Autor segons l'article: Fard, Mojtaba Goraki; Vernet, Anton; Stiriba, Youssef; Grau, Xavier
Departament: Enginyeria Mecànica
Autor/s de la URV: Grau Vidal, Francesc Xavier / Stiriba, Youssef / Vernet Peña, Antonio
Paraules clau: Vortex Turbulence Regime transitions Numerical-simulation Model Liquid velocity Large-scale structures Large-eddy-simulation Large-eddy simulation Gas-distribution Dynamics Conditional sampling Cfd simulation Bubble column reactor Behavior
Resum: This paper analyses the local and time-dependent behavior of large-scale structures responsible for liquid circulation in gas-water flow of a 3-D cylindrical bubble column of high aspect ratio with a multiple orifice for uniform aeration. The large-scale flow structures play an important role in the mixing and the mass transfer while coherent structures dominate hydrodynamic characteristics of the turbulent flow field. A three-dimensional Euler-Euler large eddy simulation (LES) model was used to calculate large-scale structures and their interaction with bubbles at inlet superficial gas velocities of U-G = 6 and 8.4 cm/s where vortical-spiral and turbulent flow regimes occur. The two-phase model gives good agreements with experimental measurements. We use a conditional sampling procedure of liquid velocity and gas hold-up time series to identify and educe the development of coherent flow structures which consists in a pair of counter-rotating vortices convected in a staggered pattern along the column in both the vortical-spiral and central plume regions. On average, the detected instantaneous events for each template account for about 12-15% of the data recorded and may appear simultaneously. These events produce important fluctuations in the axial liquid velocity and gas void fraction. The sampling procedure yielded the averaged topology of the three-dimensional large-scale structures which was visualized using isosurfaces of the vorticity for different gas flow rates. The structures have spiral tube-shaped topology rotating along the column near the walls with a pair of counter-rotating cells sustained through the flow. This work provides deep insights into turbulent flow field in gas-liquid bubble column by LES and pattern recognition. (C) 2020 Published by Elsevier Ltd.
Àrees temàtiques: Physics and astronomy (miscellaneous) Physics and astronomy (all) Mechanics Mechanical engineering Matemática / probabilidade e estatística General physics and astronomy Fluid flow and transfer processes Engenharias iv Engenharias iii Engenharias ii Ciência de alimentos Ciência da computação Biodiversidade
Accès a la llicència d'ús: https://creativecommons.org/licenses/by/3.0/es/
ISSN: 03019322
Adreça de correu electrònic de l'autor: youssef.stiriba@urv.cat anton.vernet@urv.cat francescxavier.grau@urv.cat
Identificador de l'autor: 0000-0002-0272-7807 0000-0002-7028-1368 0000-0002-4077-7338
Data d'alta del registre: 2024-10-12
Versió de l'article dipositat: info:eu-repo/semantics/acceptedVersion
Enllaç font original: https://www.sciencedirect.com/science/article/abs/pii/S0301932219306196
URL Document de llicència: https://repositori.urv.cat/ca/proteccio-de-dades/
Referència a l'article segons font original: International Journal Of Multiphase Flow. 127 (UNSP 103236): 103236-
Referència de l'ítem segons les normes APA: Fard, Mojtaba Goraki; Vernet, Anton; Stiriba, Youssef; Grau, Xavier (2020). Transient large-scale two-phase flow structures in a 3D bubble column reactor. International Journal Of Multiphase Flow, 127(UNSP 103236), 103236-. DOI: 10.1016/j.ijmultiphaseflow.2020.103236
DOI de l'article: 10.1016/j.ijmultiphaseflow.2020.103236
Entitat: Universitat Rovira i Virgili
Any de publicació de la revista: 2020
Tipus de publicació: Journal Publications