To see the other types of publications on this topic, follow the link: Ball valves.
Dissertations / Theses on the topic 'Ball valves'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 40 dissertations / theses for your research on the topic 'Ball valves.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Rossetto, Diego Rizzotto. "Avaliação da integridade estrutural de projetos de válvulas do tipo esfera trunnion e/ou gaveta utilizadas nas instalações de petróleo." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/143311.
Full textAbstract:
Esta tese propõe avaliar a integridade estrutural de projetos de válvulas do tipo esfera trunnion e/ou gaveta. Por meio desta pesquisa, são avaliados os principais modos de falhas e parâmetros funcionais. Os estudos foram realizados utilizando a técnica dos elementos finitos e permitiram a construção de modelos para avaliar os seguintes modos de falha. (i) colapso estrutural dos principais componentes; (ii) vazamento na interface esfera/sede; (iii) travamento do sistema de acionamento devido à influência da vazão de escoamento do fluido. A avaliação da integridade estrutural é de fundamental importância para mitigar e/ou evitar erros, durante a fase de desenvolvimento de válvulas. Os modelos desenvolvidos também possibilitam o aprimoramento de novos projetos de válvulas e o aperfeiçoamento de projetos já desenvolvidos. O estudo proposto pode ser utilizado como indicador da qualidade de projeto de válvulas, auxiliando a equipe de desenvolvimento no dimensionamento de novos produtos, permitindo assim a avaliação dos requisitos funcionais e a avaliação da possível melhoria do projeto. Os resultados mostraram que o uso do método dos elementos finitos durante as fases iniciais do processo de desenvolvimento de válvulas é extremamente útil na concepção de novos produtos, permitindo a elaboração de produtos otimizados, sendo que por meio de um conhecimento multidisciplinar falhas prematuras podem ser detectadas nas fases iniciais do processo de desenvolvimento de projeto de válvulas, possibilitando com isso o desenvolvimento de um projeto mais racional com melhoria significativa de qualidade, confiabilidade, desempenho e competividade. O uso do método dos elementos finitos também possibilita uma redução do número de ensaios com protótipos físicos, o tempo de desenvolvimento e consequentemente o custo final do produto.This thesis proposes to evaluate the structural integrity of the trunnion ball valves and/or gate. By means of this research, are evaluated main failure modes and functional parameters. The studies were conducted using the finite elements technique and allowed the construction of models to evaluate the following modes of failure. (i) structural collapse of the main components; (ii) leakage in the ball/seat interface; (iii) torque and/or locking of drive system due the influence of fluid flow rate. The evaluation of the integrity structural is of fundamental importance to mitigate and/or avoid errors, during the valve development phase. The models developed also enable the improvement de new valves design and the upgrade the valves design already developed. The proposed study can be used as an indicator the quality of valves design, assisting the development team in the design of new products, thus enabling the assessment of the functional requirements and evaluation of possible improvements in the design. The results showed that the use of finite element method during the early stage of valve development process is extremely useful in the conception the new products, allow to develop products optimized, and by means of a multidisciplinary knowledge premature failures can be detected in the early stages of the product design, besides enable the development of a design more rational with significant improvement in quality, reliability, performance and competitiveness. The use of finite element method also allows reduction the number of with physical prototype tests, time of development and the final cost of the product.
2
Faccio, Mateus. "Avaliação de revestimento anticorrosivo orgânico aplicado em válvulas do tipo esfera para operações subsea." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/169775.
Full textAbstract:
Motivada pelos inúmeros desafios relacionados à exploração de petróleo na região do pré-sal, onde o ambiente agressivo aliado com a grande profundidade são fatores sempre presentes, a busca por materiais alternativos para aplicações em válvulas ganhou destaque. As válvulas subsea, essenciais para projetos de exploração nestas áreas são consideradas um desafio ainda maior. Dessa maneira, estudos e ensaios de desempenho em revestimentos anticorrosivos orgânicos nesse ambiente tornam-se necessários. O objetivo deste trabalho é avaliar a resistência à corrosão e ao desgaste do revestimento anticorrosivo orgânico ECTFE (Halar®) para a aplicação em válvulas industriais do tipo esfera para operações subsea, através da realização de ensaios em corpos de prova e em protótipos, perante as condições simuladas do ambiente agressivo na qual deverão operar em conformidade com o programa de qualificação do revestimento D-SMA/ING/SPF/TCNA-14-00047. Para a realização dos ensaios, foram projetados sistemas de tubulações fechadas (loopings), nos quais os protótipos foram instalados. Os parâmetros de testes estabelecidos, assim como os dados monitorados pelos sensores instalados, foram coletados durante todo o período de teste. Os ensaios definidos para a avaliação do revestimento orgânico em protótipos foram: ciclos de pressão, circulação sob vazão, circulação com água arenosa e ensaios de corrosão com e sem defeito imposto no revestimento. Complementarmente, corpos de prova em escala reduzida foram submetidos a ensaio de adesão e de fadiga. Os resultados obtidos foram conclusivos e o revestimento mostrou-se resistente às condições impostas aos protótipos, uma vez que não foram detectadas descontinuidades consideradas relevantes segundo os critérios de aceitação pré-estabelecidos em procedimento.The search for alternative materials for applications in valves has been highlighted motivated by the numerous challenges related to oil and gas in the pre-salt region, where the aggressive environment combined with great depth are always present factors. The subsea valves, essential for exploration projects in these areas, are considered an even bigger challenge, thus, studies and performance tests on organic anti-corrosion coatings in this environment become necessary. The purpose of this study is to evaluate resistance to corrosion and wear of organic anti-corrosion coating ECTFE (Halar®) for application of industrial ball valves for subsea operations, by conducting tests on specimens and prototypes, under simulated harsh environment conditions in which they should operate in accordance with the coating qualification program D-SMA / ING / SPF / TCNA-14-00047. Closed pipes systems are designed (loops) for the carrying out of the tests, in which the prototypes were installed. The set of test parameters as well as the monitored data by installed sensors were collected during the entire test period. The defined tests for the evaluation of the organic coating in prototypes were: pressure cycles, flow rate circulation, circulation in soapy water and corrosion tests with and without defects imposed in the coating. In addition, reduced specimens were submitted to adhesion and fatigue tests. The results were conclusive and the coating was resistant to the imposed conditions on prototypes, since relevant discontinuities were not detected according to pre-established acceptance criteria for the procedure.
3
Gomes, Kirk J. "Experimental High Speed Compressible Subsonic Flow Pressure Losses Across Gate, Butterfly and Ball Valves and Their Use in Natural Gas Transmission Flow Control Simulation Software." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1301930298.
Full text
4
Costa, Mauro Luís de Oliveira. "Estudo do torque de acionamento e vida útil de um projeto de válvulas industriais." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/21587.
Full textAbstract:
O objetivo principal deste trabalho é a análise e possível otimização de um projeto de válvulas de esfera. É apresentado um estudo para determinação do torque de acionamento de válvulas de esfera industriais, bem como um estudo de vida útil das válvulas. Os estudos foram realizados utilizando projeto de experimentos e permitiram a construção de modelos de previsão de torque e de previsão de vida útil. A previsão de torque é fundamental para possibilitar a otimização do projeto das válvulas, na fase de desenvolvimento do produto. O uso dos modelos permitiu a determinação do ajuste ótimo, levando em conta pressão, temperatura, esmagamento das sedes, torque de aperto na porca da haste e torque de acionamento desejado. Já os estudos de vida útil são importantes para informar à empresa o número de ciclos até o vazamento. Os resultados do estudo, realizado através de ensaios acelerados, permitiram a construção de modelos de confiabilidade associada ao número de ciclos de operação, permitindo assim a avaliação e possível melhoria do projeto das válvulas.The main objective of this dissertation is the analysis and optimization of a ball valve project. A study for determining the operational torque of industrial ball valves as well as a life study of valves are presented. The studies were performed using design of experiments and allowed the construction of torque and life prevision models. The prevision of torque is fundamental to enable project optimization on the phase of product development. Results allowed the definition of an optimal setting regarding pressure, temperature, seats tightening, stem nut tightening torque and the desired operational torque. Further, the life studies are helpful to inform the company the number of cycles until leakage. Results, obtained through accelerated tests, allowed the construction of reliability models associated to the number of operational cycles, conducting to valve design evaluation and optimization.
5
Peloza, Michael Anthony. "Basketball dribbling performance: Differences between using one ball or two balls." CSUSB ScholarWorks, 1998. https://scholarworks.lib.csusb.edu/etd-project/1445.
Full text
6
Steiner, Paul Frederick Jr 1938. "Modern ball-banking limiting values." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/291520.
Full textAbstract:
In 1940 R. A. Moyer and D. S. Berry established ball-banking limiting values (and side friction factors) for use in determining the maximum recommended speed of horizontal curves on roads (the value shown on advisory speed plates). This speed is also referred to as the "advisory speed", "safe speed", or the "comfortable speed" of the curve. This speed is distinguished from the "critical curve speed", the speed value at which loss of control is imminent. Literature review showed some concern for the criteria for the installation of curve warning signs but no recent concern for the goodness of the limiting values. Ritchie et. al. has provided updated research on lateral acceleration values. Their research, plus results of this study, show that the 1940 values are outdated. This work concludes with recommended modern ball-banking limiting values, side friction factors, and lateral acceleration values. Recommendations regarding further research are stated.
7
Roberts, Andrew Philip. "Modelling and Experimental Investigation into the Performance of a Ball Valve from an Aircraft Fuel System." Thesis, University of Bath, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.518099.
Full textAbstract:
The performance of an aircraft fuel system ball valve has been assessed using various modelling techniques and experimental methods. The performance largely splits into two parts. The first part deals with the steady state characteristics and internal flow field for fixed valve positions. The second part looks at the dynamic performance of pressure surge and flow overshoot by closing the valve using a linear profile. For the steady state flow, a 3D CFO model was used to characterize the flow coefficient to within 10% of the measured data. The variation of the flow coefficient with angle is largely dominated by viscous effects, pressure recovery and jet contraction in that order with increasing angle. An accurate and efficient 20 model of the flow coefficient used 1/12th of the computing time of the equivalent 3D model. The 20 model was then used to look at the effect of orifice radius and it was shown that the Coanda effect has little influence on the trend in the flow coefficient. Following this, a steady state CFO model was used to predict the maximum velocity from LOV data to within 12.5%. With the LOV measurements, the presence of shear layers in the flow field creates jet contraction and is a possible source of cavitation. For the dynamic flows, a method for determining the valve fluid inertance was presented, which followed an analogy between a porous medium and the valve fluid inertance. However, the effect of this inertance on the measured pressure surge was small due to the small percentage of the total system fluid inertance that the valve fluid inertance represents. For flow rate measurement, the two transducer technique isproposed and this method is an accurate post processing technique and can predict overshoot to within less than 2% of the modelled valve. A curve fitting method was also used to characterize the surge pressure and volume overshoot across a range of test conditions, the characterized surge pressure being within 6% of the measured values.
8
Bujáková, Veronika. "Rozvoj marketingového mixu prodejny BALA." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2017. http://www.nusl.cz/ntk/nusl-318612.
Full textAbstract:
This diploma thesis proposes a design on improvement of the level of current marketing mix in a selected bussines. First part is devoted to marketing theoretical knowledge describing its individual tools. Second part is practical and it focuses on analysing the current marketing mix, internal and external environment of the bussines. In the conclusion, a proposal of possible improvement of the marketing mix is drawn based on the analytical part.
9
Lentz, Robert Dowling 1976. "Optimization of a pin-and-slot ball valve linkage : with application to wireline cutting in downhole oil well tools." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80656.
Full text
10
Kryštof, Ondřej. "Bezpečnost automatizovaných průmyslových armatur v provozních podmínkách." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254356.
Full textAbstract:
Choosing suitable and safe valve with accessories depends on general specifications for plant. Using valve for on/off, throttling, back-flow prevention, etc., pressure drop is related with Kv value or leakages from piping systems are main factors for properly valve selection. Valve have to resist chemicals and substances that may change the state, temperature and its fluctuation, pressure, corrosion and erosion. This properties determine pressure class, temperature resistance, connection into pipe and sealing material as gland packing, seats, seal between flange etc. This and other specification, listed in this thesis, can help determine suitable type of valve. This thesis deals construction design of valve and accessories as well. The last chapters are focused on calculation of safety valve and selection safe and appropriate control valve with accessories.
11
Buzz, Lu La. "The states and status of clay : material, metamorphic and metaphorical values." Thesis, University of Plymouth, 2018. http://hdl.handle.net/10026.1/11639.
Full textAbstract:
This doctoral project combines a performance-led practice with contextual research in order to demonstrate how arts practice can challenge historical perceptions of clay and enhance its material status. The core knowledge deduced from this research is that embodied performance transforms connectivity between artist and clay and produces a unified incarnation of both elements. Through the use of immersive research methods I gained insights which could not have been predicted - particularly that my experiential performances were a process of ‘clay becoming’ in which I ultimately became the clay. In terms of locality, the practice, comprising eight performance-led works and related documentation, focuses on the China Clay and Ball Clay of South West England. Traditionally in the arts, these materials are associated with ceramics, where through heating, clay becomes rigid and fixed. In contrast, my research investigates the textural fluidity and metamorphic potential of these clays in their raw state. The practice encompasses two interrelated groups of work; the In-breath and Out-breath. These terms are significant in three respects. Firstly they define two different modes and moments of practice. Secondly they refer to myself as a living component of these practices. Thirdly they reflect the cultural associations of clay as a metaphor for life. During the initial exploratory ‘In-breath’ phase of my practice, comprising four site-specific pieces, I engaged with clay at sites of historical relevance, building an expansive knowledge of my material. During the later ‘Out-breath’ phase, identification with site was relinquished. These works took place within neutral spaces, allowing the clay to be explored in relation to my body. The introduction of layering, where photographic elements of private clay rituals were situated within the context of a live performance, allowed a texturally dynamic and immersive experience to be created for both artist and viewer. By collecting and preserving clay traces from these live performances (e.g. foot and body prints) additional value was given to the embedded significance of the clay.
12
Teles, Diógenes Barbosa. "Projeto e validação de válvula industrial do tipo esfera para baixa emissão fugitiva." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/134891.
Full textAbstract:
Nos últimos anos é notável a preocupação mundial com o controle de taxas de emissões fugitivas em equipamentos instalados na indústria do petróleo e gás. Os prejuízos com a perda de produção e impacto ambiental direcionam as empresas do segmento a buscarem projetos mais eficientes, principalmente com relação às válvulas industriais, que são equipamentos utilizados para gerenciamento de fluidos com a função de bloquear, direcionar ou controlar o fluxo de determinado produto fluente em uma planta industrial. As emissões fugitivas são vazamentos de produtos químicos, que se apresentam para atmosfera de forma inesperada ou indesejada em equipamentos. O objetivo deste estudo foi desenvolver e validar um projeto de válvula industrial do tipo esfera para aplicações que requerem baixas emissões fugitivas. Inicialmente foram identificados e avaliados os requisitos apresentados na norma ISO 15848-1, quanto aos ensaios que devem ser executados em protótipo de válvula do tipo bloqueio para qualificação de projeto, onde foi possível elaborar um procedimento de ensaio. Foi realizado o dimensionamento dos sistemas de vedações para um protótipo de válvulas do tipo esfera, Top Entry, Trunnion, bitola NPS 4”, classe de pressão CL600, utilizando como padrões construtivos as normas API 6D, ASME B16.34 e ABNT NBR 15827. Fabricou-se um protótipo deste equipamento o qual foi utilizado na realização dos ensaios de qualificação do projeto. Foram realizados ciclos de abertura e fechamento do obturador da válvula, utilizando a pressão máxima de trabalho, conforme padrões construtivos e como fluido de teste foi utilizado o gás Hélio. Os ensaios foram realizados em uma câmara de ciclagem de válvulas instrumentada com um espectrômetro de massa de Hélio, onde foi possível monitorar e registrar os dados do ensaio, tais como: vazamentos, número de ciclos, pressão de teste, temperatura e torque durante os acionamentos da válvula. Os resultados obtidos com relação aos requisitos da norma ISO 15848-1 foram: número de ciclos 2500 atendendo a classificação CO3, classe de vazamento Classe B, temperatura de qualificação de -29 °C a 200 °C. Também foi realizado a qualificação Fire Test conforme norma ISO 10497 como complemento. Conclui-se que este trabalho atingiu os objetivos pré-estabelecidos quanto à homologação do protótipo e contribuiu com a preservação do meio ambiente, pois a concepção de projetos eficazes, que minimizam as taxas de poluição para a atmosfera, contribuí com a preservação dos ecossistemas.In recent years is remarkable worldwide concern over control rates fugitive emissions in equipment installed in the oil and gas industry. The loss of production and environmental impact, leads segment companies to seek more efficient projects, mainly with respect to industrial valves, which are devices used for fluid management with the function to block, to direct or to control the flow of fluent product in an industrial plant. Fugitive emissions are leaks of chemicals which present themselves to atmosphere in a manner unexpected or undesired in equipment. The objective of this study was to develop and validate a model of industrial ball valve design for applications requiring low fugitive emissions. Initially were identified and assessed the requirements of ISO 15848-1 standard, how much to the appropriate tests to be executed on the prototype of block valve for qualification. It was possible to develop a test procedure. It was made the design of the seals systems for a ball valve prototype, type Top Entry, Trunnion, NPS 4", pressure class CL600. Was used API 6D, ASME B16.34 and NBR 15827 as construction standards. A prototype of this equipment has manufactured and used in the realization of design qualification tests. Were performed opening and closing cycles of the valve plug by using the maximum working pressure conform construction standards and was used Helium gas as test fluid. The tests were performed in a valve cycling chamber instrumented with a Helium mass spectrometer, where it was possible to monitor and record the test data as: leaks, number of cycles, pressure, temperature and torque for the valve actuators. The results obtained with respect to the ISO 15848-1 standard requirements were: number of cycles 2500 attending to CO3, classification leakage Class B, qualification temperature of -29 ° C to 200 ° C. It was also performed the qualification Fire Test ISO 10497 standard as a complement. In conclusion, this work has reached the pre-established objective about the approval of the prototype and contributed to the preservation of the environment, because the conception of effective projects that minimize pollution rates to the atmosphere, contributes to the preservation of ecosystems.
13
Sabine, Neil B. "Aspects of bald eagle winter behavior in Rush Valley Utah: A Telemetry study." BYU ScholarsArchive, 1987. https://scholarsarchive.byu.edu/etd/7863.
Full textAbstract:
The diurnal behavior and nocturnal roosting patterns of 28 bald eagles outfitted with tail-mounted radios were investigated in Rush Valley, Utah between January and March 1982-1984. Casting analysis and feeding observations indicated the principal food source was jackrabbit carrion. Jackrabbit availability declined from 1982 to 1984 and eagles responded by; 1) roosting closer to feeding sites, 2) shifting from canyon to valley roosts, 3) arriving later at and departing earlier from roosts, 4) decreasing diurnal activity, and 5) decreasing residence time. Foraging efficiency appeared to be maximized by experienced eagles using familiar feeding areas and by naive birds monitoring their activity. There appeared to be a slight (8.6%) energetic advantage to roosting at valley sites because of their proximity to feeding areas. This saving was presumably dissipated under adverse weather conditions when eagles selected the sheltered microclimate of canyon slopes. Twelve eagles were tracked during spring migration and all followed northward routes.
14
Švestka, Jiří. "Studie pístového čerpadla s inversním kuličkovým šroubem a zatopeným motorem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230201.
Full textAbstract:
This thesis is focused on study of piston pump with ball screw and submersed motor. Theoretic part is about study using pump and ball screw. Equations for description of pump, motor and ball screw are in computation part. And in last part is construction of pump and valve. Valve is computed in CFD.
15
Owen, Bruce D., and Paul S. Goldstein. "Tiwanaku en Moquegua: interacciones regionales y colapso." Pontificia Universidad Católica del Perú, 2012. http://repositorio.pucp.edu.pe/index/handle/123456789/113409.
Full textAbstract:
Tiwanaku in Moquegua: Regional Interactions and CollapseThe synthesis of data from excavations and systematic survey of the Osmore drainage promotes a new vision of the relationships between Wari, Tiwanaku, and indigenous people of the region during the Middle Horizon and the beginning of the Late Intermediate Period. A series of facts are effectively established that must be considered in future interpretations. Among others, we note the apparent contemporaneity of Tiwanaku and Wari settlements in the middle and upper sections of the Osmore drainage, generally isolated in their own geographic zones. There are no signs of military conflict or fear of it during perhaps centuries of contact, even though both groups considered the site of Cerro Baúl to be a huaca that only the Wari controlled. Nor was there exchange of goods, suggesting social as well as spatial isolation. We describe the contemporaneity of two Tiwanaku traditions, marked by the Omo and Chen Chen ceramic styles, which were previously considered sequential phases. Finally, we confirm that at the end of the Middle Horizon. Wari abandoned the region, leaving people of the Tiwanaku tradition to divide into local groups and flee to distant, defensible sites at the beginning of the troubled times of the Late Intermediate Period.La síntesis de datos de excavaciones y reconocimientos sistemáticos de la cuenca del río Osmore permite una visión nueva de las relaciones entre los wari, tiwanaku y poblaciones indígenas de la región durante el Horizonte Medio y el comienzo del Periodo Intermedio Tardío. Una serie de hechos están efectivamente establecidos, los cuales tendrán que ser considerados en futuras interpretaciones. Entre otros, se nota la aparente contemporaneidad de asentamientos tiwanaku y wari en las partes medias y altas de la cuenca del Osmore, pero mayormente aisladas en zonas geográficas separadas. No hay indicios de conflicto bélico ni temor de tal durante, posiblemente, siglos de contacto, a pesar de que ambos grupos vieron al mismo sitio Cerro Baúl como una huaca, la que únicamente los wari controlaron. Tampoco había intercambio de bienes, sugiriendo un aislamiento social al igual que espacial. Se describe la contemporaneidad de dos tradiciones tiwanaku marcadas por los estilos ceramográficos Omo y Chen Chen, que antes se consideraban fases secuenciales. Finalmente, se confirma que, al fin del Horizonte Medio, la gente wari abandonó la región, mientras que los de la tradición Tiwanaku se dispersaron en grupos menores desplazándose a sitios alejados y defendibles al comienzo de los tiempos conflictivos del Periodo Intermedio Tardío.
16
Biasibetti, Fernando. "Otimização de projeto de válvula utilizando os conceitos de projeto de experimentos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/96422.
Full textAbstract:
Esta dissertação apresenta um estudo desenvolvido com o intuito de consolidar uma metodologia para a otimização de projeto de porta-sedes de uma válvula de esfera trunnion. Este trabalho está dividido em dois artigos. Primeiramente, é apresentado um estudo comparativo entre diferentes modelos de porta-sedes, realizado com o apoio do método dos elementos finitos (FEA). O porta-sede de melhor desempenho foi determinado utilizando a Função de Perda Quadrática Multivariada. O objetivo principal deste primeiro artigo é identificar os principais parâmetros da geometria de um porta-sede, que possam garantir o desempenho funcional da válvula e correspondente atendimento dos requisitos de qualidade. O segundo artigo descreve uma aplicação da metodologia de Projeto de Experimentos (DOE), conduzida com o intuito de identificar a configuração geométrica da válvula que conduza a condição ótima de funcionamento, fornecendo, desta forma, subsídio para a área de Desenvolvimento de Produtos na elaboração de válvulas mais robustas. Uma das principais contribuições deste trabalho é a constatação que os quatro fatores controláveis incluídos no estudo exercem efeito significativos sobre as variáveis de resposta utilizadas (pressão de contato e força de reação). Excetuando-se o fator “pressão de operação da válvula”, que caracteriza a condição operação, mas não é um parâmetro de projeto, o fator que revelou efeito mais pronunciado sobre as variáveis resposta foi a “área da pista de vedação”.This thesis presents a study conducted in order to consolidate a methodology for seat-retainer design optimization of a trunnion ball valve. This work is divided in two papers. Initially a comparative study between different seat-retainer models, developed with the support of the finite element analysis (FEA), is presented. The best performance seat-retainer was determined using the Multivariate Quadratic Loss Function. The main purpose of this first article is to identify the main parameters of the seat-retainer geometry, which could ensure the functional performance of the valve and corresponding quality requirements. The second paper describes an application of Design of Experiments (DOE) methodology, conducted in order to identify the geometric configuration of the valve that leads to the optimal operating condition, providing thereby, contribution to the Product Development area in designing more robust valves. The main contribution of this work is the finding that the four control factors included in the study exert significant effect on the response variables used (contact pressure and reaction force). Except for the factor "valve operating pressure" that characterizes the operation condition, but is not a design parameter, the factor that showed more pronounced effect on the response variables was the “seat sealing area”.
17
Knápek, Michal. "Posouzení výhodnosti výstavby přečerpávací vodní elektrárny velkého výkonu v lokalitě Cukrová bouda, okres Šumperk." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219416.
Full textAbstract:
The subject matter of the master´s thesis is, in particular, an evaluation of the advantageousness of the construction of a pumped-storage hydroelectric power station in the vicinity of Cukrová Bouda. In the master´s thesis introduction the utilisation of pumped-storage hydroelectric power stations in providing reserve power generation to the operator of a power transmission system is discussed. The thesis then focuses on a technical design solution where two alternatives are drawn up for which the nominal parameters of individual designs for a pumped-storage hydroelectric power station are specified. The following part deals with the impact of the structure and the plant’s subsequent operation on the environment. A further key part is the determination of investment and subsequent operating costs and an evaluation of the plant according to economic pointers. The final part of the master´s thesis contains a SWOT analysis and an assumed programme of works for the plant’s preparation and actual construction. The conclusion contains an overall evaluation.
18
Salmeh, Louay. "L'abandon sportif : des motifs d'abandon aux modèles théoriques : une recherche longitudinale chez les handballeuses et les basketteuses." Phd thesis, Université de Bourgogne, 2011. http://tel.archives-ouvertes.fr/tel-00661589.
Full textAbstract:
L'objectif de cette thèse était d'une part d'identifier les motifs d'abandon chez les handballeuses et les basketteuses syriennes et de tester d'autre part trois modèles théoriques qui expliquent l'abandon sportif. Une première étude (N = 402) s'est attachée à identifier les motifs d'abandon chez ces joueuses. Les résultats ont montré que les joueuses estiment que certains motifs (e.g., tomber enceinte, avoir un mari qui ne permet plus à sa femme de faire du sport) sont très importants pour abandonner le sport. Les motifs d'abandon sont fonction du type et du niveau des joueuses ainsi que de l'âge et du niveau d'expérience. Une deuxième étude (N = 328) a testé le modèle de l'abandon sportif de Sarrazin et al., (2002) afin d'expliquer comment le climat perçu de l'entraîneur conduit à l'abandon sportif chez ces joueuses. Les résultats ont rapporté un soutien important pour ce modèle et pour la chaîne causale du modèle hiérarchique de Vallerand (1997). Ils ont montré que l'impact du climat motivationnel de l'entraîneur sur la motivation est médié par les perceptions de compétence, d'affiliation et d'autonomie des joueuses. De plus, la motivation est corrélée aux intentions d'abandonner qui prédisent l'abandon sportif chez ces joueuses. Une troisième étude (N = 237) a testé le modèle de l'engagement sportif de Guillet et al., (2002). Les résultats n'ont pas pu appuyer ce modèle. Par contre, une version modifiée a été validée. Dans celle-ci, les résultats ont montré d'une part qu'il y a trois antécédents qui prédisent l'engagement des joueuses (i.e, les contraintes sociales, l'attrait pour d'autres activités et les bénéfices perçue). D'autre part, l'engagement est relié négativement au comportement d'abandon chez les joueuses. Une quatrième étude (N = 328) s'est focalisée sur le lien entre l'identité de genre des joueuses et leur persévérance dans les activités pratiquées. Les résultats ont montré que les joueuses typées Androgynes et Masculines ont persisté beaucoup plus dans leurs activités masculines que celles typées Féminines. Finalement, une cinquième étude (N = 328) a testé une version simplifiée du modèle d'Eccles et al., (1983) proposée par Guillet et al., (2006). Les résultats ont soutenu partiellement ce modèle en montrant que l'influence de la masculinité sur les intentions d'abandonner est médiée par les valeurs de l'activité et l'habilité perçue. Ces dernières ne jouent cependant pas un rôle médiateur entre la féminité et les intentions d'abandonner. Les intentions d'abandonner prédisent l'abandon réel chez ces joueuses. En conclusion, si les motifs d'abandon donnent une idée sur les raisons qui conduisent probablement à l'abandon, les modèles théoriques reflètent une meilleure explication à l'abandon réel.
19
Jhuang, Wun-Jia, and 莊文嘉. "Design and measurements of metal seated ball valves." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/4aqzg2.
Full textAbstract:
碩士國立中興大學
機械工程學系所
101
This study carried out detailed design and manufacture of prototype of a 2-in metal-seated ball valve. Leakage test apparatus was setup to examine the ball valve subjected to the temperatures ranging from room temperature to 450℃ and the pressures up to 720 psig. The structure and dimensions of the newly designed metal-seated are based on the one with PTFE soft ball seats that is currently manufactured by the cooperated company of the present project. A wave spring and a graphite washer are implemented in the 2-in metal-seated ball valve to apply preloaded force to the clearance between the ball and the metal seats. The leakage tests using nitrogen gas indicated that this 2-in metal-seated ball valve can be operated at temperatures up to 450℃ and pressures as high as 400 psig without leakage. However, obvious leaking clearance was found between the metal seat and the ball in the leakage tests performed for the primary contact components of the metal-seated ball valve and further study is needed to clarify the major causes of the problem. Thermal expansion measurements together with the simulations and analyses for the metal seats showed an isotropic nature in the range within 450℃ and suggested an appropriate allowance between the metal seats and the side cover.
20
Chang, Chao-Yun, and 張超昀. "Design Verification and Analysis for Metal Floating Ball Valves." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/32d497.
Full textAbstract:
碩士國立虎尾科技大學
機械與電腦輔助工程系碩士班在職專班
103
A ball valve is an important part for controlling flow directions and capacities of fluids in piping equipment in food processing, petroleum and chemical plants as well as a type of pressure vessels. Therefore, EU (EN), UK (BS) and US (ASME、API) etc. have drawn up a considerable number of design standards and testing specifications to ensure that each product is standardized. There is even certification for compliance to EU’s Pressure Equipment Directive (PED) to ensure safe operation and use. Since ball valves that are made in Taiwan have been greatly improved in production technology and quality compared to the past and technology development and trends have increasingly required better ball valve functionality, it is of value to explore in depth and study the design verification and manufacturing processes for ball valves. This study used US standard cast stainless steel (ASTM A351 CF8M=316) as the material for investment casting of ball valves. Firstly, the 3D computer-aided design software SolidWorks was used as the tool for designing the overall ball valve structure. In the design process, the finite element analysis simulation module of Solidworks, was used in combination to explore main structural components in a ball valve that are directly linked to pressure, such as valve bodies (pressure withstanding), valve covers (pressure withstanding) and valve stems (torque withstanding) etc. and analyze and verify their functionalities. Results of the analysis showed that the key factor was change in wall thickness for pressure withstanding components and size of cross-sectional area for torque withstanding ones. Therefore, the testing in this study first focused on analyzing the chemical composition and mechanical properties of materials used in the investment castings and the impact they could withstand. The data obtained from the testing and analysis were all within the range of standard values described in materials specifications. Then, traditional design calculation methods were used as the foundation in combination with computer-aided design and simulation analysis software for calculations with predefined parameters to obtain results of simulation analysis. This approach allows timely corrections and adjustments to designs if flaws are found and determined, thereby shortening the time for design development and enabling effective verification of final structural designs, which ensures that ball values comply with related testing specifications and meet customer requirements for products. It is hope that the design development and analysis for ball valves described in this paper can offer substantial contributions, suggestions and insights for the industry and academia alike.
21
Wangwatcharakul, Worawut. "Development of a passive micro-ball valve." Thesis, 2001. http://hdl.handle.net/1957/28772.
Full textAbstract:
A novel design, material, and fabrication method are presented to fabricate a
passive micro-ball valve. Microvalves are critical components in microflow
control devices used to control the fluid flows in microchannels. These microflow
control devices can be integrated with microsensors to form micro analysis
systems. Glass/silicon-based fabrication is complicated and expensive. Therefore,
other materials and fabrication methods have been proposed. In this research,
Melinex 453, a polyester film, and pressure sensitive adhesives were used to
fabricate a micro-ball valve by a microlamination method.
The valve was designed to have a 450 μm diameter glass ball floating inside a
chamber size of 800 μm. The ball will permit flow in the forward direction and
impede flow in the reverse direction. The fabrication method consists of three
steps: patterning, registration and bonding. The patterning step was accomplished
using laser micromachining. Registration and bonding were performed with the use
of a pin-alignment fixture. Pressure sensitive adhesive was used in the bonding step
using double-sided acrylic adhesive tape. The micro-ball valve has advantages over
other microvalves in terms of little dead volume, simple design, disposability, low
operating pressure in forward direction, and low leakage in reverse direction.
The micro-bal1 valve was characterized by pressure drop testing at different
flow rates from 1 to 7.5 ml/min. The experimental results tend to agree with a
simple theoretical model of the pressure drop through an orifice. Moreover, an
average pressure drop diodicity of at least 2980 has been achieved.Graduation date: 2002
22
Lv, Gun Yu, and 呂昆餘. "Performance and flow characteristic of Ball Valves using PIV measurements and computation simulations techniques." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/82584627573938734382.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
90
The performances of various ball valves are experimentally investigated by using a Valve Performance Test Rig, which is designed and manufactured in cooperation with a manufacturer. The performance parameters measured in this study include flow rate, pressure loss, and inlet pressure. Analysis on the experimental data leads to quantitative results of the pressure loss coefficient, flow coefficient, and cavitation coefficient. These valve performance indices can provide useful guidelines for improvements of valve design. In order to understand more about the inside-flows, the particle-tracing flow visualization method is employed to see the flow patterns inside and downstream the valves. The valve and near-field pipings are made of transparent plexiglass so that the laser-light sheet can go through the valve. Polyamide particles are dispersed in the water flows. Long exposure phototgraphs are taken to show the path lines of the particles. The flow features, e.g., The recirculation bubble and the cavitation phenomena, are clearly captured. The cavitation coefficient obtained by using the flow visualization method coincides the results of the valve performance test. A particle image velocimeter is employed to measure the inside-flow velocity fields. Results of the ensemble-averaged streamlines show detailed flow structures.
23
Chen, Chien-An, and 陳建安. "The Optimized Ball Valve Design - In the case of Zhejiang Y & Y Ball-Valve." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/34267688430944418009.
Full textAbstract:
碩士國立東華大學
管理學院高階經營管理碩士在職專班
99
This research was based on the optimal mechanical product design methods and theories to develop the structural optimization of ball-valve. And then the finite element method as the basis, the software of SolidWorks and ANSYS are using to create the mechanical models for ball-valve. In the analyzing structural characteristics of ball-valve, a 3D ball-valve model was created by using SolidWorks. Through the interface technology, this 3D model was transferred into ANSYS software. Therefore, according to choosing a proper type of component of ball-value in real use situation, a meshing of component is process and then imposing a reasonable load and boundary conditions; thus, a finite element model can be established and mathematical calculation and analysis can be made. An optimal design of ball-valve structure can be achieved by the analyzed results. As the results, this research has significance effects in practical to product design, product development and market development.
24
Chang, Chai Wei, and 張家瑋. "Piezoelectric Micropump with Micro Ball Valve." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/74721503919823121432.
Full textAbstract:
碩士中州技術學院
工程技術研究所
98
Micro components use semiconductor or LIGA process to fabricate in the clean room, However, it is high production costs. For creating complex three-dimensional geometry of components will be limited. Five-axis CNC engraving machine and Rapid prototyping system to machine micro-pump valve components need not be in the clean room. Therefore, the processing equipment is cheap. It reduces manufacturing costs because of their simple production process. The production methods are worthy to develop. The piezoelectric micro-pump of ball valve develop by experiments. The valve seats used Rapid prototyping system with accuracy of 16μm to fabricate and The aluminum chamber used five-axis CNC engraving machine to manufacture. Then,The PZT buzzer placed above the aluminum chamber. By using 80Vpp voltage, frequency 10 ~ 200Hz square wave to drive the piezoelectric film vibration. In the operating frequency of 70Hz of square wave, the flow rate is 8.4ml/min. In the operating frequency of 50Hz, the maximum back pressure is 5903.973Pa.
25
Chang, Chia-Yang, and 張嘉揚. "Design of Metal Seated Ball Valve Mechanism." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/69121228135912919546.
Full textAbstract:
碩士國立交通大學
機械工程系
88
A seat is a device mounted in a valve. When a ball valve is in close position, the seat makes a sealing effect in a ball valve. The seat material is usually plastic or rubber, so the seat will be damaged under high pressure or high temperature environment. The objective of this study is to design a new seat mechanism suitable for the ball valve. Related U.S. patents are surveyed for references during the design process. To design a new metal seat, there are four steps, arranged in the engineering design process: planning and clarifying the task, conceptual design, embodiment design, and detailed design. Some useful tools from Quality Function Deployment (QFD) technique and Theory of Inventive Problem Solving (TRIZ) method are used in design process. The prototype model is complete by using CAD and CAE software. Finally, a new prototype of metal seat in a ball valve is manufactured.
26
Hu, Wei-Hsing, and 胡偉興. "Characteristics of VOC Fugitive Emission from Ball Valve Leakage." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/3m3539.
Full textAbstract:
博士國立臺北科技大學
工程科技研究所
102
Hazardous Volatile Organic Compounds (VOCs) released from industrial valve leakage into the environment have been causing public concern. In this work, a series of experiments were systematically carried out to continuously measure VOCs leakage through ball valve by the blow-through method. According to operating conditions, it can be estimated emission rates, emission factors and correlation equation for ball valve VOCs leakage. These are more accurate to estimate VOCs leakage emissions than Taiwan EPA emission factor. This paper presents the leakage emission rate of VOCs increase with the VOCs flow rate, valve size and decrease with valve opening, the square root of the VOC molecular weight of the flow system. In non-flow system, the leakage emission rates of VOCs increase with the amount of material and VOCs diffusion coefficient. If we make a comparison between emission factor in laboratory and field, we found the percentage error within 10% error range. The correlation equation was found to be expressed as follows: E=Krα (R2=0.967~0.994). α seems a little increase with an increase of valve size. According to experiment result, we found α is 0.21. K is dependent on volatilisation organic compounds and the ball valve leakage concentration of VOCs. The correlation equation describing the emission rate of ball valve was developed and validated experimentally in this work. There is a statistical error of ±15％ if submitted under 95% probability limits for the correlation. However, the actual VOCs emission mechanism from a ball valve leakage could be more complex out of consideration in this study. More intensive study on other conditions would better verify the results obtained in this paper.
27
Chang, Hsun-Chen, and 張珣甄. "The Flow Coefficient of Ball Valve for DifferentOpening Design." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/22170024248883424426.
Full textAbstract:
碩士國立中興大學
機械工程學系所
105
The main purpose of this study is to investigate the pressure loss caused by the flow of fluid in ball valve piping. The ball valves used in the market are mostly full-diameter. When the valve is fully opened, the fluid will form a free-flowing structure, the probability of loss is very small. But for special valve piping, such as throttle, even if the valve is at fully open status, the reduction of the internal flow pattern changes the size of the discharge coefficient(Cd), thus results in a pressure loss ΔP(major losses). "Pressure loss is energy loss." If a part of the runner is limited, the downstream pressure will decrease from the confined area resulting in a pressure loss, not only will the downstream pressure be reduced, but also the flow rate and flow velocity will be reduced. When a pressure loss occurs on the production line, the flow will be reduced, which will lead to a variety of quality and production problems. In this paper does not consider the special function of the ball valve under the premise of the use of flow channel reduction of the parameters of the conditions to simulate and analyze the way to compare each other, and then find the cause of pressure loss as a reference for the improvement of valve products. The study is based on the flow velocity of the fluid in the flow channel and the throat opening of the pipeline area, the perimeter, the angle, the shape, the number, etc., which may affect the pressure loss conditions, were combined into the following five types for comparison: 1.The same area, different perimeter and different shapes of the opening 2.Different area, the same perimeter and different shapes of the opening 3.The same area, different perimeter and different number of holes opening 4.The same area, the same perimeter and different angles of the opening 5.Different area, different perimeter and different angles of the opening The CFD model was established according to the above five kinds of individual throttle opening types, with the hydraulic diameter of 25 mm (1 ") of the ball valve, for example, using the "Bernoulli''s principle" of the theoretical value and ANSYS Fluent software analysis of the value of each other in different conditions, the friction coefficient k value(minor losses) generated impact. According to the analysis results, the increase of flow velocity does not directly affect the change of the friction coefficient k value. The main factors depend on the area, shape and perimeter of the throttling opening, and the conclusion is: 1.The throttle opening area is smaller, the larger the value of k; when larger area, smaller the value of k. 2.The throttle opening shape is centered and symmetrical, the distribution of k is smoother and the drop is smaller. 3.The total perimeter of the throttle opening exceeds 4/5 of the perimeter of the full diameter of the runner, the k value decreases as the flow velocity increases.
28
Liu, Bang-Yu, and 劉邦宇. "The Fabrication and Flow Analysis of Piezoelectric ball valve pump." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/93150203633170330056.
Full textAbstract:
碩士中華技術學院
機電光工程研究所碩士班
97
This research is aimed at the analysis of the flow structures and characteristics of the piezoelectronic valve pump by the experiments with high-speed photography technology. The pump was made by the CO2 laser to carve and hot-press methods. The displacement of different steel ball would be influence the performance of pump. Designs conforms to the economic efficiency to have the valve pump. In main use steel ball and under steel ball design. The both sides valve starts closes the impetus fluid operation. As usingψ7mm of steel ball, urging voltage 120V and square wave frequency to drive for the operation condition of 31Hz, have large volume flow 146.66 ml/min most, can produce most heavy to is it keep 70cm-H2O to carry, of body thickness can up to 70.6mm most. As using ψ 9mm of steel ball, urging voltage 120V and square wave frequency to drive for the operation condition of 33Hz, have large volume flow 121.6 ml/min most, can produce most heavy to is it keep 25cm-H2O to carry, of body thickness can up to 106.6mm most. Carrying on systemic analysis by changing size and thickness of steel ball, in order to obtain the better operation condition. This research could be improved the complex process of traditions manufacture and the cost is more cheap. There is help in the academy and industry by control and development of the micro fluid.
29
CHIOU, JIING-SHI, and 邱景禧. "DESIGN AND ANALYSIS OF CONTROL BALL VALVE WITH V SHAPE." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/10683614264495658230.
Full textAbstract:
碩士國立臺灣大學
機械工程學研究所
88
The numerical simulation using CFX and ICEMCFD software package was applied to analyze the feature of fluid dynamics of control ball valve. In order to gain good control ball valve, the parameters such as the shapes, angles of the control ball valve and Reynold number of the flow field are investigated.The main goal of this research is to discuss the effect of valve parameters on the discharge coefficient , pressure drop and torque on the valve. From the numerical results , we found that the modified control ball valve with V shape can gain good flow control . However , one should pay the price caused by the pressure drop .
30
Liao, Yu-Sheng, and 廖祐陞. "A Study on Lightweight Design of a Ball Valve Structure." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/78260800840851650643.
Full textAbstract:
碩士國立屏東科技大學
車輛工程系所
104
In this thesis, the lightweight design and analysis process for a large ball valve is proposed. This process combines the topology optimization analysis and finite element model analysis. The structure of ball valve explored in this study are based on the commercial ball valve with diameters of 2600 mm, 2000 mm and 1000 mm. Therefore, the weight of the proposed valve structure should be less than 11276 kg, 4760 kg and 1410 kg, respectively, with a safety factor of 1.5. In this research, the commercial finite element package ABAQUS/TOSCA is used for the topology optimization analysis of ball valve structure. Three-dimensional elastic-plastic finite element models are proposed for the stress analysis of the ball valve. Firstly, a commercial ball valve with a diameter of 1200 mm is measured experimentally. The maximum difference in stress between the result obtain from the finite element simulations and the experimental result is found to be less than 5%. The result confirm that the accuracy of the proposed finite element model. The results indicate that the weights of the proposed ball valves for IV diameters of 2000 mm, 1500 mm and 1000 mm are 8520 kg, 3592 kg and 1046 kg, respectively, according to the lightweight design and analysis process. Compared with the commercial valves, the weight of proposed valves can be reduced 24.5%. The simulation results show that the strengths of the proposed ball valve structure ate greater than the commercial ones, and the safety factor is also greater than 1.5 under the same pressure condition. The result also shows that the proposed lightweight structure analysis process can be used for the lightweight reduction of a large ball valve design effectively.
31
Hsu, Chih-cheng, and 徐志誠. "Investigation of flow control and cavitations for ball valve using different shields." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/76515146294962821720.
Full textAbstract:
碩士國立中央大學
機械工程研究所碩士在職專班
98
The control valve is one of the important issues in the piping system. When controlling the flow, if the control valve is not carefully selected, it would often lead to cavitations, causing noise in the pipe-work, vibration and erosions, and thus diminishing the efficiency of the system. Over the years, the industry often used globe valves as the main control valve. However, due to the high-cost of the globe valves and its bulky size, nowadays many factories have switched to the ball valve for flow controls, which lower the cost and the weight of their products. Ball valves use different shields to control the flow, and can be programmed with computer for the angle of turning angle, therefore accurately controlling the flow. The use of different shields holds many advantages, such as the minimum flow resistance, rapid responding time, easy to control, good sealing capability, longer life-span, accurate controllability, and high reliability. Ball valves often operate to meet the requirement of high precision flow control yet in bad-condition environment, many issues are encountered, such as cavitation, noise and vibration problems. This study uses computational fluid dynamic software to simulate flow over the ball valve, and then calculate the flow coefficient, Kv. Flow coefficient is one of the main parameters for selecting the control valve, one can compare the computed Kv with the experiment, so as to design a better ball valve. This study uses the software FloEFD to simulate the flow over the ball valves with different V-shaped openings, and other custom-made opening shapes. The focus of this study is to simulate orifice, pure ball valve, and ball valve with different shields, which allow one to find the best performing shield shapes which can suppress or eliminate cavitation. Simulation results show that the orifice creates contraction region in the downstream, thus accelerating the flow, and as the flow pressure lowers than the absolute saturated vapor pressure, cavitations will occur. The smaller pressure difference is, the higher cavitations index is, and cavitation is less likely to occur. Simulation of standard ball valves (38mm and 50mm in diameter) reveal that as the opening decreases, the pressure difference across the valve increases, and the pressure difference is increasing with increment of Reynolds number. When the opening is enlarged, the flow motion is smoother, creating a smaller vortex circulation. At the same opening, the smaller angle of the V-Port shield, the faster the flow at downstream. In addition, the corresponding pressure is lower, and the cavitations and noise are more likely to occur. Choosing appropriate ball valve shields with different pipe diameters and flow speeds can accurately control the flow motion and prevent cavitation.
32
Shiang-LanYeh and 葉香蘭. "Excimer Laser Machining of 3D Microstructures with Application on Ball Valve Micro-pumps." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/90247124816726647983.
Full textAbstract:
碩士國立成功大學
奈米科技暨微系統工程研究所
100
This study applies excimer laser micro-machining technology for manufacturing 3D axially symmetrical micro-structures. It is based on a work-piece rotation method in conjunction with a contour mask imaging projection machining. Specially designed laser masks have been developed for machining various kinds of 3D surface profiles. The micromachining is carried out on polycarbonate (PC) material and the surface profiles have been characterized and compared with their theoretical counterparts. Good agreement is observed. Based on the excimer laser machined 3D micro-structures, the goal of this thesis is to design and fabricate a ball valve micro-pump for fluidic transport and can be used in biochips. In order to make it more biocompatible, polydimethylsioxane (PDMS) material is used and its flexible material property is also excellent to form the moveable membrane of micro-pumps and micro-channel. The actuation the membrane is through magnetic force generated by an electromagnetic coil. Experiments have been carried out to determine the optimal design for the ball-vale micro-pump. At a channel height of 125 μm, a voltage of 15 V, and a frequency of 50 Hz, the micropump can achieve the best performance with a flow rate is 51.67 μL/min and a maximum backpressure of 13.4 mm-H2O.
33
(6620234), Daniel A. Gutierrez. "FLOW COEFFICIENT PREDICTION OF A BOTTOM LOAD BALL VALVE USING COMPUTATIONAL FLUID DYNAMICS." Thesis, 2019.
Find full textAbstract:
This study analyzed the ability of computational fluid dynamic software to accurately predict the flow coefficient of three bottom-load ball valves to develop a design which can accurately control flow rate.
34
Hsu, Shih-Chia, and 許世佳. "The Numerical Study of Ball Valve Cavitation and Performances Using Two Phases Flow Model." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/39763129716892337830.
Full textAbstract:
碩士國立中央大學
機械工程學系
102
Ball valve has more applications, in addition to the switch as a fluid, it can regulate fluid flow and pressure. These are trend of development in the future, can be used in large-scale, high temperature and high pressure, can withstand harsh environments compared to outside, The wall can resistant corrosive, and can be used in long-distance pipeline. High temperature and pressure will rise to cavitation problems. Cavitation will damage the wall material, which will affect the performance of the whole ball valve. Severe cavitation will occur choking flow, so that the pressure difference increases, the flow rate does not increase, it will lose the flow adjustability . In this thesis, uses ANSYS FLUENT software package for numerical simulation research which focused on cavitation prediction. Cavitation will change phases, so it required two-phase flow simulation model. The results can be obtained volume fraction. It can show the fluid which contains vapor volume fraction in the ball valve. It is similar to describe cavitation phenomenon, and is more accurate to predict cavitation method. In this study, using differential pressure and the ball with different angle, discuss cavitation the effects of pressure difference and ball valve angle. Simulation results calculate ball valve performances, discuss performances the effect of pressure difference and ball valve angle, as well as the relevance of cavitation. These results compare to volume fraction to verify the accuracy of cavitation prediction. From simulation results, the most accurate way for cavitation prediction is volume fraction, secondly is cavitation index and flow coefficient, the most inaccuracy is pressure contour. Using pressure contour would overestimate a lot with volume fraction, so the pressure is lower than the vapor pressure of cavitation may not occur. Cavitation effects on factors, ball valve angle will be much effective than the pressure difference, the geometry of the flow field is a major factor in cavitation effects. Loss coefficient and flow coefficient is mainly to change ball valve angle, but has little effect on the pressure difference. For change cavitation index, ball valve angle and pressure difference will be affected. ball valve is operated suitable angle and pressure are within 30 degrees, 2 bar or less, if the ball valve is no cavitation occurs within 20 degrees angle to be adjusted.
35
Jan, Guan-Chiun, and 詹冠群. "Computer Aided Analysis of Ball-type Check Valve Response for an Injection Molding Machine." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/76937002348869415559.
Full textAbstract:
碩士國立高雄應用科技大學
機械與精密工程研究所
101
Check valve is an important component of the plasticizing system in an injection molding machine, and its design affects the quality of the molding products directly. This study uses ANSYS-CFX to simulate the behavior of the ball type check valve and the three dimensional melt flow field. The designed model is built with Solidworks software and the plastic melt is considered as Non-Newtonian flow. The properties of melt found from the simulation such as pressure, velocity, and shear rate are discussed in this study. The effects of the check valve dimensions, molding parameters, and melt viscosity on the check valve closing time are also investigated with the ANSYS simulation module built. The results show that increasing the radius of the ball, increasing the screw acceleration, and increasing the injection stroke will shorten the closing time, while increasing the melt viscosity, decreasing the ball seat angle, and decreasing the diameter of the check valve flow path will increase the closing time.
36
Lai, Chin-hao, and 賴金灝. "The Case Study of Cpk on Human Resource Management-The case of A ball valve manufacturing company." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/99782071960054506096.
Full textAbstract:
碩士朝陽科技大學
工業工程與管理系碩士班
100
In recent years, human resource management has made some improvement, However there is still a disadvantage of human resource management which needs to be improved. Cpk management model is applied in manufacturing case company of the by a in-depth discussion on the Cpk management theory, Combined with the company''s experience, the problems faced in the production. Problem-based human resources in the production process research Cpk applications in manufacturing, Provide a reference for the implementation of the application of human resource management in the enterprise.
37
Deckelman, Steven M. "Studies of holomorphic functions having absolutely continuous boundary values on curves in the unit ball of [complex number]." 1994. http://catalog.hathitrust.org/api/volumes/oclc/32145607.html.
Full textAbstract:
Thesis (Ph. D.)--University of Wisconsin--Madison, 1994.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 68).
38
Huang, Kun-Rong, and 黃崑榕. "An Investigation of the Gas Discharging through a High Pressure Vessel with a moving ball valve by Appling the Immersed Boundary Method." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/35229694949853809708.
Full textAbstract:
博士國立交通大學
機械工程系所
103
The aim of this thesis is to investigate gases discharged from a high pressure vessel numerically. To simulate this subject more realistically, the viscosity and compressibility of the gas are taken into consideration simultaneously. The methods of the Roe scheme, preconditioning and dual time stepping matching the LUSGS method are adopted to solve compressible flow problems during gaseous discharge processes. The non-reflecting boundary condition is used to prevent flow fields from being polluted by the reflection of the pressure wave induced by the compressible flow on the boundary. Computing procedures are performed on the Compute Unified Device Architecture (CUDA) computation platform which was recently developed and a highly effective technology for accelerating computational speed. The pressure ratio, which means the ratio of the pressure in the vessel to the pressure of outside, is larger than 1.89. Thus both subsonic and supersonic speeds of the discharged gas are investigated. Results show that the mass flow rate of this work is consistent with the existing experimental work. Due to a sudden expansion at a small opening, the phenomena of an alternating variation of the pressures of gases, rapid decrements of the temperature of gases and a quick acceleration of the velocities of gases are clearly observed in the mainstream direction. The ratio of the thrust caused by the gases released to the reaction force is less than 1 because of the dissipation of entropy generation. Also, a modified equation for predicting transient mass flow rates is derived. Results obtained by the equation have good agreements with results that calculated by the numerical method developed bt this work.
39
Chen, Yingju, and 陳潁如. "The Effect of Shared-experience Multicultural Curriculum on the Adolescent Students’ Life-Values ─ “Seediq Bale” Tribal Instruction for Example." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/56391706524739211501.
Full textAbstract:
碩士國立臺北教育大學
生命教育與健康促進研究所
99
The purpose of this study is to investigate the impact of shared experience of diversified cultural program on life experience, learning attitude, and life value of youngsters. Besides, such tribal instruction will combine shared experience of teaching model, focusing learning processes as “shared substantive experience, sensuous experience, rational communication and reflection, self realization, and continuous reflection in practice” of students, so that they will be develop and designed into teaching case of life education subject suitable for senior high school students. Research method will resort to case study and conduct interviews among students who had attended tribal instruction during 2005 to 2008, and immediate comments who have taken part in tribal instruction are recorded. From such records, these students and three teaching assistants are selected in 2011 to conduct interview so as to appreciate if the impact of tribal instruction upon students can be extended to life of these students. Besides, these interviewed students have rendered information of their network journal from 2005 to 2011 as proof as triangulation is used to enhance the validity of study. conclusions are as follows: 1 Students can experience impact of life experience through tribal experience program, and help establish their own cognitional concept through site experience activity as they can then compare the difference between the realistic world and second-handed information. 2. The learning attitude of students has changed, and they understand that single way of learning and status are not objective enough. It is best that it should be coped with diverse ways of information sources so as to carry out mutual comparison and correlation. 3. For the part of life value, students can, through above-mentioned impact and transformational experience, conduct further reflection and deliberation so as to review the appropriateness of their “important meaning of life,” “interpersonal relationship,” and “attitude of respect for diversity.” As such, the influence can then be continued for many more years; in other words, it won’t be merely the touch for the moment, but also become a part of life value for the students. 4. Based on the above-mentioned results as integrated with curriculum outline of life education for senior high school as well as teaching model with shared experience, students are taught to reflect about their own life value so that they can have developed the teaching case of life education with the theme of learning for multicultural. It is, therefore, suggested that “diversified cultural program of shared experience” be promoted so as to help youngsters to build up their “ life experience,” “learning attitude,” and “life value.” Furthermore, senior high school students are targeted to further implement the experimental study for teaching case as “life education program of multicultural with shared experience.”
40
Martinha, Vasco António Sousa Uva. "Evaluating the critical success factors responsible for the progress of a small/medium tourism venture towards long-term sustainability goals : the role of Tri Hita Karana values in laying the path for a successfully implemented sustainable tourism enterprise in Bali (Indonesia)." Master's thesis, 2019. http://hdl.handle.net/10400.14/29223.
Full textAbstract:
This thesis discusses the role of small tourism enterprises in contributing to a destination's delineated long-term sustainability objectives, appraising the critical success factors responsible for the thriving of a small-sized tourism venture towards long-term sustainability goals.
To develop this research, an indicator-backed framework is developed and validated through a comparative study of the impacts of tourism practices in three different areas in the island of Bali (Indonesia).
The framework’s selection of indicators has as a reference point the ‘Green Growth 2050 Roadmap for Bali (Indonesia) Sustainable Tourism Development's strategic policy framework – this means that the selected indicators were done in a way that would attend to the needs established by the foregoing Roadmap, and subsequently tested through an application in six different small tourism enterprises.
The insights gathered from the results were condensed into a set of best practices highlighting the key factors that need to be held into consideration when pondering about opening a small tourism venture in this island.Esta tese avalia o papel de pequenas empresas turísticas no que toca ao seu contributo aos objectivos de sustentabilidade a longo prazo delineados por um destino turístico, o que leva a adicionalmente aferir os fatores críticos de sucesso responsáveis pelo alinhamento de uma pequena e/ou média empresa turística com objetivos de sustentabilidade a longo prazo. Para propósitos de desenvolvimento desta pesquisa, foi realizado um quadro de aferição composto por indicadores, o qual foi posteriormente validado através da sua utilização num estudo comparativo sobre impactos de práticas detidas neste setor. O estudo foi realizado em três regiões distintas na ilha de Bali (Indonésia). O processo de seleção de indicadores adotado neste estudo utilizou o quadro de políticas estratégicas para o desenvolvimento de turismo sustentável:‘Green Growth 2050 Roadmap for Bali (Indonesia) como o seu principal ponto de referência – isto foi realizado de forma a que o quadro de aferição proposto pudesse estar alinhado com as necessidades estipuladas pelo 'Roadmap' supramencionado. Após este processo de seleção, foi possível testá-lo através da sua aplicação em seis pequenas empresas de turismo. A informação retirada dos resultados obtidos foi com densada num conjunto de 'melhores práticas', as quais representam uma curadoria dos fatores-chave que devem ser tomados em consideração por qualquer indíviduo que equacione abrir um pequeno negócio de turismo nesta ilha.