Experimental and numerical studies simulating the gas-cooled divertor plate design concept have been carried out. While thermo-fluid and thermo-mechanical analyses have been previously performed to show the feasibility of the divertor plate design and its ability to accommodate a maximum heat flux of up to 10 MW/m2, no experimental data have heretofore been published to support or validate such analyses. To that end, this investigation has been undertaken. A test module with prototypical cross-sectional geometry has been designed, constructed, and instrumented. Experiments spanning the prototypical Reynolds numbers of the helium-cooled divertor have been conducted using pressurized air as the coolant. A second test module where the planar jet exiting the inlet manifold is replaced by a two-dimensional hexagonal array of circular jets over the entire top surface of the inlet manifold has also been tested. The thermal performance of both test modules with and without a porous metallic foam layer in the gap between the outer surface of the inlet manifold and the cooled surfaces of the pressure boundary were directly compared. For a given mass flow rate, the slot design with the metallic foam insert showed the highest heat transfer coefficient, with a pressure drop lower than that of the array of circular jets without foam. Additionally, numerical simulations matching the experimental operating conditions for the two cases without foam were performed using the computational fluid dynamics software package, FLUENT® v6.2. Comparisons of the experimental and numerical pressure drop, temperature, and heat transfer coefficient were made.

Η χρήση θαλασσίου ύδατος για ψύξη μηχανών σε βιομηχανικές εγκαταστάσεις και σταθμούς παραγωγής ηλεκτρικής ενέργειας επιτυγχάνεται μέσω εγκαταστάσεων άντλησης θαλασσίου ύδατος. Οι δεξαμενές αυτών των εγκαταστάσεων πρέπει να σχεδιάζονται σύμφωνα με τις οδηγίες του Hydraulic Institute (1998) ώστε να αποφεύγονται ανεπιθύμητα φαινόμενα που επηρεάζουν την απόδοση και τη διάρκεια ζωής των αντλιών. Τέτοια φαινόμενα είναι οι στρόβιλοι, υποβρύχιοι και ελεύθερης επιφάνειας, η υπερβολική προ-ελίκωση της ροής ανάντη κάθε αντλίας, η ανομοιομορφία της ροής στην πτερωτή κάθε αντλίας, οι υπερβολικές χρονικές διακυμάνσεις της ταχύτητας και της ελίκωσης και η συμπαράσυρση αέρα και η δημιουργία φυσαλίδων. Στην παρούσα διατριβή εξετάζεται η δεξαμενή της εγκατάστασης άντλησης θαλασσίου ύδατος μέσω δύο αντλιών που βρίσκεται στον υπό κατασκευή Θερμοηλεκτρικό Σταθμό Φυσικού Αερίου της Δ.Ε.Η. στο Αλιβέρι. Σκοπός της διατριβής είναι η μελέτη της ροής στη συγκεκριμένη δεξαμενή ως προς την κυκλοφορία του ύδατος (γραμμές ροής και τύρβη), τις διατμητικές τάσεις στα τοιχώματα των αγωγών και της δεξαμενής, την προ-ελίκωση της ροής που προσεγγίζει την αντλία και την ανομοιομορφία της στο επίπεδο της πτερωτής της αντλίας, καθώς και η συμπεριφορά της ελίκωσης της ροής στους αγωγούς άντλησης. Η διερεύνηση της ροής γίνεται για αρκετές καταστάσεις λειτουργίας της δεξαμενής ως προς το βάθος ύδατος και τον αριθμό θυροφραγμάτων και αντλιών. Η γεωμετρία του υπολογιστικού πεδίου, το υβριδικό μη-δομημένο πλέγμα και η αριθμητική επίλυση των εξισώσεων ροής πραγματοποιήθηκαν με τα προγράμματα Design Modeler, Meshing και Fluent του ANSYS. Ειδικότερα για το Fluent επιλέχθηκαν τα μοντέλα τύρβης k-ε και k-ω. Τα αποτελέσματα αναλύονται και συγκρίνονται με τα πειραματικά του υδραυλικού μοντέλου (Dimas & Vouros, 2012) σε κλίμακα 1:8.7 κατά Froude. Στις περιπτώσεις όπου είναι ανοικτό μόνο το ένα θυρόφραγμα, έχουμε κυκλοφορία της ροής μεταξύ των δύο θαλάμων των αντλιών κυρίως κοντά στην ελεύθερη επιφάνεια του ύδατος. Στις περιπτώσεις όπου λειτουργεί μόνο η μία αντλία, έχουμε και έντονη κυκλοφορία στο θάλαμο της δεξαμενής που δεν γίνεται άντληση. Η φορά της ελίκωσης της ροής στον αγωγό συμπίπτει στις περισσότερες περιπτώσεις με αυτήν του υδραυλικού μοντέλου. Η γωνία ελίκωσης θ, η οποία υπολογίστηκε με βάση το μέτρο της εφαπτομενικής ταχύτητας, ήταν μεγαλύτερη στο μεγάλο βάθος ύδατος και διαφορετική σε όλες τις περιπτώσεις από αυτήν που μετρήθηκε στο υδραυλικό μοντέλο. / -

At the Torpshammar dam two rectangular beams are situated upstream of the spillway gates to stabilize the sidewalls holding the embankment of the dam. A computational fluid dynamics (CFD) simulation of the dam with the bottom outlets open was made to investigate how the flow and discharge capacity is affected by the beams. The results can be used to avoid unexpected consequences due to turbulence caused by the beams, make the beams strong enough to hold the pressure from the flow and get an estimation of the discharge capacity with the beams. Turbulence is one of the hardest things to simulate so the results were compared with previous simulation work made without the beams and physical model tests to validate the results. Also, a sensitivity analysis was made to investigate the method used. The beams lowered the velocity (to 17 m/s) and the discharge capacity (to 255 m3/s) compared to the previous work. The force on the beams was directed upward and downstream. The beams increased the turbulence and the vortex shedding frequency was higher for the beam closest to the outlet. The velocity and discharge capacity differed with 6 % compared to model test results. The results can therefore only be used as an estimation, a more detailed computational model and more computational cells are needed to get a better result. The sensitivity analysis showed that the velocity and turbulence depend on the method and further studies need to be made to decide which method gives the closest similarity with reality.

Orientador: Rosana do Carmo Novaes Pinto / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Estudos da Linguagem / Made available in DSpace on 2018-08-13T12:43:32Z (GMT). No. of bitstreams: 1 Canoas-Andrade_Rosangela_M.pdf: 2122155 bytes, checksum: e41f3e8059727d732ec7dd6d0bd9d6f8 (MD5) Previous issue date: 2009 / Resumo: A Fonoaudiologia tradicional, com relação às alterações da linguagem, ainda sofre a forte influência teórica e metodológica dos discursos que circulam na área médica. As abordagens orgânicas são geralmente priorizadas, em detrimento de análises mais abrangentes dos fenômenos e, principalmente, dos sujeitos. Essa visão redutora, inevitavelmente, também é que vai dar as diretrizes para o acompanhamento terapêutico. Orientado pela abordagem teórica e metodológica da Neurolingüística Discursiva (ND), este trabalho apresenta um estudo longitudinal de um caso de Afasia Fluente Progressiva, para o qual contribuem o histórico neurológico - constituído por imagens tomográficas e laudos que revelam lesões em várias áreas cerebrais, em decorrência de AVCs focais e isquêmicos, clipagem de aneurismas e atrofias corticais e sub-corticais, além dos resultados de avaliações neuropsicológicas e as análises lingüísticas de episódios dialógicos. Os dados analisados foram obtidos em episódios dialógicos ocorridos nas sessões semanais do Grupo III do CCA (Centro de Convivência de Afásicos) e em sessões individuais de acompanhamento fonoaudiológico, durante as quais também foram desenvolvidas algumas atividades metalingüísticas, com o objetivo de respaldar nossas hipóteses sobre suas dificuldades lingüísticas e cognitivas. Trata-se de um caso que consideramos singular, pois revela os efeitos das práticas sociais e do exercício real com a linguagem, tanto no curso do desenvolvimento de sua afasia, como das alterações cognitivas. A instabilidade presente no caso de AJ, cujos enunciados às vezes em nada diferem da normalidade, outras vezes revelam dificuldades próprias de sua afasia e, em determinados momentos assemelham-se aos quadros iniciais de demência, contribui para a reflexão acerca da relação normal/patológico.Por fim, discute-se o impacto da abordagem da ND para a clínica fonoaudiológica, na avaliação da linguagem e, principalmente, no acompanhamento terapêutico de sujeitos afásicos ou com outras alterações lingüísticas e cognitivas / Abstract: The traditional Speech Therapy, when the focus is language alterations, is still strongly influenced by the theoretical and methodological discourses from the medical field. Organic approaches are usually privileged in comparison to other approaches, other possibilities of analysis of the phenomena and, especially, of the subjects. This reductionist view, inevitably, is the one that will provide the guidelines for language therapy. Guided by the theoretical and methodological approach of Discursive Neurolinguistics (ND), this research presents a longitudinal study of a case of Fluent Progressive Aphasia. We present the neurological history of the case - which consists of tomography images and reports, which reveal lesions in various brain areas, due to strokes - focal and ischemic, clipping of aneurysms and cortical & sub-cortical atrophies. We also present the results of neuropsychological assessments and the analysis of linguistic episodes. Data were obtained during episodes occurred in the weekly discussion of Group III of CCA (Centro de Convivência de Afásicos) and in individual sessions of speech therapy, during which some metalinguistic activities were developed, with the aim of supporting our hypothesis about his linguistic and cognitive difficulties. This is a case that we consider unique, because it shows the effects of social and linguistic practices on the development of aphasia and on the cognitive changes. The instability that characterizes the case contributes to the debate / Mestrado / Linguistica / Mestre em Linguística

Magister Scientiae - MSc / The overall aim of this project is to study the heat transfer inside the reaction chamber of the Hot-Wire Chemical Vapor Deposition (HWCVD) system with a commercial software package FLUENT6.3; it is one of the most popular Computational Fluid Dynamics solvers for complex flows ranging from incompressible to mildly compressible to even highly compressible flows. The wealth of physical models in FLUENT allows us to accurately predict laminar and turbulent flows, various modes of heat transfer, chemical reactions, multiphase flows and other phenomena with complete mesh flexibility and solution-based mesh adaptation. In this study the 3-D HWCVD geometry was measured and created in GAMBIT which then generates a mesh model of the reaction chamber for the calculation in FLUENT. The gas flow in this study was characterized as the steady and incompressible fluid flow due to the small Mach number and assumptions made to simplify the complexity of the physical geometry. This thesis illustrates the setups and solutions of the 3-D geometry and the chemically reacting laminar and turbulent gas flow, wall surface reaction and heat transfer in the HWCVD deposition chamber. / South Africa

<p>This work utilized Pointwise and Fluent to generate a two-dimensional axisymmetric model a Mk 48 torpedo, with the intention of informing methods to reduce the turbulence, and therefore hydrodynamic noise, of the torpedo’s wake. However, this work was unable to gather data on the unsteady nature of the turbulence expected around the torpedo due to Fluent providing unrealistic results when run using a transient solver. This work shows that the transient solver computed boundary layers greater than one order of magnitude smaller than expected, and in some cases there was no change in boundary layer thickness over the torpedo’s body. The work does contain steady state solutions that were validated by first performing a grid convergence study for a flat plate. The steady state results for the flat plate and torpedo both showed the expected growth for a turbulent boundary layer. Additionally, there was a high level of convergence with the Log-Law showing that the steady state data is valid. Future work should use a transient solver to determine the characteristics of the turbulence to resolve unsteady flow from vortex shedding, wake characteristics, and any broadband or narrowband noise to develop solutions to reduce the noise made by the Mk 48.</p>

No description available.

This thesis is based on the series of scholarly article dedicated to the issue of pumping in the differential scanning chamber of an environmental scanning microscope. The thesis is based on Danilatos’s study where the pumping of the differential pumped chamber is solved by means of the Monte Carlo statistical method. The thesis analyzes gas flow in the experimental chamber using the Pipot tube. The analyses will be used for the design of the experimental chamber which will serve for the experimental evaluation of the flow results in the chamber using the continuum mechanics.

The thesis is focused on the medium dynamics simulation in the environmental scanning electron microscope. Specifically, it researches (examines) the conical aperture location effect in the differential pumped chamber and the width of the pumping channel in this chamber. The theoretical part deals with the environmental scanning microscope generally and other tools used in this thesis, e.g. ANSYS Fluen software, fluid turbulence, medium free path of molecules and electrons scattering. In the practical part, the work is focused on data processing from the ANSYS Fluent program and on their evaluation.

This master’s thesis deals with the simulation of flow through the normalized orifice plate. There is described flow measurement with flowmeters, which reduces the cross-section of the pipe and causes the pressure difference before and after the flowmeter. Following is a description methods of modeling of turbulent flow and a description of software for the simulation of flow from the company Ansys. The theoretical part is followed a practical part, which is focused on determining the permanent pressure loss caused by the orifice plate and the verification of straight pipeline lengths between orifice and obstacle.