%0 Book Section %1 statphys23_0237 %A Salinas-rodriguez, E. %A Rodriguez, R.F. %A Zamora, J.M. %B Abstract Book of the XXIII IUPAP International Conference on Statistical Physics %C Genova, Italy %D 2007 %E Pietronero, Luciano %E Loreto, Vittorio %E Zapperi, Stefano %K bubbly flows fraction kinetic polydispersity stability statphys23 theory topic-3 void waves %T Volume fraction correlation function for a polydispersed bubble flow %U http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=237 %X Bubble flow is characterized by discrete bubbles, which are approximately uniformly distributed in a continuous liquid phase. The homogeneous regime is characterized by almost uniformly sized bubbles and it is well known that a swarm of small bubbles enhances the rate transfer phenomena these multiphase systems. However, the effects that size polydispersity may produce on the stability of kinematic waves, mean bubble velocity, kinematic and dynamic wave velocities is, to our knowledge, not yet well established. We generalize previous kinetic models to incorporate size polydispersity of bubbles to calculate the volume fraction fluctuations correlation function for a size polydispersed bubble column. Theoretically, we adopt a statistical mechanistic point of view and use a stochastic description to calculate the above mentioned correlation function for a gas-liquid vertical bubble column. On the other hand, we also obtain this correlation function from the data obtained by an electrical impedance spectroscopy technique. We find that bubble size polydispersity may enhance significantly the stability of void fraction waves by a factor which varies between 0.4 to 23 percent as a function of its frequency and for the specific bubble column considered in our experiments. The comparison between the calculated volume fraction correlation function and the same quantity obtained from measured data is then analyzed. We find that polydispersity effects yield a better comparison between theory and experiment than the monodispersed case and lead to an absolute mean error of 5 percent, as compared with the error of 10.6 obtained for the monodispersed case. Our results reinforce the point of view advocated in this work in the sense that a description of a bubble column based on the concept of randomness of a bubble cloud and average properties of the fluid motion may be a useful approach that has not been exploited in engineering systems.

@incollection{statphys23_0237, abstract = {Bubble flow is characterized by discrete bubbles, which are approximately uniformly distributed in a continuous liquid phase. The homogeneous regime is characterized by almost uniformly sized bubbles and it is well known that a swarm of small bubbles enhances the rate transfer phenomena these multiphase systems. However, the effects that size polydispersity may produce on the stability of kinematic waves, mean bubble velocity, kinematic and dynamic wave velocities is, to our knowledge, not yet well established. We generalize previous kinetic models to incorporate size polydispersity of bubbles to calculate the volume fraction fluctuations correlation function for a size polydispersed bubble column. Theoretically, we adopt a statistical mechanistic point of view and use a stochastic description to calculate the above mentioned correlation function for a gas-liquid vertical bubble column. On the other hand, we also obtain this correlation function from the data obtained by an electrical impedance spectroscopy technique. We find that bubble size polydispersity may enhance significantly the stability of void fraction waves by a factor which varies between 0.4 to 23 percent as a function of its frequency and for the specific bubble column considered in our experiments. The comparison between the calculated volume fraction correlation function and the same quantity obtained from measured data is then analyzed. We find that polydispersity effects yield a better comparison between theory and experiment than the monodispersed case and lead to an absolute mean error of 5 percent, as compared with the error of 10.6 obtained for the monodispersed case. Our results reinforce the point of view advocated in this work in the sense that a description of a bubble column based on the concept of randomness of a bubble cloud and average properties of the fluid motion may be a useful approach that has not been exploited in engineering systems.}, added-at = {2007-06-20T10:16:09.000+0200}, address = {Genova, Italy}, author = {Salinas-rodriguez, E. and Rodriguez, R.F. and Zamora, J.M.}, biburl = {https://www.bibsonomy.org/bibtex/2cdaad0411efcdb3c3acbb1f2747e943a/statphys23}, booktitle = {Abstract Book of the XXIII IUPAP International Conference on Statistical Physics}, editor = {Pietronero, Luciano and Loreto, Vittorio and Zapperi, Stefano}, interhash = {7d2b160fc331ee447f350e9ce4deda0a}, intrahash = {cdaad0411efcdb3c3acbb1f2747e943a}, keywords = {bubbly flows fraction kinetic polydispersity stability statphys23 theory topic-3 void waves}, month = {9-13 July}, timestamp = {2007-06-20T10:16:15.000+0200}, title = {Volume fraction correlation function for a polydispersed bubble flow}, url = {http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=237}, year = 2007 }