Journal articles: 'Multiphase material optimization'

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Cai, Kun, Jing Cao, Jiao Shi, and Qing H. Qin. "Layout Optimization of Ill-Loaded Multiphase Bi-Modulus Materials." International Journal of Applied Mechanics 08, no. 03 (April 2016): 1650038. http://dx.doi.org/10.1142/s1758825116500381.

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The optimal layouts of multiple bi-modulus materials in a continuum under ill-loaded cases are found using the scheme of fractional-norm ([Formula: see text]-norm and [Formula: see text] is in (0, 1)) weighting objective function. The major ideas of the present study are as follows. First, the bi-modulus material topology optimization is solved using material replacement approach. Second, the power-law scheme is adopted to express the equivalent stiffness of multiple materials. Third, the ill-loaded topology optimization is solved by changing the value of [Formula: see text]. Combining the three techniques, a feasible solution for the ill-loaded structural optimization can be found even when there are many bi-modulus materials. Numerical tests are presented to show the characters of the materials layout in the structure.

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Catania, Rick, Abdalla Diraz, Dominic Maier, Armani Tagle, and Pınar Acar. "Mathematical Strategies for Design Optimization of Multiphase Materials." Mathematical Problems in Engineering 2019 (March 12, 2019): 1–10. http://dx.doi.org/10.1155/2019/4024637.

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This work addresses various mathematical solution strategies adapted for design optimization of multiphase materials. The goal is to improve the structural performance by optimizing the distribution of multiple phases that constitute the material. Examples include the optimization of multiphase materials and composites with spatially varying fiber paths using a finite element analysis scheme. In the first application, the phase distribution of a two-phase material is optimized to improve the structural performance. A radial basis function (RBF) based machine learning algorithm is utilized to perform a computationally efficient design optimization and it is found to provide equivalent results with the physical model. The second application concentrates on the optimization of spatially varying fiber paths of a composite material. The fiber paths are described by the Non-Uniform Rational Bezier (B)-Spline Surface (NURBS) using a bidirectional control point representation including 25 parameters. The optimum fiber path is obtained for various loading configurations by optimizing the NURBS parameters that control the overall distribution of fibers. Next, a direct sensitivity analysis is conducted to choose the critical set of parameters from the design point to improve the computational time efficiency. The optimized fiber path obtained with the reduced number of NURBS parameters is found to provide similar structural properties compared to the optimized fiber path that is modeled with a full NURBS representation with 25 parameters.

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Qiu, Ke Peng, Wei Hong Zhang, and T. Gao. "Microstructure Design with Multiphase Materials under Mass Constraints." Materials Science Forum 697-698 (September 2011): 596–99. http://dx.doi.org/10.4028/www.scientific.net/msf.697-698.596.

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The microstructure design satisfying the mass constraint can reduce the structure weight more directly and effectively in comparison with the volume constraint. This paper is devoted to the topology optimization of microstructures with multiphase materials under the mass upper limitation constraint for maximizing the equivalent elastic tensors and their combinations. Firstly, the strain energy method is applied to compute the effective elastic properties of microstructures. In order to make sure that the formulation of mass constraint is linear with separable design variables, DMO (Discrete Material Optimization) model is adopted for the element density interpolation. Therefore, this optimization problem can be solved efficiently by means of mathematical programming approaches, especially the convex programming methods. Besides, the filtering technique is adopted to avoid the checkerboard pattern. There are two categories of numerical examples. In the first category, the modulus and the stiffness ratio of the solid material phase 1 are smaller than the solid material phase 2. In the second category, the modulus of the solid material phase 1 is still smaller than the solid material phase 2, but its stiffness ratio is bigger than the solid material phase 2.

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Zhu, Ji-Hong, and Wei-Hong Zhang. "Structural optimization in ESAC: annals 2011." International Journal for Simulation and Multidisciplinary Design Optimization 5 (2014): A09. http://dx.doi.org/10.1051/smdo/2013013.

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The purpose of this paper is to give an overall introduction of the structural optimization research works in ESAC group in 2011. Four main topics are involved, i.e. 1) topology optimization with multiphase materials, 2) integrated layout and topology optimization, 3) prediction of effective material properties and 4) composite design. More detailed techniques and some numerical results are also presented and discussed here.

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KATO, Junji, Ekkehard RAMM, Kenjiro TERADA, and Takashi KYOYA. "MULTIPHASE MATERIAL OPTIMIZATION FOR FIBER REINFORCED COMPOSITES CONSIDERING STRAIN SOFTENING." Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)) 67, no. 1 (2011): 39–53. http://dx.doi.org/10.2208/jscejam.67.39.

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Kato, Junji, Andreas Lipka, and Ekkehard Ramm. "Multiphase material optimization for fiber reinforced composites with strain softening." Structural and Multidisciplinary Optimization 39, no. 1 (October 15, 2008): 63–81. http://dx.doi.org/10.1007/s00158-008-0315-7.

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Majdi, Behzad, and Arash Reza. "Multi-material topology optimization of compliant mechanisms via solid isotropic material with penalization approach and alternating active phase algorithm." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 13 (February 27, 2020): 2631–42. http://dx.doi.org/10.1177/0954406220908627.

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The present study aims at providing a topology optimization of multi-material compliant mechanisms using solid isotropic material with penalization (SIMP) approach. In this respect, three multi-material gripper, invertor, and cruncher compliant mechanisms are considered that consist of three solid phases, including polyamide, polyethylene terephthalate, and polypropylene. The alternating active-phase algorithm is employed to find the distribution of the materials in the mechanism. In this case, the multiphase topology optimization problem is divided into a series of binary phase topology optimization sub-problems to be solved partially in a sequential manner. Finally, the maximum displacement of the multi-material compliant mechanisms was validated against the results obtained from the finite element simulations by the ANSYS Workbench software, and a close agreement between the results was observed. The results reveal the capability of the SIMP method to accurately conduct the topology optimization of multi-material compliant mechanisms.

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Gao, Tong, and Wei-hong Zhang. "Topology optimization of multiphase material structures under design dependent pressure loads." International Journal for Simulation and Multidisciplinary Design Optimization 3, no. 1 (January 2009): 297–306. http://dx.doi.org/10.1051/ijsmdo/2009002.

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Gao, Tong, and Wei-hong Zhang. "Topology optimization of multiphase material structures under design dependent pressure loads." International Journal for Simulation and Multidisciplinary Design Optimization 3, no. 1 (January 2009): 297–306. http://dx.doi.org/10.1051/ijsmdo:2009002.

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Doan, Quoc Hoan, Dongkyu Lee, Jaehong Lee, and Joowon Kang. "Design of buckling constrained multiphase material structures using continuum topology optimization." Meccanica 54, no. 8 (June 2019): 1179–201. http://dx.doi.org/10.1007/s11012-019-01009-z.

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Ghasemi, Hamid, Harold S. Park, Naif Alajlan, and Timon Rabczuk. "A Computational Framework for Design and Optimization of Flexoelectric Materials." International Journal of Computational Methods 17, no. 01 (September 30, 2019): 1850097. http://dx.doi.org/10.1142/s0219876218500974.

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We combine isogeometric analysis (IGA), level set (LS) and pointwise density-mapping techniques for design and topology optimization of piezoelectric/flexoelectric materials. We use B-spline elements to discretize the fourth-order partial differential equations of flexoelectricity, which require at least [Formula: see text] continuous approximations. We adopt the multiphase vector LS model which easily copes with various numbers of material phases and multiple constraints. In case studies, we first confirm the accuracy of the IGA model and then provide numerical examples for both pure and composite flexoelectric structures. The results demonstrate the significant enhancement in electromechanical coupling coefficient that can be obtained using topology optimization and particularly by multi-material topology optimization for flexoelectric composites.

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Gangwar, Tarun, and Dominik Schillinger. "Concurrent material and structure optimization of multiphase hierarchical systems within a continuum micromechanics framework." Structural and Multidisciplinary Optimization 64, no. 3 (May 31, 2021): 1175–97. http://dx.doi.org/10.1007/s00158-021-02907-1.

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AbstractWe present a concurrent material and structure optimization framework for multiphase hierarchical systems that relies on homogenization estimates based on continuum micromechanics to account for material behavior across many different length scales. We show that the analytical nature of these estimates enables material optimization via a series of inexpensive “discretization-free” constraint optimization problems whose computational cost is independent of the number of hierarchical scales involved. To illustrate the strength of this unique property, we define new benchmark tests with several material scales that for the first time become computationally feasible via our framework. We also outline its potential in engineering applications by reproducing self-optimizing mechanisms in the natural hierarchical system of bamboo culm tissue.

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Xiao, Man Yu, Wei Hong Zhang, and Piotr Breitkopf. "Application of POD Projection to Orientation Optimization of Laminated Composite Design." Advanced Materials Research 634-638 (January 2013): 1890–95. http://dx.doi.org/10.4028/www.scientific.net/amr.634-638.1890.

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In the context of laminated composite design, the integrated stiffness of the laminate depends on the number of plies, the material and the orientation of the material in each ply. The main issue of design is the prohibitive numerical simulation cost, the early technique (DMO, discrete material optimization; BCP, Bi-value Coding Parameterization Method) consists in transforming the continuous orientation angle variables to discrete design variables as multiphase material selection problems. In this work, a set of continuous orientation angle is directly considered. More precisely, the design task is the orientation of the orthotropic material in each element of the discretization and the ratio of ply thickness. In order to reduce the computational effort, Proper Orthogonal Decomposition (POD) applied to decrease the number of design variables. The numerical results in a simple case show that the proposed method is available.

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Grujic, A., V. Cosovic, J. Stajic-Trosic, A. Maricic, and N. Talijan. "Methods of characterization of multiphase Nd-Fe-B melt-spun alloys." Science of Sintering 39, no. 2 (2007): 193–98. http://dx.doi.org/10.2298/sos0702193g.

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Nanocomposite permanent magnetic materials based on Nd-Fe-B alloys with a low Nd content are a new type of permanent magnetic material. The microstructure of these nanocomposite permanent magnets is composed of a mixture of magnetically soft and hard phases providing the so called exchange coupling effect. Beside the optimization process parameters, methods of characterization have a very important role in the design of an optimal magnetic matrix of multiphase melt-spun Nd-Fe-B alloys. Different methods and techniques of characterization were used for observation and study of the microstructure evolution during crystallization. A summary results of measurements using different methods of characterization are presented to enable a better insight into relations between the microstructure and magnetic properties of the investigated melt-spun Nd-Fe-B alloys. .

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ZHANG, Xiujuan. "Improved genetic algorithm based on family tree used for the material selection optimization of components made of multiphase materials." Chinese Journal of Mechanical Engineering 44, no. 03 (2008): 220. http://dx.doi.org/10.3901/jme.2008.03.220.

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Mausam, Kuwar, Kamal Sharma, Pradeep Kumar Singh, and Aniruddha. "Optimization of Process Productivity for Multi Phase Carbon Nanotubes (CNT) Reinforced Nanocomposites Using Taguchi-Fuzzy Model." Advanced Science Letters 24, no. 8 (August 1, 2018): 5566–69. http://dx.doi.org/10.1166/asl.2018.12150.

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The present work is focused on the processing and machining of multiphase carbon nanotubes reinforced nanocomposites. In this work the author has performed electric discharge machining on multiphase carbon nanotubes reinforced nanocomposites. Optimal combination of different process parameters have been decided determined for maximum material removal rate and minimum tool wear rate which results the improvement in productivity of the complete process. In this study four different process parameters (Peak current, gap voltage, pulse on time and duty cycle) are used and the most significant parameter is illustrated. In the present work, the factor material removal rate has been considered as productivity measure. The goal is to determine the best process condition for maximizing material removal rate and simultaneously for minimizing the tool wear rate values, which may be considered as multi-response optimization problem. Taguchi method is a well known optimization technique used for optimizing the single objective function. Consequently the conversion process of objective functions invites ambiguity, uncertainly etc. into the computation. These implications always arises the need to correlate various responses. Hence to overcome these implications a fuzzy reasoning of multiple performance characteristics has been developed. This results in the transformation of multi performance characteristics in single multi-performance characteristics (Productivity) and can be optimized using Taguchi method. Using Taguchi’s design of experiment methodology optimal combination of process parameters will be obtained for various performance measures. Process productivity Optimize using the Fuzzy logic approach and the optimal results were also validated.

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CHEN, YUHANG, SHIWEI ZHOU, and QING LI. "COMPUTATIONAL DESIGN FOR MULTIFUNCTIONAL MICROSTRUCTURAL COMPOSITES." International Journal of Modern Physics B 23, no. 06n07 (March 20, 2009): 1345–51. http://dx.doi.org/10.1142/s0217979209060920.

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As an important class of natural and engineered materials, periodic microstructural composites have drawn substantial attention from the material research community for their excellent flexibility in tailoring various desirable physical behaviors. To develop periodic cellular composites for multifunctional applications, this paper presents a unified design framework for combining stiffness and a range of physical properties governed by quasi-harmonic partial differential equations. A multiphase microstructural configuration is sought within a periodic base-cell design domain using topology optimization. To deal with conflicting properties, e.g. conductivity/permeability versus bulk modulus, the optimum is sought in a Pareto sense. Illustrative examples demonstrate the capability of the presented procedure for the design of multiphysical composites and tissue scaffolds.

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Wang, Michael Yu, Shikui Chen, Xiaoming Wang, and Yulin Mei. "Design of Multimaterial Compliant Mechanisms Using Level-Set Methods." Journal of Mechanical Design 127, no. 5 (January 23, 2005): 941–56. http://dx.doi.org/10.1115/1.1909206.

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A monolithic compliant mechanism transmits applied forces from specified input ports to output ports by elastic deformation of its comprising materials, fulfilling required functions analogous to a rigid-body mechanism. In this paper, we propose a level-set method for designing monolithic compliant mechanisms made of multiple materials as an optimization of continuum heterogeneous structures. Central to the method is a multiphase level-set model that precisely specifies the distinct material regions and their sharp interfaces as well as the geometric boundary of the structure. Combined with the classical shape derivatives, the level-set method yields an Eulerian computational system of geometric partial differential equations, capable of performing topological changes and capturing geometric evolutions at the interface and the boundary. The proposed method is demonstrated for single-input and single-output mechanisms and illustrated with several two-dimensional examples of synthesis of multimaterial mechanisms of force inverters and gripping and clamping devices. An analysis on the formation of de facto hinges is presented based on the shape gradient information. A scheme to ensure a well-connected topology of the mechanism during the process of optimization is also presented.

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Mašek, Bohuslav, H. Staňková, Jiří Malina, Ludmila Skálová, and Lothar W. Meyer. "Physical Modelling of Microstructure Development during Technological Processes with Intensive Incremental Deformation." Key Engineering Materials 345-346 (August 2007): 943–46. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.943.

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Convenient structure adjustment and thereby the achievement of suitable material and technological properties is one of the very important areas of technological as well as material research. In general, this issue includes a great number of parameters and variables. To find suitable technological conditions, it is possible to use various kinds of modeling processes. One of them is the utilization of thermomechanical simulators, which allow simulating the conditions of the real processes to be simulated with sufficient accuracy. It is then possible to perform the optimization on smaller specimens, while monitoring the real conditions with higher accuracy. This method was used for the optimization of unconventional technological processes for selected alloying strategies of low-alloyed multiphase steels. These strategies are designed to be applied to technologies, which combine anisothermal forming and thermomechanical treatment of quasimassive components using intensive plastic deformation. Incremental deformations allow a high amount of deformation to be reached. It is also possible to obtain very fine grained structures by a suitable choice of temperature. By a suitable choice of temperature it is also possible to obtain structures with very fine grain. At the same time, the morphology of the structure and thus also its final mechanical properties can be significantly influenced this way.

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Xu, Wenxiang, Hongguang Sun, Wen Chen, and Huisu Chen. "Transport properties of concrete-like granular materials interacted by their microstructures and particle components." International Journal of Modern Physics B 32, no. 18 (July 15, 2018): 1840011. http://dx.doi.org/10.1142/s0217979218400118.

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Granular materials as typical soft matter, their transport properties play significant roles in durability and service life in relevant practical engineering structures. Physico-mechanical properties of materials are generally dependent of their microstructures including interfacial and porous characteristics. The formation of such microstructures is directly related to particle components in granular materials. Understanding the interactive mechanism of particle components, microstructures, and transport properties is a problem of great interest in materials research community. The resulting rigorous component-structure-property relations are also valuable for material design and microstructure optimization. This review article describes state-of-the-art progresses on modeling particle components, interfacial and porous configurations and incorporating these internal structural characteristics into modeling transport properties of granular materials. We mainly focus on three issues involving the simulation for geometrical components, the quantitative characterization for interfacial and porous microstructures, and the modeling strategies for diffusive behaviors of granular materials. In the first aspect, in-depth reviews are presented to realize complex morphologies of geometrical particles, to detect the overlap between adjacent nonspherical particles, and to simulate the random packings of nonspherical particles. In the second aspect, we emphasize the development progresses on the interfacial thickness and porosity distribution, the interfacial volume fraction, and the continuum percolation of soft particles representing compliant interfaces and discrete pores. In the final aspect, a literature review is also provided on modeling of transport properties on the forefront of the effective diffusion and anomalous diffusion in multiphase granular materials. Finally, some conclusions and perspectives for future studies are provided.

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Rauch, Bzowski, Kuziak, Uranga, Gutierrez, Isasti, Jacolot, and Kitowski. "Computer-Integrated Platform for Automatic, Flexible, and Optimal Multivariable Design of a Hot Strip Rolling Technology Using Advanced Multiphase Steels." Metals 9, no. 7 (June 29, 2019): 737. http://dx.doi.org/10.3390/met9070737.

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The paper presents the design and implementation of a computer system dedicated to the optimization of a hot strip rolling process. The software system proposed here involves the flexible integration of virtual models of various devices used in the process: furnace, descalers, rolling stands, accelerated cooling systems, and coiler. The user can configure an arbitrary sequence of operations and perform simulations for this sequence. The main idea of the system and its implementation details are described in the paper. Besides the computer science part, the material models describing the rolling parameters, microstructure evolution, phase transformations, and product properties are also presented. Effect of precipitation was accounted for various stages of the rolling cycle. Experimental tests were performed to generate data for identification of the models. These include plastometric tests, two-step compression tests, and dilatometric tests. Following this, physical simulations of rolling cycles were performed on Gleeble 3800 to supply data for the verification and validation of the models. Finally, case studies of modern industrial processes were performed, and the selected results are presented.

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Zhou, Shiwei, and Qing Li. "A microstructure diagram for known bounds in conductivity." Journal of Materials Research 23, no. 3 (March 2008): 798–811. http://dx.doi.org/10.1557/jmr.2008.0101.

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Two important analytical means—theoretical bounds and homogenization techniques—have gained increasing attention and led to substantial progress in material research. Nevertheless, there is a lack of relating material microstructures to an entire theoretical bound and exploring the possibility of generating multiple microstructures for each property value. This paper aims to provide a microstructure diagram in relation to “bound B” constructed by translation and Weiner bounds. The inverse homogenization technique is used to seek for the optimal phase distribution within a base cell model to make the effective conductivity approach the “bound B” in two- or three-phase material cases. The design shows that the “bound B” is exactly attainable for two-phase composites even with single-length-scale microstructures. Although the multiphase translations bounds are well known to be asymptotically attainable on some parts, they still appear too roomy to be attained by single-length-scale composites. Our results showed a certain improvement in the attainability of single-length-scale structural composites when compared with new bounds established by [V. Nesi: Proc. R. Soc. Edinburgh Sect. A125, 1219 (1995)], [V. Cherkaev: Variational Methods for Structural Optimization (Springer Verlag, New York, 2000)], and (N. Albin et al.: Proc. R. Soc. London Ser. A463, 2031 (2007)]. Applicability of the translation bounds to the composites with high-contrast conductivities of phase compositions is also studied in this paper. Finally, we explore the multiple solutions to the optimal microstructures and categorize them into three classes in line with their topological resemblance, namely, spatially identical, unidirectionally identical, and bidirectionally different solutions.

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ZHOU, XUELING, YIFAN LIU, WEN YU, SHAOJIE CHENG, and JIANZHONG YIN. "SIMULATION OF SOLID–LIQUID SUSPENSION AND SCALE-UP OF AGAROSE GEL ACTIVATION REACTOR." Journal of Mechanics in Medicine and Biology 16, no. 06 (September 2016): 1650087. http://dx.doi.org/10.1142/s0219519416500871.

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Agarose gel activation reaction, which is of great importance in preparing the carrier of the column packing material for blood purification, would be significantly influenced by the configuration and parameter of reactor. In order to optimize the structure design of the reactor and operating parameters of the process, the characteristics of suspension system composed of agarose gel, NaOH, water, 3-allyl bromide, and activated alumina were simulated numerically utilizing an Eulerian multiphase flow model and multi-reference frame (MRF) approach. The effect of impeller configuration was studied with three typical impellers, including Rushton disk turbine (DT), pitched blade downflow turbine (PBTD45), and pitched blade upflow turbine (PBTU45). The results showed that the optimum solid suspension was obtained using PBTD45 impeller with a diameter of 100[Formula: see text]mm and critical suspension speed of 570[Formula: see text]rpm in a 20[Formula: see text]L stirred reactor. In addition, the critical suspension speeds using the three impellers were calculated and the errors were all within the engineering allowance. Finally, the feasibility of scale-up design for agarose gel activation reactor was preliminarily discussed. The results would be useful to the optimization and scale-up of relevant reactor design.

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Kishkentayeva, A. S., S. M. Adekenov, and P. B. Drašar. "Production Technologies of Pharmacologically Active Sesquiterpene Lactones." Eurasian Chemico-Technological Journal, no. 4 (December 28, 2018): 325. http://dx.doi.org/10.18321/ectj766.

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Sesquiterpene lactones form a large group belonging to natural terpenoids series, generally found in plants of Asteraceae family and exhibiting anti-tumor, antiviral, immunostimulant, antifungal, antimicrobial, anti-inflammatory, antimutagenic, growth stimulating, antifeedant effects. Therefore, search for new compounds with a broad spectrum of pharmacological activity in this series provides the opportunities for effective and conceptually new drug design. The basis of the technology for the isolation of sesquiterpene lactones is the extraction of raw materials with various organic solvents, followed by chromatographic purification. Sesquiterpene lactones have no common properties that can be used in their isolation. Some of them are well soluble in non – polar solvents, others-only in polar, in this regard, the methods of isolation of sesquiterpene lactones are diverse. The greatest number of sesquiterpene lactones is isolated from leaves and flowers, slightly less – from roots and bark. Therefore, the development of methods for their isolation is associated with the selection of solvents and optimization of the extraction mode. Unfortunately, very few medicines based on sesquiterpene lactones are produced by the pharmaceutical companies today. Complexity of introduction of pharmacologically active sesquiterpene lactones technology into pharmaceutical production is in imperfection of their isolation methods from plant raw material, their purification and separation from obtained extracts. Production technologies of the patented medicines "Santonin", "Alanton" on the basis of sesquiterpene lactones are multiphase, labor-intensive, implying the use of many toxic organic solvents which is against the international GMP standards.

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Chalusiak, Maciej, Weronika Nawrot, Szymon Buchaniec, and Grzegorz Brus. "Swarm Intelligence-Based Methodology for Scanning Electron Microscope Image Segmentation of Solid Oxide Fuel Cell Anode." Energies 14, no. 11 (May 25, 2021): 3055. http://dx.doi.org/10.3390/en14113055.

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Segmentation of images from scanning electron microscope, especially multiphase, poses a drawback in their microstructure quantification process. The labeling process must be automatized due to the time consumption and irreproducibility of the manual labeling procedure. Here we show a swarm intelligence-driven filtration methodology performed on raw solid oxide fuel cell anode’s material images to improve the segmentation methods’ performance. The methodology focused on two significant parts of the segmentation process, which are filtering and labeling. During the first one, the images underwent filtering by applying a series of filters, whose operation parameters were determined using Particle Swarm Optimization upon a dedicated cost function. Next, Seeded Region Growing, k-Means Clustering, Multithresholding, and Simple Linear Iterative Clustering Superpixel algorithms were utilized to label the filtered images’ regions into consecutive phases in the microstructure. The improvement was presented for three different metrics: the Misclassification Ratio, Structural Similarity Index Measure, and Mean Squared Error. The obtained distribution of metrics’ performances was based on 200 images, with and without filtering. Results indicate an improvement up to 29%, depending on the metric and method used. The presented work contributes to the ongoing efforts to automatize segmentation processes fully for an increasing number of tomographic measurements, particularly in solid oxide fuel cell research.

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Carlone, Pierpaolo, and Gaetano S. Palazzo. "Flow Monitoring and Permeability Measurements in LCM Processes by the Means of a Dielectric Sensor." Key Engineering Materials 504-506 (February 2012): 289–94. http://dx.doi.org/10.4028/www.scientific.net/kem.504-506.289.

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Liquid Composite Molding (LCM) processes, widely used to manufacture thermosetting matrix composite materials, are characterized by the impregnation of a dry fibrous perform, by the means of injection or infusion of the catalyzed resin. The increasing industrial application of LCM processes is due to the demand for high performances materials and constant quality productions, combined with the need to reduce human intervention and costs due manufacturing inefficiency. The opportune planning of LCM processes results, however, very complex, being the process characterized by non-stationary multiphase flows in a three dimensional porous domain with anisotropic permeability, by the cure reaction, influencing the temperature, the degree of cure, and the viscosity of the processing resin, and by the elastic deformation of the fiber bundle due to the applied pressure, which affects significantly preform properties. Nowadays, process planning and optimization is mainly based on trial and error procedures or on computational simulations. Although the existing simulation packages, developed thanks to the efforts spent by several research groups, led to a better understanding and more effective application of LCM processes, on line monitoring of resin flow is very desirable to account for unpredicted variations of processing conditions. Moreover, an accurate experimental evaluation of fiber preform properties is crucial for a reliable process simulation. In this paper, a dielectric capacitive system has been designed, realized, and applied to monitor the position of the saturated as well as the unsaturated flow fronts and to evaluate in plane bulk permeability and tow permeability of dual scale fibrous porous media, typically used in LCM processes. The used sensors, analysed and optimized by computational simulations, have been embedded into opportunely designed rigid dies. Several preform impregnation tests have been performed. Good agreement has been found between results provided by the used system and data obtained using conventional techniques, evidencing the capability of proposed method for process monitoring, as well as for material properties evaluation.

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Caballero-Flores, R., V. Franco, A. Conde, K. E. Knipling, and M. A. Willard. "Optimization of the refrigerant capacity in multiphase magnetocaloric materials." Applied Physics Letters 98, no. 10 (March 7, 2011): 102505. http://dx.doi.org/10.1063/1.3560445.

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Asadpoure, Alireza, Mazdak Tootkaboni, and Lorenzo Valdevit. "Topology optimization of multiphase architected materials for energy dissipation." Computer Methods in Applied Mechanics and Engineering 325 (October 2017): 314–29. http://dx.doi.org/10.1016/j.cma.2017.07.007.

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Pan, Huanquan, and Abbas Firoozabadi. "Complex Multiphase Equilibrium Calculations by Direct Minimization of Gibbs Free Energy by Use of Simulated Annealing." SPE Reservoir Evaluation & Engineering 1, no. 01 (February 1, 1998): 36–42. http://dx.doi.org/10.2118/37689-pa.

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Summary The computational problems in reservoir fluid systems are mainly in the critical region and in liquid-liquid (LL), vapor-liquid-liquid (VLL), and higher-phase equilibria. The conventional methods to perform phase-equilibrium calculations with the equality of chemical potentials cannot guarantee a correct solution. In this study, we propose a simple method to calculate the equilibrium state by direct minimization of the Gibbs free energy of the system at constant temperature and pressure. We use the simulated annealing (SA) algorithm to perform the global minimization. Estimates of key parameters of the SA algorithm are also made for phase-behavior calculations. Several examples, including (1) VL equilibria in the critical region, (2) VLL equilibria for reservoir fluid systems, (3) VLL equilibria for an H2S-containing mixture, and (4) VL-multisolid equilibria for reservoir fluids, show the reliability of the method. Introduction Consider the multicomponent-multiphase flash at constant temperature and pressure sketched in Fig. 1. The equilibrium state (the right side of Fig. 1) consists of np phases; each Phase j consists of n1j,n2j,n3j,. . . nncj, moles. From the second law of thermodynamics, the equilibrium state is a state in which the Gibbs free energy of the system is a minimum. The minimum of Gibbs free energy is a sufficient and necessary condition for the equilibrium state. At constant temperature and pressure (note that all calculations will be performed at this condition), the Gibbs free energy of the system in Fig. 1 can be written asEquation 1 where Gj is the Gibbs free energy of Phase j, and G is the total Gibbs free energy of the system. When G is minimized with respect to nij (i=1, 2, . . ., nc; j=1, 2, . . ., np) subject to the following constraints:material balance of Component i,Equation 2the non-negative mole number of Component i in Phase j,Equation 3 The optimized values, ni(i=1, 2, . . ., nc; j=1, 2, . . ., np) are the mole numbers of the equilibrium state. The global minimization with the constraints is difficult to implement; as a consequence, direct minimization of the Gibbs free energy has not been widely applied. Conventional Approach for Phase-Equilibrium Calculations The equality of chemical potentials of each species in all phases is often used to perform the phase-equilibrium calculations:Equation 4 The number of equations in Eq. 4 is nc×(np-1), plus nc material-balance equations given by Eq. 2; a total of nc×np equations are provided. The mole numbers nij (i=1, 2, . . ., nc; j=1, 2, . . ., np) of the equilibrium state are determined by solving these nc×np nonlinear equations. The widely used solution methods are the successive substitution method through phase-equilibrium constants Ki (i=1, 2, . . ., nc) and direct application of the Newton method. Both approaches require an initial guess and work quite well for VL equilibria except in the near-critical region. In the critical region, the successive substitution becomes intolerably slow and the Newton method may fail when the initial guess is not close to the true solution. In LL and VLL equilibria, both methods may compute false solutions. The falseness is because Eq. 4 is only a necessary condition for an equilibrium state.1 The tangent-plane-distance (TPD) approach has been introduced to recognize the false solution.1,2 The concept of stability analysis is used to derive the TPD. Tangent-Plane-Distance Approach Suppose w is a given overall composition. The mathematical expression of the TPD function isEquation 5a where D(u) is the distance function between the Gibbs free energy surface and its tangent plane at composition w. When D(u) is minimized with respect to ui(i=1, 2, . . ., nc) subject toEquations 5b and 5c the optimized value, D*, provides the stability analysis of the mixture at composition w. If D* 0, the system is absolutely stable; if D*<0, the system is unstable. The optimized composition u* is a good approximation of the incipient phase composition. The application of TPD criterion improves the reliability of conventional-phase equilibrium by providing a guideline to judge that the mixture is absolutely stable. When unstable, a good initial composition u* strengthens the convergence of the Newton or the successive substitution methods. Unfortunately, the solution to Eq. 5 is also an optimization problem with constraints. Michelson2 has solved the problem by locating the stationary points of the TPD function. This approach needs to solve (nc-1) nonlinear equations. A good initial guess is required to avoid the trivial solution. Because not all stationary points can be found with this method, phase stability cannot always be guaranteed.3 Later, we will give an example of a CO2-crude system for which the approach of locating the stationary points misses the true solution in spite of its novelty and strengths. Several methods have been proposed to improve the calculation of the TPD function. These include homotopy-continuation,4 branch and bound3 and differential geometry, and the theory of differential equations.5

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Gao, Tong, and Weihong Zhang. "A mass constraint formulation for structural topology optimization with multiphase materials." International Journal for Numerical Methods in Engineering 88, no. 8 (May 1, 2011): 774–96. http://dx.doi.org/10.1002/nme.3197.

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Gan, Ning, and Qianxuan Wang. "Topology optimization of multiphase materials with dynamic and static characteristics by BESO method." Advances in Engineering Software 151 (January 2021): 102928. http://dx.doi.org/10.1016/j.advengsoft.2020.102928.

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Chattopadhyay, Kinnor. "Multiphase Flows in Materials Processing: The Road Map for Modeling, Experimentation, Validation, and Optimization." JOM 70, no. 10 (August 21, 2018): 2048–50. http://dx.doi.org/10.1007/s11837-018-3095-6.

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Strnad, G., D. Biro, and I. Vida-Simiti. "Contributions to Processing of Self-Lubricated, Nanocomposite Wear Resistant Coatings by Reactive UM Magnetron Co-Sputtering." Advanced Materials Research 23 (October 2007): 197–200. http://dx.doi.org/10.4028/www.scientific.net/amr.23.197.

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Recently a great deal of attention has been devoted to sputtering technology for nanostructured coatings. Wear resistant nanocomposite coatings are very promising materials, which can be easily scaled up for industrial production. Therefore, reactive magnetron sputtering of alloy targets or co-sputtering of elemental metal targets are now intensively investigated. Present paper presents some results of our research work for optimization of tribological properties by definition of selected parameters for reactive sputtering process conditions of self-lubricated carbon doped TiAlN coating. Tailored nanocomposite thin films of multicomponent and multiphase materials have been performed by DC reactive UM magnetron co-sputtering of TiAl and TiC target materials in Ar–N2 respectively C2H2 and CH4 as carbon precursor gases.

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Lee, Joong Seok, Peter Göransson, and Yoon Young Kim. "Topology optimization for three-phase materials distribution in a dissipative expansion chamber by unified multiphase modeling approach." Computer Methods in Applied Mechanics and Engineering 287 (April 2015): 191–211. http://dx.doi.org/10.1016/j.cma.2015.01.011.

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Chen, Jinmei, Xiaosong Jiang, Hongliang Sun, Zhenyi Shao, Yongjian Fang, and Rui Shu. "Phase transformation and strengthening mechanisms of nanostructured high-entropy alloys." Nanotechnology Reviews 10, no. 1 (January 1, 2021): 1116–39. http://dx.doi.org/10.1515/ntrev-2021-0071.

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Abstract High-entropy alloys (HEAs) have become a research focus because of their easy access to nanostructures and the characteristics of high strength, hardness, wear resistance, and oxidation resistance, and have been applied in aerospace lightweight materials, ultrahigh temperature materials, high-performance materials, and biomimetic materials. At present, the study of HEAs mainly focuses on the microstructure and mechanical properties. HEAs of Mo, Ti, V, Nb, Hf, Ta, Cr, and W series have high strength, while HEAs of Fe, Co, Ni, Cr, Cu, and Mn series have good toughness. However, the emergence of medium-entropy alloys, metastable HEAs, dual-phase HEAs, and multiphase HEAs increased the complexity of the HEA system, and the phase transition mechanism and strengthening and toughening mechanisms were not fully established. In this article, the preparation, phase formation, phase transformation as well as strengthening and toughening mechanisms of the HEAs are reviewed. The inductive effects of alloying elements, temperature, magnetism, and pressure on the phase transformation were systematically analyzed. The strengthening mechanisms of HEAs are discussed, which provides a reference for the design and performance optimization of HEAs.

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Reischig, Péter, Andrew King, Laura Nervo, Nicola Viganó, Yoann Guilhem, Willem Jan Palenstijn, K. Joost Batenburg, Michael Preuss, and Wolfgang Ludwig. "Advances in X-ray diffraction contrast tomography: flexibility in the setup geometry and application to multiphase materials." Journal of Applied Crystallography 46, no. 2 (March 14, 2013): 297–311. http://dx.doi.org/10.1107/s0021889813002604.

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Diffraction contrast tomography is a near-field diffraction-based imaging technique that provides high-resolution grain maps of polycrystalline materials simultaneously with the orientation and average elastic strain tensor components of the individual grains with an accuracy of a few times 10−4. Recent improvements that have been introduced into the data analysis are described. The ability to process data from arbitrary detector positions allows for optimization of the experimental setup for higher spatial or strain resolution, including high Bragg angles (0 < 2θ < 180°). The geometry refinement, grain indexing and strain analysis are based on Friedel pairs of diffraction spots and can handle thousands of grains in single- or multiphase materials. The grain reconstruction is performed with a simultaneous iterative reconstruction technique using three-dimensional oblique angle projections and GPU acceleration. The improvements are demonstrated with the following experimental examples: (1) uranium oxide mapped at high spatial resolution (300 nm voxel size); (2) combined grain mapping and section topography at high Bragg angles of an Al–Li alloy; (3) ferrite and austenite crystals in a dual-phase steel; (4) grain mapping and elastic strains of a commercially pure titanium sample containing 1755 grains.

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Wang, Chenchong, Qing Cui, Xiaojie Huo, Chi Zhang, and Wei Xu. "Design of Reduced Activation Ferritic/Martensitic Steels by Multiphase Optimization during the Entire Processing." ISIJ International 59, no. 9 (September 15, 2019): 1715–22. http://dx.doi.org/10.2355/isijinternational.isijint-2019-143.

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Sabina, Federico J., Yoanh Espinosa-Almeyda, Raúl Guinovart-Díaz, Reinaldo Rodríguez-Ramos, and Héctor Camacho-Montes. "Effective Complex Properties for Three-Phase Elastic Fiber-Reinforced Composites with Different Unit Cells." Technologies 9, no. 1 (February 1, 2021): 12. http://dx.doi.org/10.3390/technologies9010012.

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The development of micromechanical models to predict the effective properties of multiphase composites is important for the design and optimization of new materials, as well as to improve our understanding about the structure–properties relationship. In this work, the two-scale asymptotic homogenization method (AHM) is implemented to calculate the out-of-plane effective complex-value properties of periodic three-phase elastic fiber-reinforced composites (FRCs) with parallelogram unit cells. Matrix and inclusions materials have complex-valued properties. Closed analytical expressions for the local problems and the out-of-plane shear effective coefficients are given. The solution of the homogenized local problems is found using potential theory. Numerical results are reported and comparisons with data reported in the literature are shown. Good agreements are obtained. In addition, the effects of fiber volume fractions and spatial fiber distribution on the complex effective elastic properties are analyzed. An analysis of the shear effective properties enhancement is also studied for three-phase FRCs.

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Ghiotti, Andrea, Stefania Bruschi, and Paolo F. Bariani. "Determination of Yield Locus of Sheet Metal at Elevated Temperatures: A Novel Concept for Experimental Set-Up." Key Engineering Materials 344 (July 2007): 97–104. http://dx.doi.org/10.4028/www.scientific.net/kem.344.97.

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The constant demand of increasing performances and safety in vehicle industry has led significant innovations in the materials used in sheet metal forming processes. In particular, multiphase steels and lightweight alloys have known higher and higher importance, thanks to the development of new stamping processes at elevated temperatures, which guarantee, at the same time, better formability, lower springback and more accurate micro-structural control in the formed sheets. With respect to these aspects, the correct design and optimization of the new processes cannot prescind of the mechanical characterization of materials in biaxial stress conditions, especially when it strongly varies according to the stress and temperature. In this paper, a novel experimental set-up is presented for determining the in-plane yield locus of sheet metals at elevated temperatures. A cruciform specimen, whose geometry was optimized by numerical simulation, is used for the study of the yield locus in the range of biaxial tensile stresses. The test machine concept is based on punch-wedge mechanism, which uses the vertical movement of the press for the deformation of the specimen along two perpendicular axes. In the first part of the paper, the optimization of the cruciform specimen by thermo-mechanical FE analyses is outlined. Details on the experimental set-up are then given with the description of the apparatus, the measurement of plastic strains and the heating system for tests at elevated temperatures.

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Escobar Jaramillo, Mateo, and Claudia Patricia Ossa Orozco. "Multiphase calcium phosphate nanorods produced by microwave-assisted molten salt synthesis: Particle size RSM optimization." Ceramics International 47, no. 12 (June 2021): 17202–9. http://dx.doi.org/10.1016/j.ceramint.2021.03.031.

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Samuely, Tomas, Shi-Xia Liu, Nikolai Wintjes, Marco Haas, Silvio Decurtins, Thomas A. Jung, and Meike Stöhr. "Two-Dimensional Multiphase Behavior Induced by Sterically Hindered Conformational Optimization of Phenoxy-Substituted Phthalocyanines." Journal of Physical Chemistry C 112, no. 15 (April 2008): 6139–44. http://dx.doi.org/10.1021/jp710887g.

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Lei, Jing. "Data Driven Based Method for Field Information Sensing." Mathematical Problems in Engineering 2014 (2014): 1–17. http://dx.doi.org/10.1155/2014/353970.

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Acquiring the field information on temperature, pressure, concentration, or velocity is crucial for the monitoring of chemical reactors, multiphase flow systems, heat transfer units, atmospheric pollutants diffusion, and underground pollutant migration. In this paper, a dimensionality reduction matrix completion (DRMC) method is proposed for the field information sensing (FIS) of objects of interest from the scattered point measurement data. An objective functional that casts the FIS task as an optimization problem is proposed. An iteration scheme is developed for solving the proposed objective functional. Numerical simulations are implemented to validate the feasibility and effectiveness of the proposed algorithm. It is found that differing from common inverse problems, numerical simulation approaches, and tomography based field measurement methods, in the proposed method the field information can be reconstructed without the knowledge on governing equations of the measurement objects, initial conditions, boundary conditions, and physical properties of materials, except the limited number of the measurement data. As a result, an alternative insight is introduced for the FIS problems.

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Nouri, Alireza, Hans H. Vaziri, Hadi Arbi Belhaj, and M. Rafiqul Islam. "Comprehensive Transient Modeling of Sand Production in Horizontal Wellbores." SPE Journal 12, no. 04 (December 1, 2007): 468–74. http://dx.doi.org/10.2118/84500-pa.

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Summary Installing sand control in long horizontal wells is difficult and particularly challenging in offshore fields. It is, therefore, imperative to make decisions with regard to the most optimum completion type objectively and based on reliable assessment of the sanding potential and its severity over the life of the well for the intended production target. This paper introduces a predictive tool that forecasts not only the initiation of sanding, but also its rate and severity in real time. A series of well-documented experiments on a large-size horizontal wellbore was simulated using a finite difference numerical model. The model accounts for the interaction between fluid flow and mechanical deformation of the medium, capturing various mechanisms of failure. The model allows capturing the episodic nature of sanding and the resulting changes in the geometry and formation consistency and behavior within the sand impacted regions. Sand detachment is simulated by removal of the elements that are deemed to have satisfied the criteria for sanding based on considerations of physics, material behaviour and laws of mechanics. The proposed numerical model is designed to account for many of the factors and mechanisms that are known to influence sanding in the field and as such can be used as a practical tool for predicting the frequency and severity of sand bursts and changes in operating conditions that can be considered for mitigating or managing such problems. The model shows reasonable agreement with the experimental results in terms of borehole deformation and sanding rates. The model correctly predicted initiation of shear failure from the sides of the borehole and its propagation to the boundaries of the sample. It was further seen that the propagation of the shear failed zone resulting from sand production agreed well with the numerical pattern of failure growth upon removal of elements satisfying the sanding criteria. The approach and concepts used are considered suitable for application to field problems involving horizontal wells. Introduction A significant proportion of the future oil and gas production is expected to come from sand-prone reservoirs, many of which are offshore. While these reservoirs are highly prolific they are complex to develop and manage. Typical cost of completing a major offshore well exceeds $100 million and these wells are expected to remain productive for 20 years and longer. The control of solids production in these high-rate wells over the life of the well is a challenge and requires a good understanding of the mechanical behavior of the formation under a variety of conditions. Various options are available, ranging from placing active sand control, such as gravel pack and frac pack, to natural completion, such as a cased and perforated hole. Objectivity is required in choosing the correct completion type, which must account for the production strategy and natural changes in the reservoir such as changes in the stress state, permeability, and multiphase flow, including water cut. Once the completion type is chosen, it must be operated optimally to maximize production while maintaining efficiency and longevity. For instance, in sand-control completions, operations must be tailored to mitigate generation and transport of fines that can cause plugging of the gravel pack and lead to screen erosion, whereas in natural completions, the emphasis would be in preventing formation sand production or keeping it under the tolerance that can be handled by the facility. Utilization of a reliable sand production prediction tool is essential in selecting the optimum completion technique and optimization of the operational conditions.

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Guo, Pei, Jiri Zhou, Rongjiang Ma, Nanyang Yu, and Yanping Yuan. "Biogas Production and Heat Transfer Performance of a Multiphase Flow Digester." Energies 12, no. 10 (May 22, 2019): 1960. http://dx.doi.org/10.3390/en12101960.

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Traditional static anaerobic digestion technology presents the disadvantages of a low gas production rate and long digestion cycle, which is not conducive to the treatment of livestock manure. A 12 m3 multiphase flow anaerobic digester (MFD) was developed in this study to improve the biogas production rate and maintain constant temperature digestion during winters. Full-scale field experiments were conducted on the biogas production rate at different temperatures, the dynamic digestion effects, and the dynamic heating digestion effects of the system at Sichuan, China. A comparison of the dynamic and static digestion results of 50 days indicated that the biogas production for the dynamic digestion (DD) group was 115.22 m3 or 127.1% higher than that of the static digestion (SD) group with the same digestion temperature. The results of the heat transfer performance experiment revealed that the heat transfer rate of the system increased significantly, and the temperature of the biogas slurry increased rapidly. The optimization analysis of the system was based on the experimental results of the relationship between the slurry temperature and biogas production rate, and the economical digestion temperature of the system was proposed and calculated. Different insulation materials or insulation thicknesses have an influence on the economical digestion temperature. Additionally, the economical digestion temperature of the system in which the polystyrene insulation layer with a thickness of 90 mm was used, was found to be 27.2 °C. When digestion temperature was 22.3 °C, the energy efficiency ratio (EER) of dynamic anaerobic digestion system is 1. The advantages of MFD are low biogas production unit cost and high heat and mass transfer rate. However, the disadvantage of high operation energy consumption needs further improvement. And additional energy was required when system digestion temperature below 22.3 °C. The proposed MFD and dynamic anaerobic digestion system can play a significant role in using biomass resources and promoting the development of biogas projects.

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Kang, Zhan, Yaguang Wang, and Yiqiang Wang. "Structural topology optimization with minimum distance control of multiphase embedded components by level set method." Computer Methods in Applied Mechanics and Engineering 306 (July 2016): 299–318. http://dx.doi.org/10.1016/j.cma.2016.04.001.

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Li, Hao, Zhen Luo, Mi Xiao, Liang Gao, and Jie Gao. "A new multiscale topology optimization method for multiphase composite structures of frequency response with level sets." Computer Methods in Applied Mechanics and Engineering 356 (November 2019): 116–44. http://dx.doi.org/10.1016/j.cma.2019.07.020.

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Breault, Ronald W., and Justin Weber. "Saturation Carrying Capacity for Group A Particles in a Circulating Fluidized Bed." Energies 14, no. 10 (May 13, 2021): 2809. http://dx.doi.org/10.3390/en14102809.

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Empirical models continue to play a significant role in the design process of multiphase chemical reactors, particularly riser reactors in circulating fluidized bed (CFB) processes. It is imperative that accurate, industrial relevant correlations are developed to aid these design efforts. Using poor correlations could result in startup issues and significant redesign work. In this work, a new correlation is proposed to predict the saturation carrying capacity of Geldart Group A particles. This new correlation improves upon the currently available correlations for these materials and covers a broad range of Geldart Group A particles (particle diameters from 52 to 70 µm, and Archimedes numbers ranging from 5 to 20), superficial gas velocities (1 to 4 m/s), and riser diameters (0.066 to 0.3048 m). The new correlation has an Absolute Average Percent Deviation of only 17.6%, making it the most accurate correlation for Geldart Group A particles in the current literature.

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Frimpong, Samuel, Oluropo Rufus Ayodele, and Jozef Szymanski. "Oil Sands Slurry Flow in Flexible Pipe." Journal of Fluids Engineering 126, no. 1 (January 1, 2004): 133–38. http://dx.doi.org/10.1115/1.1637929.

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Production cost and efficiency optimization for the Athabasca oil sands is a key to securing North America’s energy supply. Current oil sands production cost is about $13/bbl compared with $1.25/bbl for conventional crude oil. The effort to reduce production cost must focus on truck haulage because it contributes the dominant component of the production cost of about 26%. Toward this objective, hydraulic transportation has become a competitive means for materials handling. There is a desire to extend the hydraulic transport system to production faces using mobile train of flexible pipelines to optimize the system efficiency and cost. This flexible arrangement introduces a unique set of hydraulic transport problems, which must be addressed through rigorous modeling and analysis. This paper provides multiphase oil sand slurry models in flexible pipelines. New mathematical models are developed to characterize the multi-phase flow of oil sands slurry. The models combine the effects of dispersed particles and the carrier continuous phases. The coupled equations of each field are solved numerically for flexible pipe configuration. The models yield the productivity and deliverability of bitumen slurry between two mine facilities. The flexible arrangement allows modeling in elbow-type joint at different angles and in conventional linear pipelines, enabling adaptation of pipelines to various mine outlays. Numerical examples are presented to show the applicability of the new model and to ascertain optimum operational conditions of the flexible pipes in mine layouts.

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Finnerman, Oskar, Narges Razmjoo, Ning Guo, Michael Strand, and Henrik Ström. "Reactor modelling assessment for urea-SNCR applications." International Journal of Numerical Methods for Heat & Fluid Flow 27, no. 7 (July 3, 2017): 1395–411. http://dx.doi.org/10.1108/hff-03-2016-0135.

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Purpose This work aims to investigate the effects of neglecting, modelling or partly resolving turbulent fluctuations of velocity, temperature and concentrations on the predicted turbulence-chemistry interaction in urea-selective non-catalytic reduction (SNCR) systems. Design/methodology/approach Numerical predictions of the NO conversion efficiency in an industrial urea-SNCR system are compared to experimental data. Reactor models of varying complexity are assessed, ranging from one-dimensional ideal reactor models to state-of-the-art computational fluid dynamics simulations based on the detached-eddy simulation (DES) approach. The models use the same reaction mechanism but differ in the degree to which they resolve the turbulent fluctuations of the gas phase. A methodology for handling of unknown experimental data with regard to providing adequate boundary conditions is also proposed. Findings One-dimensional reactor models may be useful for a first quick assessment of urea-SNCR system performance. It is critical to account for heat losses, if present, due to the significant sensitivity of the overall process to temperature. The most comprehensive DES setup evaluated is associated with approximately two orders of magnitude higher computational cost than the conventional Reynolds-averaged Navier–Stokes-based simulations. For studies that require a large number of simulations (e.g. optimizations or handling of incomplete experimental data), the less costly approaches may be favored with a tolerable loss of accuracy. Originality/value Novel numerical and experimental results are presented to elucidate the role of turbulent fluctuations on the performance of a complex, turbulent, reacting multiphase flow.

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de Lima, Yuri Theodoro Barbosa, Mateus das Neves Gomes, Liércio André Isoldi, Elizaldo Domingues dos Santos, Giulio Lorenzini, and Luiz Alberto Oliveira Rocha. "Geometric Analysis through the Constructal Design of a Sea Wave Energy Converter with Several Coupled Hydropneumatic Chambers Considering the Oscillating Water Column Operating Principle." Applied Sciences 11, no. 18 (September 16, 2021): 8630. http://dx.doi.org/10.3390/app11188630.

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The work presents a numerical study of a wave energy converter (WEC) device based on the oscillating water column (OWC) operating principle with a variation of one to five coupled chambers. The main objective is to evaluate the influence of the geometry and the number of coupled chambers to maximize the available hydropneumatic power converted in the energy extraction process. The results were analyzed using the data obtained for hydropneumatic power, pressure, mass flow rate, and the calculated performance indicator’s hydropneumatic power. The Constructal Design method associated with the Exhaustive Search optimization method was used to maximize the performance indicator and determine the optimized geometric configurations. The degrees of freedom analyzed were the ratios between the height and length of the hydropneumatic chambers. A wave tank represents the computational domain. The OWC device is positioned inside it, subject to the regular incident waves. Conservation equations of mass and momentum and one equation for the transport of the water volume fraction are solved with the finite volume method (FVM). The multiphase model volume of fluid (VOF) is used to tackle the water–air mixture. The analysis of the results took place by evaluating the performance indicator in each chamber separately and determining the accumulated power, which represents the sum of all the powers calculated in all chambers. The turbine was ignored, i.e., only the duct without it was analyzed. It was found that, among the cases examined, the device with five coupled chambers converts more energy than others and that there is an inflection point in the performance indicator, hydropneumatic power, as the value of the degree of freedom increases, characterizing a decrease in the value of the performance indicator. With the results of the hydropneumatic power, pressure, and mass flow rate, it was possible to determine a range of geometry values that maximizes the energy conversion, taking into account the cases of one to five coupled chambers and the individual influence of each one.

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Journal articles on the topic 'Multiphase material optimization'

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