Dissertations / Theses on the topic 'Fuel pumps Design and construction'
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Gollapudi, Gopinath. "Design optimization of a fuel pump support." Ohio : Ohio University, 1999. http://www.ohiolink.edu/etd/view.cgi?ohiou1175880688.
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Müller, Axel, Mike Heck, Olaf Ohligschläger, Jürgen Weber, and Martin Petzold. "Brimming bubbles? On an Innovative Piston Design of Dosing Pumps." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200154.
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For delivery, dosing and pressure control of fluids in mobile and stationary applications electromagnetically operated piston pumps are an established solution. The volume per stroke is exactly defined by the geometry. Nevertheless cavitation, more likely with the new fuel blends containing a high proportion of ethanol /1/, deteriorates the dosing precision of the liquid portion. One important criterion of precise metering is the transport of the liquids through the reciprocating piston pump without transferring bubbles. Especially, pumping in the range of vapour pressure of gasoline fuels implies challenges for precision. The objective of this work is revealing potential sources of reduced cavitation by optimising the design. For doing so, optical investigations have been applied. In addition to this, cavitation can be diminished controlling the piston’s travel externally. The second important item covers pumping of degenerated fluids even without negative effects on the pump’s performance. Up to now, wide, inefficient gaps or high force surplus are necessary. A new helix-design /2/ has been investigated and built up in order to reduce the described effort. The effects coming with the helix allow a permanent rinsing of the stressed surfaces, leading to lubrication and lower temperature loads. The results are shown in simulation, fundamental tests and is validated in practical pump operation.
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Headley, F. Anthony Jr. "Performance limitations of an ejector heat pump." Thesis, Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/20290.
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Morrison, Vance. "Generation of tunable femtosecond laser pulses and the construction of an ultrafast pump-probe spectrometer." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116114.
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An ultrafast UV-visible spectrometer was designed and implemented. An optical parametric amplifier was constructed to be used as a pump source for the spectrometer. Using nonlinear optical processes and an 800 nm ultrashort pulses, tunable infrared(IR) light was produced with a wavelength range of ∼.1 mum to 3 mum. The IR light was then mixed with 800 nm light to produce tunable visible light with a wavelength range of 466 nm to 600 nm. Supercontinuum (SC) was used as the probe pulse of the spectrometer, providing a large observation bandwidth. Commercially purchased fast spectrometers were used as the detection mechanism. The characterization of the set up, as well the observation of some ultrafast molecular dynamics observed in 8-hydroxy-1,3,6-pyrenetrisulfonic acid, are presented.
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White, Susan Jennifer. "Bubble pump design and performance." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/16914.
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Gavel, Hampus. "On aircraft fuel systems : conceptual design and modeling." Doctoral thesis, Linköping : Division of Machine Design, Department of Mechanical Engineering, Linköpings universitet, 2007. http://www.bibl.liu.se/liupubl/disp/disp2007/tek1067s.pdf.
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Lagimoniere, Ernest Eugene Jr. "The Design and Construction of a High Bandwidth Proportional Fuel Injection System for Liquid Fuel Active Combustion Control." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34693.
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This last decade experienced a sudden increase of interest in the control of thermo-acoustic instabilities, in particular through the use of fuel modulation techniques. The primary goal of this research was to design, construct and characterize a high bandwidth proportional fuel injection system, which could be used to study the effect of specific levels of fuel modulation on the combustion process and the reduction of thermo-acoustic instabilities. A fuel injection system, incorporating the use of a closed loop piston and check valve, was designed to modulate the primary fuel supply of an atmospheric liquid-fueled swirl stabilized combustor operating at a mean volumetric fuel flow rate of 0.4 GPH. The ability of the fuel injection system to modulate the fuel was examined by measuring the fuel line pressure and the flow rate produced during operation. The authority of this modulation over the combustion process was investigated by examining the effect of fuel modulation on the combustor pressure and the heat release of the flame. Sinusoidal operation of the fuel injection system demonstrated: a bandwidth greater that 800 Hz, significant open loop authority (averaging 12 dB) with regards to the combustor pressure, significant open loop authority (averaging 33 dB) with regards to the unsteady heat release rate and an approximate 8 dB reduction of the combustor pressure oscillation present at 100 Hz, using a phase shift controller. It is possible to scale the closed loop piston and check valve configuration used to create the fuel injection system discussed in this work to realistic combustor operating conditions for further active combustion control studies.Master of Science
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Mwinga, Makani. "Design and development of a fuel cell power supply unit." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2524.
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Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2017.Fuel cell (FC) technology is one of the most sought-after renewable energy technology. However, the output voltage of FC stacks is inherently unstable; as such, it is of little or no use for most power supply applications. In addition to the unstable output voltage, FC stacks are susceptible to high current ripple, which can reduce the system’s life expectancy. The work carried out in order to stabilise the output voltage, and to reduce the current ripple of FC stacks involves a review of some existing converter topologies used for power conditioning units (PCUs), modelling, design, control and simulation of different converter topologies and the experiment of the prototype circuit for the interleaved boost voltage multiplier (IBVM) converter topology. In the process to stabilise the stack output voltage and to reduce the stack output current ripple, it is also required to improve the system response to load changes. This work presents results that show that system works, with the voltage stabilised, the stack output current ripple reduced and the response time reduced. A relative evaluation of the dynamic behaviour of four converter topologies in power conditioning units is carried out, and these are the isolated current-fed full-bridge (ICFFB) converter, the boost converter, the sepic converter and the IBVM converter. The simulation results of the four topologies show that the output voltage of a PEMFC stack was stabilised, and that the IBVM topology is a better topology compared to the others, especially when it comes to reducing the stack current ripple.
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Tesfai, Alem T. "Solid oxide fuel cells SOFCRoll single cell and stack design and development." Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/4505.
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This study has focused on the implementation of a stack system for a novel design of solid oxide fuel cell (SOFCRoll). The issues affecting the commercialization of SOFCs are mainly based on durability and cost. The new design offers a number of advantages over the existing designs; it seeks to retain the specific advantages of both the tubular (high unit strength, no sealing problems) and planar arrangements (high power density). This design also aims to achieve low manufacturing cost by utilizing a cheap, easily scalable production technique: tape casting, together with co-firing all components, in one single step. In this study aspects of the design and operation of SOFCRoll stacks were studied particularly those affecting the single cell test reproducibility such as pre test quality control and scale up issues such as bundle and stack gas distribution. Initially the performance of single cells was characterized and the variation of their power output with temperature was observed. The maximum power, 0.7W at 800°C was achieved with a high silver content. The OCV and total resistance of this cell were 0.93V, 0.30Ω respectively. A standard pre-test quality control and current collection technique was introduced. At 800°C reproducible performance of 0.5W power obtained, average OCV was 0.935V and average series and polarization resistances of 0.18Ω and 0.19Ω was achieved respectively. Once single cell reproducibility was achieved, the design and operation of a 5 cell SOFCRoll bundle was investigated. A FLUENT CFD model was used to optimize the gas distribution in the five cell manifold design. The value of the model as a design tool was demonstrated by the comparison of 3 different gas manifold designs. The final manifold design M3 achieved 2.5W which is consistent with the 0.5W per a cell target. This manifold was then used as the basis for the development of a 25 cell stack which was built and tested. The 25 cell stack testing results were down to 0.35W per a cell. The performance drop highlighted the problem of fuel cell manufacturing reproducibility and also the importance of introducing reproducible manufacturing tequniques. That been the case for single cell manufacturing reproducibility issue, the fundamental concern for performance drop remains a design issue. To optimize the SOFCRoll design and to assist with the development program a single-cell CFD model was developed using FLUENT. The model was validated by comparison with data from experimental measurements for the single cell. The model work was used to predict the geometrical effect of the SOFCRoll tubular and the spiral gas channel configuration and current collector configuration. Results indicate the outlet gas flow velocity is higher around the spiral, near the gas inlet (the gas interring the cell preferentially flows around the spiral) therefore, velocity decrease as the gas moves along the cell. The lowest outlet velocity is registered opposite to the gas inlet, thus creating non-uniform gas distribution. The current density distribution is not uniform and is affected primarily by reactant flow distributions along the cell and possible current collection issues particularly around the spiral part of the cell.
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Engin, Ertan. "Design, Construction And Performance Evaluation Of A Submersible Pump With Numerical Experimentation." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/12606532/index.pdf.
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Due to the increasing demand, nonclog type sewage pumps are designed and manufactured in large amounts all over the world. However, a methodology on the design of these special duty pumps is not encountered in the literature. Therefore, the manufacturers tend to develop their own empirical methodologies.
In this thesis, a nonclog pump is designed and constructed on the basis of suitable approaches of known centrifugal pump design methods. In this frame, a nonclog type submersible pump that is capable of handling solids, up to a diameter of 80 mm is aimed to be designed. The designed pump delivers 100 l/s flow rate against a head of 24 m. The rotational speed of the pump is 1000 rpm. Design procedure and the important points that differ nonclog pump design from standard centrifugal pump designs are given.
In addition, hydraulic characteristics of two nonclog pumps, one of which is the pump designed in this study, are investigated by means of computational fluid dynamics (CFD) code.
The designed pump is manufactured and tested in Layne Bowler Pump Company Inc. The test result indicates that design point is reached with a deviation in the limits of the related standard. Wire to water total best efficiency obtained by the test is 60%.
Close agreement between results of actual test and numerical experimentation performed by CFD code shows that CFD analysis is a quite useful tool in predicting the hydraulic characteristics of nonclog pumps.
Moreover, the pump is tested at 750 rpm and the test results are found to be in good agreement with the similitude anaysis results.
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Bessette, Norman F. II. "A mathematical model of a tubular solid oxide fuel cell." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/19260.
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Khan, Bruno Shakou. "Optimization of the fuel consumption of a parallel hybrid electric vehicle." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/16763.
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Zhao, Gui Quan. "Design, control and experimental testing of intelligent variable dual-fuel automotive engines." Thesis, University of Macau, 2017. http://umaclib3.umac.mo/record=b3691635.
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Chan, Kwok-wong, and 陳國煌. "The study of utilization of pulverized fuel ash in road construction in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1993. http://hub.hku.hk/bib/B31232966.
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Rooker, William E. "Enhancing the thermal design and optimization of SOFC technology." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/18881.
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Moore, Christopher Wayne. "Microfabricated Fuel Cells To Power Integrated Circuits." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7106.
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Microfabricated fuel cells have been designed and constructed on silicon integrated circuit wafers using many processes common in integrated circuit fabrication, including sputtering, polymer spin coating, reactive ion etching, and photolithography. Fuel delivery microchannels were made through the use of sacrificial polymers. The characteristics of different sacrificial polymers were studied to find the most suitable for this work. A polypropylene carbonate solution containing a photo-acid generator could be directly patterned with ultraviolet exposure and thermal decomposition. The material that would serve as the fuel cells proton exchange membrane (PEM) encapsulated the microchannels. Silicon dioxide deposited by plasma enhanced chemical vapor deposition (PECVD) at relatively low temperatures exhibited material properties that made it suitable as a thin-film PEM in these devices. By adding phosphorous to the silicon dioxide recipe during deposition, a phosphosilicate glass was formed that had an increased ionic conductivity. Various polymers were tested for use as the PEM or in combination with oxide to form a composite PEM. While it did not work well alone, using Nafion on top of the glass layer to form a dual-layer PEM greatly enhanced the fuel cell performance, including yield and long-term reliability. Platinum and platinum/ruthenium catalyst layers were sputter deposited. Experiments were performed to find a range of thicknesses that resulted in porous layers allowing contact between reactants, catalyst, and the PEM. When using the deposited glasses, multiple layers of catalyst could be deposited between thin layers of the electrolyte, resulting in higher catalyst loading while maintaining porosity. The current and power output were greatly improved with these additional catalyst layers.
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Ford, James Christopher. "Thermodynamic optimization of a planar solid oxide fuel cell." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45843.
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Solid oxide fuel cells (SOFCs) are high temperature (600C-1000C) composite metallic/ceramic-cermet electrochemical devices. There is a need to effectively manage the heat transfer through the cell to mitigate material failure induced by thermal stresses while yet preserving performance. The present dissertation offers a novel thermodynamic optimization approach that utilizes dimensionless geometric parameters to design a SOFC. Through entropy generation minimization, the architecture of a planar SOFC has been redesigned to optimally balance thermal gradients and cell performance. Cell performance has been defined using the 2nd law metric of exergetic efficiency. One constrained optimization problem was solved. The optimization sought to maximize exergetic efficiency through minimizing total entropy production while constraining thermal gradients. Optimal designs were produced that had exergetic efficiency exceeding 92% while maximum thermal gradients were between 219 C/m and 1249 C/m. As the architecture was modified, the magnitude of sources of entropy generation changed. Ultimately, it was shown that the architecture of a SOFC can be modified through thermodynamic optimization to maximize performance while limiting thermal gradients. The present dissertation highlights a new design methodology and provides insights on the connection between thermal gradients, performance, sources of entropy generation, and cell architecture.
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Svahn, Carl. "Quantified Interactive Morphological Matrix : An automated approach to aircraft fuel system synthesis." Thesis, Linköping University, Department of Mechanical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7715.
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This report is one part of a masters thesis in mechanical engineeing. Is is executed at the Department of Mechanical Engineering at Linköping Insitute of Technology in cooperation with Saab Aerosystems in Linköping.
A tool for concept generation called a quantified interactive morphological matrix has been created. It is based on rules of thumb and approximations concerning aircraft fuel systems.
The tool can be used for discarding bad concepts, with regard to weight, power consumption and MTBF, during the concept phase of a fuel system design process. The tool is ready for calibration towards a future specific area of use. It is open for validation and optimization and is specifically designed to be easily modified for different future products.
Suggestions for future use has been given concerning expansion, implementation, validation and optimization.
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Tse, Laam Angela. "Membrane Electrode Assembly (MEA) Design for Power Density Enhancement of Direct Methanol Fuel Cells (DMFCs)." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11522.
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Micro-direct methanol fuel cells (micro-DMFC) can be the power supply solution for the next generation of handheld devices. The applications of the micro-DMFCs require them to have high compactness, high performance, light weight, and long life. The major goal of this research project is to enhance the volumetric power density of direct methanol fuel cells (DMFCs). A performance roadmap has been formulated and showed that patterning the planar membrane electrode assembly (MEA) to 2-D and 3-D corrugated manifolds can greatly increase the power generation with very modest overall volume increases. In this project, different manufacturing processes for patterning MEAs with corrugations have been investigated. A folding process was selected to form 2D triangular corrugations on MEAs for experimental validations of the performance prediction. The experimental results show that the volumetric power densities of the corrugated MEAs have improved by about 25% compared to the planar MEAs, which is lower than the expected performance enhancement. ABAQUS software was used to simulate the manufacturing process and identify the causes of deformations during manufacture. Experimental analysis methods like impedance analysis and 4 point-probes were used to quantify the performance loss and microstructure alteration during the forming process. A model was proposed to relate the expected performance of corrugated MEAs to manufacturing process variables. Finally, different stacking configurations and issues related to cell stacking for corrugated MEAs are also investigated.
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Ebaid, Munzer Shehadeh Yousef. "Design and construction of a small gas turbine to drive a permanent magnet high speed generator." Thesis, University of Hertfordshire, 2002. http://hdl.handle.net/2299/14046.
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Radial gas turbines engines have established prominence in the field of small turbomachinery because of their simplicity, relatively high performance and installation features. Thus they have been used in a variety of applications such as generator sets, small auxiliary power units (APu), air conditioning of aircraft cabins and hybrid electric vehicles turbines. The current research describes the design, manufacturing, construction and testing a radial type small gas turbine. The aim was to design and build the engine to drive directly a high-speed permanent magnet alternator running at 60000 rpmand developing a maximum of 60 W. This direct coupling arrangement produces a portable, light, compact, reliable and environment friendly power generator. These features make the generator set very attractive to use in many applications including emergency power generation for hospitals, in areas of natural disasters such as floods and earthquakes, in remote areas that cannot be served from the national grid, oil rigs, and in confined places of limited spaces. It is important to recognize that the design of the main components, that is, the inward flow radial UFR turbines, the centrifugal compressor and the combustion chamber involve consideration of aero-dynamics, thermodynamics, fluid mechanics, stress analysis, vibration analysis, selection of bearings, selection of suitable materials and the requirements for manufacturing. These considerations are all inter-linked and a procedure has been followed to reach an optimum design. This research was divided into three phases: phase I dealt with the complete design of the inward radial turbine, the centrifugal compressor, the power transmission shaft, the selection of combustion chamber and the bearing housing including the selection of bearings. Phase 2 dealt with mechanical consideration of the rotating components that is stress, thermal and vibration analyses of the turbine rotor, the impeller and the rotating shaft, respectively. Also it dealt with the selection of a suitable fuel and oil lubrication systems and a suitable starting system. Phase 3 dealt with the manufacturing of the gas turbine components, balancing the rotating components, assembling the engine and finally commissioning and then testing the engine. The current work in this thesis has put the light on a new design methodology on determining the optimum principal dimensions of the rotor and the impeller. This method, also, has defined the optimum number of blades and the axial length of the rotor and the impeller. Mathematical models linking the performance parameters and the design variables for the turbine and the compressor have been developed to assist in carrying out parametric studies to study the influence of the design parameters on the performance and on each other. Also, a new graphical matching procedure has been developed for the gas turbine components. This technique can serve as a valuable tool to determine the operating range and the engine running line. Furthermore, it would decide whether the gas turbine engine operates in a region of satisfactory compressor and turbine efficiencies.
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Salinas, Mejia Oscar Roberto. "An investigation of a carbon dioxide-based fuel cell system as a power generation alternative for Mars exploration applications." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/12037.
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Suhr, Stephen Andrew. "Preliminary Turboshaft Engine Design Methodology for Rotorcraft Applications." Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14128.
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In the development of modern rotorcraft vehicles, many unique challenges emerge due to the highly coupled nature of individual rotorcraft design disciplines therefore, the use of an integrated product and process development (IPPD) methodology is necessary to drive the design solution. Through the use of parallel design and analysis, this approach achieves the design synthesis of numerous product and process requirements that is essential in ultimately satisfying the customers demands. Over the past twenty years, Georgia Techs Center for Excellence in Rotorcraft Technology (CERT) has continuously focused on refining this IPPD approach within its rotorcraft design course by using the annual American Helicopter Society (AHS) Student Design Competition as the design requirement catalyst. Despite this extensive experience, however, the documentation of this preliminary rotorcraft design approach has become out of date or insufficient in addressing a modern IPPD methodology.
In no design discipline is this need for updated documentation more prevalent than in propulsion system design, specifically in the area of gas turbine technology. From an academic perspective, the vast majority of current propulsion system design resources are focused on fixed-wing applications with very limited reference to the use of turboshaft engines. Additionally, most rotorcraft design resources are centered on aerodynamic considerations and largely overlook propulsion system integration. This research effort is aimed at bridging this information gap by developing a preliminary turboshaft engine design methodology that is applicable to a wide range of potential rotorcraft propulsion system design problems. The preliminary engine design process begins by defining the design space through analysis of the initial performance and mission requirements dictated in a given request for proposal (RFP). Engine cycle selection is then completed using tools such as GasTurb and the NASA Engine Performance Program (NEPP) to conduct thorough parametric and engine performance analysis. Basic engine component design considerations are highlighted to facilitate configuration trade studies and to generate more detailed engine performance and geometric data. Throughout this approach, a comprehensive engine design case study is incorporated based on a two-place, turbine training helicopter known as the Georgia Tech Generic Helicopter (GTGH). This example serves as a consistent propulsion system design reference highlighting the level of integration and detail required for each step of the preliminary turboshaft engine design methodology.
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Johnson, Janine B. "Fracture Failure of Solid Oxide Fuel Cells." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4847.
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Among all existing fuel cell technologies, the planar solid oxide fuel cell (SOFC) is the most promising one for high power density applications. A planar SOFC consists of two porous ceramic layers (the anode and cathode) through which flows the fuel and oxidant. These ceramic layers are bonded to a solid electrolyte layer to form a tri-layer structure called PEN (positive-electrolyte-negative) across which the electrochemical reactions take place to generate electricity. Because SOFCs operate at high temperatures, the cell components (e.g., PEN and seals) are subjected to harsh environments and severe thermomechanical residual stresses. It has been reported repeatedly that, under combined thermomechanical, electrical and chemical driving forces, catastrophic failure often occurs suddenly due to material fracture or loss of adhesion at the material interfaces. Unfortunately, there have been very few thermomechanical modeling techniques that can be used for assessing the reliability and durability of SOFCs. Therefore, modeling techniques and simulation tools applicable to SOFC will need to be developed. Such techniques and tools enable us to analyze new cell designs, evaluate the performance of new materials, virtually simulate new stack configurations, as well as to assess the reliability and durability of stacks in operation.
This research focuses on developing computational techniques for modeling fracture failure in SOFCs. The objectives are to investigate the failure modes and failure mechanisms due to fracture, and to develop a finite element based computational method to analyze and simulate fracture and crack growth in SOFCs. By using the commercial finite element software, ANSYS, as the basic computational tool, a MatLab based program has been developed. This MatLab program takes the displacement solutions from ANSYS as input to compute fracture parameters. The individual stress intensity factors are obtained by using the volume integrals in conjunction with the interaction integral technique. The software code developed here is the first of its kind capable of calculating stress intensity factors for three-dimensional cracks of curved front experiencing both mechanical and non-uniform temperature loading conditions. These results provide new scientific and engineering knowledge on SOFC failure, and enable us to analyze the performance, operations, and life characteristics of SOFCs.
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Govinder, Kuvendran. "Theoretical analyses and design, construction and testing of a flow loop for the study of generalised forced and natural convection boiling heat transfer phenomena on typical light-water nuclear reactor fuel pin configurations." Diss., University of Pretoria, 2019. http://hdl.handle.net/2263/71554.
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In a worldwide pursuit for more Accident Tolerant nuclear Fuel (ATF), the quest to obtain and certify alternative nuclear fuel cladding tubes for light-water nuclear power reactors is still a key challenge. One of the facets in this program to develop more ATF is the heat transfer evaluation between the various proposed clad tubes manufactured from suitable replacement materials and the current problematic zirconium-alloy based clad tubes used in nuclear power reactors. For the heat transfer analysis, the accurate measurement of the temperature on the heat transfer surface of heated tubes to be tested was one of the important objectives for the effective analysis of the heat transfer characteristics to the water coolant. After extensive investigations, a suitable technique was developed and validated against recognised forced-convection heat transfer correlations. The results showed that this technique was well suited for external forced convection heat transfer studies from heated surfaces exposed to forced convection water coolants.Dissertation (MSc)--University of Pretoria, 2019.
Mechanical and Aeronautical Engineering
MSc (Applied Science - Mechanics)
Unrestricted
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Yang, Xuedi. "Cathode development for solid oxide electrolysis cells for high temperature hydrogen production." Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/979.
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This study has been mainly focused on high temperature solid oxide electrolysis cells (HT-SOECs) for steam electrolysis. The compositions, microstructures and metal catalysts for SOEC cathodes based on (La₀.₇₅Sr₀.₂₅)₀.₉₅Mn₀.₅Cr₀.₅O₃ (LSCM) have been investigated. Hydrogen production amounts from SOECs with LSCM cathodes have been detected and current-to-hydrogen efficiencies have been calculated. The effect of humidity on electrochemical performances from SOECs with cathodes based on LSCM has also been studied. LSCM has been applied as the main composite in HT-SOEC cathodes in this study. Cells were measured at temperatures up to 920°C with 3%steam/Ar/4%H₂ or 3%steam/Ar supplied to the steam/hydrogen electrode. SOECs with LSCM cathodes presented better stability and electrochemical performances in both atmospheres compared to cells with traditional Ni cermet cathodes. By mixing materials with higher ionic conductivity such as YSZ(Y₂O₃-stabilized ZrO₂ ) and CGO(Ce₀.₉Gd₀.₁O₁.₉₅ ) into LSCM cathodes, the cell performances have been improved due to the enlarged triple phase boundary (TPB). Metal catalysts such as Pd, Fe, Rh, Ni have been impregnated to LSCM/CGO cathodes in order to improve cell performances. Cells were measured at 900°C using 3%steam/Ar/4%H₂ or 3%steam/Ar and AC impedance data and I-V curves were collected. The addition of metal catalysts has successfully improved electrochemical performances from cells with LSCM/CGO cathodes. Improving SOEC microstructures is an alternative to improve cell performances. Cells with thinner electrolytes and/or better electrode microstructures were fabricated using techniques such as cutting, polishing, tape casting, impregnation, co-pressing and screen printing. Thinner electrolytes gave reduced ohmic resistances, while better electrode microstructures were observed to facilitate electrode processes. Hydrogen production amounts under external potentials from SOECs with LSCM/CGO cathodes were detected by gas chromatograph and current-to-hydrogen efficiencies were calculated according to the law of conservation of charge. Current-to-hydrogen efficiencies from these cells at 900°C were up to 80% in 3%steam/Ar and were close to 100% in 3%steam/Ar/4%H₂. The effect of humidity on SOEC performances with LSCM/CGO cathodes has been studied by testing the cell in cathode atmospheres with different steam contents (3%, 10%, 20% and 50% steam). There was no large influence on cell performances when steam content was increased, indicating that steam diffusion to cathode was not the main limiting process.
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Rodriguez-Anderson, Santiago Martin. "Sensible Air to Air Heat Recovery Strategies in a Passive House." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2123.
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Due to rising energy costs and concerns about global climate change, high performance buildings are more in demand than ever before. With roughly 20% of the total energy consumption in the United States being devoted to residential use, this sector represents a significant opportunity for future savings. There are many guidelines and standards for reducing building energy consumption. One of the most stringent is the Passive House Standard. The standard requires that that air infiltration is less than or equal to 0.6 air changes per hour at a 50 Pascal pressure difference (ACH 50), annual heating energy is less than or equal to 15kWh/m2, and total annual source energy is less than or equal to 120 kWh/m2. For comparison, the typical West coast US residence has an ACH50 of 5 and annually uses more than 174 kWh/m2 of source energy according to the 2009 Residential Energy Consumption Survey. With these challenging requirements, successful implementation of the Passive House Standard requires effective strategies to substantially reduce energy consumption for all end uses.
Heating and cooling loads are low by necessity in a Passive House. As such this makes end uses like water heating a much larger fraction of total energy use than they would be in a typical building. When air to water heat pumps are employed the energy consumption by water heating is lowered significantly. By employing innovative heat recovery strategies the energy consumption for water heating and HVAC can be reduced even further. This study uses energy modeling and project cost analysis to evaluate three innovative control strategies. Results for a Passive House in Portland Oregon show a savings of about $70 annually with a payback period of 10 years. The same Passive House in Fairbanks Alaska with a different strategy would save $150 annually with a payback period of 5 years.
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Zhang, Yuelan. "Synthesis and Characterization of Nanostructured Electrodes for Solid State Ionic Devices." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14000.
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The demands for advanced power sources with high energy efficiency, minimum environmental impact, and low cost have been the impetus for the development of a new generation of batteries and fuel cells. One of the key challenges in this effort is to develop and fabricate effective electrodes with desirable composition, microstructure and performance. This work focused on the design, fabrication, and characterization of nanostructured electrodes in an effort to minimize electrode polarization losses.
Solid-state diffusion often limits the utilization and rate capability of electrode materials in a lithium-ion battery, especially at high charge/discharge rates. When the fluxes of Li+ insertion or extraction exceed the diffusion-limited rate of Li+ transport within the bulk phase of an electrode, concentration polarization occurs. Further, large volume changes associated with Li+ insertion or extraction could induce stresses in bulk electrodes, potentially leading to mechanical failure. Interconnected porous materials with high surface-to-volume ratio were designed to suppress the stress and promote mass transport. In this work, electrodes with these unique architectures for lithium ion batteries have been fabricated to improve the cycleability, rate capability and capacity retention.
Cathodic interfacial polarization represents the predominant voltage loss in a low-temperature SOFC. For the first time, regular, homogeneous and bimodal porous MIEC electrodes were successfully fabricated using breath figure templating, which is self-assembly of the water droplets in polymer solution. The homogeneous macropores promoted rapid mass transport by decreasing the tortuosity. And mesoporous microstructure provided more surface areas for gas adsorption and more TPBs for the electrochemical reactions. Moreover, composite electrodes were developed with a modified sol-gel process for honeycomb SOFCs. The sol gel derived cathodes with fine grain size and large specific surface area, showed much lower interfacial polarization resistances than those prepared by other existing processing methods.
Nanopetals of cerium hydroxycarbonate have been synthesized via a controlled hydrothermal process in a mixed water-ethanol medium. The formation of the cerium compound depends strongly on the composition of the precursors, and is attributed to the favored ethanol oxidation by Ce(IV) ions over Ce(IV) hydrolysis process. Raman studies showed that microflower CeO2 preferentially stabilizes O2 as a peroxide species on its surface for CO oxidation.
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Chvatík, Štěpán. "Asynchronní motor s vnějším rotorem." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-377075.
Full text
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Choi, Ji-Hoon. "Model based diagnostics of motor and pumps." Thesis, 2006. http://hdl.handle.net/2152/2849.
Full text
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Figueiredo, Manuel Ramos Pinto de. "Miniaturization of Microbial Fuel Cells Design, construction and performance studies." Master's thesis, 2016. https://hdl.handle.net/10216/89851.
Full text
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Figueiredo, Manuel Ramos Pinto de. "Miniaturization of Microbial Fuel Cells Design, construction and performance studies." Dissertação, 2016. https://hdl.handle.net/10216/89851.
Full text
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Sung, Min-Feng, and 宋旻峰. "Design and Fabrication of micro pumps and light weight current collectors applied on the Direct Methanol Fuel Cell." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/89012510456850117525.
Full textAbstract:
博士淡江大學
機械與機電工程學系博士班
99
Direct methanol fuel cells (DMFC) adopt a methanol solution as the liquid fuel. To maintain the stability and performance of DMFCs, an active liquid pump is typically used to supply fuel to the DMFCs. However, the power consumption of the pump affects the total efficiency of a DMFC system. Therefore, this research aims to design and fabricate both a magnetic micro pump and a diaphragm liquid/air micro pump suitable for direct use with methanol fuel cells. When applied to small DMFC charger systems, the low operation voltage and low current characteristics efficiently reduce the power consumption of the system and increase the efficiency of the entire system. The diaphragm liquid/air micro pump can drive anode liquid fuel and cathode air simultaneously. If applied to small DMFC systems, it can facilitate system miniaturization. Additionally, the material and weight of the current collector on the bipolar plates adopted in DMFCs will affect the volume and miniaturization of DMFCs. Therefore, this thesis applies the thermal coating technique, which is widely used in microelectromechanical systems (MEMS), to construct the circular lightweight current collectors by coating thin films on FR4 glass/epoxy substrate surfaces. The current collector developed in this research has the advantages of being low cost and lightweight with a flexible design, making it suitable for micro fuel cell applications. Finally, this thesis integrates the developed micro pumps, the circular light weight current collectors, and the boost circuit to construct a DMFC charge system.
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Walker, Benjamin A. "Development of a process for fabricating high-aspect-ratio, meso-scale geometries in stainless steel." Thesis, 1998. http://hdl.handle.net/1957/33710.
Full textAbstract:
Miniature energy and chemical systems (MECS) are miniature thermal, fluid, and chemical devices in the mesoscale size range between a sugar cube and a human fist. MECS take advantage of improved rates of mass and heat transfer that have been observed at the microscale. There are many potential applications for MECS, including manportable cooling and decentralized chemical processing. However, this potential has not been realized due to limitations in microfabrication. MECS devices require: 1) the fabrication of complex geometries incorporating microscale features; and 2) the thermal, mechanical and chemical properties of engineering metals. This thesis centers on developing a process for producing high-aspect-ratio, MECS devices in stainless steel.
In order to achieve this goal, laser ablation and diffusion bonding were employed in a metal microlamination (MML) process. The process involves stacking and bonding a series of laminates with low-aspect-ratio features to produce a composite device with high-aspect-ratio features (20:1). Laser ablation was used to form many laminates of 0.003" 302 stainless steel. These laminates were then joined via diffusion bonding.
The process developed in this thesis is unique in that it: 1) permits the MECS designer greater freedom in specifying microchannel widths; and 2) has produced microscale features in excess of 20:1 aspect ratio. Microchannels and microfins in excess of 20:1 aspect ratio were fabricated in stainless steel using this method. Resultant microchannels were tested by flowing air through them at various flow rates and measuring the resulting pressure drop. Experimental results were compared with theoretical calculations and other technical literature. Findings suggest that the
preliminary efforts to build a MECS device resulted in significant air blockage in the microchannel passageways. Sources of this blockage include bent fins, warpage and misalignment among others. Further process refinements are needed to prove the economic viability of this process.Graduation date: 1998
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Herron, Thomas G. "Design, modeling and performance of miniature reciprocating expander for a heat actuated heat pump." Thesis, 2004. http://hdl.handle.net/1957/31699.
Full textAbstract:
A miniature reciprocating expander is being developed as part of a larger program
to develop a heat actuated heat pump for portable applications. By utilizing the higher
energy density of liquid hydrocarbon fuels relative to batteries, a heat actuated heat pump
would be able to provide cooling for much longer than motor driven units of equal
weight. A prototype expander has been constructed and demonstrated to produce up to
22 W of shaft power at 2500 rpm using 60 psig, room temperature nitrogen as the input.
Assuming adiabatic conditions, the expander appears to operate at up to 80% isentropic
efficiency. However, when heat inflow to the expander is accounted for, the resulting
polytropic efficiency is about 10% lower. In addition to experimental results, models of
expander performance with different loss mechanisms are presented. These mechanisms
include over- and under-expansion, in-cylinder heat transfer, clearance volume, friction,
and valve pressure drop.Graduation date: 2005
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Lin, Yu-Hsiang, and 林裕翔. "Design and Construction of the Power Management Systems of a Hybrid Fuel-Cell Electric Vehicle." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/23863049969097642810.
Full textAbstract:
碩士明新科技大學
電機工程系碩士班
104
This thesis is topic in the development of a hybrid electric fuel cell power management system using on electric vehicles. The base architecture is to use DSP as the power management system for integrating electric vehicles’ motor-driven power. Electric cars usually use lithium iron phosphate batteries as the main power source. As a result, when the electric car starts, accelerating or climbing, the fuel cells are added to provide extra power to resolve the lithium iron phosphate battery power shortage. In addition, when the electric car decelerates or descents, the energy can be regenerated to lithium iron phosphate battery. Such characteristic is able to cope with the dramatic changes in loading. The hardware architecture is based on two DC motors and uses PWM to control four MOSFET switches to simulate electric car motors and their loading changes. The power portion is based on the power supply to simulate a 1 kW fuel cell and by using the boost converter to stabilize the power supply. Furthermore, we use 18650 batteries connection in series to simulate 2 kW iron phosphate lithium battery. In the software section, we use the DSP to program in achieving PWM generation, motor torque control, the boost converter voltage feedback control, and power management mechanism etc. Throughout the entire development process, we use the simulation software tools such as PSIM and MATLAB to simulate the operation of the whole system in order to verify the correctness of our circuits. From the measured results, it is certain that this system can achieve the purpose of the power management. Key words：Fuel cells、LiFePO4 battery、Boost converter、Motor drive control、Load torque control、LiFePO4 battery energy regeneration control、Power management control、Braking control.
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Smyth, Jonathan. "The design and analysis of a kerosene turbopump for a South African commercial launch vehicle." Thesis, 2013. http://hdl.handle.net/10413/11200.
Full textAbstract:
South Africa is one of the few developing countries able to design and build satellites; however it is reliant on other nations to launch them. This research addresses one of the main technological barriers currently limiting an indigenous launch capacity, namely the development of a locally designed liquid fuel turbopump. The turbopump is designed to function in an engine system for a commercial launch vehicle (CLV) with the capacity to launch 50-500 kg payloads to 500 km sun synchronous orbits (SSO) from a South African launch site.
This work focuses on the hydrodynamic design of the impeller, vaneless diffuser and volute for a kerosene (RP-1) fuel pump. The design is based on performance analyses conducted using 1D meanline and quasi-3D multi-stream tube (MST) calculations, executed using PUMPAL and AxCent software respectively. Specific concerns that are dealt with include the suction performance, cavitation mitigation, efficiency and stability of the pump. The design is intended to be a relatively simple solution, appropriate for a South African CLV application. For this reason the pump utilises a single impeller stage without a separate inducer element, limiting the design speed. The pump is designed to run at 14500 rpm while generating 889 m of head at a flowrate of 103.3 kg/s and consuming 1127.8 kW of power. The impeller has six blades with an outer diameter of 186.7 mm and axial length of 84.6 mm.
The impeller's high speed and power requirement make full scale testing in a laboratory impractical. As testing will be a critical component in the University of KwaZulu-Natal's turbopump research program, this work also addresses the scaling down of the impeller for testing. The revised performance and base dimensions of the scaled impeller are determined using the Buckingham-Pi based scaling rules. The test impeller is designed to run at 5000 rpm with a geometric reduction of 20%, using water as the testing medium. This gives an outer diameter of 147.8 mm and an axial length of 69.9 mm. At its design point the test impeller generates a total dynamic headrise of 67.7 m at a flow rate of 18 kg/s, with a power requirement of 15 kW. A method for maintaining a similar operating characteristic to the full scale design is proposed, whereby the scaled impeller's blade angle distribution is modified to maintain a similar diffusion characteristic and blade loading profile. This technique is validated by MST analysis for off-design conditions with respect to both speed and flowrate.M.Sc.Eng. University of KwaZulu-Natal, Durban 2013.
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Torres, Garibay Claudia Isela. "Manufacturing of intermediate-temperature solid oxide fuel cells using novel cathode compositions." Thesis, 2007. http://hdl.handle.net/2152/3049.
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Torres, Garibay Claudia Isela 1972. "Manufacturing of intermediate-temperature solid oxide fuel cells using novel cathode compositions." 2007. http://hdl.handle.net/2152/13229.
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Mahlangu, Winnie Mpumelelo. "Design, construction and operation of a membrane- and mediator-less microbial fuel cell to generate electrical energy from artificial wastewater with a concomitant bio-remediation of the wastewater." Thesis, 2015. http://hdl.handle.net/10539/18575.
Full textAbstract:
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Science.
April, 2015Microbial fuel cell (MFC) technology presents great potential for use as a dual system for industrial waste water remediation and electricity generation. The hurdle in up-scaling this technology has been identified as MFC-bioreactor architecture, both with regards to bioremediation and carbon source to electricity conversion rates. In addition to the latter’s limitations, the use of expensive mediators and membrane to enhance MFC performance renders the technology uneconomic to employ industrially. A 60mm high double chamber membrane and mediator-less MFC-bioreactor was designed, and constructed. The novel MFC-bioreactor made of transparent polyacrylic plastic had a total working volume of 8 litres with the anode chamber situated at the bottom and the cathode chamber at the top separated by a 10cm deep artificial membrane made up of glass wool, glass beads and marble balls. The MFC was operated under various operating parameters including; feeding modes (batch and continuous), with different substrate concentration at a range of external resistance (100-9000Ω) .The voltage produced during MFC operation was monitored and used to estimate the power density output of the MFC. The pseudo membrane was able to sufficiently separate the anode and cathode chambers allowing the development of potential difference and hence generation of current. The MFC demonstrated the potential for sustainable operation by producing and maintaining a stable power density of 2000mW/m2 when operated with an external resistance of 1000Ω. This power density was accompanied by a 73% remediation efficiency of the synthetic wastewater. It was concluded that the results of this research show proof of concept for a membrane-less MFC that can produce electrical energy in the absence of an electron shuffling mediator.
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Lee, Ki-tae 1971. "Development of perovskite and intergrowth oxide cathodes for intermediate temperature solid oxide fuel cells." 2006. http://hdl.handle.net/2152/13060.
Full text
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Rea, Jeremy Ryan. "An investigation of fuel optimal terminal descent." 2009. http://hdl.handle.net/2152/18393.
Full textAbstract:
Current renewed interest in exploration of the moon, Mars, and other planetary objects is driving technology development in many fields of space system design. In particular, there is a desire to land both robotic and human missions on the moon and elsewhere. The core of a successful landing is a robust guidance, navigation, and control system (GN&C). In particular, the landing guidance system must be able to deliver the vehicle from an orbit above the planet to a desired soft landing, while meeting several constraints necessary for the safety of the vehicle. In addition, due to the performance limitations of current launch vehicles, it is desired to minimize the amount of propellant used during the landing. To make matters even more complicated, the landing site may change in real-time in order to avoid previously undetected hazards which become apparent during the landing maneuver. The Apollo program relied heavily on the eyes of the astronauts to avoid such hazards through manual control. However, for missions to the lunar polar regions, poor lighting conditions will make this much more difficult; for robotic missions, this is not an option. It is desired to find a solution to the landing problem such that the fuel used is minimized while meeting constraints on the initial state, final state, bounded thrust acceleration magnitude, and bounded pitch attitude. With the assumptions of constant gravity and negligible atmosphere, the form of the optimal steering law is found, and the equations of motion are integrated analytically, resulting in a system of five equations in five unknowns. When the pitch over constraint is ignored, it is shown that this system of equations can be reduced analytically to two equations in two unknowns. In addition, when an assumption of a constant thrust acceleration magnitude is made, this system can be reduced further to one equation in one unknown. It is shown that these unknowns can be bounded analytically. An algorithm is developed to quickly and reliably solve the resulting one-dimensional bounded search. The algorithm is used as a real-time guidance and is applied to lunar and Mars landing test cases.text
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"Investigation of GDH/laccase enzymes for bio-energy generation." 2009. http://library.cuhk.edu.hk/record=b5896902.
Full textAbstract:
Chau, Long Ho.Thesis (M.Phil.)--Chinese University of Hong Kong, 2009.
Includes bibliographical references (leaves 73-82).
Abstract also in Chinese.
ABSTRACT --- p.III
摘要 --- p.IV
PUBLICATIONS CORRESPOND TO THIS THESIS --- p.V
ACKNOWLEDGEMENTS --- p.VI
TABLE OF CONTENTS --- p.VII
LIST OF FIGURES --- p.IX
LIST OF TABLES --- p.XI
ABBREVIATIONS AND NOTATIONS --- p.XII
Chapter CHAPTER 1 --- INTRODUCTION --- p.1
Chapter 1.1 --- Background --- p.1
Chapter 1.1.1 --- Types of Biofuel Cells --- p.1
Chapter 1.1.2 --- Properties of Using Enzymes in Bio-energy Generation Systems --- p.2
Chapter 1.1.3 --- Application of Bio-energy Generation Systems --- p.3
Chapter 1.2 --- Objectives of the Project --- p.4
Chapter 1.3 --- Organization of the Thesis --- p.5
Chapter CHAPTER 2 --- LITERATURE REVIEW --- p.7
Chapter 2.1 --- Working Principle of a Typical Fuel Cell --- p.7
Chapter 2.2 --- Introduction of Enzymes and Co-enzymes --- p.9
Chapter 2.3 --- Functions and Activities of Glucose Dehydrogenase (GDH) --- p.10
Chapter 2.4 --- Functions and Activities of Laccase --- p.11
Chapter 2.5 --- Introduction of Carbon Nanotubes (CNTs) --- p.12
Chapter 2.6 --- Introduction of Gold Nanoparticles (AuNPs) --- p.13
Chapter 2.7 --- Introduction of PdNPs --- p.14
Chapter 2.8 --- Summary of Literature Review --- p.15
Chapter CHAPTER 3 --- WORKING PRINCIPLE OF AN ENZYMATIC BIOFUEL CELL --- p.16
Chapter 3.1 --- Enzymatic Biofuel Cell Using Glucose as a Fuel --- p.16
Chapter 3.2 --- Deterministic Factors of the Fuel Cell´ةs Performance --- p.19
Chapter 3.3 --- Energy --- p.22
Chapter 3.3 --- Chapter Conclusion --- p.23
Chapter CHAPTER 4 --- ENZYMATIC BIOFUEL CELL DESIGN --- p.24
Chapter 4.1 --- Engineering Structure of the EBFC --- p.24
Chapter 4.2 --- Chemical Structures of the EBFCs --- p.25
Chapter 4.2.1 --- 1st Structure of EBFC - Au-Ll-CNTs-Ll-AuNPs-L2-{(GDH-NAD)/Laccase} --- p.26
Chapter 4.2.2 --- 2nd Structure of EBFC - Au-Ll-CNTs-Ll-AuNPs-L2-{GDH/Laccase} --- p.28
Chapter 4.2.3 --- 3rd Structure of EBFC- Pd-Ll-CNTs-Ll-AuNPs-L2-{(GDH-NAD)/Laccase} --- p.28
Chapter 4.2.4 --- 4th Structure of EBFC - Pd-Ll -A uNPs-L2-{(GDH~NAD)/Laccase} --- p.29
Chapter 4.2.5 --- 5th Structure of EBFC- Au-Ll-CNTs~L4'{(GDH-NAD)/Laccase} --- p.30
Chapter 4.2.6 --- 6th Structure ofEBFC 一 Au-Ll-CNTs-{L3- NAD-GDH/L4-Laccase} --- p.31
Chapter 4.3 --- Chapter Conclusion --- p.33
Chapter CHAPTER 5 --- FABRICATION AND CHARACTERIZATION OF EBFCS --- p.34
Chapter 5.1 --- Materials Preparation --- p.34
Chapter 5.1.1 --- Preparation of Linker 1 --- p.34
Chapter 5.1.2 --- Preparation of Linker 2 --- p.35
Chapter 5.1.3 --- Preparation of Linker 4 --- p.35
Chapter 5.1.4 --- Purification of Linkers --- p.35
Chapter 5.1.5 --- Verification of Linkers --- p.36
Chapter 5.2 --- 3-D Micro Electrode Fabrication --- p.37
Chapter 5.3 --- Electrode Modification --- p.40
Chapter 5.3.1 --- 1st Structure of EBFC --- p.40
Chapter 5.3.2 --- 2nd Structure of EBFC --- p.41
Chapter 5.3.3 --- 3rd Structure of EBFC --- p.41
Chapter 5.3.4 --- 4th Structure of EBFC --- p.42
Chapter 5.3.5 --- 5th Structure of EBFC --- p.42
Chapter 5.3.6 --- 6th Structure of EBFC --- p.42
Chapter 5.4 --- Characterization --- p.43
Chapter 5.4.1 --- Atomic Force Microscopy (AFM) --- p.43
Chapter 5.4.2 --- Scanning Electron Microscopy (SEM) & Energy-Disperse X-ray Spectroscopy (EDX) --- p.46
Chapter 5.4.3 --- Cyclic Voltammetry (CV) --- p.47
Chapter 5.5 --- Chapter Conclusion --- p.52
Chapter CHAPTER 6 --- RESULTS OF EBFCS --- p.53
Chapter 6.1 --- Experimental Setup --- p.53
Chapter 6.2 --- Results --- p.55
Chapter 6.2.1 --- Results of 1st EBFC --- p.55
Chapter 6.2.2 --- Results of 2nd EBFC --- p.57
Chapter 6.2.3 --- Results of 3rd EBFC --- p.58
Chapter 6.2.4 --- Results of 4th EBFC --- p.60
Chapter 6.2.5 --- Results of 5th EBFC --- p.60
Chapter 6.2.6 --- Results of 6th EBFC --- p.65
Chapter 6.3 --- Chapter Conclusion --- p.67
Chapter CHAPTER 7 --- CONCLUSION --- p.69
Chapter 7.1 --- Conclusion --- p.69
Chapter 7.2 --- Future Work for the Biofuel Cell Project --- p.70
Chapter 7.2.1 --- Study the Effect of Temperature Change --- p.70
Chapter 7.2.2 --- Study the Effect of the Change of pH in Substrates --- p.70
Chapter 7.2.3 --- Further Modified the Electrodes to Enhance the Output Power --- p.70
APPENDIX --- p.71
BIBLIOGRAPHY --- p.73
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"Fabrication and characterization of a porous CuO/CeO₂/Al₂O₃ biomorphic compound." 2009. http://library.cuhk.edu.hk/record=b5894162.
Full textAbstract:
Chiu, Ka Lok = 多孔生物遺態氧化銅/氧化鈰/氧化鋁之複合物料的製作及其定性分析 / 趙家樂.Thesis (M.Phil.)--Chinese University of Hong Kong, 2009.
Includes bibliographical references.
Abstract also in Chinese.
Chiu, Ka Lok = Duo kong sheng wu yi tai yang hua tong/yang hua shi/yang hua lu zhi fu he wu liao de zhi zuo ji qi ding xing fen xi / Zhao Jiale.
Abstract --- p.i
摘要 --- p.iii
Acknowledgment --- p.v
Table of contents --- p.vi
List of table captions --- p.x
List of figure captions --- p.xi
Chapter Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Carbon monoxide (CO) --- p.1
Chapter 1.2 --- Production of hydrogen from methanol for fuel cell --- p.2
Chapter 1.3 --- Catalysts for CO oxidation and methanol reforming --- p.5
Chapter 1.4 --- Copper-based catalysts --- p.6
Chapter 1.5 --- Mechanisms in the catalytic processes --- p.7
Chapter 1.6 --- Synthesis of Cu-based catalysts --- p.10
Chapter 1.7 --- Potential applications of the biomorphic CuO/CeO2/Al2O3 catalyst --- p.11
Chapter 1.8 --- Objectives and the thesis layout --- p.12
Chapter 1.9 --- References --- p.13
Chapter Chapter 2 --- Methods and Instrumentation --- p.16
Chapter 2.1 --- Sample preparations --- p.16
Chapter 2.1.1 --- Syntheses of the biomorphic samples --- p.16
Chapter 2.1.2 --- Syntheses of the control samples (R1 and R2) --- p.17
Chapter 2.2 --- Characterization --- p.18
Chapter 2.2.1 --- Scanning electron microscope (SEM) --- p.18
Chapter 2.2.2 --- Transmission electron microscopy (TEM) --- p.19
Chapter 2.2.3 --- X-ray powder diffractometry (XRD) --- p.20
Chapter 2.2.4 --- Fourier transform infrared (FTIR) spectroscopy --- p.21
Chapter 2.2.5 --- Raman scattering (RS) spectroscopy --- p.22
Chapter 2.2.6 --- Differential thermal analysis (DTA) --- p.22
Chapter 2.2.7 --- Thermogravimetric analysis (TGA) --- p.23
Chapter 2.2.8 --- Gas sorption surface analysis (GSSA) --- p.24
Chapter 2.3 --- Catalytic activity --- p.25
Chapter 2.3.1 --- CO oxidation --- p.25
Chapter 2.3.2 --- Partial oxidation of methanol (POMe) --- p.27
Chapter 2.3.3 --- Steam reforming of methanol (SRMe) --- p.28
Chapter 2.4 --- References --- p.29
Chapter Chapter 3 --- "Results, discussions and characterization" --- p.31
Chapter 3.1 --- Biomorphic samples --- p.31
Chapter 3.1.1 --- Macrostructures --- p.31
Chapter 3.1.2 --- SEM and TEM results --- p.32
Chapter 3.1.3 --- XRD analysis and chemical compositions --- p.35
Chapter 3.1.4 --- RS results --- p.41
Chapter 3.1.5 --- FTIR results --- p.44
Chapter 3.1.6 --- Thermal property --- p.46
Chapter 3.1.7 --- Porosity analysis --- p.48
Chapter 3.2 --- Control sample R1 --- p.52
Chapter 3.2.1 --- Microstructures --- p.52
Chapter 3.2.2 --- Surface area and porosity --- p.55
Chapter 3.2.3 --- Thermal property --- p.56
Chapter 3.2.4 --- "XRD, FTIR and RS results" --- p.58
Chapter 3.3 --- Control sample R2 --- p.60
Chapter 3.3.1 --- Microstructures --- p.60
Chapter 3.3.2 --- Surface area and porosity --- p.61
Chapter 3.3.3 --- "XRD, FTIR and RS results" --- p.62
Chapter 3.3.4 --- Thermal property --- p.63
Chapter 3.4 --- Formation mechanisms of the biomorphic samples --- p.64
Chapter 3.5 --- Impacts of the Cu/Ce/Al ratios on the CuO dispersion --- p.66
Chapter 3.6 --- Cotton biotemplate --- p.66
Chapter 3.7 --- Formation mechanisms of R1 and R2 --- p.67
Chapter 3.8 --- References --- p.69
Chapter Chapter 4 --- Evaluations of Catalytic Activities --- p.71
Chapter 4.1 --- CO oxidation --- p.71
Chapter 4.2 --- POMe --- p.79
Chapter 4.3 --- SRMe --- p.91
Chapter 4.4 --- Physical properties of the biomorphic samples before and after the reactions --- p.97
Chapter 4.5 --- Structure of the sample and its catalytic performance --- p.102
Chapter 4.6 --- CuO dispersion and the catalytic performance --- p.103
Chapter 4.7 --- Al2O3 and CeO2 and the catalytic performance --- p.105
Chapter 4.8 --- Catalytic performance of the biomorphic samples and R2 --- p.108
Chapter 4.9 --- References --- p.109
Chapter Chapter 5 --- Conclusions and suggestions for further studies --- p.110
Chapter 5.1 --- Conclusions --- p.110
Chapter 5.2 --- Future works --- p.112
Chapter 5.3 --- References --- p.114
44
Mai, Anh T. "Thermal hydraulic and fuel performance analysis for innovative small light water reactor using VIPRE-01 and FRAPCON-3." Thesis, 2011. http://hdl.handle.net/1957/26964.
Full textAbstract:
The Multi-Application Small Light Water Reactor (MASLWR) is a small natural circulation pressurized light water reactor design that was developed by Oregon State University (OSU) and Idaho National Engineering and Environmental Laboratory (INEEL) under the Nuclear Energy Research Initiative (NERI) program to address the growing demand for energy and electricity. The MASLWR design is geared toward providing electricity to small communities in remote locations in developing countries where constructions of large nuclear power plants are not economical. The MASLWR reactor is designed to operate for five years without refueling and with fuel enrichment up to 8 %. In 2003, an experimental thermal hydraulic research facility also known as the OSU MASLWR Test Facility was constructed at Oregon State University to examined the performance of new reactor design and natural circulation reactor design concepts.
This thesis is focused on the thermal hydraulics analysis and fuel performance analysis of the MASLWR prototypical cores with fuel enrichment of 4.25 % and 8 %. The goals of the thermal hydraulic analyses were to calculate the departure nucleate boiling ratio (DNBR) values, coolant temperature, cladding temperature and fuel temperature profiles in the hot channel of the reactor cores. The thermal hydraulic analysis was performed for steady state operation of the MASLWR prototypical cores. VIPRE Version 01 is the code used for all the computational modeling of the prototypical cores during thermal hydraulic analysis. The hot channel and hot rod results are compared with thermal design limits to determine the feasibility of the prototypical cores.
The second level of analysis was performed with a fuel performance code FRAPCON for the limiting MASLWR fuel rods identified by the neutronic and thermal hydraulic analyses. The goals of the fuel performance analyses were to calculate the oxide thickness on the cladding and fission gas release (FGR). The oxide thickness results are compared with the acceptable design limits for standard fuel rods.
The results in this research can be helpful for future core designs of small light water reactors with natural circulation.Graduation date: 2012
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Villarreal, Diego. "Reversible solid oxide cells for bidirectional energy conversion in spot electricity and fuel markets." Thesis, 2017. https://doi.org/10.7916/D8V988P6.
Full textAbstract:
The decarbonization of the energy system is one of the most complex and consequential challenges of the 21st century. Meeting this challenge will require the deployment of existing low carbon technologies at unprecedented scales and rates and will necessitate the development of new technologies that have the ability to transform variable renewable energy into high energy density products. Reversible Solid Oxide Cells (RSOCs) are electrochemical devices that can function both as fuel cells or electrolyzers: in fuel cell mode, RSOCs consume a chemical fuel (H₂, CO, CH₄, etc.) to produce electrical power, while in electrolysis mode they consume electric power and chemical inputs (H₂O, CO₂) to produce a chemical fuel (H₂, CO, CH₄, etc.). As such, RSOC systems can be thought of as flexible “energy hubs” that have unique potential to bridge the low power density renewable infrastructure with that of high energy density fuels in an efficient, dynamic, and bidirectional fashion. This dissertation explores the different operational sensitivities and design trade-offs of a methane based RSOC system, investigates the optimum operating strategies for a system that adapts to variations in the hourly spot electricity and fuel prices in Western Denmark, and provides an economic analysis of the system under a wide variety of design assumptions, operational strategies, and fuel and electricity market structures.
In order to perform such comprehensive analyses, a 0-D computational model of a methane based RSOC system was developed in Python. In fuel cell mode, the system generates power by consuming natural gas, while in electrolysis mode the system generates synthetic natural gas (SNG) by electrolyzing steam and catalytically hydrogenating recycled CO₂ into CH₄ downstream of the RSOC. The model's flexibility enables the simulation of “part-load” operation, allowing the user to assess the changes in output, efficiency, and operating cost as the system is operated across multiple points. The model has the ability to evaluate the impact that changes in design choices and operating parameters (Area Specific Resistance, temperatures, current density, etc.) have on the system as it interfaces with time varying exogenous factors such as fuel and electricity prices. As such, one of the main contributions of this model is the ability to run simulations in which the operating strategy of the RSOC system responds and adapts to varying market signals.
The computational model is used to develop a series of hourly optimizations for finding the optimal operating strategy for an RSOC system that can buy or sell electricity and gas in the spot electricity and natural gas markets in Western Denmark. After receiving an electricity and gas price signal, the optimization determines the operating mode (fuel cell, electrolysis or idle) and operating point (e.g., current density) that maximize the operating profits every hour for the given electricity and gas price pair. In order to avoid the speculation associated with traditional energy storage simulations, the system is “opened” at both ends, allowing it to instantaneously buy and sell any electricity or gas that is generated. Thus, the system never stores any of the products and it buys and sells them at the instantaneously available market price. By assuming that market prices reflect all existing information, this design choice removes the necessity of having to speculate about the future in order to determine the optimum operating strategy. This approach is one of the innovations presented in this work.
The optimizations aim at maximizing the operating profits at each hour of the year, and decisions of operating mode and point are based on marginal operating costs for each electricity and natural gas price pair. The full economic analysis, however, requires the understanding of how design choices (e.g. operating limits, heat management, gas recycling systems, etc.) affect the investment costs, and therefore a Total Plant Cost (TPC) model is developed. For each design choice, the TPC model is used to compute a cost of the system per m² of active electrode area or kW of output. This value, assumed to be a sunk cost that does not affect the operating decision, together with the operating profits resulting from the optimization is used to assess the overall profitability of the system. For a system with 100m² of active electrode area, conventional costing metrics suggest that the balance of plant (BoP) components for managing the system's heat (Heat exchangers, evaporators, condensers) are the main cost drivers and represent roughly 50% of the TPC. The cost of the electrochemical RSOC stack, assembly, power inverter and piping represent 35% of the cost, with the other 15% coming from pumps, compressors and the methanation system.
Twenty different optimization scenarios are developed in order to quantify the effect that system design choices, operating limits, and market prices have on the operating profile and on the overall economics of the system. The first 12 case studies are based on real hourly spot electricity and natural gas prices for the years 2009-2014 in Western Denmark. For the last 8 scenarios, a forecasted hourly time-series for electricity in the Danish grid for the year 2050 and two fixed SNG prices (high and a low) are used. The 2050 prices, which assume a fossil fuel free system, are used to understand the role and value that RSOC systems can offer in deeply decarbonized energy systems. For each optimization, different parameters such as the initial ASR and the operating limits (maximum current densities for each mode of operation) are varied in order to find the impact that these changes have on the system's design (balance of plant components), hourly operating mode, investment costs, hourly operating profits, and overall plant profits.
For the 2009-2014 optimizations, it is found that the sale of electricity (fuel cell mode) and fuel (electrolysis mode) is not large enough to cover the fixed costs associated with the plant. Fuel cell mode dominates the operation (61% of the time) with electrolysis representing only ~ 4% of the operating hours. ASR is found to have an important impact on the system's economics, due to the fact that a lowering of the ASR leads to a reduction in the size of the heat management system, which in turn reduces the Total Plant Cost.
For the 2050 dataset, it is found that under the high gas price scenario electrolysis mode dominates (50% of the time), and fuel cell operation represents 15% of the hours in the year. For the low SNG price, electrolysis still dominates (48% of the time), and fuel cell operation increases to 30% of the operating hours. Furthermore, for the high SNG scenario, the sale of fuel and electricity are large enough to cover the system's fixed cost, making the system attractive from an investment perspective. For the low SNG price, the system also becomes profitable when using ASR values of 0.4 ASR or below.
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Roseman, Jared. "Hybrid Biological-Solid-State Sytems: Powering an Integrated Circuit from ATP." Thesis, 2016. https://doi.org/10.7916/D8C53KNV.
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This thesis presents a novel hybrid biological solid-state system which makes use of biological components in an in-vitro environment to produce functionality incapable by CMOS circuits alone. A "biocell" comprised of lipids and ion pumps is mated to a CMOS IC in a compact configuration and the IC is powered solely from adenosine triphosphate (ATP), often referred to as the 'life energy currency.' The biocell is a fuel cell that produces a membrane potential in the presence of ATP which is used by the IC as an electrical power supply. The design represents the first of a new class of devices combining both biological and solid-state components, which exploit the unique properties of transmembrane proteins in engineered solid-state systems. This work also suggests that the richness of function of biological ion channels and pumps, functionality that is impossible to achieve in CMOS alone, may be exploited in systems that combine engineered transmembrane proteins as biological components integrated with solid-state devices.
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Schmidt, Dennis Patrick. "Design and testing of a modular hydride hydrogen storage system for mobile vehicles." 1985. http://hdl.handle.net/2097/27531.
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Aliahmad, Nojan. "Paper-based lithium-Ion batteries using carbon nanotube-coated wood microfiber current collectors." Thesis, 2013. http://hdl.handle.net/1805/3652.
Full textAbstract:
Indiana University-Purdue University Indianapolis (IUPUI)The prevalent applications of energy storage devices have incited wide-spread efforts on production of thin, flexible, and light-weight lithium-ion batteries. In this work, lithium-ion batteries using novel flexible paper-based current collectors have been developed. The paper-based current collectors were fabricated from carbon nanotube (CNT)-coated wood microfibers (CNT-microfiber paper). This thesis presents the fabrication of the CNT-microfiber paper using wood microfibers, coating electrode materials, design and assemblies of battery, testing methodologies, and experimental results and analyses. Wood microfibers were coated with carbon nanotubes and poly(3,4-ethylenedioxythiophene) (PEDOT) through an electrostatic layer-by-layer nanoassembely process and formed into a sheet, CNT-microfiber paper. The CNT loading of the fabricated paper was measured 10.1 μg/cm2 subsequently considered. Electrode material solutions were spray-coated on the CNT-microfiber paper to produce electrodes for the half and full-cell devices. The CNT current collector consists of a network structure of cellulose microfibers at the micro-scale, with micro-pores filled with the applied conductive electrode materials reducing the overall internal resistance for the cell. A bending test revealed that the paper-based electrodes, compared to metal ones, incurred fewer damages after 20 bends at an angle of 300o. The surface fractures on the paper-based electrodes were shallow and contained than metallic-based electrodes. The micro-pores in CNT-microfiber paper structure provides better adherence to the active material layer to the substrate and inhibits detachment while bending. Half-cells and full-cells using lithium cobalt oxide (LCO), lithium titanium oxide (LTO), and lithium magnesium oxide (LMO) were fabricated and tested. Coin cell assembly and liquid electrolyte was used. The capacities of half-cells were measured 150 mAh/g with LCO, 158 mAh/g with LTO, and 130 mAh/g with LMO. The capacity of the LTO/LCO full-cell also was measured 126 mAh/g at C/5 rate. The columbic efficiency of the LTO/LCO full-cell was measured 84% for the first charging cycle that increased to 96% after second cycle. The self-discharge test of the full-cell after charging to 2.7 V at C/5 current rate is showed a stable 2 V after 90 hours. The capacities of the developed batteries at lower currents are comparable to the metallic electrode-based devices, however, the capacities were observed to drop at higher currents. This makes the developed paper-based batteries more suitable for low current applications, such as, RFID tags, flexible electronics, bioassays, and displays. The capacities of the batteries at higher current can be improved by enhancing the conductivity of the fibers, which is identified as the future work. Furthermore, fabrication of an all solid state battery using solid electrolyte is also identified as the future work of this project.
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Supriya, Pawar V. "Fabrication of precipitation-hardened aluminum microchannel cooling plates for adsorption-based hydrogen storage systems." Thesis, 2013. http://hdl.handle.net/1957/38204.
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The need for clean and renewable fuel such as hydrogen is driven by a growing worldwide population and increasing air pollution from fossil fuels. One of the major barriers for the use of hydrogen in automotive industry is the storage of hydrogen. Physisorption is the most promising storage technique due to its high storage density, reversibility and rapid sorption kinetics besides being safe and volume-efficient. A major challenge for physisorption is the need to manage the heat of adsorption at cryogenic temperatures. In this thesis, a 6061 aluminum microchannel cooling plate is designed to remove the equivalent heat flux required by the adsorption of hydrogen within an adsorption bed. Therefore, the objective of this thesis is to determine whether laser welding and heat treating strategies can be developed for a 6061 aluminum microchannel cooling plate as part of a larger hydrogen storage thermal management system. Key manufacturing process requirements include controlling the hermeticity, strength and dimensional stability of the heat-treated weld joint. A hermetic microchannel cooling plate was successfully laser welded and heat treated using free convection in air to quench the solution heat treatment. The weld strength and warpage obtained were within acceptable limits. Experimental testing of the fabricated microchannel cooling plate showed acceptable percent error with an experimental heat removal rate within 13.4% of computational fluid dynamics (CFD) analyses and an average pressure drop error of 25%. Calculations show that the cooling plate developed could support a hydrogen storage thermal management system taking up 5.0% and 10.3% of the system displacement volume and mass, respectively.Graduation date: 2013
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Wang, Renxiang. "Lithium Ion Battery Failure Detection Using Temperature Difference Between Internal Point and Surface." 2011. http://hdl.handle.net/1805/2979.
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Indiana University-Purdue University Indianapolis (IUPUI)Lithium-ion batteries are widely used for portable electronics due to high energy density, mature processing technology and reduced cost. However, their applications are somewhat limited by safety concerns. The lithium-ion battery users will take risks in burn or explosion which results from some internal components failure. So, a practical method is required urgently to find out the failures in early time. In this thesis, a new method based on temperature difference between internal point and surface (TDIS) of the battery is developed to detect the thermal failure especially the thermal runaway in early time. A lumped simple thermal model of a lithium-ion battery is developed based on TDIS. Heat transfer coefficients and heat capacity are determined from simultaneous measurements of the surface temperature and the internal temperature in cyclic constant current charging/discharging test. A look-up table of heating power in lithium ion battery is developed based on the lumped model and cyclic charging/discharging experimental results in normal operating condition. A failure detector is also built based on TDIS and reference heating power curve from the look-up table to detect aberrant heating power and bad parameters in transfer function of the lumped model. The TDIS method and TDIS detector is validated to be effective in thermal runaway detection in a thermal runway experiment. In the validation of thermal runway test, the system can find the abnormal heat generation before thermal runaway happens by detecting both abnormal heating power generation and parameter change in transfer function of thermal model of lithium ion batteries. The result of validation is compatible with the expectation of detector design. A simple and applicable detector is developed for lithium ion battery catastrophic failure detection.