20.500.12556/RUL-184520 Upor v področju srednjih Reynoldsovih števil pri toku skozi natego magistrsko delo Resistance in the region of intermediate Reynolds numbers in flow through a constriction V magistrskem delu je bil eksperimentalno raziskan tok vode skozi hidravlično natego v območju srednjih Reynoldsovih števil. Posebna pozornost je bila namenjena pretvorbi mehanske energije v notranjo energijo vode ter vplivu geometrije cevi, višinske razlike, preseka cevi in dolžine cevi na tokovne razmere v sistemu. Za izvedbo raziskave je bila zasnovana eksperimentalna postavitev hidravlične natege, ki je omogočala sistematično spreminjanje posameznih okoliščin in merjenje časa pretoka vode skozi cev. Na podlagi izmerjenih časov so bili določeni prostorninski pretok, povprečna hitrost toka in Reynoldsovo število. Rezultati so bili primerjani s teoretičnimi napovedmi idealiziranega toka, določenimi z Bernoullijevo enačbo. Rezultati so pokazali, da ima geometrija cevi opazen vpliv na tokovne razmere predvsem pri manjših premerih cevi, kjer dodatni ovinki povečajo pretvorbo mehanske energije v notranjo energijo vode. Z večanjem višinske razlike se povečujeta hitrost toka in Reynoldsovo število, vendar so bile izmerjene hitrosti v vseh primerih bistveno manjše od teoretičnih vrednosti idealnega toka. Analiza vpliva preseka cevi je pokazala, da večji premeri omogočajo večje hitrosti toka in manjši delež pretvorjene mehanske energije. Osrednji del raziskave je predstavljala analiza vpliva dolžine cevi na pretvorbo mehanske energije v notranjo energijo vode. Ugotovljeno je bilo, da se energijska višina mehanskih izgub z dolžino cevi približno linearno povečuje, kar je omogočilo uporabo linearnih aproksimacij za nadaljnjo analizo rezultatov. Na podlagi presečišč aproksimacij z ordinatno osjo je bilo mogoče oceniti del energijske višine, ki je povezan s vstopom vode v cev. Raziskava potrjuje, da so mehanske izgube pri toku skozi realne cevne sisteme izrazite in da idealizirana uporaba Bernoullijeve enačbe brez upoštevanja pretvorbe mehanske energije v notranjo energijo ne opisuje ustrezno dejanskih tokovnih razmer. Poleg raziskovalne vrednosti ima uporabljena eksperimentalna postavitev tudi didaktični pomen, saj omogoča neposredno primerjavo med teoretičnimi modeli in eksperimentalnimi meritvami pri obravnavi toka tekočin. This master’s thesis presents an experimental study of water flow through a hydraulic siphon in the range of intermediate Reynolds numbers. Particular attention was given to the conversion of mechanical energy into the internal energy of water, as well as to the influence of pipe geometry, elevation difference, pipe cross-sectional area, and pipe length on the flow conditions within the system. To carry out the research, an experimental setup of a hydraulic siphon was designed, enabling systematic variation of individual conditions and measurement of the time of water flow through the pipe. Based on the measured times, the volumetric flow rate, average flow velocity, and the Reynolds number were determined. The results were compared with theoretical predictions of idealised flow derived using the Bernoulli equation. The results showed that pipe geometry has a noticeable influence on flow conditions, particularly in pipes with smaller diameters, where additional bends increase the conversion of mechanical energy into the internal energy of water. With increasing elevation difference, both flow velocity and Reynolds number increase; however, the measured velocities were in all cases significantly lower than the theoretical values for ideal flow. The analysis of the influence of pipe cross-section demonstrated that larger diameters enable higher flow velocities and a lower proportion of converted mechanical energy. The central part of the research consisted of analysing the influence of pipe length on the conversion of mechanical energy into the internal energy of water. It was found that the mechanical energy loss head associated with mechanical losses increases approximately linearly with pipe length, which enabled the use of linear approximations for further analysis of the results. Based on the intercepts of these approximations with the vertical axis, it was possible to estimate the portion of the mechanical energy loss head associated with the water entering the pipe. The research confirms that mechanical losses in flow through real pipe systems are significant and that the idealised application of the Bernoulli equation, without accounting for the conversion of mechanical energy into internal energy, does not adequately describe actual flow conditions. In addition to its research value, the experimental setup also has educational significance, as it enables a direct comparison between theoretical models and experimental measurements in the study of fluid flow. fizika hidravlična natega Bernoullijeva enačba Reynoldsovo število tok tekočine mehanske izgube pretvorba mehanske energije energijska višina tok skozi cev hidrodinamika eksperimentalno delo hydraulic siphon Bernoulli equation Reynolds number fluid flow mechanical losses conversion of mechanical energy head loss pipe flow hydrodynamics experimental study true false false K. Žugič Slovenski jezik Angleški jezik Magistrsko delo/naloga 2026-07-09 08:31:02 2026-07-09 08:31:10 2026-07-10 10:49:57 0000-00-00 00:00:00 2026 0 Ljubljana 0 Ljubljana 65 str. 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 53(043.2) 205916 284355075 52239.pdf 52239.pdf 1 EC43575045A5EB9545556324E8BB849C 84d1a4c24febd2df5adce39e06babae1a413e09ae2f109fd6a50103a6cfe0884 a728666f-7b5f-11f1-9b0d-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=237393 Pedagoška fakulteta 0 0 0