In the present work, the breakage of wastewater particles in orifice flow is investigated through numerical simulations. Using maximum strain rate along particle paths as the breakage criterion, breakage is predicted using computational fluid dynamics. The numerical simulations confirm that nominal orifice strain rate cannot explain the higher particle breakage in single-orifice systems compared to that of multi-orifice systems, instead particle breakage was found to correlate well with the maximum strain rates in the system. On the issue of effect of initial particle location on breakage, numerical modeling shows that particles travelling along the centerline are suspected to break less than those travelling near the wall. However, experiments designed to study the breakage of particles injected at various radial locations proved inconclusive. Finally, results suggest that while single orifice systems are ideal for strong particles, multi-orifice systems may be more effective in breaking weak particles.

Orientador: Ulisses Rocha Antuniassi / Banca: Otavio Jorge Grigoli Abi Saab / Banca: Marco Antonio Gandolfo / Resumo: O presente trabalho teve por objetivo verificar a interferência de adjuvantes na quantidade de ar incluído em gotas geradas por pontas com indução de ar, bem como avaliar o espectro resultante destas condições de pulverização. Para o estudo foram utilizadas nove caldas, sendo uma composta apenas por água e oito soluções contendo adjuvantes (óleo mineral, óleo vegetal, mistura de lecitina e ácido propiônico, nonil fenoxi poli etanol, dois adjuvantes a base de nonil fenol etoxilado, copolímero de poliéster e silicone, e lauril éter sulfato de sódio) e três pontas de pulverização jato plano, sendo duas com indução de ar (Air Guardian e Ultra Lo-Drift - Hypro) e uma com pré-orifício (Drift Guard - Spray Systems). O estudo foi realizado em duas etapas, sendo elas a quantificação do ar incluído nas gotas de pulverização e a análise do espectro produzido. O ar incluído foi calculado através da diferença de volume da mistura pulverizada (ar mais líquido) e apenas do líquido, que foi feito por meio de coletas de amostras de pulverização em uma proveta graduada. A determinação do espectro de gotas foi realizada por um analisador de tamanho de partículas por difração de raios laser Mastersizer S (Malvern Instruments). Para análise estatística os valores das variáveis do espectro de gotas e % ar incluído para os diferentes adjuvantes e pontas foram comparados pelo Intervalo de Confiança para Diferenças entre as Médias a 5 % de probabilidade (IC95%). Também foram feitas as correlações entre as diferentes variáveis através do coeficiente de Pearson a 5% de probabilidade. As análises do espectro de gotas demonstraram diferenças entre os adjuvantes, assim como diferenças de comportamento dos adjuvantes de acordo com o tipo de ponta. Todos os adjuvantes ocasionaram o aumento do percentual de ar incluído nas gotas em relação à água, observando... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aimed to verify the influence of adjuvants on the amount of air included in droplets generated by spray nozzles with air induction, as well as to evaluate the droplet spectrum generated in these conditions. For the study, it were used nine spray solutions, one including only water and eight containing adjuvants (mineral oil, vegetable oil, a mixture of lecithin and propionic acid, nonyl phenoxy poly ethanol, the two adjuvants based on nonyl phenol ethoxylate based, copolymer polyester and silicon, and sodium lauryl ether sulfate) and three flat fan spray nozzles, including two air induction (Air Guardian and Ultra Lo-Drift - Hypro) and a pre orifice (Drift Guardian - Spray Systems). The study was conducted in two steps: the quantification of air included in the spray droplets and the droplet spectrum produced. The amount of air included was calculated by the difference in volume of the solution after praying (liquid plus air) and only the solution (before spraying), which was done by collecting samples of the solutions in a graduated cylinder. The determination of the droplet spectrum was carried out by a particle size analyzer by laser device Mastersizer S (Malvern Instruments). Data collected for the variables of droplet spectrum and air included with different adjuvants and nozzles were subjected to statistical analysis by the calculation of the Confidence Interval at 95% (CI95%). Correlations between different variables were calculated by Pearson's correlation at 5% probability. The analysis of the droplet spectrum showed differences between the different adjuvants, as well as differences in the behavior of adjuvants according to the type of nozzle. All adjuvant caused an increase in the percentage of air included compared to the water, in which some different behaviors were observed for each nozzle. Looking at the relations between the variables... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:24:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-08Bitstream added on 2014-06-13T20:31:53Z : No. of bitstreams: 1 mota_aab_me_botfca.pdf: 2185132 bytes, checksum: bc81471882e24fbbd82fb00386fab303 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O presente trabalho teve por objetivo verificar a interferência de adjuvantes na quantidade de ar incluído em gotas geradas por pontas com indução de ar, bem como avaliar o espectro resultante destas condições de pulverização. Para o estudo foram utilizadas nove caldas, sendo uma composta apenas por água e oito soluções contendo adjuvantes (óleo mineral, óleo vegetal, mistura de lecitina e ácido propiônico, nonil fenoxi poli etanol, dois adjuvantes a base de nonil fenol etoxilado, copolímero de poliéster e silicone, e lauril éter sulfato de sódio) e três pontas de pulverização jato plano, sendo duas com indução de ar (Air Guardian e Ultra Lo-Drift – Hypro) e uma com pré-orifício (Drift Guard – Spray Systems). O estudo foi realizado em duas etapas, sendo elas a quantificação do ar incluído nas gotas de pulverização e a análise do espectro produzido. O ar incluído foi calculado através da diferença de volume da mistura pulverizada (ar mais líquido) e apenas do líquido, que foi feito por meio de coletas de amostras de pulverização em uma proveta graduada. A determinação do espectro de gotas foi realizada por um analisador de tamanho de partículas por difração de raios laser Mastersizer S (Malvern Instruments). Para análise estatística os valores das variáveis do espectro de gotas e % ar incluído para os diferentes adjuvantes e pontas foram comparados pelo Intervalo de Confiança para Diferenças entre as Médias a 5 % de probabilidade (IC95%). Também foram feitas as correlações entre as diferentes variáveis através do coeficiente de Pearson a 5% de probabilidade. As análises do espectro de gotas demonstraram diferenças entre os adjuvantes, assim como diferenças de comportamento dos adjuvantes de acordo com o tipo de ponta. Todos os adjuvantes ocasionaram o aumento do percentual de ar incluído nas gotas em relação à água, observando... / This study aimed to verify the influence of adjuvants on the amount of air included in droplets generated by spray nozzles with air induction, as well as to evaluate the droplet spectrum generated in these conditions. For the study, it were used nine spray solutions, one including only water and eight containing adjuvants (mineral oil, vegetable oil, a mixture of lecithin and propionic acid, nonyl phenoxy poly ethanol, the two adjuvants based on nonyl phenol ethoxylate based, copolymer polyester and silicon, and sodium lauryl ether sulfate) and three flat fan spray nozzles, including two air induction (Air Guardian and Ultra Lo-Drift - Hypro) and a pre orifice (Drift Guardian - Spray Systems). The study was conducted in two steps: the quantification of air included in the spray droplets and the droplet spectrum produced. The amount of air included was calculated by the difference in volume of the solution after praying (liquid plus air) and only the solution (before spraying), which was done by collecting samples of the solutions in a graduated cylinder. The determination of the droplet spectrum was carried out by a particle size analyzer by laser device Mastersizer S (Malvern Instruments). Data collected for the variables of droplet spectrum and air included with different adjuvants and nozzles were subjected to statistical analysis by the calculation of the Confidence Interval at 95% (CI95%). Correlations between different variables were calculated by Pearson's correlation at 5% probability. The analysis of the droplet spectrum showed differences between the different adjuvants, as well as differences in the behavior of adjuvants according to the type of nozzle. All adjuvant caused an increase in the percentage of air included compared to the water, in which some different behaviors were observed for each nozzle. Looking at the relations between the variables... (Complete abstract click electronic access below)

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第17867号 / 工博第3776号 / 新制||工||1577(附属図書館) / 30687 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 中川 一, 教授 戸田 圭一, 准教授 川池 健司 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Nozzles are used in a wide range of applications. Nevertheless, the geometric of non-circular orifices have not been widely studied. This project has examined fluid jets exiting through a non-circular orifice, in the gravitational direction. Furthermore, its transformation to a circular cross-section due to a surface tension forces. How the length to a circular cross-section changes with the nozzles geometry and bath depth of the tundish was the main focus of this studied. A water model and high-speed camera was used to capture the profile of the fluid jet. Four different nozzles were attached one by one to five different tundishes with different bath depths. The result showed that with deeper bath depths the circular cross-section occurred further down from the nozzles orifice. The length to the circular cross-section also depended on the orifice area, a larger area gave a longer distance than a smaller area. It was shown that the length to circular cross-section followed a quadratic function, when the measured values were analyzed based on the Weber number. The profile of the fluid jet was dependent on the material of the nozzle, the geometries of the orifice, the bath depth and the surface tension.

No description available.

<p>Flow accelerated corrosion(FAC) results in wall thinning of pipes, tubes or vessels from exposure to flow due to corrosion. If FAC is not detected, it can lead to sudden failure of piping components. Orifices are used in piping systems to monitor and control the flow. Flow separation and reattachment downstream of an orifice can enhance the mass transfer of the pipe wall. In this thesis, the effect of Reynolds numbers and surface roughness on the mass transfer rate downstream of an orifice was investigated. A dissolving wall method was used to measure the wall mass transfer. The test sections were cast from gypsum with water as the working fluid. Multiple destructive tests were performed for different test times in a 2.5 cm diameter flow loop, and the wear topology measured by a laser scanner to obtain the progression of wear with time over the pipe surface. None-destructive tests were performed in a 20 cm diameter flow loop using test section with an inner gypsum lining, and measured online at selected locations using an ultrasonic method. Experiments were performed at Reynolds numbers of 80000, 140000 and 200000 in the 2.5 cm diameter flow loop, and at 180,000 in the 20 cm diameter flow loop with an orifice to pipe diameter ratio of 0.5. The results show that different surface roughness patterns are developed at different Reynolds numbers from the initially smooth surfaces. The different surface roughness patterns have a significantly different effect on the mass transfer rate downstream of an orifice. A larger population of scallops developed from the smooth pipe surface, as the Reynolds number was increased, which enhanced the mass transfer rate. The mass transfer rate in the 20 cm diameter test section was much smaller than in the 2.5 cm diameter test section at a similar Reynolds number. The pattern of the roughness in the 20 cm diameter test section was formed as isolated roughness which is similar to the roughness pattern in 2.5 cm diameter test section at much lower Reynolds number.</p> / Master of Applied Science (MASc)

This investigation examines the effects of load, speed, exhaust gas recirculation (EGR) level and hydrogen addition level on the exhaust gas emissions, particulate matter size distribution and chemical composition. The experiments were performed on a 2.0 litre, 4 cylinder, direct injection engine. EGR levels were then varied from 0% to 40%. Hydrogen induction was varied between 0 and 10% vol. of the inlet charge. In the case of using hydrogen and EGR, the hydrogen replaced air. The load was varied from 0 to 5.4 bar BMEP at two engine speeds, 1500 rpm and 2500 rpm. For this investigation the carbon monoxide (CO), total unburnt hydrocarbons (THC), nitrogen oxides (NOX) and the filter smoke number (FSN) were all measured. The in-cylinder pressure was also captured to allow the heat release rate to be calculated and, therefore, the combustion to be analysed. A gravimetric analysis of the particulate matter size distribution was conducted using a nano-MOUDI. Finally, a GC-MS was used to determine the chemical composition of the THC emissions. The experimental data showed that although CO, FSN and THC increase with EGR, NOX emissions decrease. Inversely, CO, FSN and THC emissions decrease with hydrogen, but NOX increases. When hydrogen was introduced the peak cylinder pressure was increased, as was the maximum rate of in-cylinder pressure rise. The position of the peak cylinder pressure was delayed as hydrogen addition increased. This together with the obtained heat release patterns shows an increase in ignition delay, and a higher proportion of premixed combustion. The experimental work showed that the particulate matter size distribution was not dramatically altered by the addition of EGR, but the main peak was slightly shifted towards the nucleation mode with the addition of hydrogen. Hydrogen addition does not appear to have a large effect on the chemical composition of the THC, but does dramatically decrease the emissions.

The relationship between the Reynolds number (Re) and discharge coefficients (C) was investigated through differential pressure flow meters. The focus of the study was directed toward very small Reynolds numbers commonly associated with pipeline transportation of viscous fluids. There is currently a relatively small amount of research that has been performed in this area for the Venturi, standard orifice plate, V-cone, and wedge flow meters. The Computational Fluid Dynamics (CFD) program FLUENT© was used to perform the research, while GAMBIT© was used as the preprocessing tool for the flow meter models created. Heavy oil and water were used separately as the two flowing fluids to obtain a wide range of Reynolds numbers with high precision. Multiple models were used with varying characteristics, such as pipe size and meter geometry, to obtain a better understanding of the C vs. Re relationship. All of the simulated numerical models were compared to physical data to determine the accuracy of the models. The study indicates that the various discharge coefficients decrease rapidly as the Reynolds number approaches 1 for each of the flow meters; however, the Reynolds number range in which the discharge coefficients were constant varied with meter design. The standard orifice plate does not follow the general trend in the discharge coefficient curve that the other flow meters do; instead as the Re decreases, the C value increases to a maximum before sharply dropping off. Several graphs demonstrating the varying relationships and outcomes are presented. The primary focus of this research was to obtain further understanding of discharge coefficient performance versus Reynolds number for differential producing flow meters at very small Reynolds numbers.

The search for quieter internal combustion engines drives the quest for a better understanding of the acoustic properties of engine duct components. Simulations are an important tool for enhanced understanding; they give insight into the flow-acoustic interaction in components where it is difficult to perform measurements. In this work the acoustics is obtained directly from a compressible Large Eddy Simulation (LES). With this method complex flow phenomena can be captured, as well as sound generation and acoustic scattering. The aim of the research is enhanced understanding of the acoustics of engine gas exchange components, such as the turbocharger compressor.In order to investigate methods appropriate for such studies, a simple constriction, in the form of an orifice plate, is considered. The flow through this geometry is expected to have several of the important characteristics that generate and scatter sound in more complex components, such as an unsteady shear layer, vortex generation, strong recirculation zones, pressure fluctuations at the plate, and at higher flow speeds shock waves. The sensitivity of the scattering to numerical parameters, and flow noise suppression methods, is investigated. The most efficient method for reducing noise in the result is averaging, both in time and space. Additionally, non-linear effects were found to appear when the amplitude of the acoustic velocity fluctuations became larger than around 1~\% of the mean velocity, in the orifice. The main goal of the thesis has been to enhance the understanding of the flow and acoustics of a thick orifice plate, with a jet Mach number of 0.4 to 1.2. Additionally, we evaluate different methods for analysis of the data, whereby better insight into the problem is gained. The scattering of incoming waves is compared to measurements with in general good agreement. Dynamic Mode Decomposition (DMD) is used in order to find significant frequencies in the flow and their corresponding flow structures, showing strong axisymmetric flow structures at frequencies where a tonal sound is generated and incoming waves are amplified.The main mechanisms for generating plane wave sound are identified as a fluctuating mass flow at the orifice openings and a fluctuating force at the plate sides, for subsonic jets. This study is to the author's knowledge the first numerical investigation concerning both sound generation and scattering, as well as coupling sound to a detailed study of the flow.With decomposition techniques a deeper insight into the flow is reached. It is shown that a feedback mechanism inside the orifice leads to the generation of strong coherent axisymmetric fluctuations, which in turn generate a tonal sound. / <p>QC 20121113</p>