Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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  • Master Thesis
    Modelling of an Impact Resistant Navigation System for Gun Projectiles Based on Low Cost Mems Sensors
    (01. Izmir Institute of Technology, 2021) İnel, Selahattin Can; Özdemir, Serhan
    In this thesis, guided projectiles are studied in three aspects: a navigation system design, CFD analysis of a guided projectile for low launch velocities and durability of electronic components under extreme firing conditions. During the thesis progress, MATLAB & Simulink, FlightGear and Ansys-Fluent software are used for simulations and 3D object modelling. Basic Finner Reference Projectile is chosen as a test bed for navigation simulation, since the dimensions and some of the flight parameters are already available as open source. However, a missile state-space model which is given by Raytheon is used for navigation simulations instead of a guided projectile model due to inaccessibility of some critical aerodynamic parameters for 6-DoF model. Navigation system is designed using preset guidance methodology which uses built-in inertial sensors to correct the course for given targets which location are loaded prior to launching. CFD calculations of the Basic Finner Reference Projectile are conducted for low launching velocities to light the way for the aerodynamic conditions of non-explosive firing equipments such as catapults and airguns. Furthermore, the durability of common electronic components under extreme projectile firing conditions are visualized up to 20,000g and the functionality of regular off the shelf microcontrollers and sensors are tested using Hopkinson Bar test equipment. A navigation model simulation of a guided munition is created combining FlightGear and MATLAB & Simulink satisfying the given different criteria for pole placement method, LQR controller and observer design.
  • Master Thesis
    Improvement of the Thermal Performance of an Aluminium Window Frame With Cfd Analysis
    (Izmir Institute of Technology, 2019) Gökçen, Gökçe; Başaran, Tahsin
    Most of the primary energy used in the world belongs to fossil fuels. Energyefficient activities are carried out in many different sectors in order to prevent the depletion of the reserves of these resources. The building sector is one of them and many different studies are being carried out to reduce the energy consumed in the buildings. Windows are the main unit of heat losses and gains in buildings. In literature, the main reasons for heat losses through windows are usually stated as glass units due to their large areas and relatively higher overall heat transfer coefficient. However, windows frames are as important as glass units because they also have higher heat transfer. Since the most commonly used material in window frames, which is aluminium, has the highest thermal conductivity value, this topic should be investigated. In this study, two different strategies are presented to improve the thermal transmittance of an aluminium frame without changing the frame geometry. The first strategy presented is the improvement of the gasket and thermal break materials in which high thermal conductivity materials are used which have a considerable impact on the thermal performance of aluminium window frames. The second strategy is to fill the cavities in aluminium profiles with polyurethane foam in order to reduce convection effects. Two dimensional CFD simulations of the aluminium window frame, modelled with information from the manufacturer, were used to investigate these improvement strategies. As a result of the study, the importance of thermal break and gasket materials used in the aluminium window frame has been seen and the thermal conductivity of these materials has a considerable effect on the thermal performance of the windows. Moreover, the polyurethane foam filled air cavities in the aluminium frame have positively affected the thermal performance of window as proposed and %29.44 improvements occurred.