Počet záznamů: 1
Wall Shear Stress Induced by a Large Bubble Rising in an Inclined Rectangular Channel
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SYSNO ASEP 0431846 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Wall Shear Stress Induced by a Large Bubble Rising in an Inclined Rectangular Channel Tvůrce(i) Tihon, Jaroslav (UCHP-M) RID, ORCID, SAI
Pěnkavová, Věra (UCHP-M) RID, ORCID, SAI
Vejražka, Jiří (UCHP-M) RID, ORCID, SAIZdroj.dok. International Journal of Multiphase Flow. - : Elsevier - ISSN 0301-9322
Roč. 67, DEC (2014), s. 76-87Poč.str. 12 s. Jazyk dok. eng - angličtina Země vyd. GB - Velká Británie Klíč. slova taylor bubble ; bubble rise velocity ; bubble shape Vědní obor RIV CI - Průmyslová chemie a chemické inženýrství CEP GAP101/12/0585 GA ČR - Grantová agentura ČR Institucionální podpora UCHP-M - RVO:67985858 UT WOS 000345475700007 DOI 10.1016/j.ijmultiphaseflow.2014.07.005 Anotace The rise of single air bubbles in inclined rectangular channels was experimentally investigated. Two-segment electrodiffusion probes were used to measure wall shear rate profiles along the passing bubbles. They provided information on reverse flow in a liquid film separating the bubble from the wall, capillary waves appearing at the bubble tail, and near-wall flow fluctuations in the bubble wake. The corresponding bubble shapes and rise velocities were obtained from simultaneous visual observations done by a high-speed camera. The experiments were carried out for three channel depths (1.5, 4, and 8 mm), various channel inclinations (from 5° to 90°), bubble volumes (from 1 to 80 ml), and liquid up-flow velocities (from 0 to 0.2 m/s). In vertical channels, the wall shear rate trace of a bubble rise is primarily influenced by the channel depth. As the frontal shape of large bubbles does not change with the bubble size, also the wall shear rate measured under these bubbles evolves in the same manner. In inclined channels, the liquid film is unequally distributed above and under the bubble with the maximum reverse flow observed under the bubble at middle inclinations. Laminar liquid co-flow makes the liquid film around the bubble thicker and in inclined channels slightly pushes the bubble toward the center-line position. The bubble velocity scaling based on the channel perimeter is confirmed to be suitable for vertical channels with stagnant liquid. The linear relationship between the bubble rise and liquid mean velocity is identified under co-flowing conditions at all channel inclinations. Pracoviště Ústav chemických procesů Kontakt Eva Jirsová, jirsova@icpf.cas.cz, Tel.: 220 390 227 Rok sběru 2015
Počet záznamů: 1