Wyniki wyszukiwania - Biblioteka Nauki

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Moduł szynowy hybrydowej wyrzutni elektromagnetycznej ze wspomaganiem pneumatycznym – obliczenia elektromechaniczne

100%

Domin J. , Kroczek R.

Przegląd Elektrotechniczny

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2010

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tom R. 86, nr 12

36-37

EN

In the paper an electromagnetic and structural field model are presented of a rail of a electromagnetic launcher laboratory stand. Finally analysis is focused on evaluation of forces acting on projectile and stationary parts of the laboratory stand and resulting stresses and deflections.

2

The modelling in COMSOL environment an acoustic screen separating commercial objects from an inhabited area

100%

Idziak P. , Antczak M.

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2010

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tom No. 63

111-118

EN

Problems related to the acoustic protection of inhabited areas, bordering on large shopping centres, were presented in this article. A virtual model of an area protected with an acoustic screen was presented. The model "was built" in COMSOL environment. Calculations were done for many variants of geometric configuration of the screen. Data acquired from a measuring-experiment were used for the calculations.

3

Finite element modeling of continuous drive friction welding of Al6061 alloy

81%

Tashkandi M. A.

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tom Vol. 39, No. 1

1-14

EN

Continuous drive friction welding process is widely used in various industrial applications to assemble shafts, tubes, and many other components. This paper's motivation was developing a CDFW model using the Finite Element Method (FEM). The coupling of the process's thermal and mechanical behaviors was considered during the simulation by COMSOL Multiphysics®. The construction of phase transition curves for Al6061 allowed determining several temperature-dependent thermophysical properties of the material. These properties are then injected in a second simulation to study the temperature evolution during welding. Subsequently, these results are compared and analyzed with the experimental outcomes. Excellent comparability between the model and experimental results was achieved. A unique phenomenon in the welding temperature profile was observed and explained through the model and experimental results interpretation.

4

Comparison of time-stepping methods for transient magnetic field computations in COMSOL Multiphysics

81%

Sowa M. , Typańska D.

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tom No. 77

141--147

EN

The computations of a transient magnetic field problem are presented. The problem has been constructed and solved in COMSOL Multiphysics which is one of the most popular and versatile commercial programs that allow to deal with solving electromagnetic field problems by means of the finite element method. A simple 2D problem of a coaxial cable has been chosen so that an analytical solution can be used in order to easily compute an error. The main topic of the paper concerns the comparison of the time-stepping methods that are available in COMSOL Multiphysics i.e. the BDF and generalized alpha methods. It is also possible to select various options for these methods, which have an influence on the solution accuracy. These have been also considered in the analysis.

5

Ulepszona metoda momentów vs. funkcje pakietu obliczeniowego MATLAB System Identification Toolbox w zakresie estymacji parametrów prostych modeli dynamicznych w niestacjonarnych zagadnieniach wiroprądowych

71%

Dudziak K. , Stawicki K. , Brykalski A.

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tom No. 97

17--28

PL

Jedną z niewielu metod, pozwalających na wykorzystanie do estymacji parametrów modeli transmitancyjnych charakterystyki częstotliwościowej jest metoda momentów. W niniejszej pracy, na przykładach dynamicznych zagadnień wiroprądowych, autorzy przedstawią porównanie uproszczonych typowe modeli transmitancyjnych otrzymanych z charakterystyki częstotliwościowej i czasowej. Zbadana będzie zgodność modeli wyznaczonych ulepszoną metodą momentów z analogicznymi modelami uzyskanymi z wykorzystaniem komercyjnego pakietu obliczeniowego System Identification Toolbox™ (SIT) z pakietu MATLAB®. Adekwatność modeli uzyskanych ulepszoną metodą momentów oraz niezależnie, dzięki pakietowi System Identification Toolbox™, będzie sprawdzona przez porównanie zgodności odpowiednich charakterystyk czasowych i częstotliwościowych, uzyskanych przez rozwiązanie równania przewodnictwa lub zespolonego równania Helmholtza w programie COMSOL Multiphysics®. Autorzy wykażą konkurencyjność, a w niektórych przypadkach przewagę zmodyfikowanej metody momentów nad wybranymi funkcjami komercyjnego narzędzia.

EN

One of the few methods allowing to use the frequency response models for estimation of parameters is the improved moment method. In this paper, on selected examples of dynamic eddy current problems, the authors will practically present how simplified, typical transfer function`s models can be obtained from the frequency response of computer methods. The compatibility of the models determined by an improved method of moments with similar models obtained using the commercial System Identification Toolbox ™ from the MATLAB® package will be tested. The adequacy of the models obtained with the improved torque method and independently, thanks to the System Identification Toolbox ™, will be checked by comparing the compatibility of the relevant time characteristics and frequency characteristics obtained before direct solution of the conduct equation or complex Helmholtz equation in the COMSOL Multiphysics® program. The authors will show competitiveness and in some cases the advantage of an improved method of moments over selected features of the commercial System Identification Toolbox ™ for MATLAB®.

6

CFD simulation of heat transfer and fluid flow within metallic foam in forced convection environment

58%

Boulahrouz S. , Avenas Y. , Chehhat A.

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2017

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tom Vol. 21, nr 3

611--635

EN

In the present study, a CFD simulation of forced convection in a rectangular block of aluminum foam is investigated. A two energy equations model with the Brinkman-Forchheimer extended Darcy model is considered in the CFD investigation. The governing equations are solved using COMSOL, a commercial multiphysics finite-element PDE solver. Three types of aluminum foam 10-, 20-, 40- pore per inch with different porosity are studied. A parametric study for the range of Reynolds number Re = 250-2000 and the imposed heat flux qw = 0:8−1:6 (W/cm2) is carried out to examine the thermal and the fluid flow behaviors of the aluminum foams. It is found that the plug flow conditions are prevalence for the aluminum foams. The 40-pore per inch aluminum foam has a better heat transfer performance with a larger pressure drop, followed by the 20-, and then by the 10- pore per inch. The validation of the simulation results is made against experimental data from the literature and showed a perfect agreement.

7

Funnel and Gate Permeable Reactive Barrier Permeable Reactive Barrier Configuration for Contaminated Groundwater Remediation – Designing, Installation, and Modeling: A Review

51%

Mokif L. A. , Faisal A. A. H.

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tom Vol. 24, iss. 9

15--33

EN

Groundwater is a valuable resource whose purity is necessary for human survival. It serves as a significant source of water for household, industrial, and agricultural purposes. Traditional groundwater pollution remediation technologies include pump & treat, phase extraction, aeration gas of groundwater, bioremediation, and chemical oxidation. Permeable reactive barrier (PRB) is one of the most key technology being developed as alternatives to the pump and manage method for the remedying contaminated groundwater. An overview on the groundwater significant as important sources for water, sources of groundwater contamination, transport of contaminants, and groundwater remediation technologies have been discussed in this paper. In addition to reactive media, the design and installation of PRBs of funnel-gate configurations and their application as a remediation technique have been covered in this review. Finally reaction mechanisms in groundwater, contaminant transport governing equation, isotherms sorption models, kinetic sorption models, breakthrough curves modeling have been presented in this review. PRB technique provides financial benefits while also encouraging waste material reuse, so contributing to environmental sustainability. Funnel and gate PRB can offer one or more dense treatment areas for maximizing groundwater pollution plume capture. Funnel-gate PRB is characterized by smaller reaction area, ease in replacement and removal during the blocking of the reactive barrier by fine soil particles and reactive sediments.