Les procédés d’élaboration de Composites à Matrice Céramique (CMC) utilisés aujourd’hui à l’échelle industrielle sont longs et par conséquent coûteux. Dans ce contexte, le procédé de densification rapide ou procédé de caléfaction, jusque-là essentiellement connu pour l’élaboration de carbone, permettant de réduire considérablement les durées d’élaboration, apparaît intéressant. Cette étude est axée sur le développement du procédé de caléfaction dans le but d’élaborer des carbures, matériaux connus pour leurs bonnes propriétés à haute température, et plus particulièrement du carbure de silicium (SiC). Dans cet objectif, un équipement de laboratoire, le mini-kalamazoo, a été mis au point, adapté et instrumenté de manière à répondre aux besoins de l’étude. Les premiers essais ont été réalisés au moyen de méthyltrichlorosilane (MTS), précurseur largement connu pour la CVD/CVI du SiC. Les analyses des dépôts formés ont montré la présence de SiC mais aussi celle de carbone. Dans quelques cas spécifiques, du SiC pur peut être formé localement en début de caléfaction. Mis à part ces conditions particulières, l’utilisation de MTS pur en tant que précurseur conduit à la présence inéluctable de carbone libre dans le dépôt de SiC. Plusieurs voies d’amélioration ont alors été proposées et testées pour pallier cet excès de carbone. Certaines d’entre elles se sont avérées efficaces et prometteuses, en particulier, l’utilisation d’un mélange de MTS et d’un précurseur de silicium non carboné et l’utilisation de précurseurs de SiC non chlorés, le CVD 4000 et l’hexaméthyldisilane. Les vitesses de croissance de dépôt sont largement supérieures avec le procédé de caléfaction qu’avec les moyens d’élaboration aujourd’hui employés. L’ensemble des résultats obtenus valide l’intérêt de la caléfaction en tant que procédé d’élaboration du SiC et de nouveaux matériaux de type carbure. / The current Ceramic Matrix Composites (CMC) manufacturing processes used at the industrial scale are slow and consequently expensive. In light of this, the fast densification process, also called the film-boiling process, essentially known to produce carbon deposit up to now, reduces significantly the processing time which seems to be promising. This study was focused on the film-boiling process development in order to manufacture carbides which are materials with good properties at high temperature, and especially to synthetize silicon carbide (SiC). In this aim, a laboratory-made equipment was developed, set-up and adapted to the needs of our study. The first tests were done with the methyltrichlorosilane (MTS), precursor widely used for SiC CVD/CVI. Characterizations of the deposits showed the formation of SiC but also the occurrence of carbon. Pure SiC can be locally obtained at the beginning of the film-boiling process in some specific experimental conditions. For most of the experiments, the use of pure MTS as precursor leads inevitably to the formation of free carbon in the SiC deposit. Several improvement routes were proposed and tested to remove this carbon excess. Some of the efficient and promising routes have consisted in the use of MTS mixed with a silicon precursor free of carbon and the use of two non-chlorinated SiC precursors, CVD 4000 liquid precursor and hexamethyldisilane. The deposit growth rates were significantly superior with the film-boiling process compared to the classical processes. All the data show that the film-boiling process is promising for the manufacturing of SiC and new carbide materials.

The growing demand for the development of efficient miniature cooling systems has led to stimulating numerous investigations on two-phase flow boiling in small to microscale tubes. Because of the variation in properties of synthetic cooling fluids, this causes an inaccuracy of existing flow boiling prediction models or correlations in the literature to interpolate or extrapolate the two-phase flow boiling heat transfer and pressure drop. The purpose of this investigation was to study experimentally the parametric aspects of flow boiling characteristics inside vertical stainless-steel tubes with four different internal diameters (1.1, 2.01, 2.88 and 4.26 mm). The R245fa (1,1,1,3,3-pentafluoropropane, HFC-245fa) was used as working fluid. The experiments were carried out under a system pressure range of 185 - 310 kPa (which correspond to a saturation temperature range of 31 - 46 °C), mass flux range of 200 - 500 kg/m²s, heat flux range of 3 - 188.5 kW/m², vapour quality up to the onset of dryout and 5 K inlet subcooling. Flow pattern visualisations, two-phase pressure drops and saturated flow boiling heat transfer coefficients were presented. The experimental data of R134a employed for comparison is acquired from the previous studies of Huo et al. (2007), Shiferaw et al. (2011) and Mahmoud et al. (2014a). These studies were carried out in the same experimental facility and under the similar operating conditions. The Two-phase flow regimes inside four tubes were visualised in a borosilicate glass tube located at the heated section outlet to capture the dominant flow patterns which assist to elucidate the heat transfer results. The flow boiling visualisation was recorded by a high-speed camera with experiments of increasing and decreasing heat flux. The four observed flow regimes are identified as bubbly flow, slug flow, churn flow and annular flow. In increasing heat flux experiments, the churn and annular flows were only the dominant patterns in all four tubes. The slug flow was often discerned at lower mass flux except for the tube of 1.1 mm where it was not observed at all. This is contrary to decreasing heat flux experiments where all flow patterns including the bubble flow were observed in all the tubes. This shows a strong impact of hysteresis, which is a result of nucleation sites remained active as the heat flux is reduced. The flow patterns and transition boundaries for R245fa are affected by mass flux, system pressure, and tube diameter. The vapour quality corresponding to flow pattern transition boundary tends to decrease with increasing mass flux and tends to increase with increasing system pressure and decreasing tube diameter. Except for the bubbly-slug boundary, its vapour quality decreases with decreasing tube diameter. The experimental flow pattern maps of R245fa were fairly predicted with the predictive models developed for mini- and micro-channels by Tibiriçá et al. (2017). The two-phase pressure drop of R245fa is affected by mass flux, heat flux, system pressure, tube diameter and surface topography. The two-phase pressure drop increases with increasing mass flux and heat flux (vapour quality) and decreases with increasing system pressure and tube diameter. The two-phase pressure drop of the coated tube is higher than that of the uncoated tube. This is attributed to the coated tube having a higher surface roughness compared to the uncoated tube. The comparison between R245fa and R134a shows that the measured two-phase pressure drop of R245fa is dramatically higher than that of R134a. This arises from the difference in physical properties of the two fluids. The experimental data of two-phase pressure drop for 4.26 mm tube were reasonably predicted by Müller-Steinhagen and Heck (1986) correlation. Further, the experimental data of 2.88 mm and 2.01 mm tubes were well predicted by Chisholm (1973a), and Kim and Mudawar (2013), respectively. The experimental data of 1.1 mm tube were not well predicted by any of the selected predictive methods. The local heat transfer coefficient of all tubes increases with increasing heat flux for low and intermediate vapour qualities. After this vapour qualities, the heat flux effect diminishes. Then, the local heat transfer coefficient increased slightly with vapour quality, especially for higher heat flux near the outlet of the tube. However, the dryout inception in the 1.1 mm tube occurs after the intermediate vapour quality value and expands along the high vapour quality region. The behaviour of the local heat transfer coefficients of 1.1 and 2.88 mm tube is slightly dependent on the mass flux and vapour quality. Contrarily, there is insignificant effect of mass flux along 2.01 and 4.26 mm tube. This gives an indication of the contribution of nucleate boiling in the heat transfer process at lower and medium heat fluxes and nucleate boiling plus convective evaporation at higher heat fluxes near the tube outlet. Further, the local heat transfer coefficient increases as the system pressure increases. The tube diameter has a strong influence on the enhancement of local heat transfer coefficient. The enhancement in average heat transfer coefficient approaches 83% when the tube diameter is reduced from 4.26 to 1.1 mm. The trend of the local heat transfer coefficient of R134a was almost similar to that of R245fa with the exception of local dryout. The average heat transfer coefficient of R134a is about 106-151% larger than that of R245fa for the operational range studied. The dominant heat transfer mechanism is also represented by nucleate boiling for both fluids, particularly for 4.26 mm tube tested in this study. Also, the average heat transfer coefficient was enhanced by 33% when the inner tube surface coated with a copper coating. Finally, the correlation of Fang et al. (2017) predicted all experimental data for the four tubes with fair and similar accuracy.

Thesis (M.S.)--University of Wisconsin -- La Crosse, 1983. / Includes bibliographical references (leaves 47-51).

The environmental concerns in recent times have grown especially after signing Montreal protocol. In the last ten years, researchers have focussed mainly on understanding the boiling and condensation phenomena of HFC refrigerants in minichannels. As global warming concerns are growing day by day, due to high global warming potential, HFCs are not the ultimate option. In the near future, HFCs will probably be replaced by environmentally friendly refrigerants. Therefore, to find the potential replacements of HFCs and also to get a deeper understanding of the boiling phenomena in minichannels, more and more fluids having low GWP (Global Warming Potential) and ODP (Ozone Depletion Potential) should be tested. Recent efforts to protect the environment have led to a growing interest for natural refrigerants. However in the literature, flow boiling data of natural refrigerants in minichannels are scarce. To meet the environmental concerns and to understand the behaviour of natural refrigerants in minichannels and the performance compared to HFCs, flow boiling experiments in single circular vertical minichannels of internal diameters of 1.70 and 1.224 mm were performed using ammonia and propane as working fluids. Flow boiling heat transfer results of ammonia and propane with 1.70 mm channel showed that the heat transfer coefficient was a function of heat flux and the effect of mass flux was insignificant. The heat transfer coefficient of ammonia in 1.224 mm was dependent on heat flux at low vapour qualities then a clear dependence of the heat transfer coefficient on the mass flux was observed at higher vapour qualities. The heat transfer results of ammonia and propane were compared with well known correlations and among them Cooper (1989) correlation in case of ammonia and Liu and Winterton (1991) and Cooper (1984) pool boiling correlations in case of propane best predicted the experimental heat transfer data. Results of the two phase pressure drop studies of ammonia and propane showed that the two phase pressure drop increased with the increase of mass flux, with the increase of heat flux and with the decrease of saturation temperature. The comparison of the two phase pressure drop experimental data with well known predicting models showed that none of the correlations predicted the ammonia data well and that Müller Steinhagen and Heck (1986) was well in agreement with the propane data. Dryout of propane in 1.70 mm and 1.224 mm internal diameter channels was also investigated. Dryout heat flux was observed to increase with the increase of mass flux, with the decrease of vapour quality and with the increase of internal diameter. The effect of saturation temperature on the dryout heat flux was insignificant. The experimental dryout data were compared with macro and micro scale correlations and among them Bowring (1972) and Callizo et al. (2010a) gave best predictions. The heat transfer and pressure drop results of ammonia and propane and dryout results of propane were compared with R134a data taken on the same test rig by Owhaib (2007) and Ali (2010). The comparison of heat transfer showed that the heat transfer coefficient was a function of heat flux and the effect of mass flux was insignificant in all tested conditions except ammonia in 1.224 mm tube where the heat transfer coefficient was dependent on heat flux at lower vapour qualities and a clear dependence of mass flux was observed at higher vapour qualities. The heat transfer data of ammonia, propane and R134a were compared with correlations and among them Cooper (1989) correlation gave best predictions. The comparison of pressure drop results showed that the two phase pressure drop of all fluids was increased with the increase of mass flux, with the increase of heat flux and with the decrease of saturation temperature. At equal heat flux and mass flux, the two phase pressure drop of ammonia was increased with the decrease of internal diameter but the diametric effects of R134a were unclear. Müller Steinhagen and Heck (1986) and Zhang and Webb (2001) best predicted the experimental data of two phase pressure drop of ammonia, propane and R134a among the correlations considered for comparison. The dryout data of propane were also compared with dryout data of R134a and it was observed that the dryout heat flux of propane and R134a increased with the increase of mass flux, with the decrease of vapour quality and with the increase of internal diameter. The effect of saturation temperature on the dryout heat flux of propane and R134a was insignificant. The correlation of Bowring (1972) for conventional channels and the microscale correlation of Callizo et al. (2010a) were among the correlations which gave best predictions of experimental data of dryout. / QC 20120210

This thesis investigates the performance of compact brazed plate heat exchangers (CBE) operating as evaporator in heat pump applications. The thesis, and the performances investigated, has been divided into three main sections; One zone evaporator performance; Two zone evaporator performance; and finally Local performance. The 'One zone evaporator performance' section considers the evaporator as one "black box". It was found that "approaching terminal temperatures" were obtained as low overall heat flux is employed. It was also found that the total area averaged film heat transfer coefficient was affected by changes of the brine mass flow rate. This indicates that the widespread Wilson plot method may not be used to determine flow boiling heat transfer coefficients. Further, it seems that co- and counter-current flow configuration performs equally well if the superheat is kept low. A numerical simulation of the above investigations indicates that a nucleate boiling model better predicts the performance compared to a convective evaporation model. Finally, the significant impact of the refrigerant inlet distributor design was illustrated using several CBEs with different inlet geometries but with identical heat transfer surfaces. The 'Two zone evaporator performance section' considers the evaporator as two "black boxes", i.e. the boiling and superheating boxes. Thermochromic liquid crystals (TLC) was used to determine the boiling heat transfer area. The resulting flow boiling heat transfer coefficient was found to correlate with heat flux. The superheated heat transfer area was then estimated using single phase correlations. It was observed that the TLC measurements and the predicted superheating area did not agree. Possible causes for this deviation were discussed. The most likely explanation found was the presence of mist flow at the higher vapor quality range in the boiling section of the evaporator. The 'Local Performance' section considers local pressure drop and flow boiling heat transfer. The Chisholm parameter was found not to be a constant and was found to correlate well with the kinetic energy per volume. The resulting predictions of the pressure drop were better than ± 10%. The resulting local flow boiling heat transfer coefficient, at different vapor quality, mass flux and heat flux, was compared to flow boiling correlations available in the literature. It was found that the saturated nucleate pool boiling correlation by Cooper (1984) and narrow channel flow boiling correlations (Tran 1999, Lazarek and Black 1982) predicted the experimental data better than several traditional flow boiling correlations, developed for larger tubes. / QC 20100524

It is well known that microprocessor performance can be improved by lowering the junction temperature. Two stage cascaded vapor compression refrigeration (VCR) is a mature, inexpensive, and reliable cooling technology that can offer chip temperatures down to ?? C. Recent studies have shown that for a power limited computer chip, there is a non-linear scaling effect that offers a 4.3X performance enhancement at ?? C. The heat transfer performance of a compact evaporator is often the bottleneck in sub-ambient heat removal. For this reason, the design of a deep sub-ambient compact evaporator is critical to the cooling system performance and has not been addressed in the literature. Four compact evaporator designs were investigated as feasible designs - a baseline case with no enhancement structures, micro channels, inline pin fin arrays, and alternating pin fin arrays. A parametric experimental investigation of four compact evaporator designs has been performed aiming at enhancing heat transfer. Each evaporator consists of oxygen free copper and has a footprint of 20 mm x 36 mm, with a total thickness of 3.1 mm. The micro channel evaporator contains 13 channels that are 400 um wide by 1.2 mm deep, and the pin fin evaporators contain approximately 80 pin fins that are 400 um wide by 1.2 mm tall with a pitch of 800 um. Two phase convective boiling of R508b refrigerant was investigated in each evaporator at flow rates of 50 - 70 g/min and saturation temperatures of ??to ??C. Pressure drop and local heat transfer measurements are reported and used to explain the performance of the various evaporator geometries. The results are compared to predictions from popular macro- and micro-channel heat transfer and pressure drop correlations. The challenges of implementing a two stage cascade VCR systems for microprocessor refrigeration are also discussed.

Das Vorhaben bestand in der Validierung des gekoppelten neutronenkinetisch-thermohydraulischen Programmkomplexes ATHLET/DYN3D für Siedewasserreaktoren durch Teilnahme an dem OECD/NRC Benchmark zum Turbinenschnellschluss. Das von der OECD und der amerikanischen NRC definierte Benchmark basiert auf einem Experiment mit Schließens des Turbinenschnellschlussventils, das 1977 im Rahmen einer Serie von 3 Experimenten im Kernkraftwerk Peach Bottom 2 durchgeführt wurde. Im Experiment erzeugte das Schließen des Ventils eine Druckwelle, die sich unter Abschwächung bis in den Reaktorkern ausbreitete. Die durch den Druckanstieg bewirkte Kondensation von Dampf im Reaktorkern führte zu einem positiven Reaktivitätseintrag. Der folgende Anstieg der Reaktorleistung wurde durch die Rückkopplung und das Einfahren der Regelstäbe begrenzt. Im Rahmen des Benchmarks konnten die Rechenprogramme durch Vergleiche mit den Messergebnissen und den Ergebnissen der anderen Teilnehmer an dem Benchmark validiert werden. Das Benchmark wurde in 3 Phasen oder Exercises eingeteilt. Die Phase I diente der Überprüfung des thermohydraulischen Modells für das System bei vorgegebener Leistungsfreisetzung im Kern. In der Phase II wurden 3-dimensionale Berechnungen des Reaktorkerns für vorgegebene thermohydraulische Randbedingungen durchgeführt. Die gekoppelten Rechnungen für das ausgewählte Experiment und für 4 extreme Szenarien erfolgten in der Phase III. Im Rahmen des Projekts nahm FZR an Phase II und Phase III des Benchmarks teil. Die Rechnungen für Phase II erfolgten mit dem Kernmodell DYN3D unter Berücksichtigung der Heterogenitätsfaktoren und mit 764 thermohydraulischen Kanälen (1 Kanal/Brennelement). Der ATHLET-Eingabedatensatz für die Reaktoranlage wurde von der Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) übernommen und für die Rechnungen zu Phase III, die mit der parallelen Kopplung von ATHLET mit DYN3D erfolgten, geringfügig modifiziert. Für räumlich gemittelte Parameter wurde eine gute Übereinstimmung mit den Messergebnissen und den Resultaten anderer Codes erzielt. Der Einfluss der Modellunterschiede wurde mit Hilfe von Variantenrechnungen zu Phase II untersucht. So können Unterschiede in der Leistungs- und Voidverteilung in einzelnen Brennelementen auf die unterschiedliche neutronenkinetische und thermohydraulische Modellierung des Reaktorkerns zurückgeführt werden. Vergleiche zwischen ATHLET/DYN3D (parallele Kopplung) und ATHLET/QUABOX-CUBBOX (interne Kopplung) zeigen für räumlich gemittelte Parameter nur geringe Unterschiede. Abweichungen in den lokalen Parametern können im wesentlichen mit der unterschiedlichen Modellierung des Reaktorkerns erklärt werden (geringere Anzahl von modellierten Kühlkanälen, keine Berücksichtigung der Heterogenitätsfaktoren und ein anderes Siedemodell in der Rechnung mit ATHLET/QUABOX-CUBBOX). Die Rechnungen für die extremen Szenarien von Phase III zeigen die Anwendbarkeit des gekoppelten Programms ATHLET/DYN3D für die Bedingungen bei Störfällen, die weit über das Experiment hinausgehen.

Sur la table de sortie d’un laminoir à chaud, le refroidissement des bandes d’acier est principalement assuré par des rampes de jets d’eau gravitaires qui vont impacter directement la surface supérieure de la bande en défilement. La température de la bande est initialement entre 800 et 900 °C et on cherche à la refroidir à des températures nettement inférieures mais précises avant son bobinage, cette température allant de la température ambiante à 700 °C suivant les propriétés voulues pour l’acier. Ce refroidissement assuré par les rampes de jets est transitoire et la vitesse de refroidissement est variable suivant la nature du régime de refroidissement. Le point de remouillage est défini par la température à laquelle le régime d’ébullition en film stable se termine et s’accompagne généralement d’une hausse significative des flux de refroidissements. Dans ce travail de thèse, nous avons cherché à caractériser ce point par des mesures d’épaisseur de vapeur effectuées à l’aide de sondes optiques. Les sondes optiques permettent de savoir si leur zone sensible est majoritairement dans le gaz ou le liquide et sont généralement exploitées pour faire des mesures de taux de vide. L’utilisation qui en est faite ici, à savoir une mesure précise de position d’interface, a demandé une calibration expérimentale précise afin de connaitre la position exacte de l’interface sur la zone sensible. Afin de disposer d’un outil fonctionnel, nous avons également cherché à modéliser la réponse des sondes à l’aide d’une méthode de lancer de rayons et en prenant en compte la formation du ménisque sur la pointe. Enfin, cette calibration et ce modèle ont été confrontés à des mesures expérimentales dans le cas du refroidissement d’une zone hémisphérique porté à haute température et donnant lieu à un régime d’ébullition en film stable / On a run out table of a hot rolling mill, the cooling of steel strips is mainly provided by ramps of water jets falling down that will directly impact the upper surface of the strip. The temperature of the strip starts between 800 and 900 °C and it is intended to cool at temperatures much lower than the start but still accurate before its winding, the temperature ranges from ambient temperature to 700 °C depending on the required properties for the steel product. This water-based process ensures a transient cooling at an uneven rate depending on the nature of the boiling regime. The rewetting point is defined by the temperature at which the stable film boiling regime ends. In general, the cooling fluxes show a significant increase at this particular transition. In this thesis, we sought to characterize rewetting by vapor thickness measurements and analysis using optical probes. The optical sensors inform us whether their sensitive area is mainly in the gas or in the liquid and are generally used to make void fraction measurements. The use that is made here, namely a precise measurement of the position of the interface, required a precise experimental calibration in order to know the exact position of the interface on the sensitive area. In order to have a working tool, we also modeled the response of the probes by using a ray tracing method and taking into account the formation of the meniscus on the tipoff the probe. Finally, the calibration and model were compared with experimental measurements in the case of the cooling of a hemispherical area initially at high temperature that provides a stable film boiling regime when it is partially immersed

Orientadores: Maria Alvina Krahenbuhl, Antonio Jose de Almeida Meirelles / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-13T05:54:13Z (GMT). No. of bitstreams: 1 Falleiro_RafaelMauricioMatricarde_M.pdf: 2025398 bytes, checksum: 267d9b60efd1dc4f0a2818661c23761d (MD5) Previous issue date: 2009 / Resumo: Esse trabalho irá contribuir com alguns dados inéditos de equilíbrio líquido-vapor de compostos que constituem o biodiesel, pelo interesse imediato que este último tem despertado no mundo. Dados de Equilíbrio Líquido-Vapor (ELV) para três misturas binárias de ácidos graxos saturados foram medidos com sucesso através da Calorimetria Diferencial Exploratória (DSC). Esses dados são de grande interesse para as indústrias, principalmente as de biodiesel, já que processos como a cristalização ou a separação indesejada de componentes pode ser minimizada a partir do levantamento desses dados. Contudo, mudanças na célula de pressão do calorímetro e o uso de panelas herméticas com furo na tampa (f = 250 µm) foram necessárias para que a técnica analítica fosse possível de ser aplicada, apresentando precisão nos resultados, uso de pouca quantidade de amostra e menor tempo de operação. Foram determinados experimentalmente a 50 mmHg dados ELV dos seguintes sistemas: ácido mirístico (C14:0) + ácido palmítico (C16:0), ácido mirístico (C14:0) + ácido esteárico (C18:0), ácido palmítico (C16:0) + ácido esteárico (C18:0). Na pressão de 8 mmHg investigou-se o sistema ácido linoléico (C18:2) + ácido oléico (C18:1). Para estes quatro sistemas foram preparadas pequenas quantidades de amostras (2,5 a 4,5 mg) em diferentes composições cuja fração molar do componente mais volátil variara de 0 a 1,0 em intervalos de 0,1. Os coeficientes de fugacidade para os componentes da fase vapor foram calculados usando o método de Hayden e O'Connell (Fredenslund et al., 1977) e o coeficiente de atividade para a fase líquida foi correlacionado pelos modelos tradicionais de gE : NRTL (Renon and Prausnitz, 1968), UNIQUAC (Abrams and Prausnitz, 1975) e Wilson (Prausnitz et al., 1999). Os ajustes dos parâmetros foram então comparados afim de determinar quais dos ajustes representava melhor o ELV. A modelagem termodinâmica é importante para o desenvolvimento de equipamentos para a produção de biodiesel e fundamentais nos processos de purificação. / Abstract:This work will contribute to some unpublished data of phase equilibria of compounds that form the biodiesel, which arouses the interest immediately. Vapor-liquid equilibrium (VLE) data for three binary mixtures of saturated fatty acids have been successfully measured through differential scanning calorimetry (DSC). These data are of great interest to the industries mainly of biodiesel, since processes such as crystallization or separation of undesired components can be minimized from such data. However, changes in the calorimeter pressure cell and the use of hermetic pans with caps with holes (f = 250 µm) have been necessary so that this analytical technique was possible to be applied, showing accuracy in results, shorter sample quantity and operational time. The systems studied at 50 mmHg in this work were: myristic acid (C14:0) + palmitic acid (C16:0), myristic acid (C14:0) + stearic acid (C18:0) e palmitic acid (C16:0) + stearic acid (C18:0). The linoleic acid (C18:2) + oleic acid (C18:1) binary mixture was investigated in the pressure of 8 mmHg. The binary systems were prepared using small quantities (2.5 to 4.5 mg) of samples in different mole fractions varying between 0.0 and 1.0 in relation to the most volatile component of each diagram. The fugacity coefficients for the components in the vapor phase have been calculated using the Hayden and O'Connell's method (Fredenslund et al., 1977) and the activity coefficients for the liquid phase have been correlated to the traditional gE models: NRTL (Renon and Prausnitz, 1968), UNIQUAC (Abrams and Prausnitz, 1975) and Wilson (Prausnitz et al., 1999). The set of parameters were then compared in order to determine which adjustments would best represent the VLE. The thermodynamic modeling is important for the development of equipment for the biodiesel production and purification. / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / Relata o uso da cavitaÃÃo hidrodinÃmica como alternativa para a desinfecÃÃo de Ãgua para o abastecimento humano, ampliando a oferta de Ãgua que atenda aos padrÃes de potabilidade. No estado do CearÃ, tendo em vista as condiÃÃes de saneamento precÃrias, fontes de Ãgua utilizadas para abastecimento, sejam superficiais e ou subterrÃneas, tem apresentado um elevado Ãndice de contaminaÃÃo. A Ãgua que à fornecida a populaÃÃo deve estar isenta da presenÃa de microrganismos patogÃnicos. A desinfecÃÃo constitui-se na medida de tratamento que tem como principal meta a eliminaÃÃo dos microrganismos causadores de doenÃas, realizada por meio de agentes fÃsicos e/ou quÃmicos. O cloro tem se destacado como o desinfetante mais difundido, porÃm estudos recentemente publicados trazem a tona que, muitos desses quÃmicos, podem ser danosos aos usuÃrios de Ãguas tratadas e ao ambiente. E que alguns microrganismos causadores de doenÃas, sÃo mais resistente ao tradicional desinfetante cloro do que as bactÃrias do grupo coliformes. Com isso, existe a necessidade de se desenvolver processos de desinfecÃÃo adicionais que poderiam eliminar ou reduzir o uso dessas desinfecÃÃes quÃmicas. Por meio de um levantamento bibliogrÃfico da engenharia aplicada na concepÃÃo da tecnologia de cavitaÃÃo hidrodinÃmica, foram construÃdos protÃtipos para produÃÃo de Ãgua desinfetada atravÃs da cavitaÃÃo hidrodinÃmica; avaliando o potencial de geraÃÃo de cavitaÃÃo hidrodinÃmica atravÃs da eficiÃncia tÃrmica apresentada no protÃtipo; e o estudo da qualidade fÃsico-quÃmica e bacteriolÃgica das Ãguas utilizada no experimento. A final da prototipagem foi possÃvel inativaÃÃo total dos microrganismos observados, coliformes totais e coliformes fecais, presentes na Ãgua de alimentaÃÃo do reator que teve como vazÃo de alimentaÃÃo o valor de 60L/h e potÃncia motriz de 30KW. Apresentando-se como uma alternativa de desinfecÃÃo, caracterizada pela possibilidade de adoÃÃo em plantas de abastecimento de Ãgua individual ou em comunidades de pequeno porte, devido principalmente a nÃo geraÃÃo de subprodutos, mobilidade da vazÃo de operaÃÃo do sistema e o nÃo uso de quÃmicos. / It tells to the use of the cavitation hydrodynamics as alternative for the water disinfection for the human supplying, extending it offers of water that takes care of to the fresh standards. In the state of the CearÃ, in view of the precarious conditions of sanitation, used water sources for supplying, are superficial and or underground, it has presented one raised contamination index. The water that is supplied the population must be exempt of the presence of pathogenic. disinfection consists in the measure of treatment that has as main goal the elimination of the .causing of illnesses, carried through by means of physical and/or chemical agents. The chlorine if has detached as the spread out deodorant more, however studies recently published bring that, many of these chemistries, can be harmful to the users of treated waters and the environment. E that some .causing of illnesses, are more resistant to the traditional deodorant chlorine of what the coliform bacteria of the group. With this, the necessity exists of if to develop disinfection processes you add that they could eliminate or reduce the use of these chemical disinfections. By means of a bibliographical survey of the engineering applied in the conception of the cavitation technology hydrodynamics, they had been constructed to archetypes for water production disinfected through the cavitation hydrodynamics; evaluating the potential of cavitation generation hydrodynamics through the presented thermal efficiency in the archetype; e the study of the quality bacteriological physicist-chemistry and of waters used in the experiment. The end of the test unit was possible death of the observed microorganism, gifts in the water of feeding of the reactor that had as feeding outflow the value of 60L/h and power of 30KW. Presenting itself as an alternative of disinfection, characterized for the possibility of adoption in plants personal of water supply or in communities of small which had mainly transport, not the by-product generation, mobility of the outflow of operation of the system and not the use of chemistries.