Academic literature on the topic 'A validated 3-D CFD technique'
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Journal articles on the topic "A validated 3-D CFD technique"
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Zhiyang, Zhang, Ma Yong, Jiang Jin, Liu Weixing, and Ma Qingwei. "3-D Simulation of Vertical-Axial Tidal Current Turbine." Polish Maritime Research 23, no. 4 (December 1, 2016): 73–83. http://dx.doi.org/10.1515/pomr-2016-0072.
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Abstract Vertical-axial tidal current turbine is the key for the energy converter, which has the advantages of simple structure, adaptability to flow and uncomplex convection device. It has become the hot point for research and application recently. At present, the study on the hydrodynamic performance of vertical-axial tidal current turbine is almost on 2-D numerical simulation, without the consideration of 3-D effect. CFD (Computational Fluid Dynamics) method and blade optimal control technique are used to improve accuracy in the prediction of tidal current turbine hydrodynamic performance. Numerical simulation of vertical-axial tidal current turbine is validated. Fixed and variable deflection angle turbine are comparatively studied to analysis the influence of 3-D effect and the character of fluid field and pressure field. The method, put the plate on the end of blade, of reduce the energy loss caused by 3-D effect is proposed. The 3-D CFD numerical model of vertical-axial tidal current turbine hydrodynamic performance in this study may provide theoretical, methodical and technical reference for the optimal design of turbine.
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Garg, Nitin, Gaetan K. W. Kenway, Zhoujie Lyu, Joaquim R. R. A. Martins, and Yin L. Young. "High-Fidelity Hydrodynamic Shape Optimization of a 3-D Hydrofoil." Journal of Ship Research 59, no. 04 (December 1, 2015): 209–26. http://dx.doi.org/10.5957/jsr.2015.59.4.209.
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With recent advances in high-performance computing, computational fluid dynamics (CFD) modeling has become an integral part in the engineering analysis and even in the design process of marine vessels and propulsors. In aircraft wing design, CFD has been integrated with numerical optimization and adjoint methods to enable high fidelity aerodynamic shape optimization with respect to large numbers of design variables. There is a potential to use some of these techniques for maritime applications, but there are new challenges that need to be addressed to realize that potential. This work presents a solution to some of those challenges by developing a CFD-based hydrodynamic shape optimization tool that considers cavitation and a wide range of operating conditions. A previously developed three-dimensional compressible Reynold saveraged Navier-Stokes (RANS) solver is extended to solve for nearly incompressible flows, using a low-speed preconditioner. An efficient gradient-based optimizer and the adjoint method are used to carry out the optimization. The modified CFD solver is validated and verified for a tapered NACA 0009 hydrofoil. The need for a large number of design variables is demonstrated by comparing the optimized solution obtained using different number of shape design variables. The results showed that at least 200 design variables are needed to get a converged optimal solution for the hydrofoil considered. The need for a high-fidelity hydrodynamic optimization tool is also demonstrated by comparing RANS-based optimization with Euler-based optimization. The results show that at high lift coefficient (CL) values, the Euler-based optimization leads to a geometry that cannot meet the required lift at the same angle of attack as the original foil due to inability of the Euler solver to predict viscous effects. Single-point optimization studies are conducted for various target CL values and compared with the geometry and performance of the original NACA 0009 hydrofoil, as well as with the results from a multipoint optimization study. A total of 210 design variables are used in the optimization studies. The optimized foil is found to have a much lower negative suction peak, and hence delayed cavitation inception, in addition to higher efficiency, compared to the original foil at the design CL value. The results show significantly different optimal geometry for each CL, which means an active morphing capability was needed to achieve the best possible performance for all conditions. For the single-point optimization, using the highest CL as the design point, the optimized foil yielded the best performance at the design point, but the performance degraded at the off-design CL points compared to the multipoint design. In particular, the foil optimized for the highest CL showed inferior performance even compared to the original foil at the lowest CL condition. On the other hand, the multipoint optimized hydrofoil was found to perform better than the original NACA 0009 hydrofoil over the entire operation profile, where the overall efficiency weighted by the probability of operation at each CL, is improved by 14.4%. For the multipoint optimized foil, the geometry remains fixed throughout the operation profile and the overall efficiency was only 1.5% lower than the hypothetical actively morphed foil with the optimal geometry at each CL. The new methodology presented herein has the potential to improve the design of hydrodynamic lifting surfaces such as propulsors, hydrofoils, and hulls.
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Taco-Vasquez, Sebastian, César A. Ron, Herman A. Murillo, Andrés Chico, and Paul G. Arauz. "Thermochemical Analysis of a Packed-Bed Reactor Using Finite Elements with FlexPDE and COMSOL Multiphysics." Processes 10, no. 6 (June 7, 2022): 1144. http://dx.doi.org/10.3390/pr10061144.
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This work presents the thermochemical analysis of a packed-bed reactor via multi-dimensional CFD modeling using FlexPDE and COMSOL Multiphysics. The temperature, concentration, and reaction rate profiles for methane production following the Fischer–Tropsch (F-T) synthesis were studied. To this end, stationary and dynamic differential equations for mass and heat transfer were solved via the finite element technique. The transport equations for 1-D and 2-D models using FlexPDE consider dispersion models, where the fluid and the catalyst can be treated as either homogeneous or heterogenous systems depending on the gradient extents. On the other hand, the 3-D model obtained in COMSOL deems the transport equations incorporated in the Porous Media module. The aim was to compare the FlexPDE and COMSOL models, and to validate them with experimental data from literature. As a result, all models were in good agreement with experimental data, especially for the 2-D and 3-D dynamic models. In terms of kinetics, the predicted reaction rate profiles from the COMSOL model and the 2-D dynamic model followed the temperature trend, thus reflecting the temperature dependence of the reaction. Based on these findings, it was demonstrated that applying different approaches for the CFD modeling of F-T processes conducts reliable results.
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Amorim, Felipe Grossi L., Marcio E. Guzzo, Leonardo Mayer Reis, R. O. Coelho, and Ramon Molina Valle. "Numerical Validation of the Ethanol Spray Produced by a Direct Injection Injector for Different Pressure Conditions." Applied Mechanics and Materials 798 (October 2015): 213–18. http://dx.doi.org/10.4028/www.scientific.net/amm.798.213.
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This study presents a methodology to validate CFD simulations of the spray fuel injection using an experimental bench and optical measurement tools along with the Shadowgraph Technique. The parameter used for validating the experiments is the penetration rate, under situations of 6 bar and 100 bar injection pressures. The results show a penetration rate difference lower than 3% between the numerical model and the physical test. The visual plots, considering the shape and angles of the spray, also matched. Once validated, the numerical model could be applied to dynamic models of internal combustion engines and used to elaborate injection strategies for future projects.
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Li, Qing, Can Kang, Shuang Teng, and Mingyi Li. "Optimization of Tank Bottom Shape for Improving the Anti-Deposition Performance of a Prefabricated Pumping Station." Water 11, no. 3 (March 22, 2019): 602. http://dx.doi.org/10.3390/w11030602.
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High flexibility of prefabricated pumping stations in collecting and transporting storm water has been recognized. Nevertheless, flows inside such a complex system have rarely been reported. The present study aims to reveal water-sand flow characteristics in a prefabricated pumping station and to optimize geometric parameters of the tank to mitigate sand particle deposition. Five tank schemes, varying in the ratio of the diameter to the height of the tank bottom (D/L), were investigated. Flows in the pumping station were simulated using the computational fluid dynamics (CFD) technique. Test data were used to validate the numerical scheme. Three-dimensional water-sand flows in the pumping station were described. Underlying mechanisms of sand particle deposition were explained. The results indicate that the risk of deposition is high at the tank bottom side, close to the tank inlet. Both the tank bottom geometry and the inlet suction of the pump contribute to sand particle deposition. The averaged sand volume fraction at the pump inlet reaches its minimum at D/L = 3. Sand particle velocity at the pump inlet varies inversely with D/L. The highest intensity of the vortex at the pump inlet arises at D/L = 3. The best anti-deposition performance of the pumping station is attained at D/L = 3.
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Song, Eui-Hyeok, Kye-Bock Lee, and Seok-Ho Rhi. "Thermal and Flow Simulation of Concentric Annular Heat Pipe with Symmetric or Asymmetric Condenser." Energies 14, no. 11 (June 6, 2021): 3333. http://dx.doi.org/10.3390/en14113333.
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The current research work describes the flow and thermal analysis inside the circular flow region of an annular heat pipe with a working fluid, using computational fluid dynamics (CFD) simulation. A two-phase flow involving simultaneous evaporation and condensation phenomena in a concentric annular heat pipe (CAHP) is modeled. To simulate the interaction between these phases, the volume of fluid (VOF) technique is used. The temperature profile predicted using computational fluid dynamics (CFD) in the CAHP was compared with previously obtained experimental results. Two-dimensional and three-dimensional simulations were carried out, in order to verify the usefulness of 3D modeling. Our goal was to compute the flow characteristics, temperature distribution, and velocity field inside the CAHP. Depending on the shape of the annular heat pipe, the thermal performance can be improved through the optimal design of components, such as the inner width of the annular heat pipe, the location of the condensation part, and the amount of working fluid. To evaluate the thermal performance of a CAHP, a numerical simulation of a 50 mm long stainless steel CAHP (1.1 and 1.3 in diameter ratio and fixed inner tube diameter (78 mm)) was done, which was identical to the experimental system. In the simulated analysis results, similar results to the experiment were obtained, and it was confirmed that the heat dissipation was higher than that of the existing conventional heat pipe, where the heat transfer performance was improved when the asymmetric area was cooled. Moreover, the simulation results were validated using the experimental results. The 3-D simulation shows good agreement with the experimental results to a reasonable degree.
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Ruggles, Arthur E., Bi Yao Zhang, and Spero M. Peters. "Positron Emission Tomography (PET) for Flow Measurement." Advanced Materials Research 301-303 (July 2011): 1316–21. http://dx.doi.org/10.4028/www.scientific.net/amr.301-303.1316.
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Positron Emission Tomography (PET) produces a three dimensional spatial distribution of positron-electron annihilations within an image volume. Various positron emitters are available for use in aqueous, organic and liquid metal flows. Preliminary experiments at the University of Tennessee at Knoxville (UTK) injected small flows of PET tracer into a bulk water flow in a four rod bundle. The trajectory and diffusion of the tracer in the bulk flow were then mapped using a PET scanner. A spatial resolution of 1.4 mm is achieved with current preclinical Micro-PET imaging equipment resulting in 200 MB 3D activity fields. A time resolved 3-D spatial activity profile was also measured. The PET imaging method is especially well suited to complex geometries where traditional optical methods such as LDV and PIV are difficult to apply. PET methods are uniquely useful for imaging in opaque fluids, opaque pressure boundaries, and multiphase studies. Several commercial and shareware Computational Fluid Dynamics (CFD) codes are currently used for science and engineering analysis and design. These codes produce detailed three dimensional flow predictions. The models produced by these codes are often difficult to validate. The development of this experimental technique offers a modality for the comparison of CFD outcomes with experimental data. Developed data sets from PET can be used in verification and validation exercises of simulation outcomes.
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de Rochefort, Ludovic, Laurence Vial, Redouane Fodil, Xavier Maître, Bruno Louis, Daniel Isabey, Georges Caillibotte, et al. "In vitro validation of computational fluid dynamic simulation in human proximal airways with hyperpolarized 3He magnetic resonance phase-contrast velocimetry." Journal of Applied Physiology 102, no. 5 (May 2007): 2012–23. http://dx.doi.org/10.1152/japplphysiol.01610.2005.
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Computational fluid dynamics (CFD) and magnetic resonance (MR) gas velocimetry were concurrently performed to study airflow in the same model of human proximal airways. Realistic in vivo-based human airway geometry was segmented from thoracic computed tomography. The three-dimensional numerical description of the airways was used for both generation of a physical airway model using rapid prototyping and mesh generation for CFD simulations. Steady laminar inspiratory experiments (Reynolds number Re = 770) were performed and velocity maps down to the fourth airway generation were extracted from a new velocity mapping technique based on MR velocimetry using hyperpolarized 3He gas. Full two-dimensional maps of the velocity vector were measured within a few seconds. Numerical simulations were carried out with the experimental flow conditions, and the two sets of data were compared between the two modalities. Flow distributions agreed within 3%. Main and secondary flow velocity intensities were similar, as were velocity convective patterns. This work demonstrates that experimental and numerical gas velocity data can be obtained and compared in the same complex airway geometry. Experiments validated the simulation platform that integrates patient-specific airway reconstruction process from in vivo thoracic scans and velocity field calculation with CFD, hence allowing the results of this numerical tool to be used with confidence in potential clinical applications for lung characterization. Finally, this combined numerical and experimental approach of flow assessment in realistic in vivo-based human airway geometries confirmed the strong dependence of airway flow patterns on local and global geometrical factors, which could contribute to gas mixing.
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Karuppa Raj, R. Thundil, and M. P. Dhyan Shankar. "Effect of Convergent Angle on Flow Characteristics of Y-Shaped Diffusers Using CFD." Applied Mechanics and Materials 592-594 (July 2014): 1909–13. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.1909.
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Diffusing ducts are used in fluid flow systems, mainly in aeroplane engine inlets to decelerate the flow and to correspondingly increase the static pressure. The main problem in achieving a high pressure recovery is the flow separation which results in non-uniform distribution and excessive losses. The present work is aimed to study the flow characteristics in Y-shaped diffusing ducts. The Y-shaped diffuser has rectangular inlets and the outlet is circular with a certain settling length for the flow to be stabilized. The diffuser is modeled in CATIA V5 and further discretized using ICEMCFD12.1. Hexahedral mesh is generated for all diffuser cases, which have been used to capture the hydrodynamic boundary layers. ANSYS CFX 12.1 based on finite volume technique, using k-ε turbulence model is adopted for predicting the flow. The flow field through the 3-dimensional domain is captured by solving the appropriate governing equations namely, the continuity equation and the momentum equation. The convergence criterion is set to 10E-06 for mass and momentum. The whole investigation is done in two phases: in the first phase a commercial CFD code is validated for the results obtained for an S-shaped diffuser and in the second phase the same idea is then extended for the analysis of Y-shaped diffuser. The coefficient of static pressure, cross flow and axial flow velocity distributions are calculated based on the mass averaged quantities for the Y-shaped diffusers (30o and 40o).
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Nasraoui, Haythem, Zied Driss, Ahmed Ayadi, Abdallah Bouabidi, and Hedi Kchaou. "Numerical and experimental study of the impact of conical chimney angle on the thermodynamic characteristics of a solar chimney power plant." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 233, no. 5 (June 27, 2019): 1185–99. http://dx.doi.org/10.1177/0954408919859160.
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The goal of this paper is to study and optimize the conical chimney angle (α) of a divergent solar chimney power plant (DSCPP) by using CFD technique. The local airflow characteristics were analyzed in four configurations with different conical angles α = 0°, α = 3°, α = 6° and α = 9°. The first design is validated experimentally by using a pilot prototype build at the National School of Engineers of Sfax, Tunisia. In addition, some experimental results of the temperature, the velocity and the power output were presented during a typical day. A novel mathematical correlation was developed to prove the effect of the conical angle and the DSCPP scale on the power output. In fact, the relationship between the optimum conical angle and the system scale was performed based on both quadratic and cubic regressions. The computational results ensure that the conical chimney angle presents a parabolic tendency with the turbulence airflow characteristics and the power output. The performance of the DSCCP was degraded since the conical angle is greater than α = 3°. Furthermore, the optimum angle decreases with an increasing system scale. A commercial solar chimney with a conical angle around α = 1° presents an efficient system.
Book chapters on the topic "A validated 3-D CFD technique"
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Dalpadulo, Enrico, Fabio Pini, and Francesco Leali. "Design for Additive Manufacturing of a Topology Optimized Brake Caliper Through CAD-Platform-Based Systematic Approach." In Lecture Notes in Mechanical Engineering, 92–97. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-70566-4_16.
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AbstractTo implement the CAD platform-based approach of Design for Additive Manufacturing (DfAM) and validate it in a real case, an entire design optimization process of a Formula SAE front brake caliper has been performed, to be printed by Powder Bed Fusion (PBF) process. The DfAM consists in the use of a Ti6Al4V titanium alloy to better resist at high temperatures and a topology optimized shape allowed by the technology to save weight despite the density increase. Structural and thermal behavior has been discussed. DfAM process-specific techniques have been implemented for internal geometrical features and optimized shapes. The design for additive workflow is presented and finally the exploited design approach based on a CAD platform is synthesized.
Conference papers on the topic "A validated 3-D CFD technique"
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Wang, Ting, and T. S. Dhanasekaran. "Model Verification of Mist/Steam Cooling With Jet Impingement Onto a Concave Surface and Prediction at Elevated Operating Condition." In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-22238.
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Internal mist/steam blade cooling technology is proposed for advanced gas turbine systems that use the closed-loop steam cooling scheme. Previous experiments on mist/steam heat transfer with a 2-D slot jet impingement onto a concave surface showed cooling enhancement of up to 200% at the stagnation point by injecting approximately 0.5% of mist under low temperature and pressure laboratory conditions. Realizing the difficultly in conducting experiments at elevated pressure and temperature working conditions, CFD simulation becomes an opted approach to predict the potential applicability of the mist/steam cooling technique at real GT operating conditions. In this study, the CFD model is first validated within 3% and 6% deviation from experimental results for the flows of steam only and mist/steam flow cases, respectively. The validated CFD model is then used to simulate a row of multiple holes impinging jet onto a concave surface under elevated pressure, temperature, and Reynolds number condition. The predicted results show an off-center cooling enhancement with a local maximum of 200% at s/d = 2 and an average cooling enhancement of about 150%. The mist cooling scheme is predicted to work better on a concave surface than on the flat surface. The extent of wall jet and the size of 3-D recirculation zones are identified as a major influencing parameter on the curvature effect on mist cooling performance. The mist enhancement from a slot jet is more pronounced than a row of round jets. The effects of wall heat flux and mist ratio on mist cooling performance are also investigated in this study.
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Modareszadeh, Amirreza, Omid Abouali, and Alireza Ghaffariyeh. "CFD Analysis of Nano-Drug Transport in Vitreous Cavity due to Saccadic Eye Movements." In ASME 2011 9th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2011. http://dx.doi.org/10.1115/icnmm2011-58251.
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In the present research, the motion of the nano-drug in the vitreous chamber of human eye due to saccadic movements in post-vitrectomy eyes is investigated. The average radius of the vitreous cavity in human eye is equal to 12 mm. This cavity is filled with a liquid in post-vitrectomy eyes. A dynamic mesh technique was performed to model the eye motion. The unsteady 3-D forms of continuity, Navier-Stokes and concentrations of nano-drug equations were solved numerically. The numerical model was validated comparing the results of the flow field with available analytic solutions and experimental data for a sphere as an ideal model of vitreous chamber which a very close agreement was achieved. Then, the numerical simulation was performed to a real model of vitreous cavity filled with BSS (Balanced salt solution). The convection and diffusion of nano-drug in the filling fluids of post-vitrectomy eyes is computed and the results are compared with the diffusion of the nano-drug in the stagnant vitreous. The comparison depicts that the saccade movements of human eye accelerate the drug motion one to two orders of magnitude higher than that due to diffusion in stagnant vitreous chamber.
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Desai, Salil, and Michael Lovell. "CFD Analysis of a Continuous Inkjet Print Head for Direct Write Fabrication." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43692.
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This paper investigates the fluid generation mechanism in a modified Continuous Inkjet Print (CIJ) method. The CIJ technique is utilized to deposit a variety of conductive nano particulate materials for building miniaturized devices that can sustain harsh environments. These include devices and structures that can sustain high temperature and humidity applications. Given the complex drop formation mechanism a CFD model is developed that is further validated using an ultrahigh speed photography experimental setup. Various input parameters such as frequency, voltage and fluid pressure can be tuned using the model for different fluid types to obtain an optimal drop formation. These findings can be useful for the fabrication of freeform miniaturized devices in 3 dimensional space.
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Tan, X. Gary, Robert N. Saunders, and Amit Bagchi. "Validation of a Full Porcine Finite Element Model for Blast Induced TBI Using a Coupled Eulerian-Lagrangian Approach." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70611.
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Current understanding of blast induced traumatic brain injury (TBI) mechanisms is incomplete and limits the development of protective and therapeutic measures. Animal testing has been used as a surrogate for human testing. The correlation of animals to human responses is not well understood with a limited set of experimental data, because of ethical concerns and cost of live animal tests. The validated computational animal models can be used to supplement and improve the granularity of available data at a significantly reduced cost. A whole-body porcine high-fidelity computational model was developed based on the image data. The hyper-viscoelastic model was used for soft tissues to capture the rate dependence and large strain nonlinearity of the material. The shock wave interaction with a porcine subject in a shock tube was simulated using computational fluid dynamics (CFD) models, via a combination of 1-D, 2-D and 3-D numerical techniques. The shock wave loads were applied to the exterior of the porcine finite element (FE) model to simulate the pressure wave transmission through the body and capture its biomechanical response. The CFD and FE problems are solved using the explicit Eulerian and Lagrangian solvers, respectively, in the DoD Open Source code CoBi. The computational models were validated by comparing the simulation results with experimental data at specific instrumented locations. The predicted brain tissue stress-strain fields were used to determine the areas susceptible to blast induced TBI by using published mechanical injury thresholds. The validated porcine model can be used to better understand TBI and how injury in animals corresponds to injury in humans. The coupled Eurlerian and Lagrangian approaches developed in this paper can be extended to other simulations to improve the solution accuracy.
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Chochua, Gocha G., Amrendra Kumar, Sule F. Gurses, Aleksandar Rudic, Ashutosh Dikshit, and Nityanand Sinha. "Improving Erosion Wear Life of Completion Equipment in High Flow Rate Conditions by Numerical Design Optimization for Influx Equalization." In Offshore Technology Conference. OTC, 2022. http://dx.doi.org/10.4043/31872-ms.
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Abstract The durability of sand screen completions is essential to longer well life, especially for high rate wells with sand screen erosion concerns. An excessive fluid flow enters the conventional screens near the heel or high permeability/fracture zones, causing premature sand control loss. The high rate screens with a simulation-driven approach address this concern by achieving the annulus-to-tubing flow equalization and reducing the influx spike near the heel or high permeability/fracture zone. The study presents a comprehensive modeling approach including a single-well model workflow for initial production screening along the wellbore with different reservoir conditions, which provides input to the novel multiscale 3D-2D-3D computational fluid dynamics (CFD) modeling technique to design or validate high-rate completions for the specific operating conditions. The principle of operation is based on equalizing the production influx along the screen by achieving the distributed inflow control devices (ICD) effect on the basepipe. The modeling approach was used to compute maximum local velocities in the vicinity of the screen near the heel under 39,000 RB/D of ultra-light oil production in one case and 200 MMscf/D of gas production in another. The design methodology is validated through erosion and sand retention tests performed to verify the screens’ correct slot/gauge size. The high-rate completion case history consists of seven deepwater wells with chemical tracers. The novel design and the modeling methodology are validated by physical erosion tests and verified through field installations.
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Chochua, Gocha G., Amrendra Kumar, Sule F. Gurses, Aleksandar Rudic, Ashutosh Dikshit, and Nityanand Sinha. "Improving Erosion Wear Life of Completion Equipment in High Flow Rate Conditions by Numerical Design Optimization for Influx Equalization." In Offshore Technology Conference. OTC, 2022. http://dx.doi.org/10.4043/31872-ms.
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Abstract The durability of sand screen completions is essential to longer well life, especially for high rate wells with sand screen erosion concerns. An excessive fluid flow enters the conventional screens near the heel or high permeability/fracture zones, causing premature sand control loss. The high rate screens with a simulation-driven approach address this concern by achieving the annulus-to-tubing flow equalization and reducing the influx spike near the heel or high permeability/fracture zone. The study presents a comprehensive modeling approach including a single-well model workflow for initial production screening along the wellbore with different reservoir conditions, which provides input to the novel multiscale 3D-2D-3D computational fluid dynamics (CFD) modeling technique to design or validate high-rate completions for the specific operating conditions. The principle of operation is based on equalizing the production influx along the screen by achieving the distributed inflow control devices (ICD) effect on the basepipe. The modeling approach was used to compute maximum local velocities in the vicinity of the screen near the heel under 39,000 RB/D of ultra-light oil production in one case and 200 MMscf/D of gas production in another. The design methodology is validated through erosion and sand retention tests performed to verify the screens’ correct slot/gauge size. The high-rate completion case history consists of seven deepwater wells with chemical tracers. The novel design and the modeling methodology are validated by physical erosion tests and verified through field installations.
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Luo, Zhaoyu, Parvez Sukheswalla, Scott A. Drennan, Mingjie Wang, and P. K. Senecal. "3D Numerical Simulations of Selective Catalytic Reduction of NOx With Detailed Surface Chemistry." In ASME 2017 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icef2017-3658.
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Environmental regulations have put stringent requirements on NOx emissions in the transportation industry, essentially requiring the use of exhaust after-treatment on diesel fueled light and heavy-duty vehicles. Urea-Water-Solution (UWS) based Selective Catalytic Reduction (SCR) for NOx is one the most widely adopted methods for achieving these NOx emissions requirements. Improved understanding and optimization of SCR after-treatment systems is therefore vital, and numerical investigations can be employed to facilitate this process. For this purpose, detailed and numerically accurate models are desired for in-cylinder combustion and exhaust after-treatment. The present paper reports on 3-D numerical modeling of the Urea-Water-Solution SCR system using Computational Fluid Dynamics (CFD). The entire process of Urea injection, evaporation, NH3 formation and NOx reduction is numerically investigated. The simulation makes use of a detailed kinetic surface chemistry mechanism to describe the catalytic reactions. A multi-component spray model is applied to account for the urea evaporation and decomposition process. The CFD approach also employs an automatic meshing technique using Adaptive Mesh Refinement (AMR) to refine the mesh in regions of high gradients. The detailed surface chemistry NOx reduction mechanism validated by Olsson et al. (2008) is applied in the SCR region. The simulations are run using both transient and steady-state CFD solvers. While transient simulations are necessary to reveal sufficient details to simulate catalytic oxidation during transient engine processes or under cyclic variations, the steady-state solver offers fast and accurate emission solutions. The simulation results are compared to available experimental data, and good agreement between experimental data and model results is observed.
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Gaspar, Pedro Dinis, L. C. Carrilho Gonc¸alves, and R. A. Pitarma. "Three-Dimensional CFD Modelling and Analysis of the Thermal Entrainment in Open Refrigerated Display Cabinets." In ASME 2008 Heat Transfer Summer Conference collocated with the Fluids Engineering, Energy Sustainability, and 3rd Energy Nanotechnology Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/ht2008-56421.
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This study presents a three-dimensional Computational Fluid Dynamics (CFD) simulation of the air flow pattern and the temperature distribution in a refrigerated display cabinet. The thermal entrainment is evaluated by the variations of the mass flow rate and thermal power along and across the air curtain considering the numerical predictions of abovementioned properties. The evaluation on the ambient air velocity for the three-dimensional (3D) effects in the pattern of this type of turbulent air flow is obtained. Additionally, it is verified that the longitudinal air flow oscillations and the length extremity effects have a considerable influence in the overall thermal performance of the equipment. The non uniform distribution of the air temperature and velocity throughout the re-circulated air curtain determine the temperature differences in the linear display space and inside the food products, affecting the refrigeration power of display cabinets. The numerical predictions have been validated by comparison with experimental tests performed in accordance with the climatic class n.° 3 of EN 441 Standard (Tamb = 25 °C, φamb = 60%; νamb = 0,2 m s−1). These tests were conducted using the point measuring technique for the air temperature, air relative humidity and air velocity throughout the air curtain, the display area of conservation of food products and nearby the inlets/outlets of the air mass flow.
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Murari, Sridhar, Sunnam Sathish, Ramakumar Bommisetty, and Jong S. Liu. "CFD Analyses of a Single Stage Turbine With Inlet Hot-Streak at Different Circumferential Locations." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-94141.
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This paper presents a detailed flow and heat transfer characteristic analysis on a gas turbine first stage under hot-streak inlet conditions. Simulations were performed for two locations of hot-streak at turbine inlet with respect to the first stage vane, i.e. i) passage center and ii) blade center. The two kinds of inlet conditions have the same mass-averaged total temperature and total pressure. The passage center hot-streak total pressure and total temperature contours are obtained from the rig data published by Butler. Linear interpolation technique is used to move the hot-streak location from passage center to blade center. The ratio of highest temperature in hot-streak to free stream temperature is 2.0. Mixing plane (MP) and Non-linear harmonic (NLH) approaches are used to address the data transport across the rotor-stator station interface. The numerical solution is validated with the test data obtained from the published rig tests. NLH approach predicted the rotor blade surface temperature distributions close to rig data with a percentage deviation of 3%. The change in hot-streak circumferential position from blade center to passage center lead to decreased attenuation of hot-streak due to pronounced cross momentum transport of fluid across the viscous layers. Turbine flow with blade center hot-streak experiences transient periodic fluctuation of heat load on rotor surface. High temperature gradients are observed at turbine exit station with passage center hot-streak.
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Taher, Ahmed, Ben Jones, Peter Peumans, and Liesbet Lagae. "A Simplified Model for Species Transport in Very Large Scale Microfluidic Networks." In ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icnmm2018-7663.
Full textAbstract:
A novel modeling technique for fluid flow and species transport in very large scale microfluidic networks is developed with applications to massively parallelized microreactors. Very large scale integration (VLSI) of microfluidic circuits presents an attractive solution for many biological testing applications such as gene expression, DNA sequencing and drug screening, which require massive parallelization of reactions to increase throughput and decrease time-to-result. However, the design and modeling of VLSI microfluidics remains challenging with conventional 2D or 3D computational fluid dynamic (CFD) techniques due to the large computational resources required. Using simplified models is crucial to reduce simulation time on existing computational resources. Many microfluidic networks can be solved using resistance based networks similar to electrical circuits; however, simplified models for species transport (diffusion plus advection) in microfluidic networks has received much less attention. Here, we introduce a simplified model based on resistance network based modeling for flow dynamics and couple it with a one-dimensional discretization of the advection-diffusion transport equation. The developed model was validated against CFD simulations using ANSYS Fluent for a flow network consisting of a 4 by 4 array of microreactors. It showed good agreement with 2D CFD simulations with less than 6% error in total pressure drop across the network for channels with a length to width ratio of 10. The error was only 3% for a channel length to width ratio of 20. The developed model was then used to optimize the design of a 100-microreactors network used for high purity cyclical loading of reagents. The reactor configuration with a minimum cycle time for reagent loading and unloading and minimum operating pressure were evaluated with the code. In theory, the simulation can be scaled to much larger reactor arrays after further optimizations of the code and utilizing parallel processing.