Bubble motion and reaction in different viscous liquids

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Experimental and Computational Multiphase Flow

Bubble motion and reaction in different viscous liquids Mark W. Hlawitschka1,3 (), P. Kováts2, B. Dönmez1, K. Zähringer2, H.-J. Bart1 1. TU Kaiserslautern, Chair of Separation Science and Technology (TVT), Gottlieb-Daimler-Str. 44/475, 67663 Kaiserslautern, Germany 2. Laboratory of Fluid Dynamics and Technical Flows (LSS), Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany 3. JKU Linz, Institute of Process Engineering (IVT), Altenbergerstraße 69, 4040 Linz, Austria

Abstract

Keywords

Reactive bubble columns are omnipresent in the chemical industry. The layout of these columns

bubble column

is still limited by correlations and therefore improved simulation techniques are required to describe the complex hydrodynamics/reaction interaction. In this work, we focus on the numerical and experimental study of the viscosity influence on bubble motion and reaction

viscosity

using an Euler–Lagrange framework with an added oscillation and reaction model to bring the column layout base closer to a predictive level. For comparison and validation, experimental data in various water–glycerol solutions was obtained in a cylindrical bubble column at low gas

reaction

hold-up, where the main parameters such as bubble size, motion, and velocities were detected.

Article History

Glycerol leads thereby to a change in viscosity and surface tension. Further, the surface tension was modified by addition of a surfactant. The bubble oscillating motion in low to higher

Received: 28 February 2020

viscosity could be described using an Euler–Lagrange framework and enables a description of

Accepted: 16 April 2020

industrial bubble flows. In addition, the simulations were in good agreement concerning reactive mass transfer investigations at higher viscosity of the liquid which led to an overall

Research Article

lower mass transfer compared to the cases with lower viscosity.

© The Author(s) 2020

1

Introduction

Reactive bubble columns are widespread in chemical process engineering. The overall performance of these reactors relies on the interaction between the hydrodynamics, interfacial mass transfer, and chemical reactions. The layout of these columns is commonly based on simplified integral models that are not able to track the complex interactions between the local hydrodynamics and the reactions. Hence, a detailed knowledge about the ongoing interactions is required. For the simulation of bubbly flows, various approaches are used, ranging from the detailed resolution of individual bubbles to the prediction of industrial reactors with millions of bubbles inside. Single bubble investigations mainly include the resolution of the interface, shape deformation, and bubble oscillations that are directly simulated (Lörstad and Fuchs, 2004; Dijkhuizen et al., 2010; Pesci et al., 2018). The coarse scale Euler–Euler (EE) approach treats both phases as interpenetrating continua. The particle size distribution can be accounted for population balance modellin