No description available.

Traditionally, ventilation requirements for modern, mechanized underground mines have been based upon the power of the diesel equipment fleet, with a multiplier (determined from empirical data collected and compiled over a long period of time or required by regulations) being applied in order to determine the total airflow volume requirements of entire mines and/or individual sections or working areas. Often, in the absence of unusual geographic, climatic or geologic conditions that warranted special consideration, the airflow required for the dilution of diesel exhaust products would provide sufficient ventilation for the entire mine. However, recent studies regarding the health-effects of diesel exhaust, particularly the relationship between exposure to diesel emissions and cancer in humans, coupled with additional scrutiny on so called greenhouse gas emissions, have resulted changes to the regulations for engine and equipment manufacturers to provide cleaner burning and less polluting equipment; and are currently causing profound uncertainty in the mining industry. This influence is particularly felt in the case of ventilation engineers and those involved in long-term mine planning who have responsibility for designing the ventilation systems of both existing and future mining projects around the world. This thesis identifies the major parameters affecting airflow requirements for diesel-powered mining equipment and examines how each of them will change in scale and scope in the aftermath of regulatory changes mandating drastic reductions in the type and amount of diesel engine emissions. Culminating from this research, a new procedure for making total airflow determinations based on the underground diesel equipment fleet is proposed and tested with a practical case-study. Ultimately, the determination of the amount of airflow required for an underground mining operation or other sub-surface facility can depend on several factors, including the equipment fleet, ambient temperature, rock type, mining method and airway type (or use). Obtaining a universal, repeatable protocol for determining airflow quantities required for underground diesel equipment fleets is in the best interest of the industry as a whole, including ventilation practitioners, mine-planning engineers, mining financiers, executives, equipment manufacturers, and of course, the mine workers themselves, who perhaps have the most at stake of anyone involved in the equation. / Thesis (Master, Mining Engineering) -- Queen's University, 2013-05-23 22:33:11.36

Large eddy simulation of spray combustion in an HSDI engine is carried out in this thesis. The implementation of the code was performed in logical steps that allowed both assessment of the performance of the existing KIVA-LES and later development. The analysis of the liquid annular jet confirmed existence of typical, annular jet exclusive structures like head vortices, stagnation point and recirculation in the inner zone. The influence of the swirl in the ambient domain was found to have profound impact on the development, penetration and radial spreading of the jet. Detailed results were reported in Jagus et al. (2008). The code was further validated by performing an extensive study of large eddy simulation of diesel fuel mixing in an engine environment. The reaction models were switched off in order to isolate the effects of both swirl and the different numerical treatment of LES. Reference RANS simulation was performed and significant differences were found. LES was found to capture much better the influence of the swirl on the liquid and vapour jets, a feature essentially absent in RANS results. Moreover, the predicted penetration of the liquid was much higher for the LES case and more in accordance with experimental measurements. Liquid penetration and subsequent evaporation are very important for prediction of heat release rates and encouraging results formed a good basis to performing a full simulation with models for ignition and combustion employed. The findings were analyzed in the paper by Jagus et al. (2009). Further modifications were introduced into the LES code, among them changes to the combustion model that was originally developed for RANS and calculation of the filter width. A new way of estimating the turbulent timescale (eddy turnover time) assured that the incompatibilities in the numerical treatment were eliminated and benefits of LES maximized. The new combustion model proved to give a very good agreement with experimental data, especially with regard to pressure and accumulated heat release rates. Both qualitative and quantitative results presented a significant improvement with respect to RANS results and old LES formulation. The new LES model was proved to give a very good performance on a spectrum of mesh resolutions. Encouraging results were obtained on a coarse mesh sets therefore proving that the new LES code is able to give good prediction even on mesh sizes more suitable for RANS. Overall, LES was found to be a worthy alternative to the well established RANS methods, surpassing it in many areas, such as liquid penetration prediction, temperature-turbulence coupling and prediction of volume-averaged data. It was also discovered that the improved LES code is capable of producing very good results on under-resolved mesh resolutions, a feature that is especially important in industrial applications and on serial code structure.

No description available.

Orientador: Messias Borges Silva / Co orientador: Fernando Augusto Silva Marins / Banca: Marcela Aparecida Guerreiro Machado de Freitas / Banca: Anderson Paulo de Paiva / Resumo: Este trabalho tem por objetivo desenvolver, validar e testar modelos matemáticos multivariados com a finalidade de monitorar em tempo real a qualidade no processamento do óleo diesel numa refinaria de petróleo. Os produtos derivados têm especificações baseadas em propriedades físico-químicas que podem variar de maneira significativa com a modificação do elenco de petróleos durante o processamento, mantendo-se as mesmas condições de controle de produção, o que compromete os padrões de qualidade dos seus produtos. Isso leva à necessidade de determiná-las ou prevê-las com a maior freqüência possível em detrimento às análises pontuais tradicionais em laboratório. Foi possível modelar matematicamente as propriedades temperaturas de destilação, índice de cetano, ponto de fulgor, viscosidade cinemática e densidade do óleo diesel pela técnica multivariada - Mínimos Quadrados Parciais (PLS - Partial Least Squares) a partir de dados experimentais. Os modelos desenvolvidos foram utilizados em um processo real de produção permitindo agilidade na tomada de decisão no sistema de blending, redução da variabilidade do processo e aumento da rentabilidade da produção, eliminação de reprocessamentos, sem geração de resíduos químicos / Abstract: This study aims to develop, validate and test multivariate mathematical models in order to monitor real-time processing on the quality of diesel oil in a petroleum refinery. Their products have specifications based on physicochemical properties that can vary significantly with the change of cast during the processing of oil, keeping the same conditions of production control, which compromises the quality standards of their products. This leads to the need to determine them or provides them as often as possible in lieu of the traditional point analysis in the laboratory. It was possible to model the properties distillation, cetane index, flash point, kinematic viscosity and density of diesel by multivariate analysis - Partial Least Squares from experimental data. The models developed were used in an actual production process allowing flexibility in decision-making system in blending, reduction of process variability, increase the profitability of production, elimination of reprocessing without chemical residues / Mestre

Made available in DSpace on 2014-06-12T17:37:48Z (GMT). No. of bitstreams: 2 arquivo2410_1.pdf: 3630733 bytes, checksum: e4b1eea91bbba672bf8b2b12163d4f10 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2010 / Faculdade de Amparo à Ciência e Tecnologia do Estado de Pernambuco / Acidentes com derrames de petróleo ou seus derivados em ambientes sensíveis, como os estuários, provocam um grande impacto ambiental. A limpeza dessas áreas contaminadas necessita de cuidados e de tecnologias que reduzam os efeitos do contaminante no meio ambiente. Nesse sentido, tecnologias biológicas de degradação dos hidrocarbonetos, em processos chamados de biorremediação, são apontadas como eficazes no tratamento de áreas degradadas. Muitos trabalhos têm sido desenvolvidos no intuito de elucidar os processos degradativos dos hidrocarbonetos, aeróbios e anaeróbios, e as tecnologias de biorremediação. O presente trabalho avaliou dois tratamentos de biorremediação, atenuação natural e atenuação natural incentivada, em condições laboratoriais, de um sedimento estuarino contaminado com óleo diesel. Como forma de incentivo buscou-se uma maior biodisponibilidade do contaminante, com o uso de um biossurfatante. Foram monitorados parâmetros físico-químicos e biológicos durante 111 dias de tratamento. A avaliação da degradação foi realizada através do acompanhamento dos 16 hidrocarbonetos poliaromáticos (HPAs) considerados prioritário pela U.S. Environmental Protection Agency (U.S.EPA, 2009). A quantificação das bactérias heterotróficas totais indicou um possível período de adaptação da microbiota à contaminação. Dentre os 16 HPAs quantificados, o naftaleno apresentou uma maior percolação na coluna, uma vez que a contaminação foi realizada no topo da mesma. Isso pode ser atribuído a sua maior solubilidade em água, 31 mg/L. Os HPAs de menor peso molecular apresentaram uma maior oscilação de concentração nos primeiros 45 dias de tratamento, enquanto que os de maior peso molecular apresentaram comportamentos semelhantes, com processos de disponibilização mais tardia e significativas reduções do T62 para o T111. Foi possível observar indícios de remoção de 82% do composto pireno no tratamento de atenuação natural nos 111 dias estudados. No tratamento de atenuação natural incentivada observou-se uma redução gradual até o T62, porém no T111 ocorre uma nova disponibilização do contaminante, no entanto do T0 até o T111 ocorre uma remoção de 36% do pireno. De uma maneira geral, o somatório dos 16 HPAs, para ambos os tratamentos nas amostras de superfície, teve redução em sua concentração após o T62, período esse com um significativo crescimento no número de bactérias heterotróficas. Bons indícios de degradação anaeróbia foram observados nos tratamentos adotados, porém não foram verificadas diferenças entre os tratamentos, ou seja, o biossurfatante não solubilizou os HPAs a níveis significativos à biodegradação, como o esperado

Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2016-12-21T10:15:43Z No. of bitstreams: 1 DIS_PAULO_RICARDO_PODORODECZKI_COMPLETO.pdf: 2248928 bytes, checksum: 5045d51346076939fcea5a0a04a7a1a1 (MD5) / Made available in DSpace on 2016-12-21T10:15:44Z (GMT). No. of bitstreams: 1 DIS_PAULO_RICARDO_PODORODECZKI_COMPLETO.pdf: 2248928 bytes, checksum: 5045d51346076939fcea5a0a04a7a1a1 (MD5) Previous issue date: 2016-10-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The present work analyzes the performance and consumption of an electronically managed diesel cycle engine using the Common Rail system equipping a utility vehicle, varying the volume of Biodiesel added to the diesel. The S10 diesel fuel purchased at gas stations, consisting of 7% of Biodiesel already in its composition, and adding Biodiesel in volume of 5 in 5% up to pure Biodiesel (100%) was used for the tests. The tests were carried out on a roller dynamometer in order to obtain and analyze data of torque, power and specific consumption, in order to obtain data for further analysis and make comparisons with previously published theoretical reference. The results showed that there is a better performance range between 10% and 30% where there is a 3% increase in performance with the lowest specific consumption and with the gradual increase of the percentage of Biodiesel, the performance declines of the order of 11, 8% in the maximum torque and 8.2% in the power generated by the engine to 100% Biodiesel, being this one that presented the worst performance. / O presente trabalho analisa a performance e o consumo de um motor de ciclo Diesel gerenciado eletronicamente utilizando o sistema Common Rail equipando um ve?culo utilit?rio, variando-se o volume de Biodiesel adicionado ao Diesel. Utilizou-se para os ensaios o combust?vel Diesel S10 adquirido em postos de combust?veis, constitu?do de 7% de Biodiesel j? em sua composi??o, e adicionando Biodiesel em volume de 5 em 5% at? Biodiesel puro (100%). Os ensaios foram realizados em bancada dinamom?trica de rolos, a fim de obter e analisar dados de torque, pot?ncia e consumo espec?fico, a fim de obter dados para posterior an?lise e realizar compara??es com referencial te?rico publicado anteriormente. Os resultados demonstraram que h? uma faixa de melhor performance entre 10% e 30% onde h? um aumento de performance da ordem de 3% com o menor consumo espec?fico e com o aumento gradativo do percentual de Biodiesel, a performance declina da ordem de 11,8% no torque m?ximo e 8,2% na pot?ncia gerada pelo motor at? Biodiesel 100%, sendo esta a que apresentou a pior performance.

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains x, 54 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 49-51).

This work focuses on the cooling of diesel engines. Facing heavy constraints such as emissions control or fossil energy management, political leaders are forcing car manufacturers to drastically reduce the fuel consumption of passenger vehicles. For instance, in Europe, this fuel consumption has to reach 120 g CO2 km by 2012, namely 25 % reduction from today's level. Such objectives can only be reached with an optimization of all engines components from injection strategies to power steering. A classical energy balance of an internal combustion engine shows four main losses: enthalpy losses at the exhaust, heat transfer to the cylinder walls, friction losses and external devices driving. An optimized cooling will improve three of them: the heat transfer losses by increasing the cylinder walls temperature, the friction losses by reducing the oil viscosity and the coolant pump power consumption. A model is rst built to simulate the engine thermal behavior from the combustion itself to the temperatures of thedierent engine components. It is composed by two models with different time scales. First, a thermodynamic model computes the in cylinder pressure and temperature as well as the heat flows for each crank angle. These heat flows are the main input parameters for the second model: the nodal one. This last model computes all the engine components temperatures according to the nodal model theory. The cylinder walls temperature is then given back to the thermodynamic model to compute the heat flows. The models are then validated through test bench measurements giving excellent results for both Mean Effective Pressure and fluids (coolant and oil) temperatures. The used engine is a 1.9l displacement turbocharged piston engine equipped with an in-cylinder pressure sensor for the thermodynamic model validation and thermocouples for the nodal model validation. The model is then used to optimize the coolant mass flow rate as a function of the engine temperature level. Simulations have been done for both stationary conditions with effciency improvement up to 7% for specific points (low load, high engine speed) and transient ones with a heating time improvement of about 2000s. This gains are then validated on the test bench showing again good agreement.

Thèse de doctorat : sciences. Thermique et énergétique : Ecully, Ecole centrale de Lyon : 2006. / 91 réf.