Optimisation d'un système de chauffage dans une enceinte radiative à l'aide d'un algorithme génétique hybride

International audienceCette étude porte sur un problème d'optimisation qui consiste à chercher la distribution de puissance optimale attribuée aux éléments chauffants à l'intérieur d'une enceinte radiative afin d'obtenir un champ de température prédéfini sur une plaque en acier. L'utilisation des méthodes d'optimisations métaheuristiques telles que les Algorithmes Génétiques et la méthode du Recuit Simulé a permis d'obtenir des résultats acceptables pour ce problème. En combinant ces deux méthodes on aboutit à une méthode hybride qui garantit des solutions plus appréciables

Transient radiation and conduction heat transfer in glass sheets by the thin layer approximation

8 p.International audienceThis paper is devoted to the simulation of 3D transient radiation and conduction heat transfer occurring inside thin glass sheets undergoing high temperature processing. The glass is considered as an absorbing, emitting, and nonscattering medium. The zonal method is used to establish the governing radiation transfer model. Direct exchange areas are calculated by the flux planes approximation. The thin layer approximation (TLA) is then introduced for increasing CPU efficiency. Three different numerical integration schemes made possible by the TLA are presented. Comparisons are made, with calculations performed using the finite volume method (FVM). The transient coupled energy equation is solved by a full implicit control volume method using the incomplete Cholesky conjugate gradient method. The heat transfer analysis of a glass sheet residing inside a hot rectangular enclosure is studied. Results obtained by the zonal method, with or without the TLA, are in close agreement with those obtained by the FVM. CPU requirements for radiative heat transfer analysis of the zonal method with TLA are, depending on the numerical integration scheme used, between 8 and 23 times smaller than those of the zonal method without TLA. The difference between the results of the different models never exceeds 4%. The zonal method with the TLA offered significant improvements in CPU time when compared with the original zonal method with similar or acceptable accuracy. ©2010 American Society of Mechanical Engineer

Reducing CPU Time for Radiative Exchange and Transient Heat Transfer Analysis Using Zone Method

International audienceCPU time for radiative heat transfer analysis using the zone method is greatly reduced. Reduction in CPU time is attributed to the development of a simplified version of the plating algorithm for calculation of total exchange areas (TEAs) and of a model reduction algorithm for eliminating low-energy-level exchange areas from the matrix of radiative transfer. The accuracy and efficiency of the algorithms are examined for a windscreen bending furnace and a gas quenching chamber. Total CPU time is reduced by a factor of 17 for both applications

Optimization of radiant heater power for heating of flat plates using metaheuristic methods

International audienceIn this article, simulated annealing (SA), genetic algorithm (GA), and tabu search (TS) methods are employed separately and together for finding optimal radiant heater settings for obtaining a specific temperature profile on a design surface. Results show that all methods yield to very acceptable results for various desired temperature profiles but after different number of iterations. The GA and TS methods progress very rapidly before slowly stabilizing after a certain number of iterations, while the SA method progresses for longer periods. In addition, hybrid combinations of GA, SA, and TS proved to be better than separate ones

Shima Hajimirza Specification of Micro-Nanoscale Radiative Patterns Using Inverse Analysis for Increasing Solar Panel Efficiency

This work proposes a comprehensive and efficient optimization approach for designing surface patterning for increasing solar panel absorption efficiency using near-field radiation effects. Global and local optimization methods, such as the Broyden-FletcherGoldfarb-Shanno quasi-Newton (BFGS-QN) and simulated annealing (SA), are employed for solving the inverse near-field radiation problem. In particular, a thin amorphous silicon (a-Si) solar panel with periodic silver nanowire patterning is considered. The design of the silver patterned solar panel is optimized to yield maximum enhancement in photon absorption. The optimization methods reproduce results found in the previous literature but with reduced computational expense. Additional geometric parameters, which are not discussed in previous work, are included in the optimization analysis, further allowing for increased absorption enhancement. Both the BFGS-QN and the SA methods give efficient results, providing designs with enhanced absorption

The Re-Plating Algorithm for Radiation Total Exchange Area Calculation

International audienceGreat efforts have been made to date toward modeling nongray radiative heat transfer accurately. In this article, a new version of the plating algorithm, designated the re-plating algorithm, for total exchange areas (TEAs) calculation from direct exchange areas (DEAs) for nongray radiative problems is presented. The re-plating algorithm calculates TEAs for a given band number b from those of band number b - 1 by performing successive re-plating procedures. The effectiveness of the new algorithm is demonstrated for thermal modeling of an aluminum brazing furnace and a glass treatment furnace. CPU requirements for TEA calculation were reduced significantly

The component interaction network approach for modeling of complex thermal systems

International audienceA practical approach for the thermal modeling of complex thermal systems, called the component interaction network (UN) is presented. Its stages are explained: description of the thermal system as a set of non-overlapping components and their interactions by heat and mass exchanges, modeling of components with different levels of precision using finite volumes and finite elements, modeling of interactions by conduction, convection, radiation and advection, time resolution scheme and simulation. Non-conventional notions of conditional existence of components or time events are introduced. The approach is illustrated with a simple example of an electric furnace. It is then applied to a rapid thermal processing (RTP) furnace and validated experimentally. The advantages of the CIN approach are demonstrated

Simulation the heating cycle of a thin film photovoltaic cell during rapid thermal processing

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Modified zonal method for thin solid semi-transparent media with reflective boundary.

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Specification of Micro-Nanoscale Radiative Patterns Using Inverse Analysis for Increasing Solar Panel Efficiency

International audienceThis work proposes a comprehensive and efficient optimization approach for designing surface patterning for increasing solar panel absorption efficiency using near-field radiation effects. Global and local optimization methods, such as the Broyden-Fletcher-Goldfarb-Shanno quasi-Newton (BFGS-QN) and simulated annealing (SA), are employed for solving the inverse near-field radiation problem. In particular, a thin amorphous silicon (a-Si) solar panel with periodic silver nanowire patterning is considered. The design of the silver patterned solar panel is optimized to yield maximum enhancement in photon absorption. The optimization methods reproduce results found in the previous literature but with reduced computational expense. Additional geometric parameters, which are not discussed in previous work, are included in the optimization analysis, further allowing for increased absorption enhancement. Both the BFGS-QN and the SA methods give efficient results, providing designs with enhanced absorption