Dissertations / Theses on the topic 'Simplified dynamic method'

Abstract: Highway bridges have great values in a country because in case of any natural disaster they may serve as lines to save people’s lives. Being vulnerable under significant seismic loads, different methods can be considered to design resistant highway bridges and rehabilitate the existing ones. In this study, base isolation has been considered as one efficient method in this regards which in some cases reduces significantly the seismic load effects on the structure. By reducing the ductility demand on the structure without a notable increase of strength, the structure is designed to remain elastic under seismic loads. The problem associated with the isolated bridges, especially with elastomeric bearings, can be their excessive displacements under service and seismic loads. This can defy the purpose of using elastomeric bearings for small to medium span typical bridges where expansion joints and clearances may result in significant increase of initial and maintenance cost. Thus, supplementing the structure with dampers with some stiffness can serve as a solution which in turn, however, may increase the structure base shear. The main objective of this thesis is to provide a simplified method for the evaluation of optimal parameters for dampers in isolated bridges. Firstly, performing a parametric study, some directions are given for the use of simple isolation devices such as elastomeric bearings to rehabilitate existing bridges with high importance. Parameters like geometry of the bridge, code provisions and the type of soil on which the structure is constructed have been introduced to a typical two span bridge. It is concluded that the stiffness of the substructure, soil type and special provisions in the code can determine the employment of base isolation for retrofitting of bridges. Secondly, based on the elastic response coefficient of isolated bridges, a simplified design method of dampers for seismically isolated regular highway bridges has been presented in this study. By setting objectives for reduction of displacement and base shear variation, the required stiffness and damping of a hysteretic damper can be determined. By modelling a typical two span bridge, numerical analyses have followed to verify the effectiveness of the method. The method has been used to identify equivalent linear parameters and subsequently, nonlinear parameters of hysteretic damper for various designated scenarios of displacement and base shear requirements. Comparison of the results of the nonlinear numerical model without damper and with damper has shown that the method is sufficiently accurate. Finally, an innovative and simple hysteretic steel damper was designed. Five specimens were fabricated from two steel grades and were tested accompanying a real scale elastomeric isolator in the structural laboratory of the Université de Sherbrooke. The test procedure was to characterize the specimens by cyclic displacement controlled tests and subsequently to test them by real-time dynamic substructuring (RTDS) method. The test results were then used to establish a numerical model of the system which went through nonlinear time history analyses under several earthquakes. The outcome of the experimental and numerical showed an acceptable conformity with the simplified method.
Résumé: Les ponts routiers ont une grande valeur dans un pays parce qu’en cas de catastrophe naturelle, ils peuvent servir comme des lignes pour sauver des vies. Étant vulnérable sous des charges sismiques importantes, on peut considérer différentes méthodes pour concevoir des ponts routiers résistants et également pour réhabiliter des ponts existants. Dans cette étude, l'isolation de la base a été considérée comme une méthode efficace qui peut réduire significativement les effets des charges sismiques sur la structure. En réduisant la demande en ductilité sur la structure sans une augmentation notable de force, la structure est conçue pour rester élastique sous des charges sismiques. Le problème associé aux ponts isolés, particulièrement avec des appuis en élastomère, peut être leurs déplacements excessifs sous les charges de service et de séisme. Ceci peut défier l’objectif d'utiliser des appuis en élastomère pour les ponts typiques de petite portée où les joints de dilatation et les dégagements peuvent aboutir à une augmentation significative des frais d'exploitation et de maintenance. Ainsi, supplémenter la structure avec des amortisseurs d’une certaine rigidité peut servir de solution, ce qui peut cependant augmenter l’effort tranchant transmis à la sous-structure. Cette étude a pour but de fournir une méthode simplifiée afin d’évaluer les paramètres optimaux des amortisseurs dans les ponts isolés. Dans cette thèse, premièrement, basé sur une étude paramétrique, quelques directions sont données pour l'utilisation de dispositifs d'isolation simples, dont les appuis en élastomère, afin de réhabiliter des ponts existant avec une haute importance. Les paramètres comme la géométrie du pont, les clauses des normes et le type de sol sur lequel la structure est construite ont été appliqués sur un pont typique de deux portées. Il est conclu que les paramètres mentionnés peuvent déterminer l'emploi d'isolement de la base des ponts routiers. À la deuxième phase, basé sur le coefficient de réponse élastique des ponts isolés, une méthode de conception simplifiée d’amortisseur pour des ponts routiers réguliers isolés à la base a été présentée dans cette étude. En sélectionnant des objectifs pour la réduction du déplacement et la variation de l’effort tranchant, la rigidité et l'amortissement exigés d'un amortisseur hystérétique peuvent être déterminés. L’étude s’est poursuivie par une modélisation numérique d’un pont à deux portées pour vérifier l'efficacité de la méthode. Pour un modèle numérique d'un pont isolé typique, la méthode a été utilisée pour identifier des paramètres linéaires équivalents pour un certain déplacement et effort tranchant désigné. Par la suite, assumant un amortisseur de type hystérétique, les paramètres non linéaires de l’amortisseur ont été calculés et utilisés. La comparaison des résultats du modèle numérique sans amortisseur et avec l'amortisseur a démontré que la méthode proposée est suffisamment précise. Par la suite, un nouvel amortisseur hystérétique simple en acier a été conçu. Cinq spécimens ont été fabriqués de deux différents grades d’acier et ont été testés en combinaison avec un isolateur à l’échelle réelle dans le laboratoire de structures de l'Université de Sherbrooke. La procédure comprenait la caractérisation des spécimens par des tests cycliques en contrôle de déplacement et par la suite la réalisation d’essais par la méthode de sous-structuration dynamique en temps réel. Les résultats des essais ont été utilisés pour établir un modèle numérique du système qui a subi des analyses temporelles non linéaires sous plusieurs séismes. Le résultat des essais expérimentaux et numériques montrent une conformité acceptable avec la méthode simplifiée.

The research focuses on developing a methodology for modeling a pneumatic bias-ply tire with the finite element method for vehicle dynamics simulation. The tire as a load-carrying member in a vehicle system deserves emphasized formulation especially for the contact patch because its representation of mechanics in the contact patch directly impacts the handling and ride performance of a vehicle. On the other hand, the load transfer from the contact patch to the wheel hub is necessary for determining the inputs to a chassis. A finite element (FE) tire model has strong capability to handle these two issues. However, the high cost of computing resources restrains its application mainly in the tire design domain. This research aims to investigate how to balance the complexity of a simplified FE tire model without diminishing its capability towards representing the load transmission for vehicle dynamics simulation. The traditional FE tire model developed by tire suppliers usually consists of an extremely large number of elements, which makes it impossible to be included in a full-vehicle dynamics simulation. The material properties required by tire companies' FE tire models are protected. The car companies have an increasing need for a physical-based tire model to understand more about the interaction between the tire and chassis. A gap between the two sides occurs because the model used for tire design cannot directly help car companies for their purpose. All of these reasons motivate the current research to provide a solution to narrow this gap. Other modern tire models for vehicle dynamics, e.g. FTire or TAME, require a series of full-tire tests to calibrate their model parameters, which is expensive and time-consuming. One great merit of the proposed simplified FE tire model is that determining model inputs only requires small-scale specimen tests instead of full-tire tests. Because much of the usability of a model hinges on whether its input parameters are easily determined, this feature makes the current model low cost and easily accessible in the absence of proprietary information from the tire supplier. A Hoosier LC0 racing tire was selected as a proof of modeling concept. All modeling work was carried out using the general purpose commercial software Abaqus. The developed model was validated through static load-deflection test data together with Digital Image Correlation (DIC) data. The finite element models were further evaluated by predicting the traction/braking and cornering tire forces against Tire Test Consortium (TTC) data from the Calspan flat-track test facility. The emphasis was put on modeling techniques for the transient response due to the lack of available test data. The in-plane and out-of-plane performance of the Hoosier tire on the full-tire test data is used for model validation, not for "calibrating" the model. The agreement between model prediction and physical tests demonstrate the effectiveness of the proposed methodology.
PHD

In recent years, the aircraft industry has begun to focus its research capabilities on reducing emissions and noise produced by aircraft. Modern aircraft use two to four engines arranged on the wing or behind to produce thrust that is concentrated directly behind the engine. Kuchemann suggested a way to improve the propulsive efficiency by changing the normal configuration of engine and aircraft. This concept is the jet-wing distributed propulsion idea, which redistributes the thrust across the span of the wings. Distributed propulsion is accomplished by using many smaller engines spread across the wings or several large engines to duct the exhaust flow in a jet-wing. The jet-wing concept can be used to reduce noise and also as a replacement for flaps and slats by deflecting the jet. Since the distributed propulsion concept is also a method to reduce noise, it's important to have a simplified method of calculating the trailing edge noise of a wing.

One of the purposes of this paper was to study the effect of adding jet-wing distributed propulsion to a thick "inboard" airfoil. The two-dimensional jet-wing model was analyzed by parametric computational fluid dynamic (CFD) studies using the Reynolds-averaged, finite-volume, Navier-Stokes code GASP. The model was set up to be self-propelled by applying velocity and density boundary conditions to the blunt edge of the airfoil. A thick "inboard" airfoil from a realistic transonic wing was needed for the study and so the span station of the EET Wing was chosen. This airfoil was thick with a thickness to chord ratio of 16%. In adding distributed propulsion to this thick airfoil, it was found that there was an increase in the propulsive efficiency as compared to typical modern high-bypass-ratio turbofan engines with no negative aerodynamic consequences.

The other purpose of this study was to create and assess a simplified method to calculate the trailing edge noise metric value produced by an airfoil. Existing methods use RANS CFD, which is computationally expensive and so it seemed important to find a less expensive method. A method was formed using the Virginia Tech Boundary Layer Java Codes which calculated the characteristic turbulent velocity and characteristic turbulent length scale. A supercritical airfoil, SC(2)-0714, was used to assess the simplified method as compared to the more computationally expensive GASP runs. The results showed that this method has trends that follow those of the GASP results with the method compare well up to modest lift coefficients.
Master of Science

Le but de ces travaux est de créer un modèle aérothermique, avec un temps de calcul court, d’un alternateur automobile intégré au sein d’une simulation complète d’un environnement sous-capot d’un véhicule. La prise en compte de leur influence au sein d'un comportement moteur est recherchée. Un modèle simplifié permettant la simulation du comportement aéraulique et thermique d’un alternateur a été développé. Il utilise une approche nodale afin de simuler les phénomènes thermiques et aérauliques du système. Différents algorithmes et une interface homme-machine permettent un paramétrage facile et rapide, et une implémentation automatique du modèle. En effet, le paramétrage du réseau nodal est fait automatiquement, l’utilisateur doit seulement rentrer les différents paramètres du système : dimensions, caractéristiques matériaux, pertes thermiques... Cela nous permet d’avoir aussi un modèle adaptable facilement à tout type d’alternateur. Le comportement aéraulique de l’alternateur est simulé via des coefficients de convection, intégrés au réseau nodal. Ces coefficients sont déterminés via des corrélations en fonction du nombre de Reynolds de l’écoulement. Pour chaque zone de l’écoulement d’air dans l’alternateur, ces corrélations ont été identifiées via une modélisation CFD de l’alternateur, lui-même validé par des essais aérauliques sur banc expérimental. Le modèle a été vérifié et validé via des essais expérimentaux thermiques. Il présente une erreur moyenne inférieure à 10%, et fonctionne sur l’ensemble des régimes d’utilisation. Il présente un temps de calcul de l’ordre de 2 minutes. Le modèle a été intégré dans une simulation simplifiée d’un environnement sous-capot. Une méthodologie de couplage a été développée, permettant l’intégration des données du modèle simplifié, au sein des simulations sous-capot. Ces simulations modélisent le comportement thermique des environnements sous-capot ainsi que le compartiment aéraulique. Les flux d’air sont simulés et le couplage du modèle simplifié permet d’intégrer l’influence thermique de l’alternateur, au sein de l’environnement sous-capot, ainsi que l’impact aéraulique de ce dernier. La méthodologie de couplage permet d’importer les valeurs de températures et de débits, estimées par le modèle simplifié, au sein du maillage d’une CAO de l’alternateur. Ces travaux sont en cours d’intégration dans les processus numériques du Groupe PSA. Différentes perspectives sont en cours d’étude, afin d’utiliser ce modèle sur d’autres éléments du sous-capot, ou d’autres machines tournantes, comme des moteurs électriques présents sur les véhicules hybrides et électriques
The objective of the thesis is to create a thermal model of an alternator, with a quickly time run. This model will integrate the influence of the alternator inside an under-hood simulation. A simplify model able to simulate the aerodynamic and thermal behaviour has developed. It use a nodal approach to simulate the aerodynamic and thermal behaviour. Different algorithms and an user’s interface able to a quickly set up and a automatically implementation. Indeed, the nodal, approach was realized automatically by the model, the user inform the dimensions of the alternator, the materials characteristics and the thermal losses. Thanks to we have a model that use with any automobile alternator. The aerodynamic of the alternator is simulate with convection coefficient via the nodal approach. These coefficients are estimated with correlations based on Reynolds of the flow. The CFD simulation of the alternator identified these correlations. The CFD model has been validate with an aerodynamics tests. The model is checked and validate by thermal tests. It has an average error lower than 10% and work to any regime of the use. The time run is equal to 2 minutes. The modal has been integrate inside an under-hood simulation. A coupling methodology has been developed to allow the integration of the data, like the temperatures and the flowrate was estimate by the simplify model, inside an under-hood simulation. The under-hood simulation modelling the aerodynamic and thermal behaviour of the engine compartment. Therefore, the coupling methodology allow integrating the aerodynamic and thermal influence of the alternator inside the compartment. The work is actually in progress inside the numerical processes of the PSA group. Many perspectives are studied, to use the model on other under-hood elements, or other electric machine, like the electric engines used inside the hybrid vehicles

Les écrans de filet pare-blocs sont des ouvrages de protection souples utilisés pour protéger les habitants ainsi que leurs biens du danger des éboulements rocheux dans les régions à risques. Ces structures placées sur la trajectoire des masses en mouvement sont formées d’un filet métallique maintenu au terrain naturel par des poteaux rigides. Lorsqu’elles sont impactées par un bloc, elles subissent des grandes déformations qui nécessitent de modéliser leur comportement en tenant compte de non-linéarités à la fois géométriques et matérielles. Leurs composants sont ainsi représentés dans ce travail par des éléments discrets et le problème mécanique est résolu quant à lui avec un outil de calcul numérique adapté aux grandes transformations. Cet algorithme est ensuite utilisé pour évaluer l’influence de différentes stratégies de modélisation de la nappe de filet, toutes tirées de la littérature scientifique, sur le comportement global d’un écran de protection pare-blocs. Les conclusions de cette étude ainsi que des observations expérimentales ouvrent la voie vers de nouvelles stratégies de modélisation discrète, pour lesquelles le filet est représenté par un nombre restreint de degrés de liberté. La famille de modèles simplifiés développée dans ce travail permet de simuler le comportement d’un ouvrage avec des faibles coûts en temps de calcul, offrant ainsi l’opportunité de mettre en œuvre des études paramétriques complexes et des méthodes de dimensionnements probabilistes
Rockfall barriers are flexible structures that mitigate the risk of rockfall and thus protect people living in risk areas, as well as their property. These structures, placed on the trajectories of the moving blocks, are made of a steel net held on the natural ground by rigid posts. When they are impacted, they undergo large deformations that require modelling their behaviour by taking into account both geometric and material non-linearities. Their components are therefore represented in this work with discrete elements and the mechanical problem is thus solved with a calculation tool adapted to the large déformations problem. This algorithm is also used to assess the influence of different net modelling strategies, from the scientific literature, on the overall behaviour of a rokfall barrier. The conclusions of this study as well as experimental observations pave the way to new discrete modelling strategies, for which the net is represented by a limited number of degrees of freedom. The family of simplified models developed in this work makes it possible to simulate the behaviour of a structure with a low computation time costs, thus offering the opportunity of implementing complex parametric studies or probabilistic dimensioning methods

Le traitement en dynamique non linéaire du fonctionnement des structures en b. A. Est un problème complexe et couteux. L'aborder par des méthodes simplifiées est une solution avantageuse, a la condition de pouvoir conserver une description fine et réaliste des phénomènes majeurs. Analyse dans l'environnement d'une méthode par éléments finis multicouches, il a porte sur deux aspects majeurs : celui du traitement de l'élancement et celui de l'évaluation des erreurs liées a la discrétisation. Le code de calcul eficos initialement conçu avec des éléments poutres de type Navier-Bernoulli composés de couches superposées, permettait d'étudier le comportement d'un grand nombre d'éléments structuraux de type poutre/poteau, tant que leur élancement ne posait pas de difficultés particulières. La stratégie proposée ici permet de prendre en considération les effets de moment du second ordre. Ceci ajoute aux précédents travaux réalises sur les effets de cisaillement conduisent a un nouvel outil adapte, vis-à-vis de l'élancement, a un large domaine d'applications. S'agissant des grands déplacements, la méthode proposée, pour la prise en compte de l'effet p-delta en comportement en dommageable, a été appliquée au cas de poteaux en béton charges jusqu'a la ruine ; la comparaison avec l'expérience montre l'efficacité de la méthode. Des applications en réponse non linéaire sismique de piles de montre la capacité de l'outil à reproduire les principaux aspects critiques relatifs a la double non linéarité, matérielle et géométrique. Du cote des faibles élancements, l'étude réalisée dans le cadre du benchmark nupec met en évidence la bonne performance de la stratégie de modélisation simplifiée proposée, pour un mur arme de très faible élancement (inferieur a 1). Cependant, la qualité des résultats, notée par les organisateurs du benchmark comme étant de même niveau que ceux obtenus en éléments finis 2d ou 3 d, doit être associée à une représentation adaptée des conditions aux limites. L'étude est complétée par la proposition d'un estimateur d'erreurs dont la pertinence vis-a-vis de la discrétisation en éléments finis est montrée, aussi bien en statique qu'en dynamique. Une corrélation énergétique est également mise en évidence. C'est un nouveau pas vers l'optimisation et la fiabilité des analyses.

碩士
國立臺灣大學
土木工程學研究所
98
The key point of this thesis is integrating the soil-structure interaction system into the response spectrum method. Base on the traditional response spectrum method then adding the soil-interaction elements to get closer to the true response. The first purpose of simplified method is reducing the computation. Use the simple and convenient additional equivalent parameters to simulate the soil instead of the finite element method which is more complication. Get the additional mass, damping and stiffness parameters quickly and integrate into the combination system to modify the response of structure. Use modified combination system and takes soil affect in to condition to simplify the response structure method. Then it can be easily used by the basic components of structure and secondary system, for example the first period, damping ratio and the structure which it is connected, and use the design spectrum directly. In the chapter 5, 3 calculating examples shows the process of simplified method and compared with the state space solution, to check the applicability of the simplified method.

Testing of asphalt binders and asphalt-aggregate mixtures using dynamic mechanical analysis is becoming popular with improvements in high-speed computers, precision equipment, and computer software. Researchers are trying to describe the behavior of asphalt binders and asphalt-aggregate mixtures in terms of their time- and temperature-dependent linear viscoelastic behavior. The objectives of this thesis were to develop a simplified pneumatic test to perform dynamic mechanical analysis (DMA), to evaluate the performance of the pneumatic and hydraulic test systems using the computer software developed to perform DMA tests, and, to develop a simplified method to evaluate the experimental data obtained from DMA tests on aged asphalt-aggregate mixtures. A simplified pneumatic test system was developed to perform DMA. Computer software was also developed to perform DMA testing on both the simplified pneumatic and hydraulic test systems. DMA was performed on both test systems to compare their performance, and on aged asphalt-aggregate mixtures to evaluate the application of the simplified method. The results from the pneumatic and hydraulic test systems show that there is about a 20 percent difference in the complex modulus, especially at high loading frequencies. This is due to the compressibility of the air used in the pneumatic test system. The compressibility of air is greater at warmer temperatures than at cooler temperatures. Therefore, the application of the pneumatic test system to perform dynamic testing should be limited to low frequencies ( < 2 Hz), low temperatures ( < 25°C), and low load ( < 454 kg (1000 lbs.)) applications unless a modification can be made to increase the pneumatic cylinder's response time to match the hydraulic cylinder's response time. The simplified analysis method developed in this thesis divides the DMA results into four complex modulus and five phase angle parameters. These parameters describe the shapes of the master stiffness and phase angle curves and distinguished between the different asphalt-aggregate mixtures and the aging methods performed on the aged asphalt-aggregate mixtures. The phase angle parameters were reduced into two variables, peak frequency and peak angle, which vary with the aging of each asphalt-aggregate mixture. The peak frequency and peak angle decrease as the aging severity increases and the change of peak frequency and peak angle vary with the asphalt-aggregate mixture and aging treatment. Therefore, the complex modulus parameters and peak frequency and peak angle may be good indicators to describe how a master curve's shape varies with asphalt, aggregate, and aging type.
Graduation date: 1993

The numerical models of the railway track are fundamental tools for the study of their dynamic behaviour, with implications for the safety and comfort of rail transport and the degradation and need for maintenance of the track. The importance of these models has increased alongside the speed and capacity of the railway vehicles over the last decades. Although the use of three-dimensional finite element models is becoming common practice, simplified models are still relevant, due to their simplicity of implementation and results interpretation, and low computational cost. However, the general validity of these models has not yet been demonstrated in the relevant literature. The present thesis aims to establish the applicability and viability of such simplified models in the analysis of the dynamic behaviour of the ballasted railway track. The following questions are considered: 1. Are these models able to approximate the real rail displacement due to the passage of rail vehicles, despite their simplicity? 2. If yes, for which situations (i.e., track properties and loading conditions) can they be used reliably? 3. In these situations, is it possible to define adequate parameters for the simplified models based on the track’s geometry and mechanical properties? To that end, three linear elastic models are implemented: a detailed three-dimensional finite element model, a one-dimensional beam in discrete supports model, and a one-dimensional beam on elastic foundation model. Transient and steady-state dynamic solutions for a load moving at moderate and high speed are obtained. The vertical displacement of the rail is chosen as the reference to measure the equivalence between the models, since it is a common element between all models and is the interface between the load and the track. The three-dimensional model is validated by comparison with published experimental measurements. Its results cover a representative range of the properties of the ballast and subgrade, and are used as a reference to calibrate the simplified models using genetic algorithms and non-linear programming. It is concluded that a good approximation to the reference solution can be achieved, particularly when the load moves slower than the velocity of propagation of the elastic waves in the soil. For high velocities and/or soft soils, the wave propagation becomes more relevant to the dynamic behaviour of the track, and the simplified models become less reliable. Following a review of the existing literature, theoretical expressions for the determination of the parameters of the simplified models are proposed. It is concluded that these are suitable for the beam on discrete supports model, but not for the beam on elastic foundation model, whose optimum parameters are less consistent across the different properties of the track and load speeds.

Dottorato di Ricerca in Ingegneria dei Materiali e delle Strutture, XX Ciclo a.a. 2007
The increasing threat of extremely severe loading conditions caused by a number of explosive sources made engineers and scientists developing, during the last half century, several methods of analysis and design of blast–resistant structures. Simple, intermediate, and advanced computational approaches have been adopted, requiring increasing computational resources. These efforts led to the publication of several manuals and guidelines for the analysis and design of blast–resistant reinforced concrete and steel structures, mostly based on simple considerations derived from Single Degree of Freedom (SDOF) models. Although the development of future guidelines based on advanced numerical techniques is desirable, typical design activities cannot be effectively carried out by applying complex methods, because of their large demand of resources. Therefore the necessity to develop simplified, low time consuming, methods of analysis, capable of supporting a daily design activity and, at the same time, takeing into account issues usually neglected, such as a strong non linear material behavior and the influence of the strain rate caused by a blast load on the structural response. The development of such design tools is the object of this study. The first part of this thesis deals with the influence of the blast load shape on the dynamic response of an undamped linear elastic oscillator. Response spectrum and pressure–impulse diagrams are shown for several shape parameters, and a sensitivity analysis of the results with respect to the computational parameters is also presented. A method validation is carried out via genetic algorithms, through a careful calibration of all the genetic parameters, such as crossover fraction and number of elite elements. Non linear material modeling and strain rate dependent constitutive laws are objects of the second part of this dissertation. A non linear oscillator made of displacement, velocity, and acceleration dependent springs and dampers, under an arbitrary dynamic load, is proposed. Spring and damper constitutive laws have no restrictions as well as the load–time function, and the dynamic analysis is accomplished by a piecewise linear approximation of any input function. Numerical problems are dealt with by applying the Newton–Raphson method, in such a way that enables the error range to be estabiv lished “a priori”. Any possible drawback of this method is carefully avoided, and a quadratic speed of convergence is always ensured. Since the model provides velocity dependent springs, strain rate effects of blast loads on the structural response are taken into account by including strain rate dependent constitutive laws within the problem definition.
Università della Calabria

碩士
國立屏東科技大學
環境工程與科學系所
100
The United States Environmental Protection Agency （US EPA） ranked acenaphthylene （Acpy） as 16 among polycyclic aromatic hydrocarbons （PAHs） in terms of priority air pollutants. Despite the use of plasma technology in recent years to treat and decompose toxic compounds, power consumption costs during plasma operations are prohibitively high. Reducing plasma operational costs and validating the destructive efficiency of toxic compounds by using plasma are thus of priority concern. This study simulated an atmospheric plasma reactor by using a method based on computational fluid dynamics （CFD）. The commercial FLUENT code was then adopted to simulate the Acpy compound by using a three-dimensional atmospheric plasma reactor in order to treat cooking fume exhaust emitted from the restaurant kitchen. Next, parameters of the temperature, velocity mass fraction and efficiency of Acpy compound decompose in the code were examined to determine how they influence the atmospheric reactor. The numerical approach was based on refers to a specific finite volume method. The RNG κ-ε turbulence model, the SIMPLE algorithm and finite-rate eddy dissipation model were employed to solve in the combustion case. During simulation, the atmospheric plasma reactor size and operating parameters were taken from the self-designed atmospheric plasma reactor in our previous study （NSC95-2211-E020-020）. Additionally, CFD simulation results and measurement data were compared and discussed. According to results, CFD simulation can reduce operating costs associated with plasma reactor experiments. Results of this study provide a valuable reference for efforts to treat air carcinogenic compounds by using an atmospheric plasma reactor.