Garcia, ValdemarSobrinho Teixeira, João Alberto2010-04-302010-04-302000Garcia, Valdemar; Teixeira, João Sobrinho (2000). Gas-liquid flow dispersion in a vertical pipe. Recent advances in transport phenomena. Elsevier. p. 69-74. ISBN 97828429920719782842992071http://hdl.handle.net/10198/2268The main purpose of this work was to analyse the transport f a solute dissolved in a flowing liquid in upward direction at low velocity along a vertical column, in the bottom of which slugs are injected. These experiments were carried out in a column with an internal diameter of 19 mm and height of 344.2 cm. Liquid flowrates of 1.0, 2.5 and 5.5 cm3/s were utilized, and an enlarged variety of gas flowrates were injected; in these conditions the slugs were normally formed at a frequency between 0.78 and 88.1 s-1. The scientific techniques used in this study based on the measurement, at the top of the column, of a tracer solution injected in its bottom. A simplified physical model was developed to explain the results obtained, which was based on two hypotheses: (i) the flow of the liquid between two slugs is laminar, being the respective profile of velocity approximate to the Poiseuille law; (ii) the stirring action provoked by each slug in the liquid is limited to a small region, the wake of slug, which can be taken as a “perfectly mixed tank”. One of the most relevant conclusions derived from this work and which at first analysis would appear paradoxical, is that, it is possible to proceed in such a way that the bubbling of gas through a liquid will provoke less dispersion in the residence time of liquid than which would be obtained in the absence of the introduction of gas.engGas-liquid flowSlugsWake of slugDispersionVertical tubebook part