This master's thesis deals with the temperature-rise of selected parts of the low-voltage switchgear. The theoretical part describes the physical principles and the basic mechanisms of heat transfer. The next part describes the possible effect of elevated temperature on the device inside the switchgear. The master's thesis is awarded by ABB Ltd., so another part is dedicated to MNS switchgear. The following part describes the permitted limit of temperature-rise of switchgear in accordance with IEC 61439-1. In the practical part is a calculation temperature-rise of selected part of switchgear based on IEC 60890. Model in SOLIDWORKS Flow Simulation was created for the same part of the switchgear and thermal analysis was performed. The values of allowable temperature rise of individual parts are compared with the results obtained by calculations and simulations. In the last part is verified the possibility of calculating the temperature-rise in the EPLAN software.

This diploma thesis is focused on creating a finite element method model of a four-stroke engine with a purpose to determine an impact on cylinder bore distortion caused by several types of loading. Introduction of this work covers research of possibilities in modelling thermal-structural analysis of cylinder liner and verifications of the analysis results. An Ansys model was further created and cylinder liner radial deformation caused by head bolts tightening and thermal loading coming from combustion was determined. Finally, a whole engine working cycle was simulated with a gas pressure loading and its final impact on the total cylinder liner radial deformation was defined.

L'objectif de cette thèse est d'étudier et d'optimiser le processus de fabrication des mousses métalliques et le comportement thermique du matériau de la mousse d'aluminium/matériau de changement de phase (MCP) par des méthodes expérimentales et numériques. Le processus d’élaboration de la mousse d’aluminium à pore ouvert est développé et optimisé pour contrôler précisément les paramètres de fabrication. Deux modèles de mousse d'aluminium à haute porosité (MAHP)/MCP composite et à faible porosité (MALP)/MCP composite sont établis pour la simulation numérique. En simulant le processus de fusion d'un système de stockage d'énergie, les composites MAHP/MCP et MALP/MCP sont comparés numériquement afin d'évaluer la performance de stockage d'énergie thermique. Les résultats montrent que la mousse d'aluminium améliore nettement le processus de transfert de chaleur dans MCP en raison de sa haute conductivité thermique. La porosité des mousses d'aluminium influence non seulement le processus de fusion du composite mais aussi la performance de stockage d'énergie thermique. Grâce à la collaboration avec EPF, une nouvelle méthode d’élaboration des mousses périodiques d'aluminium à pore ouvert est développée dans cette thèse sur la base d’impression 3D. Le comportement thermique des mousses d'aluminium périodiques à pore ouvert/MCP est analysé expérimentalement et numériquement / The objective of this thesis is to study and optimize the manufacturing process of metal foams and the thermal behavior of the aluminum foam/phase change material (PCM) composite by experimental and numerical methods. The manufacturing process of open-cell aluminum foam is developed and optimized to precisely control the parameters of mufacturing. Two pore-scale models of high porosity aluminum foams (HPAF)/PCM composite and low porosity aluminum foams (LPAF)/PCM composite are established for numerical simulation. By simulating the melting process of a layer energy storage system, the HPAF/PCM and LPAFS/PCM composite are compared numerically in order to evaluate the energy storage performance. The results show that aluminum foam improves greatly the heat transfer process in PCM due to its high thermal conductivity. The porosity of aluminum foams could not only influence the melting process of composite but also the energy storage performance. Thanks to the collaboration with EPF, a new manufacturing method of periodic open-cell aluminum foams is developed based on 3D rapid tooling. The thermal behavior of the periodic open-cell aluminum foams/PCM composite is experimentally and numerically analyzed

Insulating sheets, impregnants and encapsulation materials commonly used for winding insulation offer low thermal conductivities. This leads to an increased heating of the winding of electrical machines and to the existence of hotspots. The electromagnetical utilization of the machine has to be reduced with respect to the allowed maximum winding temperature. In this paper, the development and experimental investigation of novel polysiloxane composites with ceramic fillers are presented. The materials are tested by means of impregnated and encapsulated samples of a round-wire winding as well as the main insulation of electrical steel sheets and laminated cores. Numerical models are implemented for determining the equivalent thermal conductivity of the winding compound comprising the enameled wire and the impregnant. Based on the example of a permanent-magnet synchronous machine with outer-rotor in modular construction, the potential for increasing the electromagnetical utilization is shown.

This specific-purpose mathematical model was developed for the drying process in a multi-cylinder drying section. The unsteady state of one-dimensional heat conduction equation has been applied to mathematical model of both, cylinder shell and paper web. The internal mass transfer of the paper web has not been included in this work. The calculations of the simulation program use an implicit numerical method. The drying path length along the machine direction has been divided into 4 drying phases for each drying cylinder. Each drying phase has been divided in small sub-elements. In each sub-element, the heat and mass transfer across boundary conditions have been solved simultaneously in the simulation program, which runs with MatLAB®.

<p>Rechargeable lithium ion batteries (LIBs) are widely used in various daily life applications including electronic portable devices, cell phones, military applications, and electric vehicles throughout the world. The demand for building a safer and higher volumetric/gravimetric energy density LIBs has increased exponentially for electronic devices and electric vehicles. With the high energy density and longer cycle life, the LIBs are the most prominent energy storage system for electric vehicles. Researchers are further exploring for new materials with a high specific capacity, the MXene has been a promising new anode material for LIBs. The typical MXene material Ti₃C₂T_z has 447mAh/g theoretical capacity, which is higher than traditional graphite (372 mAh/g for LiC₆) based anode.</p> <p>Though LIBs are used in most of the portable energy storage devices, LIBs are still having thermal runaway safety concern, which is caused by three main reasons: mechanical, electrical, and thermal abuse. The thermal runaway is caused by the initiation of solid electrolyte interface (SEI) degradation above 80 °C on the anode surface, generating exothermic heat, and further increasing battery temperature. The SEI is a thin layer formed on anode due to electrolyte decomposition during first few charging cycles. Its degradation at low temperature generates heat inside the LIBs and triggers the thermal runaway. The thermal runaway follows SEI degradation, electrolyte reactions, polypropylene separator melting, cathode decomposition and finally leads to combustion. The thermal runaway mechanism of graphite, which is the most common and commercialized anode material of LIBs, has been studied for years. However, the thermal safety aspects of the new MXene material has not been investigated yet. </p> <p>In this thesis, we primarily used differential scanning calorimetry (DSC) and specially designed multi module calorimetry (MMC) to measure exothermic and endothermic heat generated at <a>Ti₃C₂T_z </a>anode, associated with multiple chemical reactions as the temperature increases. The <i>in-situ</i> MMC technique is employed to study the interactions and chemical reactions of all the components (separator, electrolyte, cathode and MXene anode) in the coin cell for the first time, while the <i>ex-situ</i> DSC is used to investigate the reactions happened on anode side, including electrolyte, PVDF binder, MXene, SEI and intercalated Li. Along with other <a>complementary </a>instruments and methods, the morphological, structural and compositional studies are carried out using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET) surface area measurement and electrochemical measurement to support the thermal analysis. The electrochemical and thermal runaway mechanism of conventional graphitic anode is studied and used for comparison with MXeneanodes.</p> <p>The Ti₃C₂T_z thermal runaway is triggered by SEI decomposition around 120 °C analogous to conventional graphite. The thermal behavior of Ti₃C₂T_z anode is highly dependent on electrode material, surface area, lithiation states, surface morphology, structure and surface-terminating functional groups on Ti₃C₂T_z, which provides more active lithium sites for exothermic reactions with the electrolyte. Especially the terminal groups (-OH, -F, =O, etc.) from the etching process affect the lithium ion intercalation and thermal runaway mechanism. With annealing treatment, the surface-terminating functional groups are modified and can achieve less exothermic heat release. By normalizing the total heat generation by specific capacities of the anode materials, it is observed that Ti₃C₂T_z (2.68 J/mAh) generates slightly less exothermic heat than graphite (2.72 J/mAh) indicating slightly safer nature of Ti₃C₂T_z anode. The <i>in-situ</i> thermal analysis results on the Ti₃C₂T_z half-cell exhibited less total heat generation per mass (1.56 kJ/g) compared to graphite (1.59 kJ/g) half-cell. </p><br>

The present dissertation is motivated by the search for alternatives of lead-free soldering by nanoparticles of metals and their alloys. The research focuses on the possibility of replacing lead-free solders by nanoparticles. This issue is currently being addressed by the use of lead-free solders but their properties are not entirely equivalent to properties of lead-tin based alloys. The theoretical part of the dissertation first summarizes up-to date knowledge on the development of lead-free alloys currently used for soldering in the electronics. The work compares these lead-free solder candidates with previously used Pb-Sn alloys. The second section of the theoretical part is devoted to nanotechnology that offers possible solutions of problems associated with the use of lead-free solders. The text contains a description of the properties of nanocrystalline materials in comparison with those of compact alloys having the same chemical composition. The possibility of preparation of nanoparticles and potential problems associated with small particle sizes are also presented. Introduction of the experimental part focuses on the preparation of nanoparticles of pure metals and alloys by chemical and physical ways as well as on an instrumentation for characterisation and analysis. Attention is focused on the silver in nanoparticle form that exhibits the low temperature sintering effect, which is thermally activated by decomposition of oxide envelope covering the Ag nanoparticles. This factor is critical for low-temperature sintering and thus also for possible future applications. The thermal effects of the low sintering process were studied by methods of thermal analysis. The preparation of the Cu / Ag nano / Cu joints was carried out in-situ in inert atmosphere and under the action of atmospheric oxygen. In both cases varying conditions of thermal treatment were used. The cross sections of the prepared joints were then used for the metallographic analysis of the local mechanical properties of the resulting silver layer, for the chemical composition evaluation of the resulting layers of the joint, and for the microstructure study. Strength characteristics are represented by testing shear strength of individual joints.

E-bikes, often known as electric bicycles, are becoming more and more well-liked as green modes of mobility. High-capacity lithium-ion (Li-ion) batteries are utilised to power these e-bikes because of their extended cycle life, high energy density, and low self-discharge rate. The performance and longevity of these batteries may be impacted by temperature fluctuations, however. To guarantee the safe and dependable functioning of Li-ion batteries used in e-bikes, it is crucial to do temperature analysis on the batteries. In this dissertation, the thermal behaviour of a 48V 60AH Li-ion battery used in an e-bike will be studied under various cooling scenarios. The research specifically contrasts forced convection cooling using fans with broad and limited outlet ports to natural air convection cooling with large and reduced outlet ports. The study sheds light on the ideal cooling setups that might increase battery longevity and performance. The results of this study have important ramifications for e-bike producers and designers, battery producers, and energy storage system researchers. Simulations based on computational fluid dynamics (CFD) are used to simulate the thermal behaviour of the Li-ion battery under various cooling settings for the investigation. 25°C has been selected as the ambient temperature. For forced convection, the airflow rate is set at 3.5 m/s, whereas the airflow rate for natural convection is set at 0.1 m/s. The study's findings demonstrate that both natural and forced convection cooling methods may successfully lower the temperature of a Li-ion battery. However, forced air convection cooling using fans is more efficient than natural air convection at dispersing heat. These findings suggest that, owing to the higher air velocity, shrinking the outlet ports in both cooling approaches improves thermal performance.

Since mankind found out that she is the reason to the recent global warming shehas, in some societies, begun a conversion of her society, from driven by fossil fuel tosustainable fuel. One of these is so called wave energy.CorPower Ocean's wave energy converter consist of a buoy, which through a wire,is connected to a shaft in the plant. This shaft drives two gas lled and pressurisedpistons, which stores the energy from the buoy's upward motion and returns it at thebuoy downward motion, aiming at evening the energy production over the cycle. Inthe wave energy converter there are several seals, between hydraulic uids, betweenhydraulic uids and the gas pistons as well as between the plant and the surroundingocean where the shaft exits the plant.To select the right kind of seals the range in the working temperature of the surroundinguids need to be known, as do the load of the waves on the shaft. This inorder to select seals of the right material and to construct a linear guide.The purpose of this thesis is to acquire the initial demands for the seal and linearguide. In other words make a thermal analysis of the surrounding environmentin order to select seals and an initial load analysis in order to construct a robustlinear guide.The result is that in order to control the temperature, a reservoir volume shouldbe added to the cylinders and a change in this volume gives the most eect on thetemperature and compression rate. Regarding the linear guides, slide rings on bothsides of the two outer seals should be enough. This thesis should be viewed as aninitial analysis of the sealing problem to be able to outline the demands on the sealsand linear guides related to the gas compartments. / Sedan manninskan ck reda pa att hon ar orsaken till den senaste tidens globalauppvarming har hon, i nagra samhallen, paborjat en omstallning av sitt samhalle,fran fossila branslen som drivmedel till langsiktigt hallbara drivmedel. Ett av dessaar sa kallad vagkraft.CorPower Oceans vagkraftverk bestar av en boj, som genom en vajer faster i endragstang i sjalva kraftverket. Denna dragstang driver tva gasfyllda och trycksattakolvar, som lagrar energin fran bojens uppgaende rorelse och aterger den vid bojensnedgande rorelse, med malet att dessa jamnar ut kraftproduktionen over cykeln. Iverket nns era tatningar, mellan olika hydraulvatskor, mellan hydraulvatskor ochgaskamrarna samt mellan verket och det omgivande havet dar dragstangen gar ut urverket.For att kunna valja ratt tatningar maste spannet i arbetstemperatur pa de omgivandeuiderna, samt lasten fran vagorna pa dragstangen, vara kanda. Detta foratt tatningar av ratt material ska kunna valjas och en linjarguide konstrueras.Detta arbete syftar till att ta fram de initiella kraven pa tating och linjarguide.Med andra ord gora en termisk analys av den omgivande miljon for att kunnavalja tatningar samt en inledande kraftanalys for att kunna konstruera en robustlinjarguide.Slutsatsen blir att for att styra temperaturen, bor en reservoirvolym laggas till cylindrarnaoch en andring av volymen pa denna ger storst eekt pa gasens temperaturoch kompressionsgrad. For linjarguidens del bor det ga bra med glidringar pa badasidor om de yttersta tatningarna. Det exakta valet av tatingslosning kommer Cor-Power Ocean dock att arbeta fram med ett lampligt foretag. Denna uppsats ska sessom en inledande analys av tatningsproblemet for att kunna ange huvuddragen avkraven pa tatningar och linjarguider relaterade till gascylindrarna

Crystal Engineering is the design of crystalline material using non-covalent synthesis. Co-crystals are multi-component crystals which are constructed from complementary intermolecular interactions, they are also known as supramolecular complexes. Design of such materials utilises the synthon approach, this involves the understanding of common intermolecular interactions which occur in the crystal packing and is used to design new solids with desired physical properties and chemical properties. Primary amides form supramolecular heterosynthons, these synthons represent an opportunity for a design of multi-component crystals in which one molecule contains a primary amide and a second molecule which is complimentary to the primary amide, usually carboxylic acids. The progress with regards to the screening process for the determination of co-crystals is evident in the literature, In particular, high throughput solution growth methods and solvent drop grinding. The comparison of Isonicotinamide and Benzamide as a co-crystal component has been presented. This study was motivated by the observation that the CSD contains 24 Isonicotinamide and 1 Benzamide co-crystal. The interaction with carboxylic acids is the focus of the work, in particular those which form Isonicotinamide co-crystal are being screened with Benzamide. Our work utilises a ReactArray Microvate to carry out the low throughput solution growth on a matrix of carboxylic acid with Benzamide, this study has been coupled with the Kofler hot stage microscope method which visually aids to screen and view co-crystal phase formation. Crystallisation screens have resulted in the identification of known co-crystal phases of Isonicotinamide and Benzamide, additionally new co-crystal phases have also been identified with Fumaric, 3-hydroxybenzoic acid, Mandelic Acid, 4-Nitrobenzoic Acid and Tartaric Acid. Single crystal structures of the Fumaric and 4-Nitrobenzoic acid have been obtained. In order to develop an understanding of co-crystal formation in Isonicotinamide and Benzamide with our supramolecular library, packing landscape analysis is being undertaken using both the CSD and crystal structures we have obtained. This is undertaken as collaboration with Dr Andy Parkin and Professor Gilmore (University of Glasgow), we have identified that the dSNAP analysis is a way forward for the analysis of how co-crystals pack. The analysis highlighted the subtleties that were present in the packing motifs of the Isonicotinamide co-crystals. In particular the cis and trans orientation of the amide and acid carbonyl to each other and the planar and off planar layer assemblies. All of which are required to maximise the hydrogen bond usage of the components comprising the co-crystals. Further investigations have led to the collaborative project with Syngenta Ltd in the design of a co-crystal screen using a high through-put robot, Crissy® -Automation Platform by Zinsser Analytical, using an extended screen of 16 acid coformers with Isonicotinamide, Benzamide and Nicotinamide the sample have been characterised using a reflectance diffraction method, GADDS. Further analysis of this data involves the use of polySNAP, which has led to further collaboration with Professor Gilmore¿s group. / Syngenta