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This research focuses on the computational fluid dynamics modelling and simulation of the existing reactors and mixing tanks employed by the Australian Defence Industries to manufacture military propellants for gun projectiles and small rockets; high explosives for naval gun projectiles and aerial bombs. The main objective of this research is to gain a thorough understanding of these process vessels via research and to provide recommendations to improve their performance. Reactors and mixing tanks were chosen as the test unit operations because although they contribute significantly to the manufacturing process, reactors have frequently been poorly understood or in the case of mixing tanks, taken for granted. Consequently, there is a lack of comprehensive knowledge to support successful operations of these process vessels. In addition, this research also recommends using photocatalysis technology to destroy liquid wastes produced from such manufacturing activities. For each product, a full characterisation was provided that included detailed theoretical analyses that presents a unique insight into the hydrodynamics occurring in these process vessels. The credibility of theoretical predictions was demonstrated via qualitative and quantitative validation using particle image velocimetry. Results from characterisation showed that the reactors and mixing tanks employed in the manufacture of military propellants, high explosives or aerial bombs were operating at sub-optimum conditions. To tackle this shortcoming, four ideal geometrical configurations that promised optimum performance were proposed for each of the test studies. These included a designer reactor for the manufacture of military propellants and effective mixing tanks for suspending high explosive particles, blending different high explosives and for manufacturing aerial bombs. The correct implementation of these recommendations will provide an optimum operation that achieves high product throughput and concurrently reduces reject rate. Research was also conducted to formulate a set of multipurpose design guidelines for a suspension mixing tank. The design template created from the results will provide valuable information to researchers across industries in their quest to optimise any unit suspension mixing tank operated on the principle of mechanical agitation. Finally, modelling of reactive species was conducted on a laboratory-scale photoreactor, involving physical experiments to destroy toxic effluent aqueous phase.

Thesis (M.S.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographical references.

Report (M.S.)--Virginia Polytechnic Institute and State University. M.S. 1993. / Vita. Abstract. Includes bibliographical references (leaves 37-38). Also available via the Internet.

Orientadores : Sergio Persio Ravagnani, Choyu Otani / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-14T23:33:08Z (GMT). No. of bitstreams: 1 Libardi_Juliano_D.pdf: 1948644 bytes, checksum: 8e209152ac6e1264f50427fa51a998f2 (MD5) Previous issue date: 2009 / Resumo: Os propelentes compósitos à base de polibutadieno líquido hidroxilado (PBLH) utilizados na produção dos motores foguete a propelente sólido (MFPS), desenvolvidos no Instituto de Aeronáutica e Espaço (IAE), podem sofrer alterações em suas propriedades físicas devido ao processo de difusão de plastificantes entre as interfaces das camadas de propelente e de proteção térmica, que reveste a parede interna deste motor. A ocorrência deste fenômeno afeta diretamente a integridade estrutural dos motores e conseqüentemente seu desempenho. O objetivo deste trabalho foi desenvolver um programa computacional, em linguagem FORTRAN, para calcular os coeficientes de difusão a partir das concentrações dos plastificantes dioctilazelato (DOZ), dibutilftalato (DBF) e dioctilftalato (DOP) presentes nas camadas do propelente sólido, liner e borracha isolante, respectivamente. Para a realização dos cálculos computacionais foi adotado o modelo matemático proposto pela segunda Lei de difusão de Fick. O coeficiente de difusão foi obtido por meio da solução da equação não linear deste modelo com auxílio de métodos numéricos iterativos. Os dados de concentração utilizados no software foram obtidos em amostras contendo as interfaces de propelente/liner/borracha envelhecidas a 50°C e a 80°C. Na primeira condição, foi adotado o período de envelhecimento entre 30 a 125 dias após a cura do propelente. As amostras utilizadas nesta etapa foram preparadas com o liner LHNA que é produzido à base do polímero polibutadieno líquido hidroxilado e curado com o tolueno diisocianato. Foi verificado, por meio dos resultados obtidos, que houve pouca variação nos valores das concentrações dos plastificantes ao longo do envelhecimento, indicando que neste período a difusão entre as interfaces estudadas apresentou um estado próximo ao equilíbrio. Neste caso, os coeficientes não foram calculados devido ao modelo adotado executar os cálculos com base nas diferenças de concentração do plastificante na região estudada ao longo do tempo. Na segunda condição pesquisada as amostras foram envelhecidas a 80°C por um período entre 0 e 31 dias após o término da cura do propelente. Neste caso, os corpos de prova foram preparados com dois tipos diferentes de liner: LHNA e LHNT, este último também é produzido à base do polímero PBLH, no entanto, o LHNT é curado com o isoforona diisocianato que promove maior do reticulação do liner. O programa realizou os cálculos com sucesso e os coeficientes obtidos revelaram que a aplicação de um "liner" com maior densidade de ligações cruzadas reduz, como esperado, o processo de difusão dos plastificantes. Os dados experimentais e os simulados pelo programa exibiram bom ajuste entre si, revelando que o modelo aplicado é válido. Para verificar o efeito da difusão dos plastificantes sobre a dureza do propelente foram realizados testes de dureza Shore A em diferentes regiões dos corpos de prova. Alterações nesta propriedade, ao longo do envelhecimento, podem comprometer a integridade estrutural do motor foguete. Os testes foram executados em amostras de propelente envelhecidas a 80°C e a temperatura ambiente por um período máximo de 54 dias após a cura. Para as amostras mantidas à temperatura ambiente foi verificado o aumento dos valores de dureza ao longo de tempo de envelhecimento e para as amostras armazenadas a 80°C os valores diminuíram no mesmo período de análise. / Abstract: The hydroxyl-terminated (HTPB) based solid composite propellant used in the production of solid rocket motors, developed in the Institute of Aeronautics and Space (IAE), can suffer changes of physical properties due to the diffusion process of plasticizers between the interfaces layers of propellant and thermal insulation. The occurrence of this phenomenon affects directly the structural integrity of the rocket motor and consequently its performance. The aim of this work was to develop a computational program, in FORTRAN language, to calculate the diffusion coefficient, from the concentration data, of plasticizers dioctyl azelate (DOZ), dibutyl phthalate (DBF) and dioctyl phthalate (DOP) contained into layers of propellant, liner and insulation rubber, respectively. The mathematical model proposed by Fick's second law of diffusion was used in computational calculus. The diffusion coefficient was obtained by solution of non liner equation of this model which is solved with assistance of iterative numeric methods. The concentration data used by the software were obtained from samples containing the interfaces of propellant/liner/rubber aged at 50°C and 80°C. In the first condition, the aging was executed between 30 and 125 days after the end of cure. From these results was verified that diffusion process practically reached the equilibrium state. In this case, the diffusion coefficients were not calculated once the mathematical model is based on concentration differences of plasticizers over aging. In the second condition, the samples were aged at 80°C between 0 and 31 days after the end of cure. In this case, the samples were prepared with two different types of liners: LHNA and LHNT, which has higher crosslinking density and is also hydroxyl-terminated polybutadiene based, however, the LHNT is cured with isophorone diisocyanate which is responsible for higher crosslinking. The program executed the calculus with success and the results obtained revealed that the diffusion process is reduced by the application of the liner with higher crosslinking density. It was observed good agreement between the experimental and simulated results showing that the model applied is valid. The Shore A tests was achieved to verify the effects of diffusion on hardness of propellant in different regions of the sample. Changes in propellant hardness over the aging may compromise the structural integrity of the rocket motor. In this study, the analyses were executed in samples aged up to 54 days after the end of cure and submitted to 80°C and room temperature conditions. To samples stored at room temperature the hardness values increased with time while it decreased for samples at 80°C at the same period. / Doutorado / Ciencia e Tecnologia de Materiais / Doutor em Engenharia Química

Electrical control over propellant combustion has the opportunity to improve the functionality and performance of various propulsion systems. In solid rocket motors, active burn rate modulation has the potential to enable throttling. In spacecraft propulsion systems, electrolysis of propellants may provide a means to reduce energy requirements and eliminate the need for expensive catalysts. The work presented in this thesis is concerned with fundamental science related to propellant electrolysis and the performance of rocket propulsion systems using electrolytic ignition. Specifically, the present research is concerned with the effect of conductive and energetic additives on the ignition, combustion, and extinction characteristics of lithium perchlorate-based propellants. Particular attention is paid to the relative importance of electrochemistry and ohmic heating during ignition and steady-state combustion as well as the relative influence of pressure and voltage during steady combustion. Research into the development of an electrically initiated propellant and its integration into a rocket motor is presented as well. This work focused primarily on surveying propellants based on ammonium perchlorate, lithium perchlorate, and hydroxylammonium nitrate for use in a small rocket motor. The decomposition processes of propellants based on ionic liquids and gel polymer electrolytes are detailed. Finally, data from motor firings is presented and parameters influencing the motor's performance and consistency are identified for future improvement. / Master of Science / The principal disadvantage of solid rocket motors is the lack of an active throttling and restart capability. Put simply, once a motor is ignited, it will burn until all of the propellant is consumed and there currently isn't a good method to speed up or slow down a solid rocket on command after it has been launched. As a result, the situations in which solid rocket motors can be used are limited. For example, solid rockets are not used in satellite propulsion because satellites need periodic adjustments to attitude and altitude, not a single boost. But solid rockets are relatively cheap, simple, and reliable and so various means of throttling solid propellants are being investigated. The method relevant to this work is throttling by using an electrical stimulus. By applying voltage across a propellant, the propellant can be ignited and the burning rate can be changed. The research here investigates what materials can be added to these propellants to make them ignite and burn faster as well as the development of novel propellants for applications in a small rocket motor.

Microscopic examination of the tracheal dimensions of normal Florida mice (Peromyscus floridanus) and cotton mice (P. gossypinus) showed no significant differences between the two species, but external examination showed the tracheal length of the Florida mouse to be longer than that of the cotton mouse. Microscopic examination of the intrapulmonary apparatus (bronchioles, alveolar ducts, atria, and alveoli) of normal Florida and cotton mice showed no significant differences in measurements between the two species. Cotton mice were exposed to exhaust gases produced by the burning of solid rocket motor (SRM) fuel. Mice exposed once for a duration of 10 min demonstrated an LD50 of 52 to 56 ppm HCl/g body weight and an LD50 of 169 to 173 mg Al2O3/m3/g body weight. These LD50 values suggested that SRM exhaust components may have a synergistic lethal effect when compared to the effects of individual components of the exhaust. Cotton mice exposed to the exhaust exhibited external signs of respiratory distress and dyspnea. Those mice that received lethal exposures showed internal signs of early inflammatory reactions. However, the most likely cause of death was a sudden shift in blood pH.

M. S.