20.500.12556/RUL-139751 Analiza zastojnega učinka pri umerjanju krilnega anemometra Analysis of the blockage effect in calibration of vane anemometers Umerjanje anemometrov za merjenje hitrosti zraka izvajamo v vetrovnikih, kjer lahko zagotovimo stabilno in homogeno hitrostno polje. Zaradi prisotnosti merilnega objekta nastopi v merilni sekciji t. i. zastojni učinek, ki povzroči spremembo hitrostnega polja. Velikost zastojnega učinka je v splošnem odvisna od tipa merilnika ter razmerja prečnega prereza merilnika in efektivne velikosti merilne sekcije. Zastojni učinek ima lahko znaten vpliv na rezultate umerjanja, zato je poznavanje hitrostnega polja, ki nastopi v merilni sekciji, ključno za morebitno korekcijo rezultatov umerjanja oz. zmanjšanje merilne negotovosti, povezane z zastojnim učinkom. Z uporabo vetrovnika in laserskega Dopplerjevega anemometra (LDA) smo izvedli umerjanje krilnega anemometra pri več različnih hitrostih in na podlagi mednarodnih vodil za umerjanje merilnikov hitrosti zraka eksperimentalno ocenili velikost zastojnega učinka in njegov vpliv na merilno negotovost pri izvedenem umerjanju. Za boljšo predstavo o hitrostnih razmerah v vetrovniku smo predstavili hitrostna polja na različnih mestih merilne sekcije ter analizirali rezultate različnih metod korekcije zastojnega učinka. The calibration of anemometers made for measuring the speed of air is performed in wind tunnels, which allow us to ensure a stable and homogenous velocity field. Due to the presence of a measuring object, the so-called “blockage effect” appears in the test section, which causes disturbances in the velocity field. The size of the blockage effect generally depends on the type of anemometer used and the ratio between the anemometers cross-section and the effective surface of its test section. Blockage effect can significantly affect the results of the calibration, so having an extensive knowledge about the speed profile of the test section is crucial for any further correction of the results of the calibration or to lower any kind of measuring uncertainty regarding the blockage effect. By using a wind tunnel and Doppler’s laser anemometer (LDA) we had performed the calibration of the vane anemometer at multiple different speeds and experimentally assessed the size of the blockage effect and the impact it has on the measuring uncertainty of the preformed calibration, all of which was done on the basis of the international guidelines for anemometer calibration. To get a better understanding and perception of the velocity conditions in the wind tunnel, we presented the speed profiles at different parts of the test section and analysed the results of the different blockage effect correction methods. krilni anemometer zastojni učinek umerjanje korekcija zastojnega učinka vane anemometer blockage effect calibration blockage effect correction true false false [M. Skender] Slovenski jezik Angleški jezik Diplomsko delo/naloga 2022-09-07 08:30:47 2022-09-07 08:30:51 2023-11-29 13:25:57 0000-00-00 00:00:00 2022 0 Ljubljana 0 XXI, 50 str. 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 533.6:531.7(043.2) 244388 136850691 17617.pdf 17617.pdf 1 BB1B1BB88E412995D9A62298403003AF f6003ddea421366dac478db59ba4dd6262ef5740b071cb8b8142d7b32eb83992 916b0174-2e76-11ed-92af-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=160364 Fakulteta za strojništvo 0 0 0