Orientador: Eugênio Spanó Rosa / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-18T15:26:34Z (GMT). No. of bitstreams: 1 Lima_LuizEduardoMelo_D.pdf: 3018902 bytes, checksum: ac45ca48369c0c21398892fa2f7de5ac (MD5) Previous issue date: 2011 / Resumo: Escoamentos gás-líquido são frequentemente encontrados na natureza, bem como em diversas aplicações industriais. Na área de produção de petróleo, por exemplo, em sistemas de elevação natural ou artificial (gas-lift contínuo ou intermitente), gás e óleo escoam simultaneamente em tubulações. A previsão de escoamentos gás-líquido torna-se necessária à viabilidade técnica-econômica de muitos processos industriais, por exemplo, na indústria de petróleo devido ao aumento do consumo mundial de combustíveis e a descoberta de novos campos petrolíferos. Em escoamentos gáslíquido, as fases se distribuem espacialmente e temporalmente ao longo da tubulação dependendo das vazões, propriedades físicas das fases e das características da tubulação, entre outros parâmetros. A combinação destes fatores gera diversos padrões de escoamento gás-líquido que podem ser agrupados em três classes principais: disperso, separado e intermitente. Os principais objetivos deste trabalho são o desenvolvimento e a análise de uma modelagem unidimensional em regime permanente, baseada no modelo de mistura, que permita a simulação de escoamentos isotérmicos gás-líquido em tubulações com seção transversal circular constante, considerando a fenomenologia envolvida nestes escoamentos. Dentre as contribuições obtidas com a realização deste trabalho destacam-se: a identificação das vantagens e limitações do modelo; as análises de suas formulações, dos parâmetros de fechamento e de sensibilidade às variáveis relacionadas aos padrões; a proposição de um método de solução para um modelo fenomenológico de força de atrito na parede, aplicável aos diversos padrões de escoamento gás-líquido. Os resultados do modelo de mistura foram comparados contra dados experimentais do gradiente de pressão de escoamento nos padrões disperso, separado e intermitente, em diversas inclinações de tubo. Além disto, foram realizadas análises envolvendo transição de padrão de escoamento num tubo vertical. Os resultados obtidos demonstraram que o modelo de mistura captura de forma satisfatória o gradiente de pressão para os diversos padrões de escoamento gás-líquido, num único algoritmo de integração / Abstract: Gas-liquid flows are often found in nature as well as in various industrial applications. In the oil production, for example, in natural or artificial lift systems (continuous or intermittent gas-lift), gas and oil flow simultaneously in pipes. The prediction of gas-liquid behavior becomes necessary for technical and economic viability of many industrial processes, for example, the oil industry due to the increase of world oil consumption and the discovery of new oilfields. In gas-liquid flow, the phases are distributed spatially and temporally along the pipe depending on the flow rate, phase's physical properties and pipe characteristics, among other parameters. The combination of these factors creates different gas-liquid flow patterns that can be grouped into three main classes: dispersed, separated and intermittent. The main objectives of this work are the development and analysis of a steady one-dimensional modeling, based on the mixture model, which allows the simulation of isothermal gas-liquid flow in pipes with constant circular cross section, considering the phenomenology involved in these flows. Among the contributions obtained in this work stand out: to identify the advantages and limitations of the model; the analysis of their formulations, closing parameters and sensibility to variables related to the patterns; to propose a solution method for a phenomenological model of the wall friction force, applied to the different gas-liquid flow patterns. The mixture model results were compared against pressure gradient experimental data from flow in the dispersed, separated and intermittent patterns, in different pipe inclinations. In addition, it was performed an analysis of the flow pattern transition in a vertical pipe. The results showed that the mixture model captures satisfactorily the pressure gradient for different gas-liquid flow patterns, in a single integration algorithm / Doutorado / Termica e Fluidos / Doutor em Engenharia Mecânica

The topic of this work is the renewal of hermetic pipe penetrations within the primary loop of a nuclear power station. A description of the Dukovany nuclear power plant is included at the beginning, ranging from basic description to details of the renewed component and the reasoning for its replacement. Following is a description of the technologies, which are applied in order to restore the hermetic pipes, the choice of the placement of the heterogeneous weld and the compilation of a workflow for the renewal in the environment of the primary loop while maintaining the quality standards and the strict safety conditions. The conclusion includes a calculation of the expenses tied with the chosen variant the reasoning behind the renewal regarding the length of the outage.

The task of this thesis is the design and construction of semi-automatic control and measuring station. The station is designed for testing the presence and measurement of the correct position of light guides and seals in the connector. Station contains a tool for testing the blinding of connectors. The design and construction of a semi-automatic control and measuring station is necessary using several types of sensors and sliding linear axes controlled by servo drives. The assignment of the thesis is solved in cooperation with the company Mechatronic Design & Solutions s.r.o. in Brno.

The subject of this thesis is strength design of pipe connecting furnace of continuous catalytic reforming with reactor. First is realize analytical design of individual parts according to ASME VIII, ČSN EN 12952-3 a ČSN EN 13480-3. It is also design and optimize supporting pipe using Caesar II. At the end of work is creating isometric documentation.

The doctoral thesis deals with analysis of the ageing of concrete and reinforced concrete pipes in sewage systems. The ageing of the sewage system is caused by several reasons, for example material abrasion, chemical and biological corrosion and subsequent static overload sewer construction. One of the common causes of degradation of sewage systems made from materials bonded with cement sealant is biogenic sulphate corrosion. Due to the corrosion the degradation of the pipe walls accelerates, particularly in upper part of the pipe and reduces planned lifetime of the sewage system. There is proposed new ageing analysis monitoring method for observation and evaluation of the loss of thickness of concrete and reinforced concrete pipes, which is caused by biogenic sulphate corrosion. Residual lifetime is calculated from the expected corrosion rate, it`s the loss of wall thickness on the monitored section of the sewer system. There is designed the monitoring system of the loss of wall thickness on the sewage system for practical application of the measurement procedure, which is administrated in cooperation with the BVK, a. s. The thesis uses existing knowledge regarding this subject. We use this information for better understanding of the process of the loss of wall thickness in sewage systems in real time and the posibility to correct and in-time implementation of appropriate operational measures. This should cause the limitation of the degradation process of piping material while extended service life and safe operation in sewage systems within the required time period. Based on the methodology is proposed to determine the residual life of the sewage system and maintenance and rehabilitation can be done more effectively. There is needed to be noted that only long-term monitoring period can bring a better overview of the technical condition of sewage systems in time and thus better and more effective maintenance and rehabilitation, which is related to the effective u

The following paper presents a one-dimensional numerical model for simulating transient thermohydraulic pipe flow based on the Method of Characteristics. In addition to mass and momentum conservation, the proposed scheme also guarantees compliance with the laws of thermodynamics by solving the energy equation. The model covers transient changes in fluid properties due to pressure changes, heat transfer and dissipation. The presented methodology also allows the computation of the transient temperature distribution in the pipe wall through an additional ordinary finite difference scheme. The numerical procedure is implemented in the commercial simulation software DSHplus. The capability of the code is examined by comparing the simulation results with theoretical solutions and experimental data.

Slotborer är benämningen på en ny maskinprototyp som skall användas för att i gruvor borra och utvinna platina. För att erhålla ett visst borrdjup skarvas borrpipor vilket åstadkoms med en gängkoppling. Detta arbete har haft som syfte att utveckla en ny koppling för dessa pipor då konstruktionen med gängor har visat sig vara problematisk. Ett antal koncept genererades varefter det mest lovande, enligt diskussion med kund och Pughs beslutsmatriser, valdes för vidareutveckling. Detta valda koncept var en typ av bajonettkoppling som förfinades och det gjordes en 3D CAD-modell samt mer detaljerade analyser av kopplingens hållfasthet. Analytiskt med grundläggande hållfasthetslära visades kopplingens mest påkända delar ha Von Mises effektivspänningar på 230 MPa vid normal borrning, 360 MPa vid maxeffektsborrning och 605 MPa vid dragande borrning med maxeffekt. Kontakttryck i kopplingen analyserades enligt Hertz kontaktteori och uppgick i maximalt 2,6 GPa, 3,3 GPa och 4,5 GPa för respektive lastfall. En FEM-analys gjordes där lokala effektivspänningar upptäcktes vara i storleksordningarna 300 MPa, 500 MPa och 1200 MPa för respektive lastfall. Konceptutvecklingen och analysen pekar på att konstruktionen är lämplig för vidare detaljerad konstruktion. / Slotborer is a new machine prototype that is used for excavating platina in underground mines. To drill holes with desired depths there are several drill pipes that are bonded as the hole is drilled deeper with a threaded connection. This work have had the purpose of designing a new connection for these drill pipes as the thread design have shown to be problematic. A number of concepts were generated after which the most preferred, according to customer discussions and Pugh decision matrices, was chosen for further development and refinement. The chosen concept for development was a type of bayonet coupling and a more detailed 3D CAD model and analysis of the coupling strength were made. Analytical solid mechanics showed that the most heavily loaded parts of the coupling experienced effective Von Mises stresses of 230 MPa for normal drilling, 360 MPa for heavy drilling and 605 MPa for heavy back reaming. Contact pressures were analyzed with Hertzian contact theory and the maximum values of these were shown to be 2.6 GPa, 3.3 Gpa and 4.5 GPa for the respective load cases. An FE analysis made showed higher local effective stresses that was of the magnitude of 300 MPa, 500 MPa and 1200 MPa for the respective load cases. The conclusion of the concept development and analysis points out that the design is suitable for further detailed design.

<div>With the rapid development of the advanced two-phase flow experimental technologies, more experimental databases with extended measurement ranges have been established to support the two-phase flow model development. The advantage of the Two Fluid model in modeling the complex two-phase flow phenomena over the mixture models stands out. One key aspect in the Two Fluid model development is the accurate modeling of the interfacial area between phases, which is strongly related to the interfacial mass, momentum, and energy transfer. As a closure relation of interfacial area concentration (interfacial area per unit volume) for the Two Fluid model, the Interfacial Area Transport Equation (IATE) provides dynamic predictions on the interfacial area change. It substantially solves the shortcoming of using flow-regime-dependent empirical correlations that can introduce numerical discontinuities between flow regimes. </div><div><br></div><div>The IATE has been extensively developed over the past twenty-five years. Many studies targeted on improving its prediction capability by developing bubble interaction source terms based on their experimental data. </div><div>The existing models are usually based on medium and large flow channels, yet the models may not be physically fit the small flow channels. The major reason is that the wall effect can have a larger influence on the two-phase flow in a small flow channel, as the surface area to volume ratio greatly increases. Therefore, the primary objectives of this study are to physically investigate the wall effect on two-phase flow and develop a generalized IATE by extending the application range of existing IATE from large and medium flow channels to small flow channel.</div><div><br></div><div>To achieve the objective, this study established a rigorous database of air-water two-phase flows in a small diameter pipe with its inner diameter of 12.7 mm, focusing on the bubbly-to-slug transition regime. The experimental analysis was performed on the pipe wall effect on the interfacial characteristics, based on the current experimental database and the existing experimental database collected on vertical pipes of different sizes. It is observed that 1) the pipe wall effect can alter the non-uniform radial two-phase distribution; 2) the bubbly-to-slug flow regime transition in a small diameter pipe happens in a smaller void fraction than in a large diameter pipe; 3) the bubble coalescence phenomenon can be more dominant for small pipe flow, and an intensive intergroup transfer can happen for the two-group interfacial area transport in two-phase flows. </div><div>As the interfacial area transport is directly related to the two-phase geometrical configuration, the two-phase geometrical parameters, void fraction and relative bubble size, are identified as the key parameters for modeling.</div><div><br></div><div>In the modeling of IATE source terms, the high geometrical scalability of the model is realized by properly including the wall effect into the modeling consideration. The following major improvements on the existing models are: 1) the inertia subrange assumption on the turbulent-driven interaction is properly improved; 2) the bubble-induced turbulent-driven interactions such as wake entrainment is revised by considering the wall effect on the wake region. In summary, models of bubble interaction due to random collision, wake entrainment, turbulent impact, and shearing-off are revised based on the existing studies on the IATE source terms development. The newly proposed interfacial area transport models are evaluated against an experimental database with 112 test conditions in total from a wide range of experimental pipe diameters from 12.7 mm to 304.8 mm. The new models can accurately capture the drastic intergroup transfer of void fraction and interfacial area concentration between two groups in transition flows. Overall, the relative error of void fraction and interfacial area concentration comparing with the experimental data are within ±15\% and ±10\%, respectively.</div>

The dissertation describes the technical analysis of the pipe material of gray cast iron, which is developed on the basis of historical documents and standards. The technical analysis is a methodology for determining the technical state and theoretical residual life of the pipe section made of cast iron, which is processed into a software application Kozel 1.0. The proposed methodology operates on the basis of multi-criteria decision making. For input the data methodologies are designed to monitor the operators of water supply networks. The output of the methodology is to determine the category of the technical condition of the pipe section and time stamp, minimum and maximum residual lifetime analysis pipeline segment. Outputs of the methodology are compared with the outputs of medium-term plans of Ostrava and Brno.

Parametric design can be used for structural design. This approach has someclear advantages compared to the conventional point-based approach using differentComputer Aided Design (CAD)-software, especially in early stage of design. Since themodel is parametrically defined, alternate designs, that are within the scope of theparametric definition, can be explored with little effort from the user compared tothe point-based models. In this way, optimization routines can be used to make moreinformed decisions about the design. Pipe bridges usually have a similar design that issuitable to be defined parametrically.The aim of the thesis is to automate the modeling of pipe bridges in the earlystages of design, to make an integrated analysis and to optimize the structure withregard to material cost and carbon dioxide equivalent-emissions as well as mass ofthe structure. Further, to investigate in what way these objectives are correlated.This thesis improves an existing grasshopper script used to design pipe bridges andimplement an automatic generation of a Bill of Quantity (BoQ).The results of the thesis case study suggests that there is potential in usingoptimization with parametric design to minimize the cost of pipe bridges. With a goodparametric design definition alternate designs can be explored with little effort fromthe user. This benefit to speed up the design process, and allowing the designer towork with adaptable design, could be reasons to turn to a parametric design method.It should also be stressed that this thesis suggests a correlation between the cost of thestructure and the carbon dioxide equivalent emission from the structure. Meaning thatwhile minimizing emissions one could also be minimizing the cost.