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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Reballing BGA pouzder na zařízení PACE TF2700 / REBALLING OF BGA PACKAGES USING PACE TF2700 EQUIPMENT

Roháček, Peter January 2016 (has links)
The Diploma thesis is focused on reballing of BGA packages with the device PACE TF 2700. It describes the general types of BGA packages, their defects, importance of thermal management to the solder techniques, where it is also talked about the meaning of solders and fluxes for the joint. The work informs about the most common methods of reballing, the proper handling of components and the current situation with BGA stencils on the market. It briefly describes the device operation of PACE TF 2700, that is working on the convection and IR principle of heating components. It deals with the manufacturing of the template, dummy BGA packages, the test plates, creation of the thermo profile, comparing and examining the defects and their causes, which had the most significant impact on the results. The achievements would serve for comparing them with the results of the future laboratory exercises or as a subject for further works.
182

Konzeption eines ganzheitlichen Energiemanagements für Brennstoffzellenfahrzeuge

Rathke, Philipp, von Unwerth, Thomas 25 November 2019 (has links)
Ein Brennstoffzellenfahrzeug besteht aus vielen Teilsystemen, zu denen neben der Brennstoffzelle auch Hybridbatterie, Wärmepumpe, Tanksystem, Fahrgastzelle sowie Traktionsmaschine und Leistungselektronik gehören. Jedes dieser Systeme hat bezüglich Temperaturen und Kühl- bzw. Erwärmungsbedarf, je nach Betriebspunkt, unterschiedliche Anforderungen und benötigt für den Betrieb ein Thermomanagementsystem. Im Rahmen der aktuellen Forschungen wird untersucht, ob durch die Verwendung eines aktiven Thermomanagementmoduls die Teilsysteme des Fahrzeugs derart verknüpft werden können, sodass eine Effizienzsteigerung des Gesamtsystems erreicht werden kann. Da sich je nach Betriebszustand und Umgebungsbedingungen Größe und Richtung der Wärmeströme ändern, wird mittels eines simulationsbasierten Ansatzes eine Strategie für die Regelung des Thermomanagementmoduls entwickelt. In dieser Veröffentlichung soll dargestellt werden, welche Vorüberlegungen getroffen wurden, um ein Konzept für ein ganzheitliches Energiemanagement für ein Brennstoffzellenfahrzeug zu entwickeln.
183

PARAMETRIC ANALYSIS AND OPTIMIZATION OF LONG-RANGE BATTERY ELECTRIC VEHICLE THERMAL MANAGEMENT SYSTEMS

Tyler James Shelly (9755702) 14 December 2020 (has links)
<p>Due to increasing regulation on emissions and shifting consumer preferences, the wide adoption of battery electric vehicles (BEV) hinges on research and development of technologies that can extend system range. This can be accomplished either by increasing the battery size or via more efficient operation of the electrical and thermal systems. This thesis endeavours to accomplish the latter through comparative investigation of BEV integrated thermal management system (ITMS) performance across a range of ambient conditions (-20 °C to 40 °C), cabin setpoints (18 °C to 24 °C), and six different ITMS architectures. A dynamic ITMS modelling framework for a long-range electric vehicle is established with comprehensive sub models for the operation of the drive train, power electronics, battery, vapor compression cycle components, and cabin conditioning. This modelling framework is used to construct a baseline thermal management system, as well as for adaptation to four common systems. Additionally, a novel low-temperature waste heat recovery (LT WHR) system is proposed and shown to have potential benefits at low ambient temperatures through the reduction of the necessary cabin ventilation loading. While this system shows performance improvements, the regular WHR system offers the greatest benefit for long-range BEV drive cycles in terms of system range and transient response. With an optimal thermal management system found for long range BEV’s this system is then used as a boundary condition for a study on cooling of the battery. Battery conditioning, health, and as a result their along cell and system lifetime remains an additional concern of consumers as well as thermal systems engineers seeking to ensure safety and ensure longevity of EV battery cells. Three typical coolant flow orientations are studied to compare them under different flow conditions and thermal interface material performance. The battery cooling model is then coupled to the previously established dynamic modelling environment to demonstrate the added modelling capability (and necessity) for incorporating module-level cooling performance in both battery cooling studies and transient ITMS environments. </p>
184

Modellbildung und Simulation der Thermomanagementstrukturen von Brennstoffzellenfahrzeugen

Rathke, Philipp, Ehrlich, Florian, von Unwerth, Thomas 27 May 2022 (has links)
Das Thermomanagement in Brennstoffzellenfahrzeugen (FCEV) stellt eine komplexe Herausforderung dar. Insbesondere, wenn im Zuge thermischer Optimierungen, wie sie bereits im Bereich batterieelektrischer Fahrzeuge etabliert sind, komplexe Verschaltungen der beteiligten Fahrzeugsysteme vorgenommen werden. Im Rahmen des Forschungsprojektes HZwo:InTherm wurden an der TU Chemnitz verschiedene Ansätze zur Simulation von Thermomanagementstrukturen in Brennstoffzellenfahrzeugen (FCEV) sowohl in Matlab/Simulink als auch in KULI untersucht. Augenmerk lag hierbei auf einem stabilen Zusammenspiel der Teilsysteme Brennstoffzelle, Hybridbatterie, Tanksystem, Wärmepumpe, Fahrgastzelle sowie Traktionsmaschine und Leistungselektronik. Als besondere Herausforderung zeigte sich hierbei die Simulation geschlossener Kühlkreisläufe mit inkompressiblem Kühlmedium sowie die Umsetzung eines möglichst generalisierten Modellaufbaus für die implementierten Teilmodelle. Im Rahmen dieses Beitrags sollen sowohl die Modellierungsansätze als auch die erzielten Ergebnisse vorgestellt und diskutiert werden. / Thermal management in fuel cell electric vehicles (FCEV) poses a complex challenge. Especially for thermal optimisations with complex interconnections, as it is already state of the art in battery electric vehicles. Within the research project HZwo:InTherm different approaches for the simulation of thermal management systems of FCEV have been under investigation, in both Matlab/Simulink as well as in KULI. Focus was the stable interaction of the subsystems fuel cell, hybrid battery, tank system, heat pump, passenger cabin as well as traction motors and inverters. A particular challenge is the simulation of a closed coolant loop with incompressible coolant liquid and its model realization with generalized model structures for the different parts of the model. This article presents both the modelling approach as well as the simulation results.
185

Evaluation of improved Airflow in TM-102/II-DC

Kazemi, Claudia January 2022 (has links)
Within the company Infinera, there is a need for an improved thermal design of an existing chassis product for use in telecommunications for distribution of services within the Edge &amp; Metro network. To enable an optimized airflow design of the chassis, there is a need of analyzingdifferent simulation cases performed in FloTHERM. Mechanical and electrical airflow design has been examined in different cases that cover the system requirements.Thermal analyzes of the product have been performed using the FloTHERM tool, and changes and improvements to the design have been performed via the CAD SolidWorks software tool.Problem formulation for this thesis is to further develop the design of the chassis for improved airflow for electrical and optical components that are placed in an existing chassis for the temperature range of 0-70 ℃ according to the industry standard NEBS (Level 3). The slot-in card has been analyzed in a worst-case scenario to identify the most critical components on the PCB board. The result that has been achieved is six different simulation cases with different airflow designs and models of fans that are adapted to today's existing chassis. An updated final version based on simulation results has been modeled as a proposal for the product in the CAD program. A 2D drawing of the design of the product is included as an appendix.The conclusion of this work has shown an improved airflow design on a chassis with a side-byside airflow configuration with the use of four replaceable fans within a fan bay. A bypass block ontop of the cover has shown good results as a cooling method on electrical and optical components. In this work, due to limited time, the bypass block has not been completed as a 3D modeling part. This will be continued as a suggested future work. In addition, a front-to-side airflow design has been analyzed in FloTHERM, this can also be further developed and investigated in more detail in future work for an optimized airflow design of the chassis.Keywords: Airflow systems for electronics, thermal management, telecommunication equipment, airflow resistance, cooling of electronics. Keywords: Airflow systems for electronics, thermal management, telecommunication equipment, airflow resistance, cooling of electronics. / Inom företaget Infinera finns det ett behov av en förbättrad termisk design av en existerande chassiprodukt för användning inom telekommunikation för distribution av tjänster inom Edge &amp;Metro nätverk. För att kunna optimera luftflödet av chassit behövs termiska simuleringar utförastillsammans med mekaniska och elektroniska designflöden för att kunna undersöka luftflödet i olika situationer som täcker systemkraven. Termiska analyser på produkten har utförts genom simuleringsverktyget FloTHERM, samtförändringar och förbättringar av konstruktionen har utförts via programverktyget CAD SolidWorks. Problemformulering för det här examensarbetet är att vidareutveckla designen för chassit för ett förbättrat luftflöde för elektriska och optiska komponenter som placeras i ett existerande chassitför temperaturområdet 0–70 ℃. Samt att chassit förhåller sig till bransch standarden NEBS (Nivå 3) och analyseras i värsta utfallscenariot av ett slott-in kort.Det resultat som har uppnåtts är sex olika utfall av chassit med olika luftflödes design och modeller av fläktar som är anpassade för dagens chassiprodukt med uppföljda kravkriterier. En uppdaterad slutgiltig version baserat på simuleringsresultat har modellerats som förslag på produkten i CAD programmet. En 3D ritning på designen av produkten medföljs som bilaga. Slutsatsen för det här arbetet i syfte till ett förbättrad luftflödes design är ett chassi med en sida-tillsida luftflödes design med fyra utbytbara fläktar i ett utbytbart fläktpaket. Ett nedsänkt tak i chassit ovanför kortet har visat goda resultat som en kylningsmetod på elektriska och optiska komponenter. I detta arbete, på grund av begränsad tid, har ett nedsänkt tak inte fullföljts som en 3D modellering som en tillhörande del av chassit. Ett sänkt innertak kommer att behövaskompletteras i ett fortsatt arbete för framtiden. Även en luftflödesdesign som har undersökts framifrån-till-sida av chassit i FloTHERM kan vidareutvecklas och undersökas närmare i ett framtida arbete för en optimerad luftflödesdesign av chassi produkten. Nyckelord: Luftflödessystem för elektronik, termisk hantering, telekommunikations applikationer, luftflödesmotstånd, kylning av elektronik. Nyckelord: Luftflödessystem för elektronik, termisk hantering, telekommunikations applikationer, luftflödesmotstånd, kylning av elektronik
186

Model Predictive Climate Control for Electric Vehicles

Norstedt, Erik, Bräne, Olof January 2021 (has links)
This thesis explores the possibility of using an optimal control scheme called Model Predictive Control (MPC), to control climatization systems for electric vehicles. Some components of electric vehicles, for example the batteries and power electronics, are sensitive to temperature and for this reason it is important that their temperature is well regulated. Furthermore, like all vehicles, the cab also needs to be heated and cooled. One of the weaknesses of electric vehicles is their range, for this reason it is important that the temperature control is energy efficient. Once the range of electric vehicles is increased the down sides compared to traditional combustion engine vehicles decrease, which could lead to an increase in the usage of electric vehicles. This could in turn lead to a decrease of greenhouse gas emission in the transportation sector. With the help of MPC it is possible for the controller to take more factors into consideration when controlling the system than just temperature and in this thesis the power consumption and noise are also taken into consideration. A simple model where parts of the climate system’s circuits were seen as point masses was developed, with nonlinear heat transfers occurring between them, which in turn were controlled by actuators such as fans, pumps and valves. The model was created using Simulink and MATLAB, and the MPC toolbox was used to develop nonlinear MPC controllers to control the climate system. A standard nonlinear MPC, a nonlinear MPC with custom cost functions and a PI controller where all developed and compared in simulations of a cooling scenario. The controllers were designed to control the temperatures of the battery, power electronics and the cab of an electric vehicle. The results of the thesis indicate that MPC could reduce power consumption for the climate control system, it was however not possible to draw any final conclusions as the PI controller that the MPC controllers were compared to was not well optimized for the system. The MPC controllers could benefit from further work, most importantly by applying a more sophisticated tuning method to the controller weights. What was certain was that it is possible to apply this type of centralized controller to very complex systems and achieve robustness without external logic. Even with the controller keeping track of six different temperatures and controlling 15 actuators, the control loop runs much faster than real time on a modern computer which shows promise with regard to implementing it on an embedded system.
187

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

Salvador Iborra, Josep 02 September 2020 (has links)
[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/10251/149575 / TESIS
188

Understanding Gate Adsorption Behavior on Flexible Metal-Organic Frameworks with the Aid of X-Ray Structural Analysis Toward Their Potential Applications / X線構造解析に立脚したソフト多孔性錯体が示すゲート吸着挙動の解明とその潜在能力検討

Hiraide, Shotaro 26 March 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21129号 / 工博第4493号 / 新制||工||1698(附属図書館) / 京都大学大学院工学研究科化学工学専攻 / (主査)教授 宮原 稔, 教授 山本 量一, 教授 佐野 紀彰 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
189

Steam-Assisted Catalysis of n-Dodecane as a Jet Fuel Analogue in a Flow Reactor System for Hypersonic Thermal Management

Smith, Bradley Joseph January 2019 (has links)
No description available.
190

Modellering och Simulering av Värmehanteringssystem för Batteridrivna Elektriska Fordon (BEV) / Modelling and Simulating Thermal Management System of a Battery Electric Vehicle (BEV)

Bajalan, Ismail, Nors, Petter January 2023 (has links)
I detta examensarbete simuleras ett värmehanteringssystem i Matlab Simulink för en elektrisk lastbil, det för att värmehantera fordonets klimat. Där en värmepump används för nedkylning av kupé och batteri samt en PTC (elektrisk värmare) för uppvärmning av detsamma. Värmepumpen fungerar genom att kompressorn förångar R-134a kylmedlet i systemet som sedan omvandlas till vätska vid nedkylning av kondensorn som utbyter energi med omgivande luften. Vätskan skickas vidare till en mottagare som filtrerar kylmedlet för att sedan överföras till en expansionsventil som kontrollerar trycket i systemet. Vätskan går sedan till evaporatorn för att kylas ned av ett utbyte med varmare omgivande luft från kupén, därefter börjar nedkylningsproessen om. PTC värmaren har en passiv uppvärmningsfunktionaliteten som tar emot ström genom ett motstånd och värmer komponenten med hjälp av en vattencykel. Batteriets räckvidd minskar vid fel temperaturer därav kan batteriets temperatur kontrolleras i drift. Det för att teoretiskt öka räckvidden på fordonet genom att ha batteriet vid en mer gynnsam temperatur. En förstudie genomförs där data samlas in för att sedan modellera och redovisa simulerade resultat som åstadkoms för olika scenarion med uppvärmning och nedkylning. Det visar sig att systemets batteri tar för lång tid vid nedkylning och uppvärmning på grund av dess stora massa. Detta då batteriet inte når måltemperaturen under simuleringens gång som körs i 1 timme och därav inte efter komforttiden som är 10 minuter. Vidare når kupéns delar önskad temperatur inom simuleringstiden förutom under kupéns nedkylning där taket kyls långsammare än önskat. Den enda delen av kupén som uppnår komforttiden är kupéns sidor vid uppvärmning. Vilket betyder att optimeringar på systemet bör tillämpas för att åstadkomma bättre och mer realistiska resultat. / In this thesis, a thermal management system is simulated in Matlab Simulink for an battery electric truck, in order to thermally manage the vehicle's climate. A heat pump is implemented to cool down the cabin and battery while a PTC (electric heater) is implemented to heat the systems respectively. The heat pump works by the compressor vaporizing the R-134a refrigerant in the system, which is then converted to liquid when cooled by the condenser, which exchanges energy with the surrounding air. The liquid is sent further to a receiver that filters the refrigerant and is then transferred to an expansion valve that controls the pressure in the system. The liquid then goes to the evaporator to be cooled by an exchange with warmer ambient air from the vehicle cabin, after which the cooling process begins again. The PTC heater has a passive heating functionality that receives current through a resistor and heats the component using a coolant loop. The battery's range is reduced at incorrect temperatures, therefore the battery's temperature can be checked during operation. This is to theoretically increase the range of the vehicle by having the battery at a more favorable temperature. A pre-study is carried out where data is collected to then model, and present simulated results that were achieved for different scenarios with heating and cooling. It turns out that the system's battery takes too long to cool down and warm up due to its large mass. This is because the battery does not reach the target temperature during the course of the simulation, which is run for 1 hour, and therefore not after the comfort time which is 10 minutes. Furthermore, the parts of the cabin reach the desired temperature within the simulation time, except during the cooling down of the cabin, where the roof cools more slowly than desired. The only part of the cabin that achieves the comfort time is the sides of the cabin when heated. Which means that optimizations to the system should be applied in order to achieve better and more realistic results.

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