陈茹 , 赵尧 ,
激光激光沉积是激光增材制造的一种，激光照射靶材表面，同时合金粉末同步送入工件表面，激光与粉末相互作用，并在基体表面形成金属熔池，随着热源和粉末流的相对移动，熔池快速冷却，形成沉积道。该快速熔凝过程复杂，涉及传热（热传导与热对流）、流动、相变、质量添加、多组分传质、自由表面移动等。 本算例使用了传热模块、流动模块和组分传输模块，研究激光增材制造过程中的高温金属熔池的温度场、速度场和浓度场。分析表面张力、重力、等对熔池形成的影响；引入液相分数描述固液糊状区，在动量方程和能量方程中添加源项建立固液混合区的控制方程；采用动网格技术（ALE）实现移动自由界面；可添加组分传输模块研究特定成分在熔池中的扩散过程。 热量输入、质量添加和散热条件直接影响熔池的形貌特征和内部流动特征。着重分析了不同的热量分布及质量分布对熔池特征量的影响。比较了高斯分布、宽带分布（长宽比5:1）和线分布 ...
T. Müller, A. Schwenger, and H. Haase
Institut für Grundlagen der Elektrotechnik und Messtechnik, Leibniz Universität Hannover, Germany
Volkswagen AG, Germany
This paper describes the automatic optimization of an electromagnetic actuator using a genetic algorithm. The actuator modeled here is dedicated for charge changing valve actuation in internal combustion engines. In the first step of the simulation, several operating points are calculated using the script language of COMSOL Multiphysics. In order to reduce computation time, only one segment of ...
M. Benilov, and M. Faria
Departamento de Física, Universidade da Madeira, Funchal, Portugal
Current transfer from high-pressure arc plasmas to thermionic cathodes may occur in a diffuse mode, when the current is distributed over the front surface of the cathode, or in a spot mode, when most of the current is localized in one or more small areas. Spectra of perturbations of 3D steady-state current transfer to thermionic cathodes of a high-pressure argon arc have been computed in the ...
R. Hamou, P. Biedermann, M. Rohwerder, and A. Blumeneau
Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany
The present work focuses on modeling a new experimental technique: Scanning Electro-chemical Potential Microscopy (SECPM), which is used to probe the potential profile of the electric double layer (EDL). We used an electrostatic approach to compute the EDL potential measured within the metallic probe. Also, we investigated the effect of the interaction of the electrode/probe double layers on the ...
Electric Field Distributions and Energy Transfer in Waveguide-Based Axial-Type Microwave Plasma Source
H. Nowakowska, M. Jasínski, and J. Mizeraczyk[1,2]
The Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Gdansk, Poland
Dept. of Marine Electronics, Gdynia Maritime University, Gdynia, Poland
In this paper, we examine changes of the electric field distributions in waveguide-based axial-type microwave plasma source (MPS) during tuning procedure. The distributions strongly depend on position of the movable short, so does the wave reflection coefficient of the incident wave. A method of determining tuning characteristics of the MPS consisting in treating the MPS as a two-port network, ...
INFN/LNL, Laboratori Nazionali di Legnaro, Legnaro, Italy
Many scientific instruments are based on high vacuum equipment with a gas pressure maintained in the order of 1 Pa or below. The gas flow in the low pressure limit, called the molecular flow regime, is a case of transport with zero viscosity. The ability to solve an integral equation on the boundary with finite elements methods allows us to find the gas densities and flows in the ...
Hyperbolic Heat Transfer Equation for Radiofrequency Heating: Comparison between Analytical and COMSOL Solutions
V. Romero-García, M. Trujillo, M.J. Rivera, J.A. López Molina, and E.J. Berjano
Centro de Tecnologías Físicas Acústica, Universidad Politécnica de Valencia, Valencia, Spain
Dpto. Matemática Aplicada, Instituto Universitario de Matemática Pura y Aplicada, Universidad Politécnica de Valencia, Valencia, Spain
Institute for Research and Innovation on Bioengineering, Universidad Politécnica de Valencia, Valencia, Spain
The Radiofrequency Heating (RFH) is widely employed to heat biological tissue in different surgical procedures. Most models analyze the RFH employing a Parabolic Heat Transfer Equation (PHTE) based on Fourier's theory. The PHTE can be used for problems involving long heating times or low thermal gradients. However, when the problem involves short heating times or extreme thermal gradients it is ...
M.H. Baghban, P. Jostein Hovde, and A. Gustavsen
Civil and Transport Engineering Department, Norwegian University of Science and Technology, Trondheim, Norway
Department of Architectural Design, History and Technology, Norwegian University of Science and Technology, Trondheim, Norway
Simulation tools for building physics problems play an important role in design and understanding the behavior of energy efficient buildings. There are different tools available for simulation of these problems, but each simulation tool has its own advantages and limitations. In this paper, a heat transfer problem in an exterior building wall with high performance materials has been simulated in ...
S. Druart, D. Flandre, and L.A. Francis
Université catholique de Louvain - ICTEAM, Louvain-la-Neuve, Belgium
In this paper, a methodology to simulate the electric behavior of spiral inductances is presented and discussed. All the methodology is built with the COMSOL software used with the Matlab scripting interface and then allows performing fully parameterized simulations. The program architecture is explained and is used to simulate two applications. The first calculates the voltage induced by an ...
D-S. Jeng, X. Luo, and J. Zhang
Division of Civil Engineering, University of Dundee, Dundee, Scotland, UK
Offshore wind and wave energy industries have developed considerably in the last two decades. Most offshore energy structures used in the existing projects are mono-piles in shallow water due to simplicity of installations, design and control. Numerous research for the design and modeling of offshore wind energy system have been carried out in the past. However, most previous studies have been ...