Simulation of Gas – Non-Newtonian Liquid Flow in a Rectangular Bubble Column by Considering Bubbles Interactions

2012 ◽  
Author(s):  
Erfan Niazi ◽  
Mehrzad Shams ◽  
Arash Elahi ◽  
Goodarz Ahmadi
Keyword(s):  
Liquid Flow ◽  
Bubble Column ◽  
Three Dimensional ◽  
Methyl Cellulose ◽  
Newtonian Liquid ◽  
Bubble Coalescence ◽  
Break Up ◽  
Bubble Rising ◽  
Momentum Coupling ◽  
Fluid Rheology

In this article a CFD model of a three-dimensional Eulerian-Lagrangian is developed for a gas - non-Newtonian liquid flow in a rectangular column. The model resolves the time-dependent, three-dimensional motion of gas bubbles in a liquid to simulate the trajectory of bubbles. Our model incorporates drag, gravity, buoyancy, lift, pressure gradient and virtual mass forces acting on a bubble rising in a liquid, and accounts for two-way momentum coupling between the phases. Population balance equation is solved to model bubble coalescence and break up. In bubble coalescence, Prince and Blanch model is used which can consider the effect of fluid rheology. Luo and Svendosen model was selected for bubble break up. The standard k-e turbulence model is selected for calculating turbulent flow properties. Power-law non-Newtonian liquid is selected for analysis of effect of different solutions of carboxy methyl cellulose in water. The effect of changing fluid to non-Newtonian is discussed in terms of velocity profile and gas hold up.

Numerical Simulation of the Transient Three-Dimensional Gas-Liquid Flow in a Cylindrical Bubble Column

2006 ◽  
Author(s):  
Santiago Lai´n Beatove ◽  
Martin Sommerfeld
Keyword(s):  
Liquid Flow ◽  
Bubble Column ◽  
Three Dimensional ◽  
Dynamic Structure ◽  
Point Of View ◽  
Pressure Drag ◽  
Eddy Simulation ◽  
Discrete Phase ◽  
Quantitative Results ◽  
Gas Liquid Flow

In this paper the transient three-dimensional flow developing in a cylindrical laboratory bubble column is addressed from a numerical point of view. The simulation scheme combines a Large Eddy Simulation (LES) for describing the liquid phase and a Lagragian approach for the gas (discrete) phase. The bubble equation of motion considers all the relevant forces, i.e., buoyancy, pressure, drag, added mass and transverse lift. From the calculations, the transverse lift in combination with the drag is identified as the main mechanism allowing the bubbles to spread over the column cross-section. The liquid and gas velocity profiles obtained are compared with the experimental data and k–ε results presented in Lai´n et al. (2001). As a matter of fact, the dynamic structure of the liquid flow induced by the rising bubbles is well reproduced and also good quantitative results for all measured variables of both phases, gas and liquid, are obtained.

Numerical Calculation of Mass Transfer With Heterogeneous Chemical Reactions in Three-Phase Bubble Columns

2007 ◽  
Author(s):  
Dieter Mewes ◽  
Dierk Wiemann
Keyword(s):  
Balance Equation ◽  
Bubble Column ◽  
Three Dimensional ◽  
Population Balance ◽  
Kernel Functions ◽  
Time Dependent ◽  
Bubble Coalescence ◽  
Population Balance Equation ◽  
Heterogeneous Chemical ◽  
Three Phase

Bubble column reactors are used for several processes in the chemical industry, e.g. hydrogenation or oxidation reactions. At the bottom of the reactor a gaseous phase is dispersed into a continuous liquid phase with suspended particles. The resulting bubble swarm induces three-dimensional, time-dependent velocity and concentration fields, which are predicted numerically. All phases are described by an Eulerian approach. The numerical calculations of the local interfacial area density and the interphase transfer terms for mass and momentum are based on a population balance equation approach which enables an effective way to couple population balance and computational fluid dynamics. In three-phase gas-liquid-solid flow particles with diameters of 100 μm are considered as catalyst for a heterogeneous chemical reaction. The influence of particles on bubble coalescence has been investigated in order to extend an existing model for the kernel functions in the population balance equation describing bubble coalescence and dispersion. The resulting three-dimensional, time-dependent velocity and concentration fields are described and graphically presented for the hydrogenation of anthra-chinone.

Population Balance Modeling for Non-Homogeneous Bubble Column: Effect of Fluid Rheology on Gas Dispersion

2012 ◽  
Author(s):  
Erfan Niazi ◽  
Mehrzad Shams ◽  
Goodarz Ahmadi
Keyword(s):  
Volume Fraction ◽  
Liquid Velocity ◽  
Bubble Column ◽  
Methyl Cellulose ◽  
Population Balance ◽  
Population Balance Modeling ◽  
Gas Dispersion ◽  
Model Equations ◽  
Liquid Flows ◽  
Fluid Rheology

This work describes the development of a two-dimensional CFD model for gas-liquid flows in a bubble column. Population balance dynamic equation is solved for babbles including bubbles coalescence and break up in the column. Prince and Blanch model for bubbles coalescence extended to non-Newtonian rheology and used in the analysis. Luo and Svendsen model is used for bubbles breakup modeling and the k-e model equations are solved for analysis of primary fluid turbulence. Solutions of carboxy methyl cellulose in water with different concentrations are used as a non-Newtonian pesudoplastic liquid. Raise velocity of bubbles, which play an important role in population balance modeling, is discusses in details for non-Newtonian fluid. As a first step the results for Newtonian bubble column are presented and verified by comparison with the previous studies. Then the effect of changing fluid rheology is discussed in terms of gas volume fraction and continuous liquid velocity.

Three-dimensional simulation of bubble column flows with bubble coalescence and breakup

AIChE Journal ◽  
2005 ◽  
Vol 51 (3) ◽  
pp. 696-712 ◽  
Author(s):  
P. Chen ◽  
M. P. Dudukovi? ◽  
J. Sanyal
Keyword(s):  
Bubble Column ◽  
Three Dimensional ◽  
Bubble Coalescence ◽  
Dimensional Simulation

ESTIMATION OF PRESSURE DROP FOR NON-NEWTONIAN LIQUID FLOW THROUGH BENDS USING ADAPTIVE NON-PARAMETRIC MODEL

2020 ◽  
Vol 47 (1) ◽  
pp. 59-69
Author(s):  
Suman Debnath ◽  
Anirban Banik ◽  
Tarun Kanti Bandyopadhyay ◽  
Mrinmoy Majumder ◽  
Apu Kumar Saha
Keyword(s):  
Pressure Drop ◽  
Liquid Flow ◽  
Parametric Model ◽  
Newtonian Liquid ◽  
Flow Through ◽  
Non Parametric

Linearized Theory of Supercavitating Hydrofoils in Subsonic Liquid Flow

1977 ◽  
Vol 99 (2) ◽  
pp. 311-318
Author(s):  
Tetsuo Nishiyama
Keyword(s):  
Incompressible Flow ◽  
Liquid Flow ◽  
Sound Speed ◽  
Gas Flow ◽  
Three Dimensional ◽  
Cavitation Number ◽  
Compressibility Effect ◽  
Linearized Theory ◽  
Velocity Pressure ◽  
Subsonic Region

In order to clarify the compressibility effect, the perturbed flow field of the supercavitating hydrofoil in subsonic region is examined by a linearized technique and, as a result, the general corresponding rule of the compressible flow to the incompressible one is proposed to obtain the characteristics of the supercavitating hydrofoil. The main contents are summarized as follows: (i) Basic relations between velocity, pressure, and sound speed are shown in subsonic liquid flow within the framework of linearization. (ii) The correspondence of the steady, characteristics of the two and three dimensional supercavitating hydrofoils in subsonic liquid flow to ones in incompressible flow is clarified. Hence we can readily calculate the characteristics by simple correction to ones in incompressible flow. (iii) Numerical calculations are made to show the essential differences of the compressibility effect between liquid and gas flow, and also the interrelated effect between cavitation number and Mach number on the characteristics of the supercavitating hydrofoils.

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