20.500.12556/RUL-180941 Merjenje pretoka CO▫$_2$▫ z vsebnostjo nečistoč s kritičnimi zvočnimi šobami Flow rate measurement of CO▫$_2$▫ containing impurities using critical flow venturi nozzles Kritične zvočne šobe so na področju merjenja pretoka plinov pogosto uporabljene kot sekundarni etaloni. V povezavi s kritičnimi zvočnimi šobami je ogljikov dioksid (CO▫$_2$▫) zaradi svojih lastnosti in vse širše uporabe zanimiv za raziskavo. Ker se v praktičnih aplikacijah pojavlja z nečistočami, smo se osredotočili na merjenje pretoka CO▫$_2$▫ z nečistočami, ki jih je v našem primeru predstavljal dušik (N▫$_2$▫). Glavni rezultat vsake meritve je bil potek pretočnega koeficienta v odvisnosti od Re števila. Pretočni koeficient je lastnost šobe in je odvisen od medija in razmer, predstavlja razmerje med dejanskim masnim pretokom in idealnim teoretičnim. Najprej smo izvedli umerjanje šob z zrakom, čistim CO▫$_2$▫ in N▫$_2$▫ ter primerjali eksperimentalne rezultate z napovedjo teoretičnega modela in rezultati predhodnih umerjanj. Nato smo vzpostavili merilno progo za generiranje plinskih mešanic. Umerili in kasneje uporabljali smo krmilnike masnega pretoka, kot referenčni merilnik je bil uporabljen merilnik s pomičnim batom. Pokazali smo linearno povezavo med pretočnim koeficientom in deležem N▫$_2$▫. Pri vseh meritvah smo ocenili merilno negotovost. Critical flow nozzles are widely used as secondary standards in gas flow measurement. In the context of critical flow nozzles, carbon dioxide (CO▫$_2$▫) is of particular interest for investigation due to its properties and its increasingly widespread use. Since CO▫$_2$▫ typically contains impurities in practical systems, this study focuses on the measurement of CO▫$_2$▫ flow with impurities, represented by nitrogen (N▫$_2$▫). The primary result of each measurement is the discharge coefficient as a function of the Reynolds number. The discharge coefficient is a nozzle-specific parameter that depends on the working fluid and operating conditions and is defined as the ratio of the actual mass flow rate to the theoretical mass flow rate. The nozzles were first calibrated using air, pure CO▫$_2$▫, and N▫$_2$▫, and the experimental results were compared with theoretical model predictions and previous calibration data. A dedicated measurement system for generating gas mixtures was subsequently established. Gas mixtures were prepared using calibrated mass flow controllers, while a piston prover was employed as the reference flow measurement device. A linear relationship between the discharge coefficient and the N▫$_2$▫ fraction in the gas mixture was demonstrated. Measurement uncertainty was evaluated for all measurements. merjenje pretoka kritične zvočne šobe pretočni koeficient ogljikov dioksid plinske mešanice vibracijska relaksacija flow measurement critical sonic nozzles discharge coefficient carbon dioxide gas mixtures vibrational relaxation true false false [N. Golob] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2026-03-20 08:30:52 2026-03-20 08:30:58 2026-03-24 11:16:13 0000-00-00 00:00:00 2026 0 Ljubljana 0 XX, 58 str. 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 532.57:543.272.62:62-225(043.2) 283337 272782595 46666.pdf 46666.pdf 1 481B03DC5D61DA9E951B6151652D98A3 fb919dd2b84e69786c8f2f7bc6e329ae6abbdc5bef32617c23934bb62cfafaa5 a7a1eced-242e-11f1-b0ab-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=230947 Fakulteta za strojništvo 0 0 0