Presentazioni e Articoli Tecnici

In questa sezione troverete i lavori presentati alle Conferenze mondiali COMSOL. Le presentazioni descrivono ricerche e prodotti innovativi progettati con COMSOL Multiphysics da colleghi di tutto il mondo. I temi delle ricerche presentate abbracciano un'ampia gamma di settori produttivi e aree applicative, in ambito elettrico, meccanico, fluidodinamico e chimico. Lo strumento di Ricerca Rapida vi permetterà di trovare le presentazioni che si riferiscono all'area di vostro interesse.

Transient Heat Conduction in Semi-Infinite Solids Irradiated by a Moving Heat Source

N. Bianco1, O. Manca2, S. Nardini2, and S. Tamburrino2
1Dipartimento di Energetica, Termofluidodinamica applicata e Condizionamenti ambientali, Università degli Studi Federico II, Napoli, Italia
2Dipartimento di Ingegneria Aerospaziale e Meccanica, Seconda Università degli Studi di Napoli, Napoli, Italia

An analysis of the transient temperature distribution in a semi-infinite solid, irradiated by a moving Gaussian laser beam, is carried out numerically using COMSOL Multiphysics.Variable thermo-physical properties are accounted for. The workpiece is considered semi-infinite along the motion direction. Temperature distributions are evaluated both for different Peclet numbers and surface heat ...

Mass Transfer from a Single Spherical Bubble with the Presence of Chemical Reaction - the Effect of Interface Contamination at Low Reynolds Number

A. Dani, A. Cockx, and P. Guiraud
Ingénierie des Systèmes Biologiques et des Procédés, CNRS, INRA, INSA, Toulouse, France

The objective of this work is to compute the mass transfer with chemical reaction (first order reaction) from a single spherical bubble at a low Reynolds number by Direct Numerical Simulation. Firstly, the contamination of the bubble's surface by the surfactants is considered, since this can reduce the slip velocity at the interface. The stagnant cap model is used to represent these phenomena and ...

Simulation of Salt Diffusion in a Pork (bacon) Side using 3D Imaging

R. Said1, R. B. Schüller2, P. Young3, A. Aastveit2, and B. Egelandsdal2
1Simpleware Ltd, Exeter, UK
2Norwegian University of Life Sciences, Ås, Norway
3University of Exeter, SECAM, Exeter, UK

Simulation of salt diffusion in a pork (bacon) side is a relatively complex task since such a piece often consists of different regions of skin, meat, fat and bone; each with diffusion coefficients that vary by orders of magnitude. Adding to this complexity is the arbitrary shape and topology of each region; separately and combined.This paper will present a comprehensive solution for constructing ...

A Material Model for Simulating Volume Changes during Phase Transformations

M. Tehler, and S. Jonsson
Materials Science and Engineering, Royal Institute of Technology, Stockholm, Sweden

The present work describes the first steps in creating a robust material model able to predict volume changes due to thermal expansion and phase transformations.A dilatometer test is simulated starting from room temperature, with an original microstructure constituting a mixture of ferrite and pearlite. During heating, the structure transforms to austenite, which upon quenching will transform ...

Parameter Extraction and Support-Loss in MEMS Resonators

Peter Steeneken
Project Leader
RF MEMS Research Group
NXP Semiconductors
Eindhoven, The Netherlands

In this paper it is shown how the equivalent circuit parameters of a MEMS resonator can be simply obtained from an eigenfrequency simulation. Additionally, it is demonstrated that the Q-factor as a result of support losses in a MEMS resonator can be determined using a matched boundary layer. The method is applied to calculate the frequency dependent admittance of a diamond disk resonator. Results ...

Numerical Modeling of Dielectrophoretic Forces Acting upon Biological Cells in Silicon Lab-On-Chip Devices

S. Burgarella, M. Bianchessi, and M. De Fazio
Advanced System Technology, R&I e-Health, STMicroelectronics, Agrate Brianza, Italy

Dielectrophoresis (DEP) is a promising method for the automated separation of biological cells in a miniaturized format. This technology allows cells to be manipulated electronically while suspended in a microfluidic channel embedded in a silicon lab-on-chip. In this work, several dielectrophoretic configurations have been designed and fabricated using micro-electro-mechanical-systems (MEMS) ...

Design of Light Emitting Diodes (LED)

E. Baur, M. Sabathil, and N. Linder
Osram Opto Semiconductors GmbH, Regensburg, Germany

For a proper design shaping of light emitting diodes, the exact knowledge of the current distribution in the active area is essential. On the one hand, one has to achieve a uniform current density over the chip area, on the other hand, one has to avoid current crowding in the neighborhood of the electrical contacts. In this paper it is shown first how a LED can be modeled by COMSOL Multiphysics. ...

Numerical Simulation of the Electrical Double Layer Based on the Poisson-Boltzmann Models for AC Electroosmosis Flows

P. Pham1, M. Howorth1, A. Planat-Chrétien1, and S. Tardu2
1Département des microTechnologies pour la Biologie et la Santé, CEA/LETI, Grenoble, France
2LEGI, Grenoble, France

In this paper, the analytical validation of Poisson-Boltzmann (PB) equation computed with COMSOL Multiphysics in the case of a polarized surface in contact with an electrolyte, is first presented.COMSOL Multiphysics algorithms easily handle the highly nonlinear aspect of the PB equation. The limitations of the PB model, that considers ions as point like charges, are outlined. To account for the ...

Implementation of Hysteresis Material Characteristics in Finite Element Computations

P. Sergeant, and L. Dupré
Department of Electrical Energy, Systems and Automation, Ghent University, Ghent, Belgium

The hysteresis loss in a sample is obtained by evaluating the drag force profile when slowly moving the sample forward and backward through the strong field of a permanent magnet.A numerical time-stepping model is presented that calculates the drag force profile. At every time step, the sample is slightly moved relative to the magnet. The model is based on 2D-FE computations (COMSOL AC/DC module, ...

Design of UV reactors by CFD: Model Development and Experimental Validation

J. Hofman1,2,3, L. Shao2, B. Wols2, W. Uijttewaal2, G. I. J. Pelaar1, E. Beerendonk1, and H. van Dijk2
1Kiwa Water Research, Rijkswijk, The Netherlands
2Delft University of Technology, Delft, The Netherlands
3Waternet, Amsterdam, The Netherlands

UV technology is an emerging technology for drinking-water treatment. It can either be used as a disinfection barrier, where the UV light is used to inactivate pathogenic microorganisms, or in combination with hydrogen peroxide as an advanced oxidation process. The design of UV reactors is very complex. The water flow and related aspects of mixing, the UV light distribution, and the reaction ...

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