Berlin, Techn. University, Diss., 2008.

Univ., Diplomarb., 2004--Kassel / Diese Arbeit wurde mit dem VDI-Preis 2006 ausgezeichnet.

ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / The ability to accurately measure the temperature of different materials has always been a challenge for the Instrumentation Engineer. The use the classic contact type temperature detector such as thermocouples or RTD’s (Resistance Temperature Detectors) has not always shown to be the best approach to obtain the expected measurement. When not used carefully in closed environments, thermocouples and RTD’s could report the environmental temperature rather than the temperature from the product under examination. They are also temperature limited and when needed for applications above those limits, very expensive and low reliable materials are necessary to do the job. The use of non-contact thermometers has become the preferred choice for such applications. They have also come as a solution for the difficulties involved in the temperature measurements of moving targets. The industry has used portable and spot type infrared thermometers for some time, but the demand for better and more precise measurements has brought an incredible number of new products to the market. By means of advanced electronics and new software developments these products are used to cope with the difficulties of acquiring challenging measurements. Some of the same demands have made necessary the use of non-contact temperature measurement devices on aircraft instrumentation applications. The use of these capabilities has allowed the data acquisition community to get valuable data that was very difficult if not impossible to obtain before. In spite of all these facts, this promising emerging technology demands very careful attention before it is put to good use. The many products and solutions available do not accurately address every problem and the selection of the wrong technology for a specific task can prove to be fatal. The use of non-contact temperature devices is not an easy “off the shelf” pick but rather an option that demands knowledge of the infrared measurement theory as well as a complete understanding of the material under observation. The intention of this paper is to provide a practical understanding on the non-contact temperature measurement methods to the Aircraft Instrumentation Engineer who has not benefited from the use of this exiting technology.

Doctor of Philosophy / Physics / Christopher M. Sorensen / We demonstrated that gram quantities of pristine graphene nanosheets (GNs) can be produced via detonation of a hydrocarbon. This one-step and catalyst-free method is eco-friendly and economical for the production of GNs. The hydrocarbons detonated were C₂H₂, C₂H₄, C₃H₈ and CH₄ in the presence of O₂. The carbon products obtained from the detonation were analyzed by XRD, TEM, XPS and Raman spectroscopy. Depending upon the ratio of O₂ to C₂H₂, the GNs of size up to ~ 250 nm, SSA up to ~ 200 m²/g and yield up to 70% with 2-3 layers' stack have been obtained so far. N₂O was determined as a good alternative to O₂ as an oxidizer to produce GNs by detonating C₂H₂ with it. A two-color pyrometer was designed and calibrated to measure the temperature of the detonation of hydrocarbons. The measured detonation temperatures were in between 2700 K and 4300 K. Along with the high detonation temperature, the composition of precursor hydrocarbon was observed to be crucial as well to determine its suitability to detonate with oxidizer to produce GNs. The hydrocarbons C₂H₂ and C₂H₄ were determined as the suitable precursors to produce GNs whereas detonation of C₃H₈ yields mere amorphous carbon soot and CH₄ gives no solid carbon while detonated with O₂. It has been proposed that the hydrocarbons with C/H≥0.5 are suitable for GNs production by detonation method. Highly oxidized graphene nanosheets (OGNs) were produced by solution-based oxidation of GNs prepared via a controlled detonation of acetylene at O₂/C₂H₂=0.8. The produced OGNs were about 250 nm in size and hydrophilic in nature. The C/O ratio was dramatically reduced from 49:1 in the pristine GNs to about 1:1 in OGNs, as determined by X-ray photoelectron spectroscopy. This C/O in OGNs is the least ever found in all oxidized graphitic materials that have been reported. Thus, the OGNs produced from the detonated GNs with such high degree of oxidation herein yields a novel and promising material for future applications.

The objective my diplom work is acquaint with problems non-contact temperature measuring. After division kinds pyrometers and description their part I'm deal with calibration pyrometer and errors at measuring. To comparing contacting and non-contacting thermometer I'm used measuring on model.

he objective diploma work is clarification problems contactless temperature measuring and objective comparison measurement contact thermometer and pyrometer on laboratory model.

Sebastian Zetterström, Master of Science in energy systems, Mälardalens University in Västerås. Abstract of Master’s thesis, submitted 16th of August. Evaluation of a suction pyrometer by heat and mass transfer methods. The aim of the thesis is to evaluate the cooling of a specific suction pyrometer which is designed by Jan Skvaril, doctorate at Mälardalens University. First part is explained how the balances and correlations are performed before being implemented in MATLAB, after this  a ANSYS Fluent model is constructed and explained, which is used for the comparison of results. The cooling is performed by using water at an inlet temperature of 10°C and an assumed flue gas temperature of 810°C. Sensitivity analysis are performed to test the stability of the models which yield good results for stability, done by adjusting both flue gas temperature and inlet cooling water temperature which are as well presented for observation. From doing further MATLAB sensitivity analysis which show that the model still performs well and is stable. The resulting cooling water is heated to approximately 24, 8°C and the flue gas is cooled to 22, 4°C, in ANSYS Fluent the answer differs approximately 2°C and results in 20, 4°C which can be considered by looking at the flue gas inlet temperature of 810°C that this can be deemed an insignificant change and can therefore conclude that the comparison between the two platforms match each other good and that calculations can be considered accurate. Keywords:  Suction pyrometer, cooling, heat transfer, thermal resistance network, MATLAB, ANSYS Fluent, simulation

The boiler flue gas furnace exit temperature (FET) is a key operating parameter of coal fired steam boilers. From the design perspective, the FET is vital for materials selection and sizing of heat transfer surfaces. From an operating perspective, it is a major indicator of the rate of combustion and heat transfer that is occurring within the furnace. Downstream of the furnace, the FET has a significant impact on both the performance and reliability of the boiler heat exchangers, which ultimately impacts on both boiler efficiency and availability. Monitoring of the FET can advise operating and engineering corrective actions which will ultimately result in better efficiency, reliability and availability together with the associated economic benefits. Therefore, methods of determining FET are investigated. Two methods are focused on for this study, one indirect and one direct. The indirect method studied is a mass and energy balance method which begins with a global boiler mass and energy balance to calculate the major boiler flow rates of coal, air and flue gas which are difficult to measure online. These parameters are then used as inputs into a furnace or backpass mass and energy balance to calculate the furnace exit temperature. The method is applied to a case study, and is evaluated in terms of the measurement uncertainties which are propagated on the intermediate parameters calculated, as well as on the final calculated FET. The main conclusions are that this indirect method contains various uncertainties, due to parameters which have to be assumed such as (i) the distribution of ingress air (also called tramp air) in the different sections of the boiler and (ii) the estimation of the share of water evaporation heat transfer occurring in the water walls of the furnace part of the boiler. The method is however still useful and can be easily applied to any boiler layout and can be used as a reference tool to verify other measurements. The direct method studied is acoustic pyrometry. The work specifically focuses on the sources of error in determining the temperature from the measurement of the time of flight of sound, the impact of particle concentration on the speed of sound through a gas-particle mixture, and the temperature profile reconstruction from acoustic time of flight measurements. A limited set of physical testing was also carried out using one acoustic generator and receiver to take measurements on a real coal power plant. As part of this physical testing, the detection of time of flight from acoustic signals was explored. Already installed radiation pyrometers were also used as a reference for interpreting the acoustic measurements. The indications are that the acoustic pyrometer provides a more representative temperature measurement than the radiation pyrometers. The uncertainty of the acoustic measurement for the same case study as the indirect method was determined and compared with the calculated result. While many aspects still need to be researched further, this initial study and experimental testing produced very promising results for future application of acoustic pyrometry for better monitoring of the coal combustion processes in power plant boilers.

Le soudage est un procédé clef dans l'industrie nucléaire. L'utilisation de ce procédé d'assemblage est nécessaire pour assurer la continuité physique et chimique indispensable à la sûreté des composants des centrales. Pour la société AREVA, un axe de développement important consiste à augmenter la productivité tout en garantissant une qualité optimale.L'approche expérimentale présentée dans ce travail a pour double objectif de proposer un dispositif de contrôle des températures des zones de métal liquide et de caractériser leur comportement dynamique, dans le cas du soudage MAG. Une méthode de mesure de température, en pyrométrie bichromatique, a été développée pour la mesure textit{in-situ} des champs de température des zones liquides. Les premiers essais réalisés en configuration industrielle permettent d'envisager l'utilisation de ce type de méthode pour le contrôle temps réel d'opérations de soudage. La méthode de pyrométrie bichromatique, couplée à l'observation et à l'étude des déformations des gouttelettes au cours de leur transfert, permet également d'évaluer l'influence de la température sur la tension superficielle, en interaction avec le plasma d'arc. Le rôle majeur de la tension superficielle dans le comportement dynamique des phases liquides apparaît clairement dans les résultats obtenus. Les outils d'investigation et d'analyse développés ont été utilisés pour étudier un procédé de soudage par court-circuit contrôlé (CMT). Il est ainsi possible d'analyser la rupture du pont liquide, mais aussi le comportement du dépôt de métal liquide, qui peut entraîner des défauts de forme, et la dynamique des transferts de masse pour identifier l'apparition des défauts opératoires. / Welding is a key process in nuclear industry. The use of this assembly process is needed to ensure chemical and physical continuity required for installations safety. For the firm AREVA, one of the major axis of development is improving the productivity of nuclear components with the guaranty of optimum quality.Experimental approach presented in the present work has the double objectives of proposing a monitoring device for temperature fields of liquid metal and characterising its dynamic behaviour in GMAW. A two colour measurement method has been developed for textit{in-situ} surface temperature measurement of liquid zones. First tests realised in an industrial configuration allow to consider this method as a possible real-time control device for welding. This two colour pyrometer, coupled to the observation and the study of droplets deformations during their transfer, allows to study the influence of temperature on surface tension, with the interaction of arc plasma. Main role of surface tension on liquid phase behaviour is clearly exposed in the obtained results. The developed investigating and analysis tools have been used to study a GMAW controlled short arc process. So, it is possible to analyse liquid bridge rupture, but also liquid metal deposition behaviour, which can induce shape defects, and mass transfer dynamic to identify the apparition of operative defects.

En las últimas décadas, la investigación en motores de combustión ha estado enfocada fundamentalmente en la reducción de las emisiones contaminantes y la eficiencia de los mismos. Estos hechos junto con un aumento de la concienciación sobre el cambio climático han llevado a un aumento en la importancia de la eficiencia térmica respecto a otros criterios en el diseño de motores de combustión interna (MCIA). Para alcanzar este objetivo, existen diferentes estrategias a aplicar. En concreto, la transferencia de calor a las paredes de la cámara de combustión puede ser considerada como una de las principales fuentes de disminución de la eficiencia indicada. En particular, en los modernos motores diésel de inyección directa, la emisión de radiación de las partículas de hollín puede constituir un componente importante de las pérdidas de eficiencia. En este contexto se enmarca el objetivo principal de la tesis: contribuir a la comprensión de la transferencia de calor por radiación en la combustión diésel de inyección directa junto con la mejora del conocimiento en el proceso de formación-oxidación de hollín. El trabajo se ha basado tanto en resultados experimentales mediante la aplicación de técnicas ópticas en diversas tipologías de motor como en resultados simulados a partir de modelos unidimensionales validados. En la primera parte de resultados experimentales, se ha evaluado la cantidad de energía por radiación respecto a la energía química del combustible mediante la aplicación de una sonda optoelectrónica (basada en la técnica del 2-Colores) tanto en un motor óptico DI como en motor poli-cilíndrico DI de producción. En este estudio se han obtenido valores de intensidad espectral emitida por el hollín y posteriormente, la radiación total emitida por las partículas de hollín en todo el espectro. Como se ha citado anteriormente, las partículas de hollín son las principales responsables de la transferencia de calor por radiación, además de uno de los principales agentes contaminantes emitidos por los motores diésel. Las emisiones de hollín son el resultado de dos procesos antagonistas: la formación y oxidación del hollín. Los mecanismos de formación de hollín se discuten extensamente en la literatura. Sin embargo, existen deficiencias en cuanto al conocimiento de la oxidación de hollín. Por lo tanto, el objetivo de esta sección ha sido evaluar el impacto del proceso de mezcla y la temperatura del gas sobre el proceso de oxidación de hollín durante la última parte de la combustión bajo condiciones reales de operación. Finalmente, y en base a los resultados y conocimientos adquiridos hasta el momento, se ha desarrollado un modelo capaz de predecir las pérdidas de calor por radiación para un chorro diésel. El modelo está basado en tres sub-modelos: modelo de chorro, el cual analiza y caracteriza la estructura interna del chorro en términos de mezcla y combustión en un proceso de inyección con resolución temporal y espacial. Un modelo de hollín, en el que los resultados se justifican en función de procesos de formación y oxidación del hollín. La cohesión de estos dos sub-modelos se utiliza para obtener los valores de entrada al modelo de radiación, con el que se obtiene los valores de transferencia de calor por radiación para una llama diésel. / En els últims anys, la recerca en motors de combustió ha estat focalitzada principalment en la reducció de les emissions contaminants i la millora de la eficiència. Aquests fets afegits al fet del augment de la conscienciació del canvi climàtic han impulsat el interés per incrementar la eficiència tèrmica per damunt de altres criteris en el disseny de motors de combustió interna alternatius (MCIA). Per aconseguir aquest objectiu, existixen diferents estratègies a aplicar. Concretament, la transferència de calor a les parets de la càmera de combustió pot ser considerada un dels principals focs de reducció de eficiència indicada. En particular, en els moderns motors dièsel de injecció directa, la emissió de radiació de les partícules de sutja pot constituir un component important de les pèrdues de eficiència. En aquest context s'emmarca el objectiu principal de la tesis: contribuir a la comprensió de la transferència de calor per radiació en la combustió dièsel de injecció directa i la millora del coneixement del procés de formació-oxidació de la sutja. El treball esta basat tant en resultats experimentals mediant l'aplicació de tècniques òptiques en diverses tipologies de motor com en resultants simulats a partir de models unidimensionals validats. En la primera part dels resultats experimentals, s'ha avaluat la quantitat de energia per radiació respecte a la energia química del combustible mediant la aplicació de una sonda optoelectrònica (basada en la tècnica del 2-Colors) tant en un motor òptic DI com en un motor poli-cilíndric DI de producció en serie. En aquest estudi s'han obtingut valors de intensitat espectral emesa per la sutja i posteriorment, la radiació total emesa per les partícules de sutja en tot el espectre. Com s'ha citat amb anterioritat, les partícules de sutja son les principals responsables de la transferència de calor per radiació, a més de un del principals agents contaminants emès per els motors dièsel. Les emissions de sutja son el resultat de dos processos antagonistes: la formació i la oxidació de sutja. Els mecanismes de formació de sutja es discuteixen àmpliament en la literatura. No obstant això, existeixen deficiències pel que fa al coneixement de l'oxidació de sutja. Per tant, l'objectiu d'aquesta secció ha sigut avaluar l'impacte del procés de mescla i la temperatura del gas sobre el procés d'oxidació de sutja durant l'última part de la combustió sota condicions reals d'operació. Finalment, i en base als resultats i coneixements adquirits fins aquest moment, s'ha desenvolupat un model que permet predir les perdudes de calor però radiació per a un raig dièsel. El model esta basat en tres sub-models: model de raig, el qual analitza i caracteritza la estructura interna del raig en termes de mescla i combustió en un procés de injecció amb resolució temporal i espacial. Un model de sutja, en el qual els resultats es justifiquen en funció del procés de formació i oxidació de la sutja. La cohesió d'aquests dos sub-models s'utilitza per obtindre els valors d'entrada al model de radiació, amb el que s'obté els valors de transferència de calor per radiació per a una flama dièsel. / In the last two decades engine research has been mainly focused on reducing pollutant emissions and increasing efficiency. These facts together with growing awareness about the impacts of climate change are leading to an increase in the importance of thermal efficiency over other criteria in the design of internal combustion engines (ICE). To achieve the objective, there are different strategies to apply. The heat transfer to the combustion chamber walls can be considered as one of the main sources of indicated efficiency diminution. In particular, in modern direct-injection diesel engines, the radiation emission from soot particles can constitute a significant component of the efficiency losses. In this context, the main objective of the thesis is framed: to contribute to the understanding of the radiation heat transfer in DI diesel combustion together with the improvement of the knowledge in the soot formation-oxidation processes. The work has been based on experimental results through the optical technique application in different types of engine and on simulated results from validated one-dimensional models. In the first part of experimental results, the amount of energy lost to soot radiation relative to the input fuel chemical energy has been evaluated by means of the optoelectronic probe application (based on the 2-Color technique) in both an optical engine DI and a production 4-cylinder DI engine. In this study, the values of soot spectral intensity emitted have been obtained and later, the total radiation emitted by the soot particles in the whole spectrum. As mentioned above, soot particles are the main responsible for the radiation heat transfer, in addition to one of the important concern in meeting emissions regulations. Soot emissions are the result of two competing processes: soot formation and soot oxidation. Mechanisms of soot formation are discussed extensively in the literature. However, there are deficiencies in the knowledge of soot oxidation. Therefore, the objective of this section has been to evaluate the impact of mixing process and bulk gas temperature on late-cycle soot oxidation process under real operating conditions. Finally, based on the results and knowledge acquired, a model able to predict heat losses by radiation for a spray diesel has been developed. The model is based on three sub-models: spray model, which analyzes and characterizes the internal spray structure in terms of mixing and combustion process with temporal and spatial resolution. A soot model, in which the results have been justified according to soot formation and oxidation processes. The link of these two sub-models has been used to obtain the input values to the radiation model, which the radiation heat transfer values for a diesel flame are obtained. / Villalta Lara, D. (2018). RADIATION HEAT TRANSFER IN DIRECT-INJECTION DIESEL ENGINES [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/114793 / TESIS