Measurement Accuracy of a Mono-fiber Optical Probe in a Bubbly Flow

0343074 - ÚCHP 2011 RIV GB eng J - Journal Article
Vejražka, Jiří - Večeř, M. - Orvalho, Sandra - Sechet, Ph. - Růžička, Marek - Cartellier, A.
Measurement Accuracy of a Mono-fiber Optical Probe in a Bubbly Flow.
International Journal of Multiphase Flow. Roč. 36, č. 7 (2010), s. 533-548. ISSN 0301-9322. E-ISSN 1879-3533
R&D Projects: GA ČR GA104/07/1110; GA ČR GP104/06/P287; GA AV ČR(CZ) IAA200720801
Institutional research plan: CEZ:AV0Z40720504
Keywords : optical probe * bubble-fiber interaction * void fraction
Subject RIV: CI - Industrial Chemistry, Chemical Engineering
Impact factor: 1.772, year: 2010

The measurement accuracy of a mono-fiber optical probe is studied experimentally using isolated bubbles rising freely in a still liquid. The dwell time of the probe tip within the gas phase, which is obtained from both the optical probe signal and high-speed visualization, is compared with the dwell time expected for a non-perturbed bubble. The measurement error results mainly from the intrusive nature of the optical probe, which modifies the behavior of the bubble when it comes into contact with the probe tip. The measured dwell time therefore differs from its ideal value that would be found with an unperturbed bubble. For a wetting liquid, the interaction increases the dwell time if the bubble is pierced near its pole, and shortens it for piercing near the equator. It is shown that the error can be correlated with a modified Weber number, and this correlation is helpful for sensor selection and for uncertainty estimate.
Permanent Link: http://hdl.handle.net/11104/0185636