A contribution to the global modeling of heat transfer processes in Diesel engines

[EN] Current challenges in research and development of powertrains demand new computational tools capable of simulating vehicle operation under very diverse conditions. This is due, among other reasons, to new homologation standards in the automotive sector requiring compliance of exhaust emissions regulations under any possible driving condition on the road. Global engine or vehicle models provide many advantages to engineers because they allow to reproduce the entire system under study, considering the physical processes that take place in different components and the interactions among them. This thesis aims to enable the modeling of heat transfer processes in a complete engine simulation tool developed at CMT-Motores Térmicos research institute. This 0D/1D simulation tool is called Virtual Engine Model (VEMOD). The development of heat transfer models comprises the engine block and the ancillary systems. The model of heat transfer in the engine block deals with the central problem of in-cylinder convection by means of a combination of experimental research, CFD simulation and multizone 0D modeling. The other thermal processes present in the engine block are examined in order to implement suitable submodels. Once the model is complete, it undergoes a validation with experimental transient tests. Afterwards, the ancillary systems for engine thermal management are brought into focus. These systems are considered by means of two new models: a model of heat exchangers and a model of thermo-hydraulic circuits. The development of those models is reported in detail. Lastly, with the referred thermal models integrated in the global simulation tool, a validation study is undertaken. The goal is to validate the ability of the Virtual Engine Model to capture the thermal response of a real engine under various operating conditions. To achieve that, an experimental campaign combining tests under steady-state operation, under transient operation and at different temperatures is conducted in parallel to the corresponding simulation campaign. The capacity of the global engine simulations to replicate the measured thermal evolution is finally demonstrated.[ES] Los retos actuales en la investigación y desarrollo de trenes de potencia demandan nuevas herramientas computacionales capaces de simular el funcionamento de un vehículo en condiciones muy diversas. Esto se debe, entre otras razones, a que los nuevos estándares de homologación en el sector de la automoción obligan al cumplimiento de las regulaciones de emisiones en cualquier condición posible de conducción en carretera. Los modelos globales de motor o de vehículo proporcionan muchas ventajas a los ingenieros porque permiten reproducir el sistema entero a estudiar, considerando los procesos físicos que tienen lugar en los distintos componentes y las interacciones entre ellos. Esta tesis pretende hacer posible el modelado de los procesos de transmisión de calor en una completa herramienta de simulación de motor desarrollada en el instituto de investigación CMT-Motores Térmicos. Esta herramienta de simulación 0D/1D se denomina Motor Virtual o Virtual Engine Model (VEMOD). El desarrollo de modelos de transmisión de calor comprende el bloque motor y los sistemas auxiliares. El modelo de transmisión de calor en el bloque motor aborda el problema central de la convección en el interior del cilindro mediante una combinación de investigación experimental, simulación CFD y modelado 0D multizona. El resto de procesos térmicos presentes en el bloque motor son examinados para poder implementar submodelos adecuados. Una vez el modelo está terminado, se realiza una validación con ensayos experimentales en régimen transitorio. A continuación, el foco de atención pasa a los sistemas auxiliares de gestión térmica. Estos sistemas se toman en consideración por medio de dos nuevos modelos: un modelo de intercambiadores de calor y un modelo de circuitos termohidráulicos. El desarrollo de los modelos se explica en detalle en esta tesis. Por último, con los citados modelos integrados en el Motor Virtual, se lleva a cabo un estudio de validación. El objectivo es validar la capacidad del Motor Virtual para reproducir la respuesta térmica de un motor real en varias condiciones de funcionamento. Para conseguirlo, se realiza una campaña experimental que combina ensayos en régimen estacionario, en régimen transitorio y a diferentes temperaturas, en paralelo a la campaña de simulación correspondiente. La capacidad de las simulaciones globales de motor para replicar la evolución térmica medida experimentalmente queda finalmente demostrada.[CA] Els reptes actuals en la recerca i el desenvolupament de trens de potència demanden noves eines computacionals capaces de simular el funcionament d'un vehicle en condicions molt diverses. Açò es deu, entre altres raons, a que els nous estàndards d'homologació al sector de l'automoció obliguen al compliment de les regulacions d'emissions en qualsevol condició possible de conducció en carretera. Els models globals de motor o de vehicle proporcionen molts avantatges als enginyers perquè permeten reproduir el sistema sencer a estudiar, considerant els processos físics que tenen lloc als distints components i les interaccions entre ells. Aquesta tesi pretén fer possible el modelat dels processos de transmissió de calor en una completa eina de simulació de motor desenvolupada a l'institut de recerca CMT-Motores Térmicos. Aquesta eina de simulació 0D/1D s'anomena Motor Virtual o Virtual Engine Model (VEMOD). El desenvolupament de models de transmissió de calor comprén el bloc motor i els sistemes auxiliars. El model de transmissió de calor al bloc motor aborda el problema central de la convecció a l'interior del cilindre mitjançant una combinació de recerca experimental, simulació CFD i modelat 0D multizona. La resta de processos tèrmics presents al bloc motor són examinats per a poder implementar submodels adequats. Una vegada el model està acabat, es fa una validació amb assajos experimentals en règim transitori. A continuació, el focus d'atenció passa als sistemes auxiliars de gestió tèrmica. Aquests sistemes es prenen en consideració per mitjà de dos nous models: un model d'intercanviadors de calor i un model de circuits termohidràulics. El desenvolupament dels models s'explica en detall en aquesta tesi. Per últim, amb els referits models integrats al Motor Virtual, es porta a terme un estudi de validació. L'objectiu és validar la capacitat del Motor Virtual per a reproduir la resposta tèrmica d'un motor real en diverses condicions de funcionament. Per a assolir-ho, es realitza una campanya experimental que combina assajos en règim estacionari, en règim transitori i a diferents temperatures, en paral·lel a la campanya de simulació corresponent. La capacitat de les simulacions globals de motor per a replicar l'evolució tèrmica observada experimentalment queda finalment demostrada.European funds received in the framework of Horizon 2020’s DiePeR project have contributed to the validation and improvement of the Virtual Engine Model. My own dedication has been funded by Universitat Politècnica de València through the predoctoral contract FPI-S2-2016-1357 of “Programa de Apoyo para la Investigaci´on y Desarrollo (PAID-01-16)”.Salvador Iborra, J. (2020). A contribution to the global modeling of heat transfer processes in Diesel engines [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/149575TESI

Holding the Stick at Both Ends: The Design of Network Administrative Organizations

L’objecte d’aquesta tesi doctoral és el disseny de les Network Administrative Organizations (NAOs), les unitats especialment establertes de forma intencionada pels membres de les xarxes publiques inter-organitzacionals per a governar i administrar les mateixes. Tot i l'interès mostrat per la recent investigació en gestió pública i pels estudiosos de les organitzacions en l'àmbit de la governança de les xarxes públiques creades amb objectius específics (goal-directed networks), pocs estudis teòrics s'han basat en la contribució seminal de Provan i Kenis (2008). Com a resultat, aquest camp continua sent una via prometedora per a la recerca. Unint la literatura sobre xarxes, col·laboracions inter-organitzatives, disseny organitzatiu i govern corporatiu, aquesta tesi revela dos factors íntimament relacionats amb el disseny de les Network Administrative Organizations: la interdependència estratègica i l’evitació de la incertesa en els resultats.El objeto de esta tesis doctoral es el diseño de las Network Administrative Organizations (NAOS), las unidades especialmente establecidas de forma intencionada por los miembros de las redes públicas inter-organizacionales para gobernar y administrar las mismas. A pesar del interés mostrado por la reciente investigación en gestión pública y por los estudiosos de las organizaciones en el ámbito de la gobernanza de las redes públicas creadas con objetivos específicos (goal-directed networks), pocos estudios teóricos han basado en la contribución seminal de Provan y Kenis (2008). Como resultado, este campo sigue siendo una vía prometedora para la investigación. Uniendo la literatura sobre redes, colaboraciones inter-organizativas, diseño organizativo y gobierno corporativo, esta tesis revela dos factores íntimamente relacionados con el diseño de las Network Administrative Organizations: la interdependencia estratégica y la evitación de la incertidumbre en los resultados.The focus of this Ph.D. dissertation is the design of Network Administrative Organizations (NAOs), the separate units purposefully set up by public inter-organizational goal-directed network partners for to govern and manage it. Despite the interest shown by both public management and organizational scholars in the field of Goal-Directed networks governance, few theoretical studies have built on Provan and Kenis’s (2008) seminal contribution. As a result, this field remains a promising avenue for research. By bringing together the literature on networks, inter-organizational collaborations, organizational design, and corporate governance, this Ph.D. dissertation sheds light on two factors intimately associated with the design of Network Administrative Organizations: strategic interdependence and outcome uncertainty avoidance

Development and Validation of a Submodel for Thermal Exchanges in the Hydraulic Circuits of a Global Engine Model

[EN] To face the current challenges of the automotive industry, there is a need for computational models capable to simulate the engine behavior under low-temperature and low-pressure conditions. Internal combustion engines are complex and have interconnected systems where many processes take place and influence each other. Thus, a global approach to engine simulation is suitable to study the entire engine performance. The circuits that distribute the hydraulic fluids -liquid fuels, coolants and lubricants- are critical subsystems of the engine. This work presents a 0D model which was developed and set up to make possible the simulation of hydraulic circuits in a global engine model. The model is capable of simulating flow and pressure distributions as well as heat transfer processes in a circuit. After its development, the thermo-hydraulic model was implemented in a physical based engine model called Virtual Engine Model (VEMOD), which takes into account all the relevant relations among subsystems. In the present paper, the thermo-hydraulic model is described and then it is used to simulate oil and coolant circuits of a diesel engine. The objective of the work is to validate the model under steady-state and transient operation, with focus on the thermal evolution of oil and coolant. For validation under steady-state conditions, 22 operating points were measured and simulated, some of them in cold environment. In general, good agreement was obtained between simulation and experiments. Next, the WLTP driving cycle was simulated starting from warmed-up conditions and from ambient temperature. Results were compared with the experiment, showing that modeled trends were close to those experimentally measured. Thermal evolutions of oil and coolant were predicted with mean errors between 0.7 °C and 2.1 °C. In particular, the warm-up phase was satisfactorily modeled.This research has been partially funded by the European Union’s Horizon 2020 Framework Programme for research, technological development and demonstration under grant agreement 723976 (“DiePeR”) and by the Spanish government under the grant agreement TRA2017-89894-R. Josep SalvadorIborra was supported by Universitat Politècnica de València through the contract FPI-S2-2016-1357 of the program PAID01-16. The authors wish to thank Renault SAS, especially P. Mallet and E. Gaïffas, for supporting this research. Jaime Monfort San Segundo is acknowledged for his helpful collaboration in the code implementationBroatch, A.; Olmeda, P.; Martín, J.; Salvador-Iborra, J. (2018). Development and Validation of a Submodel for Thermal Exchanges in the Hydraulic Circuits of a Global Engine Model. SAE Technical Papers. https://doi.org/10.4271/2018-01-0160

Cerro Colorado : un asentamiento de época púnica en la costa occidental malagueña

Con motivo de la construcción de unas villas de lujo en la costa marbellí, tuvimos la oportunidad de excavar en extensión el yacimiento que nos ocupa, excavación de la que presentamos sus resultados debido a la magnitud de los hallazgos aparecidos y que pueden arrojar luz sobre uno de los periodos peor conocidos en la zona adyacente del estrecho de Gibraltar como es el de la Segunda Guerra Púnica.In the occasion of the construction of villas of luxury in the marbellí coast, we had the opportunity to excavate in extension the deposit that occupies to us, excavation of which we presented its results due to the magnitude of the appeared findings and that they can throw light on one of the periods worse known in the adjacent zone of the Straits of Gibraltar as is the Second Punic War

Experimental study of the influence of exhaust gas recirculation on heat transfer in the firedeck of a direct injection diesel engine

[EN] Emissions control is a key topic for internal combustion engine development. One of the most widespread technologies to reduce the formation of nitrogen oxides is the recirculation of exhaust gas to the engine intake. Besides, carbon dioxide emissions from internal combustion engines can be reduced by increasing engine efficiency. A relevant factor for engine efficiency is heat rejection. The interaction between heat transfer and exhaust gas recirculation is not fully understood. In this paper, an experimental study is presented which aims to shed light on the influence of high pressure exhaust gas recirculation on heat transfer. Three operating points were analyzed. Heat flux was calculated at several locations of the firedeck from temperature measurements. The results showed that the influence of exhaust gas recirculation on heat transfer was significant. Reductions of heat flux up to 18% were observed. The largest reduction was found in the area near the center of the firedeck. To contextualize the findings in the framework of emissions reduction, the trade-off between nitrogen oxides and carbon dioxide was assessed for all test points.The authors acknowledge General Motors Global R&D for supporting this research. The equipment used in this work was partially supported by FEDER project funds Dotación de infraestructuras científico técnicas para el Centro Integral de Mejora Energética y Medioambiental de Sistemas de Transporte (CiMeT), (FEDER-ICTS-2012-06) , framed in the operational program of unique scientific and technical infrastructure of the Ministry of Science and Innovation of Spain. Josep Salvador-Iborra was partially supported through contract FPI-S2-2016-1357 of Programa de Apoyo para la Investigación y Desarrollo (PAID-01-16) of Universitat Politècnica de València.Torregrosa, AJ.; Broatch, A.; Olmeda, P.; Salvador-Iborra, J.; Warey, A. (2017). Experimental study of the influence of exhaust gas recirculation on heat transfer in the firedeck of a direct injection diesel engine. Energy Conversion and Management. 153:304-312. https://doi.org/10.1016/j.enconman.2017.10.003S30431215

Impact of swirl on in-cylinder heat transfer in a light-duty diesel engine

[EN] One of the key strategies to reduce CO2 emissions is to improve the efficiency of engines in order to diminish fuel consumption. A way to increase engine efficiency is to reduce the heat losses. Internal heat transfer in engines depends on combustion chamber conditions. Swirl is an important parameter for combustion that also changes in-cylinder variables relevant to heat transfer. In this work, influence of swirl on combustion chamber heat fluxes was investigated employing wall temperature data and a 0-D thermal model. Local wall temperatures were measured at various locations of the cylinder liner and the cylinder head using thermocouples. A sweep of swirl ratios was carried out at different engine operating conditions. It was observed that the effect of swirl effect was highly dependent on location and was more important near the center of the firedeck. Results from the 0-D thermal model were evaluated by comparing measured and predicted wall temperatures. Using a convenient arrangement of thermocouples and the 0-D thermal model, it was possible to calculate heat flux from combustion chamber to cylinder walls. By analyzing heat flux through the firedeck, an increase in heat losses between 4 and 12% was observed for each unit that swirl number was increased. Results from the 0-D thermal model indicate that similar effects occur for other surfaces in the combustion chamber. (C) 2016 Elsevier Ltd. All rights reserved.The authors acknowledge General Motors Global R&D for supporting this research. The equipment used in this work was partially supported by FEDER project funds "Dotacion de infraestructuras cientifico tecnicas para el Centro Integral de Mejora Energetica y Medioambiental de Sistemas de Transporte (CiMeT), (FEDER-ICTS-2012-06)", framed in the operational program of unique scientific and technical infrastructure of the Ministry of Science and Innovation of Spain.Broatch, A.; Olmeda, P.; García Martínez, A.; Salvador-Iborra, J.; Warey, A. (2017). Impact of swirl on in-cylinder heat transfer in a light-duty diesel engine. Energy. 119:1010-1023. doi:10.1016/j.energy.2016.11.040S1010102311

Catalytic hydroxyalkylation/alkylation of 2‑methylfuran with butanal to form a biodiesel precursor using acidic ion-exchange resins

The catalytic hydroxyalkylation/alkylation of 2-methylfuran (2MF) with butanal has been investigated over several acidic ion-exchange resins within the temperature range 50−90 °C and at a stoichiometric reactant molar ratio of 2MF/butanal (2:1). Butanal conversion increases with temperature and also the formation of undesired 2-methylfuran oligomers, leading to a decrease in yield to the target product. The highest butanal conversion (90%) is achieved at 50 °C over Dowex 50Wx2 with a negligible formation of 2-methylfuran oligomers. The observed catalytic activity and final yield to the target product have been rationalized on the basis of morphological properties of resins and their dynamic behavior within the present reaction medium. The findings reveal that gel-type resins are more active and render higher product yields than their macroreticular congeners due to the enhanced accessibility to acid centers because of their improved ability to swell throughout the reaction. Macroreticular resins with a low cross-linking degree, e.g., Amberlyst 39, also produce interesting catalytic results. The stability of the most promising catalyst has been evaluated after three reaction cycles, and the full reusability outcome speaks for its appropriateness as a potential catalyst for the studied process

Coadministration of the Three Antigenic Leishmania infantum Poly (A) Binding Proteins as a DNA Vaccine Induces Protection against Leishmania major Infection in BALB/c Mice

Highly conserved intracellular proteins from Leishmania have been described as antigens in natural and experimental infected mammals. The present study aimed to evaluate the antigenicity and prophylactic properties of the Leishmania infantum Poly (A) binding proteins (LiPABPs). Three different members of the LiPABP family have been described. Recombinant tools based on these proteins were constructed: recombinant proteins and DNA vaccines. The three recombinant proteins were employed for coating ELISA plates. Sera from human and canine patients of visceral leishmaniasis and human patients of mucosal leishmaniasis recognized the three LiPABPs. In addition, the protective efficacy of a DNA vaccine based on the combination of the three Leishmania PABPs has been tested in a model of progressive murine leishmaniasis: BALB/c mice infected with Leishmania major. The induction of a Th1-like response against the LiPABP family by genetic vaccination was able to down-regulate the IL-10 predominant responses elicited by parasite LiPABPs after infection in this murine model. This modulation resulted in a partial protection against L. major infection. LiPABP vaccinated mice showed a reduction on the pathology that was accompanied by a decrease in parasite burdens, in antibody titers against Leishmania antigens and in the IL-4 and IL-10 parasite-specific mediated responses in comparison to control mice groups immunized with saline or with the non-recombinant plasmid. The results presented here demonstrate for the first time the prophylactic properties of a new family of Leishmania antigenic intracellular proteins, the LiPABPs. The redirection of the immune response elicited against the LiPABP family (from IL-10 towards IFN-γ mediated responses) by genetic vaccination was able to induce a partial protection against the development of the disease in a highly susceptible murine model of leishmaniasis.The study was supported in Spain by grants from Ministerio de Ciencia e Innovación FIS PI11/00095 and FISPI14/00366 from the Instituto de Salud Carlos III within the Network of Tropical Diseases Research (VI P I+D+I 2008-2011, ISCIII -Subdirección General de Redes y Centros de Investigación Cooperativa (RD12/0018/0009)). This work was also supported in Brazil by a grant from CNPq (Ciencia sem Fronteiras-PVE 300174/2014-4)Peer Reviewe

Kinetics of 1-pentanol etherification without water removal

The effect of water on the kinetics of the liquid-phase dehydration of 1-pentanol to di-n-pentyl ether (DNPE) and water over Amberlyst 70 is revisited. To explain the strong inhibitor effect of water, two approaches were compared. First, a model stemming from a Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism was used, wherein the inhibitor effect of water was explained by the competitive adsorption of water and pentanol. Second, a modified Eley-Rideal (ER) model was used that includes an inhibition factor, in which a Freundlich-like function is used to explain the inhibitor effect of water by blocking the access of pentanol to the active centers. Both models fitted data quite well, although the best results were obtained with the modified ER model. The activation energy was 118.7 ± 0.2 kJ/mol for the LHHW model and 114.0 ± 0.1 kJ/mol for the modified ER one