–7. http://dx.doi.org/10.4028/www.scientific.net/msf.1032.101.
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In this paper, a thermal inkjet printing simulation model is established in the CFD simulation platform, and the influence of inkjet driver parameters and ink physical parameters on the printing process is studied by numerical simulation. The evaporation-condensation model is coupled with the VOF multiphase flow model in Fluent software to establish a thermal inkjet printing process simulation model. Based on the orthogonal test method, we investigate the influence of fluid physical parameters (ink viscosity, surface tension) and inkjet driver parameters (heater temperature value) on droplet formation by changing the physical parameters of the material and the boundary conditions of the model. Through the comparison of the results, exploring the adjustment rules of thermal inkjet technology and obtaining the optimal combination of material and process parameters for high-quality ink drop formation.
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KUMAR, KUNAL, VILJAMI MAAKALA, and VILLE VUORINEN. "Integrated study of flue gas flow and superheating process in a recovery boiler using computational fluid dynamics and 1D-process modeling." June 2020 19, no. 6 (July 1, 2020): 303–16. http://dx.doi.org/10.32964/tj19.6.303.
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Superheaters are the last heat exchangers on the steam side in recovery boilers. They are typically made of expensive materials due to the high steam temperature and risks associated with ash-induced corrosion. Therefore, detailed knowledge about the steam properties and material temperature distribution is essential for improving the energy efficiency, cost efficiency, and safety of recovery boilers. In this work, for the first time, a comprehensive one-dimensional (1D) process model (1D-PM) for a superheated steam cycle is developed and linked with a full-scale three-dimensional (3D) computational fluid dynamics (CFD) model of the superheater region flue gas flow. The results indicate that: (1) the geometries of headers and superheater platens affect platen-wise steam mass flow rate distribution (3%–7%); and (2) the CFD solution of the 3D flue gas flow field and platen heat flux distribution coupled with the 1D-PM affect the platen-wise steam superheating temperature (45%–122%) and material temperature distribution (1%–6%). Moreover, it is also found that the commonly-used uniform heat flux distribution approach for the superheating process is not accurate, as it does not consider the effect of flue gas flow field in the superheater region. These new observations clearly demonstrate the value of the present integrated CFD/1D-PM modeling approach.
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Mehrtash, Hadi, Dinara Konakbayeva, Solmaz Tabtabaei, Seshasai Srinivasan, and Amin Reza Rajabzadeh. "A New Perspective to Tribocharging: Could Tribocharging Lead to the Development of a Non-Destructive Approach for Process Monitoring and Quality Control of Powders?" Foods 11, no. 5 (February 26, 2022): 693. http://dx.doi.org/10.3390/foods11050693.
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This study explores a new perspective on triboelectrification that could potentially lead to the development of a non-destructive approach for the rapid characterization of powders. Sieved yellow pea powders at various particle sizes and protein contents were used as a model system for the experimental charge measurements of the triboelectrified powders. A tribocharging model based on the prominent condenser model was combined with a Eulerian–Lagrangian computational fluid dynamics (CFD) model to simulate particle tribocharging in particle-laden flows. Further, an artificial neural network model was developed to predict particle–wall collision numbers based on a database obtained through CFD simulations. The tribocharging and CFD models were coupled with the experimental tribocharging data to estimate the contact potential difference of powders, which is a function of contact surfaces’ work functions and depends on the chemical composition of powders. The experimentally measured charge-to-mass ratios were linearly related to the calculated contact potential differences for samples with different protein contents, indicating a potential approach for the chemical characterization of powders.
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Fernandes del Pozo, David, Mairtin Mc Namara, Bernardo J. Vitória Pessanha, Peter Baldwin, Jeroen Lauwaert, Joris W. Thybaut, and Ingmar Nopens. "Computational Fluid Dynamics Study of a Pharmaceutical Full-Scale Hydrogenation Reactor." Processes 10, no. 6 (June 9, 2022): 1163. http://dx.doi.org/10.3390/pr10061163.
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The pharmaceutical industry has been quite successful in developing new hydrogenation processes, and the chemistry of hydrogenation is currently well understood. However, it is a complex process to scale and optimize due to its high exothermicity, use of expensive catalysts and solvents, and its mass transfer requirements. Therefore, the aim of this work is to develop a CFD model to be able to describe the mass transfer, hydrodynamics, and mixing with respect to changes in rotational speed for a full-scale pharmaceutical hydrogenation reactor. In the first stage, a simple CFD model is used to predict the development of the surface vortex, and it is validated against literature data. In the second stage, the CFD model is tested on a full-scale configuration equipped with a Rushton turbine and a bottom kicker to study the formation of the surface vortex. Simulation results show the ability to predict the development of the surface vortex. These results are used to estimate the liquid height and mixing time as a function of several rotational speeds, allowing us to propose novel process correlations for this particular configuration. Although modelling the complete hydrogenation process would be challenging, this work is seen as a first step towards developing models that demonstrate the use of CFD at such large reactor scales.
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Nakahara, Koki, Mahbubul Muttakin, Kiyoshi Yamamoto, and Kazuhide Ito. "Computational fluid dynamics modelling of the visible light photocatalytic oxidation process of toluene for indoor building materials with locally doped titanium dioxide." Indoor and Built Environment 29, no. 2 (June 11, 2019): 163–79. http://dx.doi.org/10.1177/1420326x19854499.
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Computational fluid dynamics (CFD) is one of the promising methods that can precisely predict non-uniform air flow and contaminant distribution in indoor environments. The overarching objective of this study was to develop a mathematical model for describing the photocatalytic oxidation (PCO) reaction mechanism of gas phase toluene with titanium dioxide (TiO2)-bound indoor building materials. This mathematical model was developed based on Langmuir-Hinshelwood type kinetics and for the integration with CFD simulations as a wall surface boundary condition. The effects of gas phase toluene concentration, illuminance and humidity on the toluene oxidation reaction were considered with locally TiO2-doped building materials. Especially, humidity dependence was explicitly integrated as a competitive adsorption model between toluene and water vapour. Moreover, surface compositions of TiO2 and the substrate (ceramic tile in this study), and the physical adsorption properties of those materials, were modelled and integrated into the mathematical model. A 0.02 m3 chamber experiment and adsorption isotherm measurements were conducted to identify the model parameters. CFD analysis was carried out according to experimental scenarios, and an optimization procedure for the model parameters was proposed for their application as the boundary conditions in the CFD analysis.
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Liu, Daoyin, Zhonglin Zhang, Yaming Zhuang, and Xiaoping Chen. "Comparison of CFD Simulation and Simplified Modeling of a Fluidized Bed CO2 Capture Reactor." International Journal of Chemical Reactor Engineering 14, no. 1 (February 1, 2016): 133–41. http://dx.doi.org/10.1515/ijcre-2015-0058.
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AbstractCO2 capture using solid sorbents in fluidized bed reactors is a promising technology. The multiphase CFD model is increasingly developed to study the reactors, but it is difficult to model all the realistic details and it requires significant computational time. In this study, both the multiphase CFD model (i.e., CFD-DEM model coupled with reaction) and the simplified reactor models (i.e., plug flow model and bubbling two-phase model) are developed for modeling a fluidized bed CO2 capture reactor. The comparisons are made at different gas velocities from fixed bed to fluidized bed. The DEM based model reveals a detailed view of CO2 adsorption process with particle flow dynamics, based on which the assumptions in the simplified models can be evaluated. The plug flow model predictions generally show similar trends to the DEM model but there are quantitative differences; thus, it can be used to determine the reactor performance limit. The bubbling two-phase model gives better predictions than the plug flow model because the effect of bubbles on the inter-phase mass transfer and reaction is included. In the future, a closer combination of the multiphase CFD simulation and the simplified reactor models will likely be an efficient design method of CO2 capture fluidized bed reactors.
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Ryan, Jarod, Markus Bussmann, and Nikolai DeMartini. "CFD Modelling of Calcination in a Rotary Lime Kiln." Processes 10, no. 8 (August 1, 2022): 1516. http://dx.doi.org/10.3390/pr10081516.
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A 2D axisymmetric computational fluid dynamics (CFD) model, coupled to a 1D bed model, has been developed to capture the key processes that occur within rotary lime kilns. The model simulates the calcination reaction using a shrinking core model, and predicts the start of calcination and the degree of calcination at the end of the kiln. The model simulates heat transfer due to radiation, convection and conduction between the gas, wall, chains, and bed. The 2D gas and 1D bed models are coupled by mass and heat sinks to simulate heat transfer, evaporation, and the calcination reaction. The model is used to simulate two industrial kilns, one wet and one dry. The steady-state simulation results are compared to mill data, and good agreement is found. A sensitivity analysis is also presented, to obtain insight on how operating conditions and model variables impact the calcination location and degree of calcination.
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N., Ganesh, Paras Jain, Amitava Choudhury, Prasun Dutta, Kanak Kalita, and Paolo Barsocchi. "Random Forest Regression-Based Machine Learning Model for Accurate Estimation of Fluid Flow in Curved Pipes." Processes 9, no. 11 (November 22, 2021): 2095. http://dx.doi.org/10.3390/pr9112095.
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In industrial piping systems, turbomachinery, heat exchangers etc., pipe bends are essential components. Computational fluid dynamics (CFD), which is frequently used to analyse the flow behaviour in such systems, provides extremely precise estimates but is computationally expensive. As a result, a computationally efficient method is developed in this paper by leveraging machine learning for such computationally expensive CFD problems. Random forest regression (RFR) is used as the machine learning algorithm in this work. Four different fluid flow characteristics (i.e., axial velocity, x-velocity, y-velocity and z-velocity) are studied in this work. The accuracy of the RFR models is assessed by using a number of statistical metrics such as mean-absolute error (MAE), mean-squared-error (MSE), root-mean-squared-error (RMSE), maximum error (Max.Error) and median error (Med.Error) etc. It is observed that the RFR models can produce considerable cost reductions in computing by surrogating the CFD model. Minor loss in estimation accuracy as compared to the CFD models is observed. While the magnitude of intricate flow characteristics such as the additional vortices are correctly predicted, some error in their location is observed.
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O'Doherty, T., D. A. Egarr, M. G. Faram, I. Guymer, and N. Syred. "Assessment of residence time in a hydrodynamic vortex separator by applying distribution models." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 223, no. 3 (April 15, 2009): 179–88. http://dx.doi.org/10.1243/09544089jpme224.
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A number of models exist to simulate the residence time distribution (RTD) of a system or process. Four of these models known as the tanks in series model, axial dispersion model (ADM), aggregated dead zone model, and the advection dispersion equation, have been used to assess which is most suitable for representing the RTD of a hydrodynamic vortex separator (HDVS) when compared to RTD measurements taken under laboratory conditions on a full-scale 3.4 m diameter unit. Computational fluid dynamics (CFD) is also used to model the HDVS and compare with the RTD models and experimental measurements. It has been shown that the fit by each of the RTD models to observed RTDs vary quite considerably, with the ADM being the most appropriate for the HDVS studied, based on having the highest R t2 value. Given the number of model variables that influence CFD predictions, the outputs from the CFD models appear to be reasonable.
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Ghasemzadeh, Kamran, Milad Mohammad Alinejad, Milad Ghahremani, Rahman Zeynali, and Amin Pourgholi. "Theoretical Study of Palladium Membrane Reactor Performance During Propane Dehydrogenation Using CFD Method." Indonesian Journal of Chemistry 17, no. 1 (April 1, 2017): 113. http://dx.doi.org/10.22146/ijc.23625.
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This study presents a 2D-axisymmetric computational fluid dynamic (CFD) model to investigate the performance Pd membrane reactor (MR) during propane dehydrogenation process for hydrogen production. The proposed CFD model provided the local information of temperature and component concentration for the driving force analysis. After investigation of mesh independency of CFD model, the validation of CFD model results was carried out by other modeling data and a good agreement between CFD model results and theoretical data was achieved. Indeed, in the present model, a tubular reactor with length of 150 mm was considered, in which the Pt-Sn-K/Al2O3 as catalyst were filled in reaction zone. Hence, the effects of the important operating parameter (reaction temperature) on the performances of membrane reactor (MR) were studied in terms of propane conversion and hydrogen yield. The CFD results showed that the suggested MR system during propane dehydrogenation reaction presents higher performance with respect to once obtained in the conventional reactor (CR). In particular, by applying Pd membrane, was found that propane conversion can be increased from 41% to 49%. Moreover, the highest value of propane conversion (X = 91%) was reached in case of Pd-Ag MR. It was also established that the feed flow rate of the MR is to be the one of the most important factors defining efficiency of the propane dehydrogenation process.
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Smith, S. R., T. Taha, and Z. F. Cui. "Using an improved 1D boundary layer model with CFD for flux prediction in gas-sparged tubular membrane ultrafiltration." Water Science and Technology 51, no. 6-7 (March 1, 2005): 69–76. http://dx.doi.org/10.2166/wst.2005.0623.
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Tubular membrane ultrafiltration and microfiltration are important industrial separation and concentration processes. Process optimisation requires reduction of membrane build-up. Gas slug introduction has been shown to be a useful approach for flux enhancement. However, process quantification is required for design and optimisation. In this work we employ a non-porous wall CFD model to quantify hydrodynamics in the two-phase slug flow process. Mass transfer is subsequently quantified from wall shear stress, which was determined from the CFD. The mass transfer model is an improved one-dimensional boundary layer model, which empirically incorporates effects of wall suction and analytically includes edge effects for circular conduits. Predicted shear stress profiles are in agreement with experimental results and flux estimates prove more reliable than that from previous models. Previous models ignored suction effects and employed less rigorous fluid property inclusion, which ultimately led to under-predictive flux estimates. The presented model offers reliable process design and optimisation criteria for gas-sparged tubular membrane ultrafiltration.
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Pan, Xiao Qiang, Hong Zhu Sun, Jun Da Chen, and Yu Ling Zhu. "Numerical Study on Mold Filling Process of Casting." Materials Science Forum 575-578 (April 2008): 87–92. http://dx.doi.org/10.4028/www.scientific.net/msf.575-578.87.
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Techniques of numerical simulation on mold filling process of casting are investigated in this paper. The mathematical model is formed on the ground of some selected theories in computational fluid dynamics (CFD), Numerical Heat Transfer (NHT) and computational methods to interfacial tracking. The discrete solution to the governing equations appeals to Finite Volume Method (FVM) on structured mesh. As for viscous turbulence flow and multiphase fluid flow in mold filling, engineering turbulence model and Volume of Fluid (VOF) method are adopted in the algorithms, respectively. As a debut, the general-purpose CFD software is used to establish the practicable mechanical model for the simulation. By means of numerical simulation, variation and distribution of velocity, temperature, stress and configuration of casting, etc. with respect to time and space in the filling process can be quantitatively analysed in detail, which is helpful for engineers to optimize their design of technics with less time and less cost and is meaningful to provide the subsequent simulation, solidification process of casting, with initial conditions.
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Aldhayee, Khaled, Mahmoud T. Ali, and Hisham A. Nasr-El-Din. "Modeling Wormhole Propagation During Closed-Fracture-Acidizing Stimulation in Tight-Carbonate Formations." SPE Journal 25, no. 05 (July 13, 2020): 2373–400. http://dx.doi.org/10.2118/201252-pa.
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Summary Closed-fracture acidizing (CFA) is a well-stimulation technique that can be applied to stimulate carbonate reservoirs at the end of acid-fracturing treatments. In CFA, acid is injected into the closed fracture at rates lower than the fracturing pressure to enhance the fracture conductivity. The objective of this study is to develop a robust model that can capture the dissolution process and wormhole-propagation phenomena that occur during CFA. This work develops a CFA model using computational-fluid-dynamics (CFD) techniques coupled with a two-scale continuum model that can predict accurately the reactive-flow mechanisms of hydrochloric acid (HCl) in carbonate formations. The developed CFA model is constructed and populated with the actual porosity-distribution profiles of tight carbonates. The model was tested against the experimental work performed on a fracture-conductivity apparatus. Sensitivity analysis is performed for several parameters that affect the performance of CFA in tight-carbonate formations. The developed model has successfully captured the dissolution patterns and wormhole-propagation phenomena that occur during CFA. In calcite formations, high temperatures promote acid leakoff into the formation, resulting in inefficient fracture stimulation. On the contrary, low temperatures reduce the overall reaction kinetics and attenuate the HCl reaction with calcite. Also, simulation results show that high acid concentration is favorable in treating low-conductivity fractures. In dolomite formations, it is essential to adapt a strong-acid system with an extended treatment duration to ensure efficient acid stimulation to the closed fractures. This paper provides a simulation study of the CFA process in a carbonates formation by establishing a 3D CFD model using the two-scale continuum approach. Fracture-surface etching and the associated acid-wormhole behavior during CFA are experimentally validated. This study optimizes the acid volumes and injection rates that can be used in conducting CFA.
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Knatz, Carrie, Stephen Rafferty, and Anthony Delescinskis. "Optimization of water treatment plant flow distribution with CFD modeling of an influent channel." Water Quality Research Journal 50, no. 1 (November 8, 2014): 72–82. http://dx.doi.org/10.2166/wqrjc.2014.024.
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In the design of water and wastewater treatment plants, proper flow and solids distribution can be as critical as process design considerations. Insufficient treatment and even plant failures can result from unequal and unmanageable flow and solids distribution. Computational fluid dynamics (CFD) modeling is a valuable tool in the evaluation of flow distribution to multiple units within a treatment process. This article reviews the benefits achieved by performing a CFD analysis of an Infilco high-rate dissolved air flotation (DAF) influent channel prior to finalizing the design of the plant. The CFD model was used to optimize the DAF influent channel configuration with respect to flow distribution to 10 identical process units that were inserted into an existing facility footprint. For the initial configurations modeled, the largest deviation of flow rate to an individual DAF unit was over 60%. Using CFD, design engineers developed a DAF influent channel configuration predicted to achieve less than 10% deviation. The upgraded facility is constructed and in service and the results of the CFD model were confirmed using actual turbidity data, which indicate that the solids are evenly distributed to the DAF process trains.
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Bušs, Armands, Normunds Jēkabsons, Artūrs Šuleiko, Dagnija Loča, and Juris Vanags. "VISUALIZATION APPROACHES FOR STIRRED TANK BIOREACTORS." ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 3 (June 20, 2019): 18. http://dx.doi.org/10.17770/etr2019vol3.4077.
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Computational Fluid Dynamics (CFD) is the analysis of fluid behaviour employing numerical solution methods. Using CFD it is possible to analyse simple and complex fluid-gas, fluid-fluid or fluid-solid interactions. Fluid dynamics is described with laws of physics in the form of partial differential equations also known as Navier-Stokes equations. Sophisticated CFD solvers transform these laws into algebraic equations which are solved by numerical methods. In this paper Ansys CFX and Fluent analysis systems as research methods are used to visualize flow patterns in a stirred tank bioreactor. The results obtained are informative and can be used to improve the yield of biomass. CFD analysis can save time and aid fluid system designing process. This approach is cheaper and faster compared to conventional build-and-test process. However, it should be noted that CFD analysis results are as accurate as the level of skill possessed by a CFD engineer therefore there are still place for hands-on testing. Authors have developed a stirred tank model and visualized flow patterns. The research presents experimental computation methods and the model setup key parameters. The developed model allows to predict flow patterns inside stirred systems and evaluate efficiency of the mixing process by analysing parameters such as velocity field, turbulence eddy frequency, shear strain rate and power input.
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Chen, Meng, Zhao Chen, Yaping Tang, and Malin Liu. "CFD-DEM simulation of particle coating process coupled with chemical reaction flow model." International Journal of Chemical Reactor Engineering 19, no. 4 (March 9, 2021): 393–413. http://dx.doi.org/10.1515/ijcre-2020-0241.
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Abstract Particle coating process, one of the main methods to improve the particle properties, is widely used in industrial production and pharmaceutical industry. For the scale up and optimization of this process, a mechanistic and detailed study is needed or numerical simulation as an alternative way. Decomposition of substances usually involves multiple chemical reactions and produces multiple substances in the actual chemical reaction. In the study, a chemical reaction flow (CRF) model has been established based on kinetic mechanism of elementary reaction, the theory of molecular thermodynamics and the sweep theory. It was established with the comprehensive consideration of the decomposition of substances, deposition process, adhesion process, desorption process, hydrogen inhibition, and clearance effect. Then the CFD-DEM model was coupled with CRF model to simulate particle coating process by FB-CVD method, and the CFD-DEM-CRF coupling model was implemented in the software Fluent-EDEM with their user definition function (UDF) and application programming interface (API). The coating process in the spouted bed was analyzed in detail and the coating behavior under different conditions were compared at the aspects of CVD rate, coating efficiency, particle concentration distribution, particle mixing index and gas concentration distribution. It is found that the average CVD rate is 6.06 × 10−4 mg/s when the inlet gas velocity is 11 m/s and bed temperature is 1273 K, and simulation result agrees with the experimental result well. Average CVD rate and coating efficiency increase with temperature increasing, but decrease acutely with mass fraction of injected hydrogen increasing. The CFD-DEM-CRF coupling model can be developed as a basic model for investigating particle coating process in detail and depth and can provide some guidance for the operating conditions and parameters design of the spouted bed in the real coating process.