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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Scoop optimization : A preliminary study

Artola, Bixente January 2019 (has links)
Scoops are important parts in an aircraft engine design, as they provide airflowto different equipment and subsystems. The optimization of such a component isessential in order to find a design that can perform properly within a range of flightconditions, with a minimum impair of main flow aerodynamic performances. Scoopdesign methods are generally based on previous experimental results and are usuallyconstrained by the limited space available. The studied configuration concerns theflush scoop located inside the secondary flow of turbofans which provides flow fora turbine cooling equipment. Depending on flight conditions and engine workingpoint, this scoop will experience various flow regimes, from low mass flow rates tochoke flows. Therefore, the study of several scooped mass flow rates is mandatoryto extract the scoop behaviour. The thesis concerns the preliminary step beforea 3D CFD optimization : a study of influence is run on the baseline geometry inorder to investigate the robustness of the solution computed using different methodsand to determine the parameters to be optimized. Firstly, the full post-processingmethodology is defined to properly evaluate the performance of a design (scoopefficiency, induced pressure losses). A second step consists in analysing the abilityof CFD solvers to capture the different flow behaviour. This point is addressed bycomparing solvers (Fluent, elsA, PowerFLOW), meshes (structured, unstructured)and turbulence models. The third step deals with the optimization strategy definitionto improve the scoop design and thus the engine fuel consumption.
2

Solar powered motorized blinds: A case study on using energy harvesting to power internet of things applications

Drake, David January 2016 (has links)
Smart devices capable of harvesting their own energy have advantages over their wired or battery-powered alternatives including improved portability, simplified installation, and reduced maintenance and operating costs. This thesis studies energy harvesting technology through a case study of a solar-powered motorized window shade. An analytical and experimental evaluation of window attenuation found that windows reduced the ability of solar cells to produce photocurrent by 30%-70%. This still allows significant potential to power small electronics so a prototype motorized window blind was designed and assembled. The solar array was mounted to the roller blind's bottom rail and power is conveyed to the control electronics and motor in the unit’s top cylinder through wires embedded in the shade’s fabric. A simple battery system was implemented to ensure the prototype could remain powered in the absence of light. Various forms of powerflow in the prototype were evaluated. Experimental evaluation of joule heating within the conductive textile indicates that a temperature gradient that is less than 10 °C develops, meaning it is safe for use. The prototype was designed with artificial friction to prevent the blinds from slipping when not in use. An experimentally validated motor model was developed and used to determine that the system could use up to 46% less energy if the artificial friction was removed. A pseudo-empirical system model was developed to simulate the interaction between system electronics. Simulation results indicate that the system would remain consistently powered if placed behind a south-facing window that receives a consistent supply of direct sunlight and attenuates that light by less than 75%. These results also indicate that the unit would remain powered in the absence of light for 13 days. Similar methods could be used to evaluate future energy harvesting systems. / Thesis / Master of Applied Science (MASc)

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