Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
ANALYSIS OF SINGLE-BUBBLE DYNAMICS IN CONFINED CHANNELS
Submission Author:
Thiago Sirino , PR
Co-Authors:
Thiago Sirino, Fabio Ernesto Mancilla Ramos, Rigoberto Morales
Presenter: Thiago Sirino
doi://10.26678/ABCM.ENCIT2022.CIT22-0486
Abstract
Bubbly flows are widely found in several situations, both in industrial processes and in Nature. Additionally, many of these flows occur in confined geometries such as oil and gas reservoirs, where the fluid movement is restricted within porous channels and natural fractures. Despite the importance of this topic, most studies found in the literature refer to non-confined systems and just a few deal with the influence of the confinement geometries on the bubble dynamics. For years, it has been recognized that a deeper understanding of the bubble dynamics and of the physical phenomena involved in such flows is needed. This lack of information about bubble behavior in confined systems and its importance to different aspects of daily life is what motivates the present work. Therefore, the influence of the walls on the dynamics of single bubbles rising through a vertical channel filled with deionized water will be investigated. The inner cross-section of the channel was modified by adding moving walls. Additionally, the diameters of those bubbles varied between 1.3 mm and 3.5 mm, and they were binned in three different sets of bubble sizes, namely small, medium, and large. Two experimental techniques will be used; shadowgraph and particle image velocimetry (PIV) which will be applied to channels with confinements in one and two directions. The confinement degree for the confinement in one direction is defined as the ratio of the distance between walls (GAP) to the bubble diameter (D); for the confinement in two directions, it is defined as the ratio of bubble diameter to the channel hydraulic diameter (Dh). The bubble dynamics will be analyzed from their trajectories, wakes and velocity fields around the bubbles and the results obtained will be compared to results found in literature for non-confined systems. Moreover, the variation of bubble terminal velocities, drag coefficient, velocity fluctuation and shapes as a function of the confinement degree will be discussed
Keywords
bubbly flow, confinement degree, bubbles dynamics, wakes
