Дисертації з теми "Thermal radiators"
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Wu, Ziran. "Electromagnetic Crystal based Terahertz Thermal Radiators and Components." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/195207.
Повний текст джерелаMora, Akhil, and Raghavendra Machipeddi. "Development of Tool in MATLAB for the Durability Prediction of Radiators." Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-15653.
Повний текст джерелаMyhren, Jonn Are. "Potential of Ventilation Radiators : Performance evaluation by numerical, analytical and experimental means." Doctoral thesis, KTH, Strömnings- och klimatteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-31813.
Повний текст джерелаQC 20110328
STEM Projektnummer:30326-1 Energieffektiva lågtemperatursystem i byggnader
Gerova, Klementina. "Thermo-fluid effects associated with modelling subscale automotive heat exchangers." Thesis, Cranfield University, 2015. http://dspace.lib.cranfield.ac.uk/handle/1826/9875.
Повний текст джерелаPyszczyková, Anna. "Vytápění střední školy." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240443.
Повний текст джерелаDvořák, Václav. "Vytápění staveb. objektu zdroji na různé druhy paliv s vyhodnocením ekonomické výhodnosti." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226821.
Повний текст джерелаValášek, Martin. "Návrh otopné soustavy pro rekonstruovaný dům." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231107.
Повний текст джерелаBrembilla, Christian. "Modelling and simulation of building components : thermal interaction between multilayer wall and hydronic radiator." Licentiate thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-121201.
Повний текст джерелаAdvisors: Ronny Östin and Mohsen Soleimanni Mohseni, Department of Applied Physics and Electronics, Umeå University
Kabiri, Rahani Ehsan. "Modeling of Ultrasonic and Terahertz Radiations in Defective Tiles for Condition Monitoring of Thermal Protection Systems." Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/203011.
Повний текст джерелаDalke, Phillip Allen. "Model-Based Design and Analysis of Thermal Systems for the Ohio State EcoCARMobility Challenge Vehicle." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu159545443238678.
Повний текст джерелаLee, Kuan-Lin. "Development of a Compact Thermal Management System Utilizing an Integral Variable Conductance Planar Heat Pipe Radiator for Space Applications." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1484168448272184.
Повний текст джерелаTranchant, Laurent. "Transferts radiatifs de champ proche guidés : nanostructures à phonon-polaritons de surface." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2015. http://www.theses.fr/2015ECAP0001/document.
Повний текст джерелаMiniaturization of transistors, whose sizes reach a few tens of nanometers nowadays,implies new problems of heat control at very short scales. This big challenge among others enabled the emergence of nanoscale heat transfer as a new research domain. Near-field heat transfer is one of the axis of this thematic.It concerns the behavior of thermal waves at a scale shorter than their wave lengths.Under these conditions the waves with the highest energy density are evanescent, that is confined at the surface. Surface phonon-polariton (SPhP) is a particular case of an evanescent wave propagating at the surface of a polar dielectric material. This PhD work consists in examining SPhP propagation along the surface of micrometric glass tubes and in proving the ability of these waves to enhance heat transfer in these systems.A theoretical analysis has been carried out to justify the use of such heat waveguides whose thermal conductivity can be doubled due to SPhP. The experimental detection of those waves based on their diffraction at the tip of the glass tubes is then presented. This emission is measured thanks to the assembly of a microscope and a Fourier-transform IR spectrometer. The presence of SPhPs is proved through measured spectra exhibiting their characteristic spectral signature
Lalanne, Nicolas. "Modélisation des échanges thermiques et radiatifs en environnement urbain à très haute résolution spatiale : aide à l'interprétation des mesures par télédétection infrarouge." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4731/document.
Повний текст джерелаThe main origin of the energy consumption in France is the residential and commercial sector. In urban environment, housing is mostly old, which means high heat losses. The improvement of energy performances requires the quantification of heat losses. This quantification may be based on a global measurement by an infrared camera with high spatial resolution.The infrared image interpretation requires a description of the radiative terms that make up the signal. For that purpose, a novel simulator is developed. The temperature field is calculated from a meshed three-dimensional scene composed of 1D walls and 2D thermal bridges. This operation is realized by the developed thermal software SUSHI, which is based on solar irradiance pre-computation and on 2D unitary response pre-computation. The software uses as input environmental data measured in the field. The infrared sensor signal is then modelled by adapting the radiative program MOHICANS. This software chain has the distinct advantage of an efficient fusion of dynamic response simulations of temperature and radiance, for areas with unidirectional and 2D heat transfer.The experimental campaign BATIR was set-up for measuring the thermal behavior of a building façade and its convective and radiative environment. A local validation of temperature calculation by SUSHI was realized through a comparison with thermocouple measurement results. Infrared cameras were operated in order to collect the radiance coming from the analyzed façade in band II and III. The radiances calculated by MOHICANS were compared with these acquisitions in order to validate the software chain at this level
SOUZA, CLECIA de M. "Utilização da radiação ionizante na reciclagem de pneus inservíveis de automóvel e sua destinação ambiental adequada." reponame:Repositório Institucional do IPEN, 2013. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10613.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Kasali, Suraju Olawale. "Thermal diodes based on phase-change materials." Thesis, Poitiers, 2021. http://www.theses.fr/2021POIT2254.
Повний текст джерелаThe thermal rectification of conductive and radiative thermal diodes based on phase-change materials, whose thermal conductivities and effective emissivities significant change within a narrow range of temperatures, is theoretically studied and optimized in different geometries. This thesis is divided into three parts. In the first part, we comparatively model the performance of a spherical and cylindrical conductive thermal diodes operating with vanadium dioxide (VO2) and non-phase-change materials, and derive analytical expressions for the heat flows, temperature profiles and optimal rectification factors for both diodes. Our results show that different diode geometries have a significant impact on the temperature profiles and heat flows, but less one on the rectification factors. We obtain maximum rectification factors of up to 20.8% and 20.7%, which are higher than the one predicted for a plane diode based on VO2. In addition, it is shown that higher rectification factors could be generated by using materials whose thermal conductivity contrast is higher than that of VO2. In the second part, on the other hand, we theoretically study the thermal rectification of a conductive thermal diode based on the combined effect of two phase-change materials. Herein, the idea is to generate rectification factors higher than that of a conductive thermal diode operating with a single phase-change material. This is achieved by deriving explicit expressions for the temperature profiles, heat fluxes and rectification factor. We obtain an optimal rectification factor of 60% with a temperature variation of 250 K spanning the metal-insulator transitions of VO2 and polyethylene. This enhancement of the rectification factor leads us to the third part of our work, where we model and optimize the thermal rectification of a plane, cylindrical and spherical radiative thermal diodes based on the utilization of two phase-change materials. We analyze the rectification factors of these three diodes and obtain the following optimal rectification factors of 82%, 86% and 90.5%, respectively. The spherical geometry is thus the best shape to optimize the rectification of radiative heat currents. In addition, potential rectification factors greater than the one predicted here can be realized by utilizing two phase-change materials with higher emissivities contrasts than the one proposed here. Our analytical and graphical results provide a useful guide for optimizing the rectification factors of conductive and radiative thermal diodes based on phase-change materials with different geometries
Martinsson, Richard, and Niclas Johansson. "Utredning av kyleffektfördelning i kylrum : En analys av kyleffektbehov samt förlustfaktorer gällande två kylrum för livsmedel." Thesis, Linnéuniversitetet, Sjöfartshögskolan (SJÖ), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-64013.
Повний текст джерелаThis study is conducted on behalf of DGL AB. The purpose was to investigate why the temperature does not drop to the desired level in two different cooling storages whom are used for cooling and storing of prepackaged groceries. The project was carried out with the help of loss calculations and temperature measurements to identify and estimate size as well as percentage differences in different loss factors. The sites measurements outlined the basis for this project. The cooling effect requirement is calculated based on the company's actual maximum production amount per day. The results showed that the effect of the cooling unit is oversized, however the cooling radiators capacity was too low considering the amount of losses. The outcome of the study suggest a decrease in thermal transmission losses through isolation of walls and ceilings in each of the cooling storages as well as isolation of the cooling water tank located in cooling storage 2. Cleaning of the cooling radiators flanges, supplementing or replacing with other cooling radiators that has more power output was additional suggestions to the result.
LUGAO, ADEMAR B. "Estudos da sintese por irradiacao, da estrutura e do mecanismo de formacao de polipropileno com alta resistencia do fundido." reponame:Repositório Institucional do IPEN, 2004. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11212.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
Rodrigues, Pedro. "Modélisation multiphysique de flammes turbulentes suitées avec la prise en compte des transferts radiatifs et des transferts de chaleur pariétaux." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLC041/document.
Повний текст джерелаNumerical simulations are used by engineers to design robust and clean industrial combustors. Among pollutants, soot control is an urgent societal issue and a political-industrial priority, due to its harmful impact on health and environment. Soot particles size plays an important role in its negative effect. It is therefore important to predict not only the total mass or number of emitted particles, but also their population distribution as a function of their size. In addition, soot particles can play an important role in thermal radiation. In confined configurations, controlling heat transfer related to combustion is a key issue to increase the robustness and the life cycle of combustors by avoiding wall damages. In order to correctly determine these heat losses, radiative and wall convective heat fluxes must be accounted for. They depend on the wall temperature, which is controlled by the conjugate heat transfer between the fluid and solid domains. Heat transfer impacts the flame stabilization, pollutants formation and soot production itself. Therefore, a complex coupling exists between these phenomena and the simulation of such a multi-physics problem is today recognized as an extreme challenge in combustion, especially in a turbulent flow, which is the case of most industrial combustors. Thus, the objective of this thesis is to develop a multi-physics modeling enabling the simulation of turbulent sooting flames including thermal radiation and wall heat transfer. The retained methods based on Large-Eddy Simulation (LES), a soot sectional model, conjugate heat transfer, a Monte Carlo radiation solver are combined to achieve a stateof- the-art framework. The available computational resources make nowadays affordable such simulations that will yield present-day reference results. The manuscript is organized in three parts. The first part focuses on the definition of a detailed model for the description of soot production in laminar flames. For this, the sectional method is retained here since it allows the description of the particle size distribution (PSD). The method is validated on laminar premixed and diffusion ethylene/air flames before analyzing the dynamics of pulsed diffusion flames. In the second part, an LES formalism for the sectional method is developed and used to investigate two different turbulent flames: a non-premixed jet flame and a confined pressurized swirled flame. Predicted temperature and soot volume fraction levels and topologies are compared to experimental data. Good predictions are obtained and the different soot processes in such flames are analyzed through the study of the PSD evolution. In these first simulations, wall heat losses rely on experimental measurements of walls temperature, and a coarse optically-thin radiation model. In the third part, to increase the accuracy of thermal radiation description, a Monte Carlo approach enabling to solve the Radiative Transfer Equation with detailed radiative properties of gaseous and soot phases is used and coupled to the LES solver. This coupled approach is applied for the simulation of the turbulent jet flame. Quality of radiative fluxes prediction in this flame is quantified and the nature of radiative transfers is studied. Then, a whole coupled modeling of turbulent combustion accounting for soot, conjugate heat transfer and thermal radiation is proposed by coupling three dedicated codes. This strategy is applied for a high-fidelity simulation of the confined pressurized burner. By comparing numerical results with experimental data, the proposed approach enables to predict both the wall temperature and the flame stabilization. The different simulations show that soot formation processes are impacted by the heat transfer description: a decrease of the soot volume fraction is observed with increasing heat losses. This highlights the requirement of accurate description of heat transfer for future developments of soot models and their validation
HEILMAN, SONIA. "Efeito da radiação ionizante nos revestimentos de cateteres de poliuretano com nanopartículas de prata." reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/25674.
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Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Servadio, Zarah. "Apports de l’imagerie à haute résolution spectrale et spatiale dans les bilans de volume et bilans radiatifs au Piton de La Fournaise." Thesis, La Réunion, 2011. http://www.theses.fr/2011LARE0020/document.
Повний текст джерелаRemote sensing opens new perspectives for the study and monotoring of volcanoes. In this thesis, different approaches were discussed. optical and thermal satellite imagery provides a synoptic view over a wide area. The understanding of surface state changes is particulary important in the monotoring of the activity of active volcanoes. Several, questions arise: • What advantages offer optical observation satellites of the Earth for calculations of lava volumes issues? • What are their limits? • Calculations of flow by remote sensing are reliable? • What is the interest of a multi-tool and multi-source approach? These issues were addressed by taking the Piton de la Fournaise to target. Several methods have been implemented and tested: 1) automatic extraction of the contours of flows of lava, 2) the cretion of numerical model of elevation (DEM) imaging satellite, 3) the calculation of flows from thermal images, 4) follow-up post eruptive flow modelling of cooling and the observed deformations in-situ measurement. The added value of this work is the ability to validate the results of remote sensing measurements from models because of the proximity of the sites studied in situ. The use of these techniques to obtain the average flow rates of lavas to several eruptions and follow topographic evolution of the volcano and its large structures. Satellite thermal measurements provide the means of forcing changes in the flow of eruptions over time, while Dems helped to obtain a total volume in the case of flows with high thicknesses. With these techniques, it was possible to define two types of erutions with changes similar to those observed on different volcanoes
Kassir, Abdel Majid. "Spectres radiatifs de plasmas d'air, N2, Ar-N2-H2 à l'équilibre et en déséquilibre thermique : étude théorique et caractérisation d'une décharge micro-ondes." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30140.
Повний текст джерелаPlasma radiation plays an important role in many applications, ranging from surface modification to aerospace sciences. In a medium constituted of atoms and molecules, such as a plasma, the spectral emission analysis of these species allows one to calculate the medium's characteristic temperatures and electron number density. This study aims to characterize a plasma through its radiation in both thermal equilibrium and weak non-equilibrium conditions. To achieve this goal, a radiative spectra simulation code was developed to study the plasma radiation as a function of the medium's characteristic temperature(s). Additionally, a microwave plasma torch experimental setup was assembled allowing the generation of a weak non-equilibrium plasma, which was then characterized by means of optical emission spectroscopy. First, the context of this study will be positioned in respect to the literature and scientific project of the team. The physical laws governing equilibrium and non-equilibrium plasma will be detailed, and optical emission spectroscopy diagnostic methods normally used to probe these plasmas will be presented. In addition, radiative spectra simulation software, such as LIFBASE, SPECAIR, and SPARTAN, will be described at the end of the first chapter; spectra calculated via these software serve as a reference and comparison basis for the code developed for this work. The second part of this study focuses on the radiative spectra simulation of equilibrium and non-equilibrium plasmas. The theory of molecular radiation will be thoroughly reviewed, as will the diatomic molecules energy levels calculation. The selection rules allowing the radiative transitions between these states and leading to the particular structure of molecular spectra will be discussed, and the spectra simulated by our code will be compared to the reference spectra for the molecular systems of an air plasma and an argon-nitrogen-hydrogen plasma. The agreements and discrepancies noted during these comparisons will be underlined, as well as the necessity to compare the calculated spectra with experimental spectra in order to judge the validity of our model and those implemented in the software used as references. The third part of this work presents the experimental study that was led at the LAPLACE laboratory on the characterization of the radiation emitted by a microwave plasma torch operating at atmospheric pressure. The theory of microwaves propagation along a waveguide and the energy coupling efficiency between the microwaves and the plasma will be briefly reviewed. The experimental setup will then be detailed, and the physical conditions for generating and sustaining the discharge will be discussed. [...]
Hamrat, Sonia. "Etude des échanges thermiques et conception d’un système de refroidissement pour le système de lecture du trajectographe SciFi de LHCb." Thesis, Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAC104/document.
Повний текст джерелаIn the context of the evolution of the biggest circular accelerator of particles «LHC», an important program of upgrade on all the detectors which establishes itself was thrown. Among them, we find the upgrade of the detector LHCb which includes the complete replacement of several sub-detectors. The frequency of high reading of 40MHz, an unprecedented in an experiment of physical appearance of particles, and the environment of severe radiation bound to the increase of the intensity of the LHC, are the main challenges by the new sub-detectors. The work presented in this manuscript, described as a small part of the evolution of the LHCb detector. The development and the construction of a new wide-scale tracker, based on a new technology with scintillating fiber «SciFi», read with photomultipliers to the silicon «SiPM», is one of the key projects of the LHCb upgrade program. The first part, consists in studying the thermal exchanges and designing a cooling system for every Read-Out Box «ROB» which contains two electronic front-end « FE », and which allow to read the data of the detector. The latter has a thermal dissipation about 110W. To ensure the smooth running of electronic components, it is compulsory to set up a cooler. Important constraints are taken into account in this study, the first one represents the space limited compared to the need for the cooling system, the electronic interfaces and mechanical, the second concerns the SiPM. Connected with the electronics by flexible cables, they are located near the electronics «FE» and their temperature of operation is perfectly settled around -40 ° C. Works of digital simulations on the software FloTHERM and ANSYS were led on the experimental bench realized within the laboratory, and which allowed us to determine the best adapted solution of cooling. This study also showed to us that he is more than necessity to integrate thermal interfaces «IT» such as thermal pastas to assure a better transfer of heat between electronic components and cooler. The second part, represents an in-depth study on the thermal interfaces which are a delicate point of transfer of heat, because they can have dozens percent of the global thermal resistance. To guarantee an adequate and sustainable use of these materials, several parameters were verified, in particular hardness, consistency (no production of fat or oil) and the thermal conductivity, thanks to a bench of measures adapted according to the method normalized ASTM D5470, with this bench we could measure the flow of heat through the tested thermal interface sample and which is generated by a hot source and a cold source that are mounted at the ends of our bench.With the installation CHARME (CERN) and PAVIRMA (Cézeaux), a series of measure of irradiations at the neutrons and the X-rays are also made, correspond-ing to the environment in which they will be exposed in the experience, on one side to identify the damages and the possible changes on the thermal resistances by the analysis of the thermal impedance, the other one to identify the thermal interface which suits best our application and which allows to assure an excellent thermal exchange and thus a good cooling of the frontal electronics within the trajectographe of the detector LHCb
Roggero, Aurélien. "Analyse du vieillissement d'un adhésif silicone en environnement spatial : influence sur le comportement électrique." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30267/document.
Повний текст джерелаThis PhD thesis falls within the technical field of electrostatic discharges occurring on the solar arrays of communications satellites in the geostationary orbit. Its main objective consists in assessing the evolutions of a space-used commercial silicone adhesive's electrical properties, and to correlate them with the evolutions of its chemical structure. The main components of this material have been identified, and neat samples (deprived of fillers) were elaborated so as to study the isolated polymer matrix. In order to assess the influence of filler incorporation, neat samples were systematically compared with the commercial ones in this study. The material's physicochemical structure in the initial state was characterized by studying its enthalpy relaxations, mechanical response, and by performing chemical analysis. Its electrical behavior (dipole relaxations and conductivity) was investigated thanks to an original experimental approach combining surface potential decay measurements, broadband dielectric spectroscopy, and thermally stimulated depolarization currents. Aging in the space environment was experimentally simulated by exposing the samples to high fluxes of high energy electrons. Chemical analysis (solid state NMR in particular) revealed the predominant crosslinking tendency of this material under ionizing radiations, and allowed to suggest degradation mechanisms at the microscopic scale. These structural evolutions also strongly impact its electrical behavior: a great increase in electrical resistivity has been observed with increasing ionizing dose. It is believed that electrical resistivity directly depends on the degree of crosslinking, which affects charge carrier mobility, in the theoretical frame of hopping and percolation models. The increase in resistivity is considerably more pronounced in the filled material, which could be associated with crosslinking occurring at the matrix-particles interface. Such crosslinks are thought to represent deeper traps for charge carriers. This work brought better understanding of aging phenomena in silicone elastomers exposed to the ionizing space environment. This knowledge will help predicting structural evolutions that may compromise vital properties such as adhesion, and the evolutions of intrinsic conductivity, a critical factor involved in the triggering of electrostatic discharges
Tajouri, Afif. "Amélioration de la précision de modèles des fours radiatifs et optimisation des paramètres de chauffage par méthodes métaheuristiques : Application au procédé de thermoformage de pare-brise." Thesis, Paris, ENMP, 2012. http://www.theses.fr/2012ENMP0109.
Повний текст джерелаThe manufacturing of automobile windshield is produced by a thermoforming process in a tunnel furnace where glass undergoes differential heating radiation by hundreds of electrical heating elements individually controlled. The final purpose of this work is to answer a real industrial problem, which is formulated as an optimization problem. It aims at assisting the furnace driver to find the setting that allows obtaining the required temperature distribution on the glass design in order to achieve the desired shape. Based on the method of network components, a model of the furnace is used to simulate the heating cycle. As a first step of this work, the accuracy of the temperature calculated is improved by parametric identification by referring to the data of measurements taken in situ. A local and global sensitivity analysis was performed beforehand. Thereafter, in order to accelerate these calculations, an original and optimization method is proposed. It consists in combining the Simulated Annealing metaheuristic method and the Replating Algorithm to identify multi-band emissivity. First, the original method validation is performed on a simplified 3D model of radiative enclosure, and then applied to the real furnace model. The new approach significantly reduces the computation time while improving the accuracy of the simulation results. In the second part of this work, several metaheuristic methods, such as Genetic Algorithm, Simulated Annealing, Tabu Search, and their hybridization are tested on a simplified model of a radiative enclosure. Results show that the combination of Genetic Algorithm and Simulated Annealing has accelerated the convergence to achieve the desired temperature fields on the product surface. This new method is successfully applied to the real furnace model to find the optimal control parameters
Diatel, Jakub. "Vytápění bytových domů." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392111.
Повний текст джерелаDavidsson, Lukas, and Isak Alsterlund. "Badrumsrenovering i bostäder : Jämförelse mellan radiatorsystem och golvvärmesystem ur energi-, fukt- och komfortaspekt i Västerås." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-45091.
Повний текст джерелаMARTINHO, JUNIOR ANTONIO C. "Estudo dos efeitos da radiação ionizante em cartilagem costal humana por meio de termogravimetria e tomografia por coerência óptica." reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10126.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Liu, Yang. "Développement de méthodes d'identification des propriétés thermo-physiques de matériaux semi-transparents Résolution de problèmes conducto-radiatifs instationnaires en 2d axisymétrique pour l'identification de propriétés thermophysiques de matériaux semi-transparents." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2019. http://www.theses.fr/2019ESMA0019.
Повний текст джерелаThis thesis aims to develop the methods for characterizing the thermophysical properties of semi-transparent materials. First of all, an unsteady axisymmetric 2D conductive-radiative direct model aiming at modeling a "flash method" experiment in which excitation is localized in space and time is developed. The radiative heat transfer within the material characterized by the mean absorption coefficient is simplified by using the P1 method. The simplified radiative heat transfer equation, as well as the energy equation, are solved by the finite volume method. Afterwards, an identification model coupling the direct simulation, the experimental data and the particle swarm algorithm (PSO) is developed to simultaneously identify the thermal conductivity and the mean absorption coefficient of the semi-transparent material. In the next part, an identification model based on a multilayer artificial neural network is proposed and tested. The training and test phases of the neural network are performed using a database generated by the direct model. Synthetic data with different noise levels and experimental data are used to respectively demonstrate the robustness and feasibility of this approach to solve practical problems. Finally, in order to reduce the calculation time and increase the identification efficiency, a low-order reduced model of the direct model is built using the modal identification method and tested under different boundary conditions. The coupling of this reduced model with experimental data is not implemented, which are considered as one of the perspectives of this thesis
SARTORI, MARIANA do N. "Estudo e desenvolvimento de nanocompósitos PBT/argila bentonita tratados por radiação ionizante - preparação e caracterização." reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23701.
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Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
UEHARA, VANESSA B. "Efeito da radiação ionizante de feixe de elétrons em propriedades de biopolímeros comestíveis a base de proteína isolada de soja e fécula de mandioca." reponame:Repositório Institucional do IPEN, 2017. http://repositorio.ipen.br:8080/xmlui/handle/123456789/27971.
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Nas últimas décadas, têm aumentado substancialmente a quantidade de pesquisas focando no desenvolvimento e caracterização de materiais biodegradáveis, particularmente, filmes comestíveis. O uso de polímeros de fontes renováveis, preparados a partir de produtos vegetais, vem ganhando importância nessa abordagem. O concentrado de proteína de soja e amido de mandioca podem ser considerados uma alternativa aos polímeros petroquímicos. O processamento pela radiação ionizante pode ser empregado para a modificação de polímeros e macromoléculas, resultando em novos materiais com grandes perspectivas de utilização industrial. A indústria de alimentos, uma das indústrias tradicionalmente mais inovadoras, exige o desenvolvimento constante de novos produtos. A capacidade de proteínas e polissacarídeos de formar filmes, amplamente conhecida, é um ponto de partida para o desenvolvimento de novos materiais que atendam os variados requerimentos dessa pungente indústria. Neste trabalho elaboraram-se filmes a base de fécula de mandioca e proteína isolada de soja em duas proporções diferentes e posteriormente irradiados e analisados quanto às suas propriedades mecânicas, cor, absorção de água, permeabilidade ao vapor de agua, análise térmica TGA e DSC entre outros. Os filmes tornaram-se aparentemente mais solúveis e menos resistentes a perfuração com o aumento da dose de radiação aplicada. Com relação às propriedades térmicas observou-se que os filmes com maior proporção de proteína são mais resistentes. Os filmes apresentaram-se menos permeáveis na dose de 40 kGy, e, com relação a absorção de água, esta foi reduzida em função da dose de radiação. Filmes com boa resistência ao vapor de água e com reduzida absorção podem ser considerados adequados para embalagens de alimentos. A radiação mostrou ser uma ferramenta conveniente na modificação de materiais poliméricos principalmente para elaboração de filmes solúveis onde esta é uma nova tendência para embalagens bioativas.
Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
Duda, Jiří. "Vytápění objektu hotelového typu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225456.
Повний текст джерелаSALES, JORGE N. DE. "Estudo do efeito da incorporação das argilas branca de Cubati e Cloisite Na® nas propriedades do termoplástico acrilonitrila butadieno estireno submetido à radiação ionizante." reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/27128.
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O polímero Acrilonitrila Butadieno Estireno (ABS) é um dos polímeros mais versáteis disponíveis nos dias de hoje. Atualmente o Brasil não produz o ABS, o que limita a indústria brasileira de plásticos a utilizar as variações deste polímero importadas, ofertadas no mercado nacional por distribuidores locais. Este estudo avaliou os efeitos da adição das argilas Cloisite Na® e Branca de Cubati na matriz polimérica ABS e também os efeitos decorrentes do tratamento por radiação ionizante no ABS e nos compósitos ABS/Argila como formas de modificação de um ABS convencional. Visando avaliar a diferença entre uma argila organofílica e uma organofóbica, a argila Branca de Cubati foi organofilizada e a argila Cloisite Na® foi utilizada como recebida. Foram preparados, utilizando uma extrusora dupla rosca, concentrados a 30 % em massa da argila Branca de Cubati, previamente organofilizada e da Cloisite Na® em Estireno Acrilonitrila (SAN). Os concentrados foram adicionados ao ABS a 1, 3 e 5 % em massa das argilas e foram injetados corpos de prova. Parte dos corpos de prova foi submetida à irradiação por feixe de elétrons à uma dose de 600 kGy. Os compósitos irradiados e não irradiados foram caracterizados por meio de ensaios de resistência a tração, resistência a flexão, resistência ao impacto, temperatura de distorção térmica, ponto de amolecimento Vicat, análise de termogravimétrica (TG), difração de raios X e microscopia eletrônica de varredura com emissão de campo (MEVFEG) e a correlação entre os resultados foi discutida. Foram observadas melhorias nas propriedades mecânicas, exceto resistência ao impacto, nos materiais aditivados com as argilas, sendo os melhores resultados obtidos com a argila Branca de Cubati. O tratamento por radiação ionizante favoreceu o processo de reticulação do ABS.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
Boztepe, Sinan. "Understanding of infrared heating for thermoforming of semi-crystalline thermoplastics." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2018. http://www.theses.fr/2018EMAC0017.
Повний текст джерелаThermoplastics and thermoplastic composites are promising candidates for manufacturing highly cost- effective and environmental-friendly components in terms of rapid forming and recyclability. Thermoforming is extensively used for the processing of thermoplastics where IR heating is widely applied. The major advantage of radiative heating is that the significant portion of radiation penetrates into the semi-transparent polymer media.This thesis focuses on understanding of IR heating of semi-crystalline thermoplastics which aims to analyze the driven mechanisms for radiation transport in optically heterogeneous unfilled semi-crystalline polymer media. Considering the relatively narrow thermoforming window of semi-crystalline thermoplastics, accurate temperature control and close monitoring of temperature field is crucially important for successful forming process. It is thus required to build a numerical model robust enough to allow a good prediction of the temperature field while maintaining acceptable calculation times. In this research work, a combined experimental-numerical approach has been proposed which enables both to characterize the radiation absorption capacity of semi-crystalline polymer media and, to model the radiation heat transfer considering the crystalline/amorphous phases change under heating. This research focuses on a particular polymer - highly crystalline HDPE- which is supported by Procter & Gamble.In this thesis, the literature was reviewed at first for highlighting the existing coupled relation between the optical properties and the crystalline structure of semi-crystalline polymers. The role of crystalline morphology on the optical properties and optical scattering of two type of polyethylene, namely HDPE and LLDPE, were addressed. More specifically, the morphological and optical analyses were performed at room temperature and under heating to determine: which crystalline formations are responsible for optical scattering in semi-crystalline polymer media and, how does their coupled relationship evolve under heating conditions? Hence, one of the key contributions of this research is on establishing a temperature-dependent spectral extinction coefficient of HDPE allowing to describe temperature- dependent radiation absorption capacity of its semi-crystalline medium and, to model radiative transfer considering an equivalent homogeneous medium. Based on the characterization of radiation absorption capacity of semi-crystalline media, a temperature-dependent conduction-radiation model was developed. In order to assess the modeling accuracy, an experimental methodology was proposed for non-invasive surface temperature measurements via IR thermography on semi-transparent polymer media. The final step was to compare the results of numerical simulations with the several IR heating experiments to prove the strong influence of the crystalline morphology on heat transfer
Acuña, Paz y. Miño Jairo. "Application des méthodes d’imagerie au rayonnement dans les scènes urbaines." Thesis, Pau, 2020. http://www.theses.fr/2020PAUU3023.
Повний текст джерелаThis work relies on imagery, photographic and thermographic, allowing a better understanding of the radiative exchanges of an urban scene by giving both visual and quantitative results. Two types of images are constructed and exploited: spherical panoramas, referred to as 4π as they cover a solid angle of 4π steradians, and urban perspectives.The study of urban scenes in different places and conditions, Bayonne in winter and Cordoba in summer, are presented through two applications. The first focuses on urban thermal comfort and the second on heat exchanges between the surfaces of a street.In the first application, the study focuses on the incident radiation coming from all directions at a single point. The radiation is measured in both the visible and infrared range and then extrapolated to the whole spectrum. The resulting image 4π represents the radiative spatial distribution and is used to calculate the mean radiant temperature. This result is validated by comparisons with measurements performed using the black globe, accepted as the reference method. The 4π method offers a fast, convection-independent measurement with spectral discrimination in two bands. It serves to evaluate a city from few measurement points, but also to obtain precise spatialized information. The study carried out in Cordoba shows that the roughness of the ground in two scenes evaluated under similar conditions influences the thermal comfort of the pedestrian.For the second application, the study focuses on surface temperatures. We use a simplified 3D model combined with ray tracing to correct the thermography by filtering parasitic fluxes. The result is validated on a perspective street by comparison with the result of several contact thermometers. This comparison, which can only be punctual and limited to certain surfaces, gives satisfactory results that allow us to extend the correction to the entire image.A corrected thermogram reveals phenomena that were formerly not visible, the temperature difference of the windows being the most remarkable. Indeed, glass, a material with high heat transmission, exhibits the heat loss that occurs through its surface. This is particularly noticeable on a cold winter's day when the heating is in operation. In a canyon-type street, the qualitative study of the radiation discriminated in two spectral bands shows the interest of including a third one, that of the near infrared, to better understand the passage from diffuse to specular reflection. These two applications provide fundamental knowledge on the radiative landscape of the city and show the relationship between geometry and radiation. Only through this relationship is it possible to identify the physical phenomena that must be accounted in an urban thermal simulation
Este trabajo se basa en el uso de la imagen: fotográfica y termográfica. Esta permite una mejor comprensión de los intercambios radiativos de la escena urbana al proporcionar un resultado tanto visual como cuantitativo mediante la construcción y manipulación de dos tipos de imágenes: las panorámicas esféricas, llamadas 4π porque cubren un ángulo sólido de 4π estereorradianes, y las perspectivas urbanas.El estudio de escenas urbanas bajo diferentes condiciones ambientales, Bayona en invierno y Córdoba en verano, se presenta a través de dos aplicaciones. La primera se centra en el confort térmico urbano y la segunda en los intercambios térmicos entre las superficies de una calle.En la primera aplicación, el estudio se enfoca en la radiación incidente en un punto proveniente de todas las direcciones. La radiación se mide en dos rangos del espectro, el visible y el infrarrojo, y se extrapola a todo el espectro. La imagen 4π resultante representa la distribución espacial de la radiación y se utiliza para calcular la temperatura media radiante. Este resultado se valida mediante comparaciones con mediciones utilizando el globo negro, considerado como método de referencia. El método 4π ofrece una medición rápida e independiente de la convección con una discriminación espectral en dos bandas. Ésta sirve para evaluar una ciudad a partir de pocos puntos de medición, pero también para obtener información espacializada precisa. El estudio realizado en Córdoba muestra que la rugosidad del suelo en dos escenas evaluadas en condiciones similares influye en el confort térmico del peatón.En la segunda aplicación, el estudio se concentra en las temperaturas de la superficie. Nos servimos de un modelo 3D simplificado en combinación con el trazado de rayos para corregir la termografía filtrando los flujos parásitos. El resultado se valida en la perspectiva de una calle comparándolo con el resultado de varios termómetros de contacto. Esta comparación, que sólo puede ser puntual y limitada a ciertas superficies, da resultados satisfactorios que permiten extender la corrección a toda la imagen.Una termografía corregida revela fenómenos que antes no eran visibles, destacándose la diferencia de temperatura de las ventanas. Efectivamente, el vidrio, un material con una alta transmitancia térmica, pone en evidencia la energía que se pierde a través de su superficie. Esto es particularmente visible en un día frío de invierno, cuando la calefacción está en funcionamiento. En el caso de una calle tipo cañón, el estudio cualitativo de la radiación discriminada en dos bandas espectrales muestra el interés de incluir una tercera para comprender mejor el paso de la reflexión difusa a la especular, la del infrarrojo cercano. Las dos aplicaciones proporcionan conocimientos fundamentales sobre el paisaje radiativo de la ciudad y muestran el vínculo entre la geometría y la radiación. Es sólo a través de esta relación que es posible identificar los fenómenos físicos que deben ser tenidos en cuenta para una simulación térmica urbana
Vích, Pavel. "Účinnost rozvodů tepla." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227296.
Повний текст джерелаOravec, Jakub. "Dynamika otopných ploch." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392042.
Повний текст джерелаMunaretto, Fabio. "Étude de l'influence de l'inertie thermique sur les performances énergétiques des bâtiments." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 2014. http://pastel.archives-ouvertes.fr/pastel-01068784.
Повний текст джерелаNguyen, Hoang Quan. "Modélisation et simulation du remplissage de moules verriers : "Prise en compte du transfert radiatif"." Thesis, Vandoeuvre-les-Nancy, INPL, 2009. http://www.theses.fr/2009INPL054N/document.
Повний текст джерелаThe aim of this study is to propose an adapted model for the simulation of mould filling that must be a compromise solution between computational time and results accuracy. The double difficulty is to take into account the filling phenomenon that is a complex problem due to the presence of free boundaries and to the Glass specificities: viscosity that is highly thermal dependant and high melting temperature that requires taking into account radiation effects. Chapter I is devoted to the melting Glass flow. The numerical libraries Aquilon/Thétis, adapted for solving such type of problems and the thermal coupling between Air/Glass/Walls, has been used. (V.O.F method for front tracking, Augmented Lagrangian/Vector Projection methods for solving Pressure/Velocity coupling). For radiative aspect, different approaches are proposed: equivalent radiative conductivity (Chapter II), direct explicit method for validation (Chapter III) and spherical harmonics method or PN method (Chapter IV). In the Chapter V, the selected PN method is validated through simple cases and is then applied in other cases with convective coupling in complex geometries including semi-transparent inclusions (1D, 2D and 3D, 2D axi-symmetric and non grey medium). A P1 modified version is presented. The results are close to those given by P3 method but with reduced computational time. The main interest of this model is that it can be easily implemented in existing numerical codes: a single stationary second order partial differential equation to solve in 3D
LIN, JUN-HONG, and 林俊宏. "Investigation on the Thermal and Flow Characteristics of Power Transformer Radiators." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/87920515956026119953.
Повний текст джерела國立臺灣科技大學
機械工程系
92
The purpose of this project is to study the thermal and flow characteristics of power transformer radiators using commercial CFD code , Icepak. The effect of various factors , such as:the flow speed , flow leakage at the ends of the radiator , the temperature depend viscosity , on the thermal performance of the radiator were studied and explained。Finally , empirical correlation for Nusselt number , Nu , and friction coefficient , f ,were proposed for both the air and oil sides.
Chiu, Yu-Wei, and 邱育暐. "The Test and Analysis of Thermal-Hydraulic Performance of Radiators and the Development of Computer Aided-Design Softwares." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/ja7dhp.
Повний текст джерела國立成功大學
機械工程學系碩博士班
90
There are two parts in this paper. In the first part of this paper, an induced open wind tunnel was used to measure the thermal-hydraulic characteristics of automotive radiators. Three kinds of fins were tested. The experimental results indicated that the heat transfer coefficients for the louver fins are 10﹪higher than those for the slit fins; and the slit fins are 26﹪higher than those for the flat fins. In addition, the relationship for the Colburn factor j and friction factor f versus the Reynolds number was presented. In the second part of the paper, an interactive computer-aided design software for the automotive radiators was developed. It is written by Visual Basic 6.0 and can be run in any personal computer. The software has the following two functions: (1) Prediction the performance of a radiator when the dimensions are given. (2) Determination the necessary size of a radiator when given the required performance.
Worn, Cheyn. "An Evaluation of Shadow Shielding for Lunar System Waste Heat Rejection." Thesis, 2012. http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11202.
Повний текст джерелаKou, Hau-Shiang, and 寇皓翔. "The Study of Thermo-Hydraulic Performance for Automobile Radiator with Carbon Nanocapsules Materials Coating." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/9cz6fp.
Повний текст джерела國立高雄應用科技大學
模具工程系碩士班
102
Automobile radiator is the key component in the cooling system of the engine for a car. There are some problems will be caused if the thermo- hydraulic performance overheating such as the parts soften, abrasion, amount of oil consumption and the power decrease. However, how to enhance the thermo-hydraulic performance of automobile radiators is a key problem in the vehicle industry. The methods of enhance the automobile radiator performance such as change the angle of the fin and shape, change the working fluid and coated surface. But the method of the coated surface cannot enhance the thermo-hydraulic performance for automobile radiator. Therefore, the objectives of this study will use carbon nanocapsules material coating to enhance the automobile radiator performance without increase the principle. And also enhance the anti-fouling and the corrosion resistant features of the automobile radiator. This study used carbon nanocapsules material coating to enhance the automobile radiator performance of wave-fin and plate-fin. And use the wind tunnels, thermostatic water bath, data miner and differential pressure gauges to measurement the automobile radiator performance of coated and uncoated carbon nanocapsules material. Finally, investigate the effects of automobile radiator thermo-hydraulic performance in different air-side Reynolds number (Rea=0~6214.2) and water-side Reynolds number (Rew=1222.8~5502.8). The results show that, the averaged heat transfer performances of wave-fin radiator with coating the carbon nanocapsules materials have 8-23% higher than without coating. The averaged heat transfer performances of plate-fin radiator coating the carbon nanocapsules materials have 5-17% higher than without coating. When the air-side flow field is laminar, the plate-fin of automobile radiator without coating which heat transfer performance will higher than wave-fin automobile radiator without coating (increase about 9%). When the air-side flow field is turbulence, the wave-fin of automobile radiator without coating which heat transfer performance will higher than plate-fin of automobile radiator without coating (increase about 12%). When the air-side flow field is laminar, the plate-fin of automobile radiator with coating which heat transfer performance will higher than wave-fin of automobile radiator with coating (increase about 5%). When the air-side flow field is turbulence, the wave-fin of automobile radiator with coating which heat transfer performance will higher than plate-fin of automobile radiator with coating (increase about 16%).