• Title/Summary/Keyword: Multiphysics

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Multi-level Modeling and Simulation of Electrical Vehicles (전기자동차의 다중레벨 모델링과 시뮬레이션)

  • Oh, Yong-Taek;van Duijsen, P.J.
    • The Journal of Korean Institute for Practical Engineering Education
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    • v.4 no.2
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    • pp.129-135
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    • 2012
  • There are many ways in which electric vehicles are mathematically modeled and simulated. The components have different physical background and models, but have to fit into one mathematical model. A multiphysics model structure is required. Depending on the goal of the simulation, there are various levels on which the simulation can be performed. This is called multilevel, consisting of a conceptual system level, a circuit level and a more detailed component level. This paper discusses which multiphysics models and multilevel simulations are required for the various components in an electric vehicle. Also, this simulation approach could improve the effectiveness of learning in engineering education.

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Process design for solution growth of SiC single crystal based on multiphysics modeling (다중물리 유한요소해석에 의한 SiC 단결정의 용액성장 공정 설계)

  • Yoon, Ji-Young;Lee, Myung-Hyun;Seo, Won-Seon;Shul, Yong-Gun;Jeong, Seong-Min
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.26 no.1
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    • pp.8-13
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    • 2016
  • A top-seeded solution growth (TSSG) is a method of growing SiC single crystal from the Si melt dissolved the carbon. In this study, multiphysics modeling was conducted using COMSOL Multiphysics, a commercialized finite element analysis package, to get analytic results about electromagnetic analysis, heat transfer and fluid flow in the Si melt. Experimental results showed good agreements with simulation data, which supports the validity of the simulation model. Based on the understanding about solution growth of SiC and our set-up, crystal growth was conducted on off-axis 4H-SiC seed crystal in the temperature range of $1600{\sim}1800^{\circ}C$. The grown layer showed good crystal quality confirmed with optical microscopy and high resolution X-ray diffraction, which also demonstrates the effectiveness of the multiphysics model to find a process condition of solution growth of SiC single crystal.

Testbed Design of PWM Controlled High Voltage Relay (PWM 제어용 고전압 릴레이의 테스트베드 설계)

  • Kim, Jin-Kwang
    • Journal of the Korean Society of Industry Convergence
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    • v.20 no.5
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    • pp.419-424
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    • 2017
  • The purpose of this study is to develop a virtual testbed capable of predicting the functional performance of a linear electromagnetic actuator for a high voltage relay in order to reduce its development costs and time. The virtual testbed is defined by a multiphysics coupling approach in order to consider the complex interactions of multi-domains such as the solenoid model of electromagnets, the mass-spring-damper model of mechanical systems, the electric circuit model for an external control unit, and the thermal model for predicting temperature variations. The performances of the existing high voltage relay were estimated by the virtual testbed, and then the effectiveness and validation of the proposed testbed were discussed in comparison with the experimental test results. This study showed that the virtual testbed can be applied in design, optimization, and investigation of high voltage relays.

DEVELOPMENT AND VALIDATION OF COUPLED DYNAMICS CODE 'TRIKIN' FOR VVER REACTORS

  • Obaidurrahman, K.;Doshi, J.B.;Jain, R.P.;Jagannathan, V.
    • Nuclear Engineering and Technology
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    • v.42 no.3
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    • pp.259-270
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    • 2010
  • New generation nuclear reactors are designed using advanced safety analysis methods. A thorough understanding of different interacting physical phenomena is necessary to avoid underestimation and overestimation of consequences of off-normal transients in the reactor safety analysis results. This feature requires a multiphysics reactor simulation model. In this context, a coupled dynamics model based on a multiphysics formulation is developed indigenously for the transient analysis of large pressurized VVER reactors. Major simplifications are employed in the model by making several assumptions based on the physics of individual phenomenon. Space and time grids are optimized to minimize the computational bulk. The capability of the model is demonstrated by solving a series of international (AER) benchmark problems for VVER reactors. The developed model was used to analyze a number of reactivity transients that are likely to occur in VVER reactors.

MC21/CTF and VERA multiphysics solutions to VERA core physics benchmark progression problems 6 and 7

  • Kelly, Daniel J. III;Kelly, Ann E.;Aviles, Brian N.;Godfrey, Andrew T.;Salko, Robert K.;Collins, Benjamin S.
    • Nuclear Engineering and Technology
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    • v.49 no.6
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    • pp.1326-1338
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    • 2017
  • The continuous energy Monte Carlo neutron transport code, MC21, was coupled to the CTF subchannel thermal-hydraulics code using a combination of Consortium for Advanced Simulation of Light Water Reactors (CASL) tools and in-house Python scripts. An MC21/CTF solution for VERA Core Physics Benchmark Progression Problem 6 demonstrated good agreement with MC21/COBRA-IE and VERA solutions. The MC21/CTF solution for VERA Core Physics Benchmark Progression Problem 7, Watts Bar Unit 1 at beginning of cycle hot full power equilibrium xenon conditions, is the first published coupled Monte Carlo neutronics/subchannel T-H solution for this problem. MC21/CTF predicted a critical boron concentration of 854.5 ppm, yielding a critical eigenvalue of $0.99994{\pm}6.8E-6$ (95% confidence interval). Excellent agreement with a VERA solution of Problem 7 was also demonstrated for integral and local power and temperature parameters.

Multiphysics response of magneto-electro-elastic beams in thermo-mechanical environment

  • Vinyas, M.;Kattimani, S.C.
    • Coupled systems mechanics
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    • v.6 no.3
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    • pp.351-367
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    • 2017
  • In this article, the multiphysics response of magneto-electro-elastic (MEE) cantilever beam subjected to thermo-mechanical loading is analysed. The equilibrium equations of the system are obtained with the aid of the principle of total potential energy. The constitutive equations of a MEE material accounting the thermal fields are used for analysis. The corresponding finite element (FE) formulation is derived and model of the beam is generated using an eight noded 3D brick element. The 3D FE formulation developed enables the representation of governing equations in all three axes, achieving accurate results. Also, geometric, constitutive and loading assumptions required to dimensionality reduction can be avoided. Numerical evaluation is performed on the basis of the derived formulation and the influence of various mechanical loading profiles and volume fractions on the direct quantities and stresses is evaluated. In addition, an attempt has been made to compare the individual effect of thermal and mechanical loading with the combined effect. It is believed that the numerical results obtained helps in accurate design and development of sensors and actuators.

A Fully Optimized Electrowinning Cell for Achieving a Uniform Current Distribution at Electrodes Utilizing Sampling-Based Sensitivity Approach

  • Choi, Nak-Sun;Kim, Dong-Wook;Cho, Jeonghun;Kim, Dong-Hun
    • Journal of Electrical Engineering and Technology
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    • v.10 no.2
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    • pp.641-646
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    • 2015
  • In this paper, a zinc electrowinning cell is fully optimized to achieve a uniform current distribution at electrode surfaces. To effectively deal with an electromagnetically coupled problem with multi-dimensional design variables, a sampling-based sensitivity approach is combined with a highly tuned multiphysics simulation model. The model involves the interrelation between electrochemical reactions and electromagnetic phenomena so as to predict accurate current distributions in the electrowinning cell. In the sampling-based sensitivity approach, Kriging-based surrogate models are generated in a local window, and accordingly their sensitivity values are extracted. Such unique design strategy facilitates optimizing very complicated multiphysics and multi-dimensional design problems. Finally, ten design variables deciding the electrolytic cell structure are optimized, and then the uniformity of current distribution in the optimized cell is examined through the comparison with existing cell designs.