FLUID FLOW

Author: LOROÑO LUCENA JOSE IGNACIO.
Year: 2004.
University: PAÍS VASCO [www.ehu.es].
Place of defense: E.T.S. DE INGENIERIA.
Place of preparation: E.T.S. DE INGENIERIA.

Summary: This thesis analyzes the current status of the individual channels collective boiler type B abordándola from different approaches and entering the computational fluid dynamics (CFD) technology as a validation of methods of calculation are proposed. It is structured according to the following pattern: Analysis of the smoke evacuation systems in facilities with individual boilers to gas. Contextualizing of all European legislation, state and autonomic on the evacuation of smoke. Impact of proper design, quality control and enforcement of chimneys in the building, with respect to indoor air quality. Evaluation of the adequacy of software for solving methodologies for calculating raised. Establishment of a procedure for calculating stacks based on the Standard UNE 123001:1994 / 1m: 2002. Establishment of a procedure for calculating stacks based on Standard EN 13384-2:2003. Entering CFD technology as a method of validating the procedures for calculating chimneys. It outlines the assumptions of departure, physical models and postproceso, along with analysis of the results.

Author: FIGUEROA RODRIGUEZ JESUS MANUEL.
Year: 2005.
University: GIRONA [www.udg.es].
Place of defense: EDIFICI POLITECNICA IV.
Place of preparation: UNIVERSITAT DE GIRONA.

Summary: It analyzes the structure of the surface layer of the ocean (and its dynamic mixture) using a data set (adcp, qty, meteorological and microstructure) in the region close to the 53 degrees north latitude, crossing across the Atlantic Ocean during the time of transition from winter to spring.

Author: FIGUEROA RODRIGUEZ JESUS MANUEL.
Year: 2005.
University: GIRONA [www.udg.es].
Place of defense: EDIFICI POLITECNICA IV.
Place of preparation: UNIVERSTIAT DE GIRONA.

Summary: It analyzes the structure of the surface layer of the ocean (and its dynamic mixture) using a data set (adcp, qty, meteorological and microstructure) in the region close to the 53 degrees north latitude, crossing across the Atlantic Ocean during the time of transition from winter to spring.

Author: Silva Rojas Orlando.
Year: 2006.
University: ROVIRA I VIRGILI [www.urv.cat].
Place of defense: E.T.S. de Ingeniería Química.
Place of preparation: Escuela Técnica Superior de Ingeniería Química.

Summary: The most common way to model the transport of solutes in the unsaturated zone is considered to have behaved passively and use the solution to the movement of fluid phases as input. The presence of some chemicals can affect the physical properties of fluids producing transport processes not passive. The main aim of this thesis has been formulating a detailed model that describes not passive transport in the unsaturated zone and conditions isotérmicas of volatile organic compounds soluble in water. The proposed model includes units of the density, viscosity, interfacial tension, the rate of molecular diffusion in the liquid phase, and the coefficients of distribution gas-líquido, with the composition of the aqueous mixture. It has also taken into account the reduction coefficients of distribution gas-líquido due to capillary pressure high, according to the Kelvin equation applies to mixtures multicomponentes.Se has implemented the model in two numerical simulation codes: 1D and 2D with symmetry cylindrical. In 1D illustrates the infiltration and redistribution of aqueous mixtures of alcohols. The simulation of the infiltration of aqueous mixtures of sand in butanol agreed with the simulations and experimental data are reported in the literature. La simulación de la infiltración, redistribución y volatilización de mezclas acuosas de metanol en dos suelos diferentes, mostró que la composición afecta significativamente los perfiles de contenido volumétrico de líquido y concentración, al igual que los flujos normalizados de volatilización y evaporación. The dispersion in liquid phase was the dominant transport mechanism for a dispersividad longitudinal saturation of 7.8 cm. The liquid flow was ruled mainly by capillary pressure gradients induced changes in the content of the liquid. However, considering a dispersividad longitudinal saturation 0.2 cm, changes in the interfacial tension due to variations in the composition attracted an important flow of liquid, and the convection in the liquid phase was the most active transport mechanism. By ignoring the effect Kelvin within the soil, the gas phase diffusion is significantly reduced, resulting in reduced flow of water evaporation and higher volume of liquid content near the surface of suelo.Europe 2D, the model was applied to the simulation two-dimensional infiltration of aqueous mixtures of methanol from a source shaped disk, reassignments and volatilization in soil homogeneous and heterogeneous. The simulations showed that for homogeneous soils are obtained similar results and conclusions in 1D. The dependence of viscosity with the concentration was greater impact on the flow of liquid, acting in the same direction or counteracting the effects of interfacial tension, depending on the composition and the magnitude of the concentration gradients developed on the ground. The heterogeneity of soil favored to be expressed effects rather than passive, and that differences in liquid content and concentration of methanol increased during transport through a floor consisting of a block of clay immersed in a matrix main sandy texture franc arcillo . Since the bloc clay and drying more than the top soil attenuate the concentration gradients above the block for soil mixed with a lower dispersividad dispersion in liquid phase was again the dominant transport mechanism. Finally, it has been proposed as a retention able to consistently describe the movement of water and solutes in the adsorption of dry conditions. To that end, BET isotherm is used to describe the curve of water retention in the region drier. To cover the entire range of water contents, it is considered the classic function of 8 Brooks-C 5a8 orey in the range moist, while the transition between the mechanisms for adsorption and capillary action is obtained by means of a generalization of the adsorption isotherm for Bradley. There was a good match between the new model retention and seven sets of experimental data. We evaluated the performance of the new role of containment within a model of water transport, with its validity to describe the dynamics of flows throughout the range of conditions of water content. It is well known that the adsorption of volatile organic compounds in soil is almost dry on a competitive basis with water vapor. This proposal makes it possible to calculate these competitive adsorption processes in a manner consistent with the processes of evaporation and flow of water.

Author: PÉREZ GARCÍA JOSÉ.
Year: 2006.
University: POLITÉCNICA DE CARTAGENA [www.upct.es].
Place of defense: E.T.S. DE INGENIERÍA INDUSTRIAL.
Place of preparation: ESCUELA TÉCNICA SUPERIOR DE INGENIERÍA INDUSTRIAL.

Summary: This Doctoral Thesis is a numerical and experimental study on the flow understandable in joints channels. The study has a practical interest in engineering and also a component of basic research. It consisted in the development and validation of a comprehensive methodology to provide knowledge about the behavior and the internal structure of the flow ducts understandable in joints. The developed methodology is to apply the model of one-dimensional flow, compressible and adiabatic, to obtain first the friction coefficient flow fully developed, based on the results obtained by numerical simulation with the commercial code Fluent. Then, it uses the same model and the friction coefficient calculated to offset any losses due to the viscous friction in each of the branches of the union. At magnitude fluid on the union, once discounted these losses, are called "extrapolated values." The "jump" extrapolated to determine property losses due exclusively the union. Starting with the "jump" of properties calculated defines a ratio that characterizes dimensional flow, and that depends on the number of Mach extrapolated common in the branch and the relationship between costs másicos branches. The methodology of numerical simulation, as well as the installation and experimental procedure has been validated by comparing the results obtained for the ratio of losses pressure backwater Miller (1984), with the experimental data of Aboud-Haidar and Dixón (1992, 1994) for joints like "T" at 90 º. In general, there is an acceptable level of coincidence, but there was some irregularity and dispersion of data in some configurations flow studied. This makes it difficult to obtain correlations to be used as a boundary condition in the simulation codes comprehensive 1D analysis and design of transport systems fluids. One of the factors influencing the irregularity and dispersion of data observed is that the rate of loss of Miller amplifies the uncertainty of the measures. For this reason, it has carried out an analysis of propagation of errors in detail and has concluded that the only mistake of magnitude whose average is amplified is the static pressure. Since this study was obtained from a new analytical expression for the ratio of losses, called "liaison coefficient," which amplifies not errors of departure and it has other advantages, such as increased sensitivity to its Mach number and the linear dependence of the latter in logarithmic scale. Once validated the methodology developed and defined the new ratio liaison, has been carried out experimental characterization and numerical compressible flow stationary in a union directional at 30 ° of more complex geometry, for which there is no information in compressible flow . The numerical results obtained to analyze in detail the characteristics and internal structure of the flow, as it has a very comprehensive information on any scale fluid. One can thus identify the source of losses for each type of flow, evaluate the size of the regions and recirculation flows separately, or determine the length necessary to fully develop the flow downstream from the union. This Doctoral Thesis also provides results of practical interest, since it had obtained partial correlation coefficient of reliable and comprehensive liaison depending on the number of Mach extrapolated common in the branch and the relationship between branches másicos costs for the two types unions studied. These correlations respond to simple mathematical equations, which provide a boundary condition very compact and easy to implement in simulation codes comprehensive 1D.