采用有限元模拟软件 COMSOL Multiphysics® 对液封直拉法（LEC）生长锑化镓（GaSb）晶体的物理过程进行计算机建模。模拟分析了晶体旋转与坩埚旋转工艺对 GaSb 固-液界面形貌的影响。模拟结果表明，晶体旋转与坩埚旋转工艺将导致强烈的熔体强制对流，并进一步影响固液相变物理过程。上述工艺将分别具有促使凸向熔体的固液界面曲率减小和增大的作用，且同等转速条件下，坩埚旋转对固液界面形貌影响更大。基于上述模拟结果优化了实验中坩埚转速、晶体转速参数，最终获得了近似“平面”形貌的固液界面，由此获得了低位错密度的 GaSb 单晶。
B. Xu, M. Heydrich, S. Edmondson, A. Jahangir 
ShawCor Ltd., Toronto, ON, Canada
In oil and gas industries, electrical heaters are often used to control the internal pipe temperature. One important criterion for such test, is to maintain a uniform temperature range during the test. The objective of this study was to evaluate the heat transfer of one design of the internal electrical pipe heaters, by simulating both conduction and convection heat transfer around the heater ...
V. Rakesh, and A. Datta
Dept. of Biological and Environmental Engineering, Cornell University, Ithaca, NY, USA
Although microwave heating has been studied in great detail, microwave combination heating has not. This work investigated this in a novel microwave combination system that heats the sample through a combination of microwaves and hot air. The study used a coupled electromagnetics-multiphase porous media model in COMSOL to determine the effect of combining different heating modes on heating ...
Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
We are developing approximations of electrically anisotropic materials for use in novel imaging methods. Our modeling work in COMSOL comprises comparisons of anisotropic and layered models in terms of electrical conductivities measured using different strategies. We tested solution stability in one anisotropic case by varying mesh anisotropy. In our case, good approximations to the true ...
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 ...
Error Analysis in Estimating Temperature-Dependent Thermal Diffusivity and Kinetic Parameters using Heat Penetration Data
K.D. Dolan[1,2], A.R. Sommerlot, and D.K. Mishra
Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan, USA
Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan, USA
Growing consumer demand for nutraceuticals has stimulated interest by food companies to increase levels of these health-promoting compounds. Thermal processing of canned foods in a retort produces a unique problem: some of the nutraceuticals are highly sensitive to temperature, and require accurate parameter estimates to predict their fate during processing. Error in temperature measurement due ...
L. Yuan and P.C. Pedersen
Department of Electrical and Computer Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
Finite element models using COMSOL Multiphysics and MATLAB were developed to solve the problem of stress distribution interior homogeneous, isotropic, incompressible elastic solid material under known vertical external compression with a rectangular contact surface. Moreover, comparison between these results and analytical solutions was used to further validate that stress drops off with ...
Computation of the Longitudinal Dispersion Coefficient in an Adsorbing Porous Medium Using Homogenization
A. Rijnks, M. Darwish, and H. Bruining
StatoilHydro ASA, Bergen, Norway
Shell Exploration & Production International Centre, Rijswijk,
Section of Geoengineering, Faculty of Civil Engineering and Geosciences, TU Delft, Delft, The Netherlands
The method to derive upscaled expressions for the dispersion coefficients for reactive flow in a porous medium uses a periodic unit cell (PUC), which consists for instance of a spherical grain in a cube, but nothing prohibits defining more complex PUC's. Homogenization leads to a coupled system of equations where the flow is described by Stokes equation and the concentration fluctuation is ...
Effects of the Film Thickness on the Transient Conjugate Opticalthermal Fields in Thin Films Irradiated by Moving Sources in Back and Front Treatments
N. Bianco, O. Manca, S.Nardini, and D. Ricci
DETEC, Università degli Studi di Napoli Federico II, Napoli, Italy
DIAM, Seconda Università degli Studi di Napoli, Aversa, CE, Italy
A two dimensional transient analysis of the conjugate optical-thermal fields induced in a multilayer thin film structure by a moving Gaussian laser source is carried out numerically in order to compare back and front laser treatment processes. Thermal and optical nonlinearity is induced during transient heating, since the response of weakly absorbing thin films depends on temperature. The heat ...
Underground Coal Fire Extinction Model Using Coupled Reactive Heat and Mass Transfer Model in Porous Media
S. Suhendra, M. Schmidt, and U. Krause
Laboratory II.2: “Flammable Bulk Materials and Dusts, Solid Fuels”, Federal Institute for Materials Research and Testing (BAM), Berlin, Germany
Green house gases emission associated with natural hazard of underground coal seam fire has been recognized as a worldwide problem leading to global warming threat. Therefore, in this paper a model to study underground coal fire is presented and the results will be devoted to strategic development of coal fire extinction technology within the framework of Sino-German Coal Fire Research ...