Monitoring environmental conditions in harsh environments
| Autor: | Padilha Leitzke, Juliana |
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| Jazyk: | angličtina |
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| Popis: | Ice formation can occur in many applications and adversely affect the performance of a system. Examples are heat exchangers in cooling systems, ice accretion on wind turbines or overhead powerlines or even icing on surfaces of aircraft. In addition, in certain industrial processes, ice formation on surfaces can occur under almost vacuum conditions and at very low to cryogenic temperatures due to residual water molecules. In order to control and monitor ice formation, capacitive sensors are a powerful tool that can be used together with other sensors that monitor relevant environmental conditions parameters, such as pressure and temperature.In this thesis, a capacitive sensor setup was developed for ice measurement under almost vacuum conditions and at very low to cryogenic temperatures with a separation of sensor element and sensor electronics, such that the sensor electronics can reside outside the cold environment. It is demonstrated that the permittivity of such ice formation is enough for measurement using the proposed sensor configuration even at long-term measurements. In addition, a wing model was used in order to test a portable system in real atmospheric conditions including altitude variations for pressure distribution measurement. The data from the sensors is transmitted to a base station using wireless communication and the pressure difference between the sensor located on the wing and the reference sensor can be used to estimate speed. Furthermore, Electrical Impedance Tomography Spectroscopy (EITS) simulations were performed to investigate the feasibility of reconstructing different distributions of ice and water mixtures as well as a study on electrode geometry optimization, reconstruction algorithm, and measurement system investigations. Important parameters such as relaxation time could be reconstructed from the simulated measurement data.In summary, it is shown that portable, wireless and low-cost sensor systems can be used for monitoring ice accretion as well as relevant environmental parameters such as pressure and temperature in different applications. Juliana Padilha Leitzke Dissertation Alpen- Adria-Universität Klagenfurt 2021 |
| Databáze: | OpenAIRE |
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