Orientador: Milton Mori / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-26T06:44:29Z (GMT). No. of bitstreams: 1 AlvarezCastro_HelverCrispiniano_D.pdf: 5280150 bytes, checksum: 96fb29e2849d11c06890186cb8af2f51 (MD5) Previous issue date: 2014 / Resumo: Conversão de matéria-prima e rendimento são estudados através de um modelo 3D que simula o principal reator do processo de craqueamento catalítico fluidizado (FCC). Fluidodinâmica computacional (CFD) é usada como técnica com abordagem Euleriana-Euleriana para prever o comportamento do riser da FCC. O modelo considera 12 grupos com desativação do catalisador dada por coque e envenenamento por nitritos alcalinas e adsorção aromático policíclico para estimar o comportamento cinético, o qual partindo de uma determinada matéria prima, se craquea a diversos produtos. Composições diferentes para matérias-primas foram consideradas. Para validação o modelo foi comparado com dados experimentais em condições de operação industrial. O modelo é capaz de representar com precisão a geração de produtos para as diferentes condições de operação consideradas. Todas as condições consideradas foram resolvidos usando o solver Ansys CFX 14.0. As diferentes variáveis do processo de operação e efeitos hidrodinâmicos do riser industrial de craqueamento catalítico fluidizado (FCC) foram avaliadas. As previsões do modelo são apresentados e comparadas; conversão e produtos são apresentados. Recomendações para criar condições para obter maior rendimento do produto no processo industrial foram dadas / Abstract: Feedstock conversion and yield products are studied through a 3D model simulating the main reactor of the fluid catalytic cracking (FCC) process. Computational Fluid Dynamic (CFD) is used with Eulerian-Eulerian approach to predict the fluid catalytic cracking behavior. The model considers 12 lumps with catalyst deactivation by coke and poisoning by alkaline nitrides and polycyclic aromatic adsorption to estimate the kinetic behavior which, starting from a given feedstock, produces several cracking products. Different feedstock compositions are considered. The model is compared with sampling data at industrial operation conditions. The simulation model is able to represent accurately the products behavior for the different operating conditions considered. All the conditions considered were solved using a solver Ansys CFX 14.0. The different operation process variables and hydrodynamic effects of the industrial riser of a fluid catalytic cracking (FCC) are evaluated. Predictions from the model are shown and comparison with experimental conversion and yields products are presented; recommendations are drawn to establish the conditions to obtain higher product yields in the industrial process / Doutorado / Engenharia de Processos / Doutor em Engenharia Química

Thermochemical nonequilibrium widely exists in supersonic combustion, cold plasma and hypersonic flight. The effect can influence heat transfer, surface ablation and aerodynamic loads. One distinct feature of it is the coupling between internal energy excitation and chemical reactions, particularly the vibration-dissociation coupling. The widely used models are empirical and calibrated based on limited experimental data. Advances in theories and computational power have made the first-principle calculation of thermal nonequilibrium reaction rates by methods like quasi-classical trajectory (QCT) almost a routine today. However, the approach is limited by the uncertainties and availability of potential energy surfaces. To the best of our knowledge, there is no study of thermal nonequilibrium transport properties with this approach. Most importantly, non-trivial effort is required to process the QCT data and implement it in flow simulation methods. In this context, the first part of this work establishes the approach to compute transport properties by the QCT method and studies the influence of thermal nonequilibrium on transport properties for N₂-O molecules. The preponderance of the work is the second part, a comprehensive study of the development of a new thermal nonequilibrium reaction model based on reasonable assumptions and approximations. The new model is as convenient as empirical models. By validating against recent QCT data and experimental results, we found the new model can predict nonequilibrium characteristics of dissociation reactions with nearly the same accuracy as QCT calculations do. In general, the results show the potential of the new model to be used as the standard dissociation model for the simulation of thermochemical nonequilibrium flows.

The simulation of natural phenomena such as clouds, smoke, fire and water is one of the most important research areas in computer graphics. Clouds are an essential component of any outdoor virtual environment, they add an important element of visual detail without which the environment would feel unrealistic. This paper describes an approach for setting up a cloud simulation. Clouds in our system are modeled using cellular automaton. To accelerate the simulation and its visualization, we implement both  entirely on programmable floating-point graphics hardware. The main part of the algorithm is implemented in a fragment shader and therefore takes full advantage of the highly parallel structure. The algorithm can generate result at real-time or near real-time frame rates. We also simulate the interaction of clouds with light, including self-shadowing.

An attempt to numerically predict flow rate of experimental configuration of orifices in transition between molecular and viscous flow regime is described in detail. Discretization of Boltzmann kinetic equation known as lattice-Boltzmann method is derived and applied unfortunately with very little connection to the original experimental problem due to nearly supersonic nature of the experimental setup. Current quite unsatisfactory state of the art of compressible lattice-Boltzmann method is also presented.

This document is a report summering the master thesis work dealing with the Computational Fluid Dynamic (CFD) study of the flow around a high-speed train. The model is a scaled 1:50 generic train with two cars, one inter-car gap and simplified bogies. A platform is set on the side of the train since one of the aim of the study is to look at the consequences of the phenomena in the wake on people or objects standing on the platform. The slipstream is one of this phenomena, it is due to the fact that the viscous air is dragged when the train is passing. If too strong, it can move or destabilize people or objects on the platform. In addition of the slipstream study, a velocity profile study, a drag and lift coefficients analyze as well as a Q-factor study and a frequency study have been realized. Some results of these different studies are compared with the ones obtained on the same model with a Delayed Detached Eddy Simulation (DDES). Since the flow is turbulent, for those different studies, the flow has been simulated with a Reynolds Averaged Navier-Stokes equation model (RANS) which is the k-ω SST model for the turbulence. The study of the slipstream allowed to calculate the Technical Specification for Interoperability (TSI) which must not be higher that the European Union requirement set at 15.5 m/s, the result obtained is 8.1 m/s which is then lower than the limit. The velocity profile shows similarities with the DDES results even though it is less detailed. The same conclusion is done for the Q-plot where is clearly visible the two counter-rotating vortices in the wake. Finally, a Fast Fourier Transform algorithm has been applied to instantaneous velocity results in the wake of the train in order to get the frequency of the aerodynamic phenomena in that wake. The main frequency is 25 Hz and corresponds to a Strouhal number of 0.1, quite closed to the results obtained with DDES which is 0.085. The results of the RANS and DDES are reasonably similar and by regarding at the large difference between the cell numbers (respectively 8 500 000 and 20 000 000) it can be conclude that in some ways the RANS model can be preferred at the DDES to save time for the computation but it does not contain the small scales resolved by the DDES.

Avstängda kärnkraftverk berövar många människor av elektricitet och det skulle ha en negativ inverkan både på företagets framtoning och mänskliga aktiviteter. På grund av detta behöver tillgängligheten av utrustningen i alla byggnaderna som kärnkraftverken består ses till. HVAC-system (Heating, Ventilation and Air Conditioning) spelar en viktig roll när det gäller tillgänglighet av utrustning eftersom dessa system ser till pålitligheten är på topp genom att anpassade omgivningsförhållanden till utrustningen. Att designa ventilationssystemet rätt är därför mycket viktigt och måste göras noggrant. Denna rapport introducerar metodologin för att designa och optimera ett ventilationssystem för en av byggnaderna i ett kärnkraftverk. Utöver detta utvecklas och beskrivs en metodologi för att designa ett rökkontrollssystem för en byggnad som ingår i kärnkraftverket. Dessa metodologier har implementerats för en byggnad i en demineraliseringsstation, Hinkley Point C project. / During nuclear power plants shutdown many people could be deprived of electricity and it would have a negative impact both on the company’s image and on people activities. As a consequence, availability of equipments in the different buildings which compose the power plant needs to be assured. HVAC system (Heating, Ventilation and Air Conditioning) plays an important role on the reliability of these equipments as it makes sure that ambient conditions in the buildings fit the operating temperature range of the equipments. Consequently sizing a ventilation system is really important and it needs to be carried out seriously. This paper introduces the methodology to size and optimize a ventilation system for nuclear power plants’ building. This paper also develops the methodology used to size a smoke control system in a nuclear related building. Direct application of this methodology has been realised for a specific building which is the demineralization station of Hinkley Point C project.

Clouds are ubiquitous and ever-changing feature of the outdoors. They are an integral factor in Earth's weather systems. Component of water circulation in a nature and a strong indicator of weather patterns and changes. Clouds are important component of the visual simulation of any outdoor scene, but the complexity of cloud formation, dynamics, and light interaction makes cloud simulation and rendering difficult in real time. In an interactive flight simulation, users would like to fly in and around realistic, volumetric clouds. I Present, two main ways of representation cloud in computer graphic, where one way use for modelling Perlin noise and second one use for modelling fluid dynamic system.

<p dir="ltr">Increased scrutiny from customers and regulators to design aeroengines that are more efficient and environmentally friendly has pushed the need to investigate new engine architectures, manufacturing techniques, and computational fluid dynamic methods. This has led to the development of the CSTAR Gen. 2.5 centrifugal compressor, which uses an additively manufactured diffusion system and investigates the aerodynamic performance of an axi-centrifugal aeroengine. Additionally, an isolated unsteady diffuser computational model was previously developed that seeks to significantly reduce the computational cost of unsteady CFD in the diffuser.</p><p dir="ltr">The research presented in this paper is part of an ongoing attempt to utilize the capabilities of isolated unsteady diffuser modeling and rapid prototyping enabled through additive manufacturing in CSTAR Gen. 2.5 to develop a design framework that allows for quick computational and experimental analysis of diffusion systems in centrifugal compressors. Specifically, the scope of isolated unsteady diffuser modeling, which was previously only implemented in CSTAR Gen. 1 and at a single loading condition, is expanded by analyzing computational instabilities when applying the methodology to CSTAR Gen. 2.5 and analyzing results from four loading conditions (high loading, design point, low loading, and near choke) along a speedline.</p><p dir="ltr">Computational instabilities in the CSTAR Gen. 2.5 isolated diffuser models were determined to be caused by the decreased vaneless space compared to Gen. 1, which led to less “mixed” flow at the impeller outlet and a stronger diffuser potential field affecting the inlet profile. A boundary profile correction approach was developed which slightly increased very low total pressure near the diffuser shroud and negative radial velocity regions near the shroud and pitchwise locations of the diffuser vane leading edges while minimizing the overall affected area. The correction was successfully validated using 3D flow structure and minimum, average, and maximum total pressure, absolute velocity magnitude, and pressure comparisons at the diffuser inlet between an isolated and full-stage model.</p><p dir="ltr">Prediction capabilities of 3D flow structures and 1D performance parameters by isolated unsteady diffuser models were validated with results from full-stage unsteady models at each loading condition. The analysis indicated consistent performance by the isolated unsteady diffuser model at all loading conditions. An overall agreement in 3D flow structures was found, and trends in the full-stage unsteady models along the speedline were tracked well by the isolated unsteady model. At all loading conditions, there was a consistent over-representation of the separation region along the diffuser vane pressure side in the diffuser passage, overprediction of total pressure magnitude at the core of the flow at the diffuser outlet, and over- or underprediction of total pressure loss and static pressure recovery respectively. The similarity in the results between full-stage and isolated unsteady models, tracking of trends along the speedline, and consistent differences in 3D flow structure predictions and 1D performance parameters validates the isolated unsteady diffuser methodology for use at loading conditions from surge to choke.</p>

Die Herstellung hochqualitativer Produkte in der Lebensmittel-, Kosmetik- und Pharmaindustrie erfordert den Einsatz reproduzierbarer Reinigungsprozesse. Häufig wird die nasschemische Reinigung als Cleaning in Place Verfahren angewandt. Diese Arbeit leistet einen Beitrag zur Optimierung von Reinigungsprozessen im nicht immergierten System insbesondere bei der Anwendung gravitationsgetriebener Flüssigkeitsfilme. Inhalte sind Untersuchungen zum Benetzungs- und Strömungsverhalten im Vergleich zur Reinigungswirkung von Flüssigkeitsfilmen. Als Modellverschmutzungen wurden zwei lebensmitteltypische Bestandteile in Kombination mit partikulären Anteilen eingesetzt. Im Ergebnis konnte nachgewiesen werden, dass sich das Reinigungsverhalten der gewählten Verschmutzungen mit der Hydrodynamik am Beispiel von Flüssigkeitsfilmen beschreiben lässt. Zusätzlich wurde ein neuartiger Ansatz zur Optimierung der Reinigungseffizienz durch die Anwendung diskontinuierlicher Flüssigkeitsfilme untersucht. Dadurch konnte gezeigt werden, dass der Ressourceneinsatz gegenüber einer kontinuierlichen Flüssigkeitsfilmströmung signifikant verringert werden kann, wobei die Reinigungszeit nur geringfügig steigt.:Danksagung ... II Inhaltsverzeichnis ... III Verzeichnis der verwendeten Formelzeichen ... VI Abkürzungsverzeichnis ... XVI 1 Einleitung, Motivation und Gegenstand der Arbeit ... 1 2 Grundlagen der Reinigung ... 3 2.1 Begriffserklärung ... 3 2.2 Industrielle Reinigungsprozesse ... 3 2.2.1 Einordnung ... 3 2.2.2 Reinigungsgeräte für die Nassreinigung im nicht immergierten System ... 8 2.3 Reinigungsvorgänge im nicht immergierten System ... 10 2.3.1 Komponenten des Reinigungssystems ... 10 2.3.2 Schmutzhaftmechanismen ... 20 2.3.3 Reinigungsmechanismen und Wirkzusammenhänge ... 23 2.3.4 Reinigungskinetik ... 28 3 Methoden für Reinigungsuntersuchungen ... 32 3.1 Einordnung ... 32 3.2 Industrielle Methoden ... 33 3.3 Wissenschaftliche Methoden ... 35 4 Gravitationsgetriebene Flüssigkeitsfilmströmungen ... 37 4.1 Einteilung von Filmströmungen und Filmkennzahlen ... 37 4.2 Kennzahlen zur Oberflächenbenetzung ... 40 4.3 Filmdicke und Filmoberflächenwelligkeit ... 47 4.3.1 Modellvorstellungen und Kennzahlen ... 47 4.3.2 Experimentelle Methoden ... 50 4.4 Strömungsgeschwindigkeit ... 54 4.4.1 Modellvorstellungen und Kennzahlen ... 54 4.4.2 Experimentelle Methoden ... 58 5 Zielsetzung und Lösungsweg ... 61 5.1 Problemstellung ... 61 5.2 Arbeitshypothese ... 62 5.3 Vorgehen ... 62 5.4 Zusammenhang mit anderen Arbeiten ... 63 6 Material und Methoden ... 64 6.1 Auswahl Substrate ... 64 6.2 Topografiebestimmung ... 64 6.3 Kontaktwinkelmessung ... 66 6.4 Untersuchungsobjekt ... 68 6.5 Grundaufbau der Versuchsanlage ... 68 6.6 Auswahl der Flüssigkeit ... 70 6.7 Festlegung der Einstellparameter für die Strömungs- und Reinigungsmessungen ... 71 6.8 Charakterisierung des Stoffsystems ... 71 6.8.1 Quellverhalten ... 71 6.8.2 Bindungskräfte ... 77 6.9 Hydrodynamik ... 79 6.9.1 Oberflächenbenetzung ... 79 6.9.2 Filmdicke ... 85 6.9.3 Strömungsgeschwindigkeit ... 102 6.10 Reinigungsuntersuchungen ... 115 6.10.1 Auswahl der Modellverschmutzungen ... 115 6.10.2 Auswahl und Konzeption der Messdatenerfassung ... 117 6.10.3 Versuchsaufbau ... 119 6.10.4 Aufnahmeparameter ... 121 6.10.5 Benetzungseinfluss auf die Phosphoreszenzintensität ... 123 6.10.6 Methode zur reproduzierbaren Verschmutzung ebener Substrate ... 125 6.10.7 Überprüfung der Reproduzierbarkeit und Gleichmäßigkeit der Verschmutzungsmethode ... 128 6.10.8 Versuchsablauf ... 130 6.10.9 Messdatenaufbereitung und -auswertung ... 130 7 Versuchsauswertung und Ergebnisse ... 140 7.1 Charakterisierung der Verschmutzung ... 140 7.1.1 Quellverhalten ... 140 7.1.2 Bindungskräfte ... 144 7.1.3 Zusammenfassung der Verschmutzungscharakterisierung ... 150 7.2 Hydrodynamik gravitationsgetriebener Flüssigkeitsfilme ... 151 7.2.1 Oberflächenbenetzung ... 151 7.2.2 Filmdicke und Filmdickenverteilung ... 163 7.2.3 Strömungsgeschwindigkeit ... 171 7.2.4 Zusammenfassung der Hydrodynamik gravitationsgetriebener Flüssigkeitsfilme ... 180 7.3 Reinigungsverhalten gravitationsgetriebener Flüssigkeitsfilme ... 182 7.3.1 Reinigungskinetik ... 182 7.3.2 Gereinigte Zonen ... 185 7.3.3 Einfluss des Flächenverschmutzungsgewichtes ... 187 7.3.4 Einfluss der Betriebsparameter ... 188 7.3.5 Reinigungseffizienz ... 191 7.3.6 Einfluss der Oberfläche ... 193 7.3.7 Fehlerdiskussion ... 195 7.3.8 Zusammenfassung des Reinigungsverhaltens ... 197 8 Vergleich Reinigungsverhalten und Hydrodynamik gravitationsgetriebener Flüssigkeitsfilme ... 198 8.1 Vorbemerkungen zum Vergleich ... 198 8.2 Einfluss Strömungsparameter auf das Reinigungsverhalten ... 198 8.2.1 Einfluss der Filmdicke und Filmdickenverteilung ... 198 8.2.2 Einfluss der Strömungsgeschwindigkeit ... 199 8.3 Einfluss abgeleiteter Größen auf das Reinigungsverhalten ... 201 8.3.1 Einfluss der Wandschubspannung ... 201 8.3.2 Einfluss der Grenzschichtdicke ... 202 8.4 Zusammenfassung des Vergleiches zwischen Reinigungsverhalten und Hydrodynamik ... 205 9 Optimierungsansatz: diskontinuierliche Flüssigkeitsfilme ... 207 10 Zusammenfassung und Ausblick ... 211 Literaturverzeichnis ... 214 Anhangverzeichnis ... 229

都市地區因人口增長、大量人工建成環境與能源使用等緣故，將產生都市熱島效應。都市熱島效應產生都市高溫化，進而衍生各種都市環境問題，如都市微氣候改變、能源消耗與供給壓力增加、空氣汙染物不易擴散等(Landsberg, 1981)。臺灣位於亞熱帶氣候地區，人口多集中於都市地區，尤其是臺北市。先前相關研究指出臺北市具有都市熱島效應。本研究從有高蓄熱特性的道路與建築量體所構成之「都市街道」為尺度範圍，將進行固定監測站之量測，實際取得都市微氣候之數據（溫度與熱舒適性指標），配合都市街道熱環境因子之調查，一併探討都市街道熱環境因子產生都市高溫化的關係，有別於其他研究探討都市整體的熱島效應，或是單一影響因素導致的都市高溫化，如街廓、材料、植栽、人工排熱等對微氣候的影響。此外，本研究輔以計算流體力學（Computational Fluid Dynamics，簡稱CFD），將量測的數據做為模擬之基本條件，進而模擬都市街道的風場與溫度場，搭配實測數據與模擬值作分析，並且加入都市街道熱環境因子與兩者作探討。研究成果指出植栽綠化與遮蔭將有效改善都市高溫化現象。