V. Babbar, and T. Krause
Department of Physics, Royal Military College of Canada, Kingston, Ontario, Canada
Transient eddy current (TEC) technique is being developed for detection of flaws located at depth within multilayer aluminum structures. The present work involves finite element modeling using COMSOL Multiphysics software to simulate different types of probes by changing some of these parameters in an attempt to generate an output signal of optimum magnitude and shape. Some of the model results ...
Senior Materials Scientist, NASA Marshall Space Flight Center
A scientific hypothesis states that cryogenic trapped water is just under the surface of lunar soil at the poles in permanently shadowed craters. Microwave energy can be used to efficiently extract this water from permafrost. COMSOL permits calculation of the heating of simulated lunar soil using measured temperature dependent dielectric properties. Calculations at different microwave ...
An Analysis of Heat Conduction with Change of Phase with Application to the Solidification of Copper
J. Michalski, and E. Gutirrez-Miravete
Rensselaer at Hartford, Hartford, Connecticut, US
The goal of this study was to determine the possibility of using the finite element in COMSOL Multiphysics program to obtain a high accuracy solution to a moving boundary problem, specifically, the solidification of copper. A one-dimensional geometry in Cartesian coordinates was used to investigate the solidification of initially liquid copper from a chilled wall maintained at fixed temperature. ...
Importance of Assembly Discontinuity Factors In Simulating Reactor Cores Containing Highly Heterogeneous Fuel Assemblies
Atomic Energy of Canada Limited, Mississuaga, Ontario, Canada
To assess the importance of assembly discontinuity factors (ADF), a highly heterogeneous reactor core was simulated using a COMSOL model in which ADF are not used. The resulting errors in assembly powers were found to be unacceptably high. This indicates that for highly heterogeneous cores such as one with MOX and LEU fuel assemblies, the use of techniques that counter the effect of ...
Department of Mechanical Engineering, University of Washington, Seattle, Washington, USA
A comparison of the commercial code COMSOL is performed with the bench-mark solutions provided by the literature for a tall, differentially heated rectangular cavity for aspect ratios of 8, 15, 20, and 33. At small Rayleigh numbers the flow is dominated by conduction. As the Rayleigh number is increased the flow becomes unstable, first resulting in multicellular secondary flow patterns, and then ...
B. L. Crossley, M. Kossler, P.J. Collins, R. A. Coutu Jr., and L. A. Starman
Air Force Institute of Technology, Wright-Patterson AFB, Ohio, USA
Carbon nanotubes (CNTs) have been proven experimentally to be well suited for field emission applications. An optimized triode configured CNT field emission array is developed using the COMSOL Multiphysics Electrostatics Application to adjust five key physical dimensions to investigate the effects on the enhanced electric field at the CNT emitter tips. The five dimensions studied are CNT ...
Z. Qin, Y. Zeng, and D.W. Shoesmith
The University of Western Ontario, London, Ontario, Canada
Models that describe hydrogen permeation through a thin TiO2 film deposited on Pd have been developed based on a mass-balance equation consisting of diffusion, reversible hydrogen absorption/desorption, and irreversible hydrogen trapping. These models are solved by the finite element method using COMSOL Multiphysics. By comparing model simulations with experimental permeation curves, values of ...
Boundary conditions in multiphase, porous media, transport models of thermal processes with rapid evaporation
A. Datta, and A. Halder
Biological and Environmental Engineering, Cornell University, Ithaca, New York, USA
In modeling of thermal processing of biological materials with rapid evaporation, it is critical to provide boundary conditions consistent with the phenomena happening at the surface to accurately predict spatial temperature and moisture content for quality and safety assurance. Boundary conditions in a mathematical model are as important as governing equations itself and describe how the heat ...
P. Zheng[1,4], D.W. Greve[2,4], and I.J. Oppenheim[3,4]
Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
National Energy Technology Laboratory, Pittsburgh, Pennsylvania, USA
Surface acoustic wave gas sensors use a chemically sensitive resistive layer to detect gas concentration. The resistivity of the sensing material, the sensing layer thickness, and the spacer layer thickness all affect the surface wave propagation velocity. Existing analytic theory relates the change in velocity to various parameters. However some variables in this theory are not ...
TM Wave Propagation in Optical Nanostructures with a Third-Order Nonlinear Response: Modeling and Validation with COMSOL
A. Kildishev, E. E. Narimanov
Birck Nanotechnology Center, School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana, USA
An enhanced method is used for analysis of third-order nonlinearities in optical nanostructures with scalar TM (H-field) frequency domain formulation. After embedding it in COMSOL Multiphysics it is shown to produce fast and accurate results without superfluous vector E-field formalism. A standard TM representation based on cubic non-linear susceptibility χ(3) results in an intractable ...