20.500.12556/RUL-125728 Media flow analysis of single-channel pre-mixed liquid CO2 and MQL in sustainable machining Analiza pretoka enokanalne mešanice kapljevitega CO2 in MQL pri trajnostnem odrezavanju Single-channel supply of pre-mixed liquid carbon dioxide (LCO2) and minimum quantity lubrication (MQL) represents a state-of-the-art LCO2 assisted machining. However, to fully understand and optimize cooling and lubrication provided by the LCO2 + MQL, a fundamental media flow analysis is essential, yet not researched enough. Therefore, in this paper, media flow velocity and oil droplet size were analysed in supplying line and at the nozzle outlet using high-speed camera and proprietary single-channel system. Results indicate that pre-mixed media flow velocity is mainly influenced by the LCO2 expansion rate upon the nozzle outlet, wherein oil droplet size is largely dependent on the solubility between oil and LCO2. Media flow velocity increases significantly from an average of 40 m/s in the supplying line to the excess of 90 m/s at the nozzle outlet due to the pressure drop and LCO2 expansion. Furthermore, this volume expansion causes the oil droplet to increase to the point of critical, unstable droplet size. Afterward, the unstable oil droplet breaks up into smaller oil droplets. It was found, that nonpolar oil, with greater solubility in LCO2, compared to the polar oil, provides droplets as small as 2 [micro]m in diameter. Smaller oil droplets positively reflect on tool wear and tool life in LCO2 assisted machining, as the longest tool life was achieved by using the nonpolar oil for pre-mixed LCO2 + MQL flow analysis flow velocity droplet size single-channel supply liquid carbon dioxide - LCO2 minimum quantity lubrication - MQL LCO2 assisted machining analiza pretoka hitrsot pretoka velikost kapljic enokanalni dovod kapljeviti ogljikov dioksid oljna megla LCO2 podprto odrezavanje true false true Angleški jezik Slovenski jezik Članek v reviji 2021-04-06 10:50:51 2021-04-06 10:51:01 2022-09-05 03:52:18 0000-00-00 00:00:00 2021 0 0 Str. 3-10 no. 1/2 Vol. 67 Jan.-Feb. 2021 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 621.9(045) 0039-2480 10.5545/sv-jme.2020.7076 54067971 762116 RAZ_Grguras_Damir_2021.pdf RAZ_Grguras_Damir_2021.pdf 1 D7BCBFA5CFD4592800EF6F5F658DCD7E 4bb2bdfba7b0db6ba784b177437c3acd9b3635b5c3d9a86b575568fac8be67c7 c751c226-a1bb-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=141585 https://www.sv-jme.eu/sl/article/media-flow-analysis-of-single-channel-pre-mixed-liquid-co2-and-mql-in-sustainable-machining/ 1 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=141583 Fakulteta za strojništvo Strojniški vestnik 0 0 0