A thermophotovoltaic (TPV) system is able to convert directly thermal energy, generated by a high temperature heat source, into electricity through thermophotovoltaic cells. Although the energy flux has three steps, designing a TPV system with high efficiency is a challenging task. This particular device has been studied for house heating applications in order to reach better performances and higher efficiency values, compared to traditional boilers. The main issue is to achieve high and uniform temperature values on the emitter surface. In the first step of this project a novel swirl gas burner is being developed and optimized in order to fulfill these objectives. Experimental tests have been performed on a first prototype considering different values of input power, thus fuel flow rate and air mass flow rate, changing some geometrical characteristics of the burner. Collected results have then be used to create response surface functions, to be used in a multi-objective optimization considering efficiency, maximum and mean temperature of the emitter.
{"title":"Design and Optimization of a Gas Burner for TPV Application","authors":"Giulio Cassio, C. Poloni, V. Pediroda, G. Mosetti","doi":"10.1299/JCST.7.156","DOIUrl":"https://doi.org/10.1299/JCST.7.156","url":null,"abstract":"A thermophotovoltaic (TPV) system is able to convert directly thermal energy, generated by a high temperature heat source, into electricity through thermophotovoltaic cells. Although the energy flux has three steps, designing a TPV system with high efficiency is a challenging task. This particular device has been studied for house heating applications in order to reach better performances and higher efficiency values, compared to traditional boilers. The main issue is to achieve high and uniform temperature values on the emitter surface. In the first step of this project a novel swirl gas burner is being developed and optimized in order to fulfill these objectives. Experimental tests have been performed on a first prototype considering different values of input power, thus fuel flow rate and air mass flow rate, changing some geometrical characteristics of the burner. Collected results have then be used to create response surface functions, to be used in a multi-objective optimization considering efficiency, maximum and mean temperature of the emitter.","PeriodicalId":196913,"journal":{"name":"Journal of Computational Science and Technology","volume":"126 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113982612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There are two major methods, experimental and numerical approaches, for dealing with the strain and stress analysis essential to reliability assessment of electronic packaging. Both approaches are mutually complementary in view point of their assessment capability. In this paper, experimental and numerical simulation results for analyzing some reliability issues of electronic packages were reviewed, and the role of both approaches were discussed.
{"title":"Experimental and Numerical Approaches for Reliability Evaluation of Electronic Packaging","authors":"Soon-Bok Lee, J. Jang","doi":"10.1299/JCST.7.265","DOIUrl":"https://doi.org/10.1299/JCST.7.265","url":null,"abstract":"There are two major methods, experimental and numerical approaches, for dealing with the strain and stress analysis essential to reliability assessment of electronic packaging. Both approaches are mutually complementary in view point of their assessment capability. In this paper, experimental and numerical simulation results for analyzing some reliability issues of electronic packages were reviewed, and the role of both approaches were discussed.","PeriodicalId":196913,"journal":{"name":"Journal of Computational Science and Technology","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114912289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In our previous papers, the two-layer viscous shallow-water equations were derived from the three-dimensional Navier-Stokes equations under the hydrostatic assumption. Also, it was noted that the combination of upper and lower equations in the two-layer model produces the classical one-layer equations if the density of each layer is the same. Then, the two-layer equations were approximated by a finite element method which followed our numerical scheme established for the one-layer model in 1978. Also, it was numerically demonstrated that the interfacial instability generated when the densities are the same can be eliminated by providing a sufficient density difference. In this paper, we newly show that conservation laws are still valid in the two-layer model. Also, we show results of a new physical experiment for the interfacial instability.
{"title":"Two-Layer Viscous Shallow-Water Equations and Conservation Laws","authors":"H. Kanayama, Hiroshi Dan","doi":"10.1299/JCST.3.373","DOIUrl":"https://doi.org/10.1299/JCST.3.373","url":null,"abstract":"In our previous papers, the two-layer viscous shallow-water equations were derived from the three-dimensional Navier-Stokes equations under the hydrostatic assumption. Also, it was noted that the combination of upper and lower equations in the two-layer model produces the classical one-layer equations if the density of each layer is the same. Then, the two-layer equations were approximated by a finite element method which followed our numerical scheme established for the one-layer model in 1978. Also, it was numerically demonstrated that the interfacial instability generated when the densities are the same can be eliminated by providing a sufficient density difference. In this paper, we newly show that conservation laws are still valid in the two-layer model. Also, we show results of a new physical experiment for the interfacial instability.","PeriodicalId":196913,"journal":{"name":"Journal of Computational Science and Technology","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121242582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A lattice Boltzmann method (LBM) for two-phase viscoelastic fluid flows is proposed. The method is mainly an extension of the LBM for two-phase flows with large density differences proposed by Inamuro et al. [Journal of Computational Physics Vol. 198, No. 2 (2004), pp. 628-644]. The viscoelastic effects are introduced by the constitutive equation based on the Maxwell model, which has a spring and a dashpot connected with each other in series. The method is applied to simulations of a drop under shear flow in viscoelastic fluids and of a bubble rising in viscoelastic fluids. In the simulation of drop deformation under shear flows, the effects of viscoelasticity on the deformation and orientation angle are evaluated. In the simulation of bubble rising in viscoelastic fluids, a cusp configuration at the trailing edge is investigated and compared with the theoretical prediction and other numerical results.
提出了两相粘弹性流体流动的晶格玻尔兹曼方法。该方法主要是对Inamuro等人提出的具有大密度差的两相流的LBM的扩展[Journal of Computational Physics Vol. 198, No. 2 (2004)， pp. 628-644]。采用基于麦克斯韦模型的本构方程，引入了弹簧和阻尼器串联的粘弹性效应。将该方法应用于粘弹性流体剪切流下液滴和粘弹性流体中气泡上升的模拟。在剪切流作用下的液滴变形模拟中，研究了粘弹性对液滴变形和取向角的影响。在粘弹性流体中气泡上升的模拟中，研究了气泡尾缘的尖端结构，并与理论预测和其他数值结果进行了比较。
{"title":"Lattice Boltzmann Simulation of Two-Phase Viscoelastic Fluid Flows","authors":"M. Yoshino, Yasuyuki Toriumi, M. Arai","doi":"10.1299/JCST.2.330","DOIUrl":"https://doi.org/10.1299/JCST.2.330","url":null,"abstract":"A lattice Boltzmann method (LBM) for two-phase viscoelastic fluid flows is proposed. The method is mainly an extension of the LBM for two-phase flows with large density differences proposed by Inamuro et al. [Journal of Computational Physics Vol. 198, No. 2 (2004), pp. 628-644]. The viscoelastic effects are introduced by the constitutive equation based on the Maxwell model, which has a spring and a dashpot connected with each other in series. The method is applied to simulations of a drop under shear flow in viscoelastic fluids and of a bubble rising in viscoelastic fluids. In the simulation of drop deformation under shear flows, the effects of viscoelasticity on the deformation and orientation angle are evaluated. In the simulation of bubble rising in viscoelastic fluids, a cusp configuration at the trailing edge is investigated and compared with the theoretical prediction and other numerical results.","PeriodicalId":196913,"journal":{"name":"Journal of Computational Science and Technology","volume":"2008 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130731377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The balancing domain decomposition (BDD) method is a well-known preconditioner due to its excellent convergence rate. The BDD method includes the Neumann-Neumann preconditioner and a coarse grid correction. Several studies have considered applications of the BDD method to various phenomena and improvement of its convergence rate. However, in applying the BDD method to large-scale problems, it is difficult to solve the coarse problem of a coarse grid correction since the size of the coarse problem increases in proportion to the number of subdomains (i.e., the size of the original problem). Other preconditioners with a coarse grid correction have the same problem. To overcome this problem, use of a new preconditioner, namely, incomplete balancing domain decomposition with a diagonal-scaling (IBDD-DIAG) method is proposed in this study. The method is based on the BDD method, and constructed by an incomplete balancing preconditioner and a simplified diagonal-scaling preconditioner. Moreover, it is parallelized by the hierarchical domain decomposition method. To evaluate this new approach, some computational examples of large-scale problems are demonstrated.
{"title":"An Inexact Balancing Preconditioner for Large-Scale Structural Analysis","authors":"M. Ogino, R. Shioya, H. Kanayama","doi":"10.1299/JCST.2.150","DOIUrl":"https://doi.org/10.1299/JCST.2.150","url":null,"abstract":"The balancing domain decomposition (BDD) method is a well-known preconditioner due to its excellent convergence rate. The BDD method includes the Neumann-Neumann preconditioner and a coarse grid correction. Several studies have considered applications of the BDD method to various phenomena and improvement of its convergence rate. However, in applying the BDD method to large-scale problems, it is difficult to solve the coarse problem of a coarse grid correction since the size of the coarse problem increases in proportion to the number of subdomains (i.e., the size of the original problem). Other preconditioners with a coarse grid correction have the same problem. To overcome this problem, use of a new preconditioner, namely, incomplete balancing domain decomposition with a diagonal-scaling (IBDD-DIAG) method is proposed in this study. The method is based on the BDD method, and constructed by an incomplete balancing preconditioner and a simplified diagonal-scaling preconditioner. Moreover, it is parallelized by the hierarchical domain decomposition method. To evaluate this new approach, some computational examples of large-scale problems are demonstrated.","PeriodicalId":196913,"journal":{"name":"Journal of Computational Science and Technology","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127544915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Because of the large scale model of the finite element method in these days, it is required to find a method, which can be applied to the optimal analysis, to minimize the time of the estimate of the dynamic characteristics in changing the structure. We develop here a new perturbation method with a complimentary term which is effective for this purpose. By both the theoretical and numerical analysis, we show that the accuracy of the estimate is greatly improved even when the lower modes are not used by using the complimentary vector. This correction vector is obtained by Ma-Hagiwara modal method and adjusted to the change of the structure and the input style. We can show the possibility by using this method proposed here to reduce the analysis time drastically even when the structure is changed greatly on a large scale model.
{"title":"Proposal of New Perturbation Method with Complementary Term for Dynamic Characteristics Prediction of Modified Structure","authors":"K. Yamazaki, I. Hagiwara","doi":"10.1299/JCST.2.173","DOIUrl":"https://doi.org/10.1299/JCST.2.173","url":null,"abstract":"Because of the large scale model of the finite element method in these days, it is required to find a method, which can be applied to the optimal analysis, to minimize the time of the estimate of the dynamic characteristics in changing the structure. We develop here a new perturbation method with a complimentary term which is effective for this purpose. By both the theoretical and numerical analysis, we show that the accuracy of the estimate is greatly improved even when the lower modes are not used by using the complimentary vector. This correction vector is obtained by Ma-Hagiwara modal method and adjusted to the change of the structure and the input style. We can show the possibility by using this method proposed here to reduce the analysis time drastically even when the structure is changed greatly on a large scale model.","PeriodicalId":196913,"journal":{"name":"Journal of Computational Science and Technology","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124655711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, in-plane equivalent elastic modulus Ey of a hexagonal honeycomb sandwich, which includes the effect of face sheet interference, is studied by using numerical results of FEM. It is shown by comparing with deformation of practical honeycomb sandwich that there are two error factors to apply the rule of mixture to honeycomb sandwich. One of error factors is that the deformation of honeycomb core does not coincide with the face sheet since an inclined cell wall deforms much larger than a vertical cell wall. Another one is that the non-uniformity deformation of core along the height direction is induced by the interference effect with face sheet. Then, a method to calculate elastic modulus based on the compatibility condition of core and face sheet is proposed, and its validity is verified by using numerical results of FEM.
{"title":"Analysis of Equivalent Elastic Modulus of a Honeycomb Sandwich Considering Interference Effect with Face Sheet","authors":"Dai-heng Chen, Takeshi Matsumoto, S. Ozaki","doi":"10.1299/JCST.2.597","DOIUrl":"https://doi.org/10.1299/JCST.2.597","url":null,"abstract":"In this paper, in-plane equivalent elastic modulus Ey of a hexagonal honeycomb sandwich, which includes the effect of face sheet interference, is studied by using numerical results of FEM. It is shown by comparing with deformation of practical honeycomb sandwich that there are two error factors to apply the rule of mixture to honeycomb sandwich. One of error factors is that the deformation of honeycomb core does not coincide with the face sheet since an inclined cell wall deforms much larger than a vertical cell wall. Another one is that the non-uniformity deformation of core along the height direction is induced by the interference effect with face sheet. Then, a method to calculate elastic modulus based on the compatibility condition of core and face sheet is proposed, and its validity is verified by using numerical results of FEM.","PeriodicalId":196913,"journal":{"name":"Journal of Computational Science and Technology","volume":"1999 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128100807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The extended finite element method (X-FEM), which can model the domain without explicitly meshing the crack surface, can be used to perform stress analyses for solving fracture mechanics problems efficiently. In the present study, the principle of superposition is used to solve crack problems in conjunction with the X-FEM. In the proposed method, the surface load distributed on the crack surface, which is modeled implicitly by the interpolation functions with enrichment terms, is introduced to X-FEM analysis. Moreover, the energy release rate at the crack front is evaluated by the domain integral method with boundary integral terms for the surface load. The proposed method is verified through numerical analyses of two- and three-dimensional crack problems in linear fracture mechanics.
{"title":"Crack Analysis in Residual Stress Field by X-FEM","authors":"T. Nagashima, N. Miura","doi":"10.1299/JCST.3.136","DOIUrl":"https://doi.org/10.1299/JCST.3.136","url":null,"abstract":"The extended finite element method (X-FEM), which can model the domain without explicitly meshing the crack surface, can be used to perform stress analyses for solving fracture mechanics problems efficiently. In the present study, the principle of superposition is used to solve crack problems in conjunction with the X-FEM. In the proposed method, the surface load distributed on the crack surface, which is modeled implicitly by the interpolation functions with enrichment terms, is introduced to X-FEM analysis. Moreover, the energy release rate at the crack front is evaluated by the domain integral method with boundary integral terms for the surface load. The proposed method is verified through numerical analyses of two- and three-dimensional crack problems in linear fracture mechanics.","PeriodicalId":196913,"journal":{"name":"Journal of Computational Science and Technology","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114395702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With the rapid growth of WAN infrastructure and development of Grid middleware, it's become a realistic and attractive methodology to connect cluster machines on wide-area network for the execution of computation-demanding applications. Many existing parallel finite element (FE) applications have been, however, designed and developed with a single computing resource in mind, since such applications require frequent synchronization and communication among processes. There have been few FE applications that can exploit the distributed environment so far. In this study, we explore the feasibility of FE applications on the cluster-of-clusters. First, we classify FE applications into two types, tightly coupled applications (TCA) and loosely coupled applications (LCA) based on their communication pattern. A prototype of each application is implemented on the cluster-of-clusters. We perform numerical experiments executing TCA and LCA on both the cluster-of-clusters and a single cluster. Thorough these experiments, by comparing the performances and communication cost in each case, we evaluate the feasibility of FEA on the cluster-of-clusters.
{"title":"Feasibility Study of Parallel Finite Element Analysis on Cluster-of-Clusters","authors":"Masae Muraoka, H. Okuda","doi":"10.1299/JCST.3.77","DOIUrl":"https://doi.org/10.1299/JCST.3.77","url":null,"abstract":"With the rapid growth of WAN infrastructure and development of Grid middleware, it's become a realistic and attractive methodology to connect cluster machines on wide-area network for the execution of computation-demanding applications. Many existing parallel finite element (FE) applications have been, however, designed and developed with a single computing resource in mind, since such applications require frequent synchronization and communication among processes. There have been few FE applications that can exploit the distributed environment so far. In this study, we explore the feasibility of FE applications on the cluster-of-clusters. First, we classify FE applications into two types, tightly coupled applications (TCA) and loosely coupled applications (LCA) based on their communication pattern. A prototype of each application is implemented on the cluster-of-clusters. We perform numerical experiments executing TCA and LCA on both the cluster-of-clusters and a single cluster. Thorough these experiments, by comparing the performances and communication cost in each case, we evaluate the feasibility of FEA on the cluster-of-clusters.","PeriodicalId":196913,"journal":{"name":"Journal of Computational Science and Technology","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115364801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abrupt growth of displacement observed in the relationship between indent load and indent depth in nanoindentation of crystalline materials, so-called displacement burst, has been recognized as one of the representative examples of nanoscale plastic behavior (nanoplasticity). This phenomenon corresponds to the early stage of plastic deformation and is greatly influenced by the collective dislocation emission. In the present paper a simplified model is constructed for the first displacement burst with use of the elastic theory based on both the Hertzian contact theory and the classical dislocation theory to evaluate the displacement burst in nanoindentation. The result of the analytical model for the energy equilibrium revealed that there is a strong correlation between burst width and critical indent depth that corresponds to the dislocation emission. Finally, it is shown that more than one hundred high-density dislocations are generated simultaneously and surface step corresponding to the Burgers vector of dislocation dipole of each emitted dislocation causes significant displacement burst.
{"title":"Theoretical Investigation of the Displacement Burst Observed in Nanoindentation by Collective Dislocation Loops Nucleation Model","authors":"T. Tsuru, Y. Shibutani","doi":"10.1299/JCST.2.559","DOIUrl":"https://doi.org/10.1299/JCST.2.559","url":null,"abstract":"Abrupt growth of displacement observed in the relationship between indent load and indent depth in nanoindentation of crystalline materials, so-called displacement burst, has been recognized as one of the representative examples of nanoscale plastic behavior (nanoplasticity). This phenomenon corresponds to the early stage of plastic deformation and is greatly influenced by the collective dislocation emission. In the present paper a simplified model is constructed for the first displacement burst with use of the elastic theory based on both the Hertzian contact theory and the classical dislocation theory to evaluate the displacement burst in nanoindentation. The result of the analytical model for the energy equilibrium revealed that there is a strong correlation between burst width and critical indent depth that corresponds to the dislocation emission. Finally, it is shown that more than one hundred high-density dislocations are generated simultaneously and surface step corresponding to the Burgers vector of dislocation dipole of each emitted dislocation causes significant displacement burst.","PeriodicalId":196913,"journal":{"name":"Journal of Computational Science and Technology","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131209315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：