Hydrodynamics and axial mixing in a packed gas-liquid column

The objective of this study was to investigate the pilot-plant gas absorption packed column hydrodynamics, as well as axial mixing in the system air-water. The pressure drop and the gas phase holdup data were determined in dependence on the flow rates of gas and liquid phases. The influence of superficial velocities of liquid and gas phases on the liquid axial dispersion in a gas-liquid packed bed column (ID 15 cm) consisting of Raschig rings (15x15x2 mm) were investigated. The pressure drop was measured with a U-type manometer, connected to the bottom and the top of the working part of the column. The gas phase holdup data in the air-water two-phase system was calculated as a ratio of the gas phase volume to the total volume of the two-phase system. Axial dispersion in the water phase has been determined by examining of the distribution of residence times of a salt tracer (NaCl) in the packed bed. The tracer was injected in the liquid flow above the packed bed; samples of liquid were simultaneously taken from two sites at 1 m distance along the bed. Salt concentrations in the samples were determined by conductivity measurements. The mean residence time and the axial dispersion number were calculated by the moment method. The axial dispersion increases with an increase of liquid flow velocities and decrease of superficial air velocities.

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Hydrodynamic and gas phase axial dispersion in an air-molten salt two-phase system (molten salt oxidation reactor)

Chemical Engineering and Processing - Process Intensification ◽

10.1016/j.cep.2005.01.006 ◽

2005 ◽

Vol 44 (10) ◽

pp. 1054-1062 ◽

Cited By ~ 5

Author(s):

Yong-Jun Cho ◽

Hee-Chul Yang ◽

Hee-Chul Eun ◽

Jae-Hyung Yoo ◽

Joon-Hyung Kim

Keyword(s):

Molten Salt ◽

Gas Phase ◽

Axial Dispersion ◽

Phase System ◽

Two Phase ◽

Oxidation Reactor

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Hydrodynamic characteristics of a two-phase gas-liquid flow upward through a fixed bed of spherical particles

Journal of the Serbian Chemical Society ◽

10.2298/jsc0101053s ◽

2001 ◽

Vol 66 (1) ◽

pp. 53-64 ◽

Cited By ~ 1

Author(s):

Snezana Serbula ◽

Velizar Stankovic

Keyword(s):

Pressure Drop ◽

Liquid Velocity ◽

Fixed Bed ◽

Particle Diameter ◽

Packed Bed ◽

Spherical Particles ◽

Hydrodynamic Characteristics ◽

Phase System ◽

Relative Pressure ◽

Two Phase

The influence of an electrochemically generated gas phase on the hydrodynamic characteristics of a three-phase system has been examined. The two-phase fluid, (gas-liquid), in which the liquid phase is the continuous one, flows through a packed bed with glass spheres. The influence of the liquid velocity was examined, as well as the gas velocity and particle diameter on the pressure drop through the fixed bed. It was found that with increasing liquid velocity (wl = 0.0162-0.03 m/s), the relative pressure drop decreases through the fixed bed. With increasing current density, the pressure drop increases, since greater gas quantities stay behind in the fixed bed. Besides, it was found that with decreasing diameter of the glass particles, the relative pressure drop also decreases. The relationship betweeen the experimentally obtained friction factor and the Reynolds number was established.

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Estimation of Gas and Liquid Flow Rates in Gas-Liquid Two-Phase System

Energy Conversion ◽

10.1115/imece2002-39311 ◽

2002 ◽

Author(s):

Koji Mori ◽

Tetsumasa Ono ◽

Masuo Kaji ◽

Toru Sawai

Keyword(s):

Gas Phase ◽

Liquid Flow ◽

Annular Flow ◽

Water System ◽

Phase System ◽

Two Phase ◽

Flow Rates ◽

Mean Values ◽

Pressure Drops ◽

Flow Channels

A new method of estimating gas and liquid flow rates is proposed for a gas-liquid two-phase flow system. The method involves measurement of pressure drops in horizontal and vertical flow channels, and calculation of flow rates by Lockhart-Martinelli correlation. The method does not require the insertion of sensing device into the flow channel and does not rely on previously calibrated correlations. Experiments are performed in slug, froth and annular flow regimes for an air-water system, and the usefulness of the proposed method is examined. The results reveal that gas and liquid flow rates can be estimated with the accuracies of 45% for gas phase and 37% for liquid phase with respect to mean values.

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Numerical modeling of the influence of bubbles on flow and heat transfer in the descending gas-liquid flow in a pipe

Proceedings of the Mavlyutov Institute of Mechanics ◽

10.21662/uim2012.1.025 ◽

2012 ◽

Vol 9 (1) ◽

pp. 131-135

Author(s):

M.A. Pakhomov

Keyword(s):

Heat Transfer ◽

Gas Phase ◽

Liquid Flow ◽

Bubble Diameter ◽

Gas Content ◽

Two Phase ◽

Eulerian Description ◽

Flow And Heat Transfer ◽

Gas Liquid Flow ◽

The Mathematical Model

The paper presents the results of modeling the dynamics of flow, friction and heat transfer in a descending gas-liquid flow in the pipe. The mathematical model is based on the use of the Eulerian description for both phases. The effect of a change in the degree of dispersion of the gas phase at the input, flow rate, initial liquid temperature and its friction and heat transfer rate in a two-phase flow. Addition of the gas phase causes an increase in heat transfer and friction on the wall, and these effects become more noticeable with increasing gas content and bubble diameter.

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Two-phase countercurrent flow through a bed of packing. VII. Pressure drop at flooding and critical flow rates of both phases in packed bed of spheres

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19721666 ◽

1972 ◽

Vol 37 (5) ◽

pp. 1666-1670

Author(s):

V. Kolář ◽

Z. Brož

Keyword(s):

Pressure Drop ◽

Packed Bed ◽

Critical Flow ◽

Countercurrent Flow ◽

Two Phase ◽

Flow Rates ◽

Flow Through

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The effect of two-phase flow regime on hydrodynamics and mass transfer in a horizontal-tube gas-liquid reactor

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19850745 ◽

1985 ◽

Vol 50 (3) ◽

pp. 745-757 ◽

Cited By ~ 3

Author(s):

Andreas Zahn ◽

Lothar Ebner ◽

Kurt Winkler ◽

Jan Kratochvíl ◽

Jindřich Zahradník

Keyword(s):

Mass Transfer ◽

Pressure Drop ◽

Flow Regime ◽

Liquid Flow ◽

Horizontal Tube ◽

Liquid Holdup ◽

Two Phase ◽

Flow Rates ◽

Type Relation ◽

Good Agreement

The effect of two-phase flow regime on decisive hydrodynamic and mass transfer characteristics of horizontal-tube gas-liquid reactors (pressure drop, liquid holdup, kLaL) was determined in a cocurrent-flow experimental unit of the length 4.15 m and diameter 0.05 m with air-water system. An adjustable-height weir was installed in the separation chamber at the reactor outlet to simulate the effect of internal baffles on reactor hydrodynamics. Flow regime maps were developed in the whole range of experimental gas and liquid flow rates both for the weirless arrangement and for the weir height 0.05 m, the former being in good agreement with flow-pattern boundaries presented by Mandhane. In the whole range of experi-mental conditions pressure drop data could be well correlated as a function of gas and liquid flow rates by an empirical exponential-type relation with specific sets of coefficients obtained for individual flow regimes from experimental data. Good agreement was observed between values of pressure drop obtained for weirless arrangement and data calculated from the Lockhart-Martinelli correlation while the contribution of weir to the overall pressure drop was well described by a relation proposed for the pressure loss in closed-end tubes. In the region of negligible weir influence values of liquid holdup were again succesfully correlated by the Lockhart-Martinelli relation while the dependence of liquid holdup data on gas and liquid flow rates obtained under conditions of significant weir effect (i.e. at low flow rates of both phases) could be well described by an empirical exponential-type relation. Results of preliminary kLaL measurements confirmed the decisive effect of the rate of energy dissipation on the intensity of interfacial mass transfer in gas-liquid dispersions.

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Liquid flow distribution in a two-phase countercurrent packed column

Chemical Engineering Science ◽

10.1016/0009-2509(77)80220-0 ◽

1977 ◽

Vol 32 (3) ◽

pp. 343-345

Author(s):

A.A.Badr El-Din ◽

M.M. El-Halwagi ◽

M.A. Saleh

Keyword(s):

Liquid Flow ◽

Packed Column ◽

Flow Distribution ◽

Two Phase

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A Developed Numerical Method for Turbulent Unsteady Fluid Flow in Two-Phase Systems with Moving Interface

International Journal of Computational Methods ◽

10.1142/s0219876217500633 ◽

2017 ◽

Vol 14 (06) ◽

pp. 1750063 ◽

Cited By ~ 1

Author(s):

A. M. Hegab ◽

S. A. Gutub ◽

A. Balabel

Keyword(s):

Numerical Model ◽

Gas Phase ◽

Level Set ◽

The Body ◽

Phase System ◽

Computational Domain ◽

Two Phase ◽

Moving Interface ◽

Level Set Function ◽

Gas System

This paper presents the development of an accurate and robust numerical modeling of instability of an interface separating two-phase system, such as liquid–gas and/or solid–gas systems. The instability of the interface can be refereed to the buoyancy and capillary effects in liquid–gas system. The governing unsteady Navier–Stokes along with the stress balance and kinematic conditions at the interface are solved separately in each fluid using the finite-volume approach for the liquid–gas system and the Hamilton–Jacobi equation for the solid–gas phase. The developed numerical model represents the surface and the body forces as boundary value conditions on the interface. The adapted approaches enable accurate modeling of fluid flows driven by either body or surface forces. The moving interface is tracked and captured using the level set function that initially defined for both fluids in the computational domain. To asses the developed numerical model and its versatility, a selection of different unsteady test cases including oscillation of a capillary wave, sloshing in a rectangular tank, the broken-dam problem involving different density fluids, simulation of air/water flow, and finally the moving interface between the solid and gas phases of solid rocket propellant combustion were examined. The latter case model allowed for the complete coupling between the gas-phase physics, the condensed-phase physics, and the unsteady nonuniform regression of either liquid or the propellant solid surfaces. The propagation of the unsteady nonplanar regression surface is described, using the Essentially-Non-Oscillatory (ENO) scheme with the aid of the level set strategy. The computational results demonstrate a remarkable capability of the developed numerical model to predict the dynamical characteristics of the liquid–gas and solid–gas flows, which is of great importance in many civilian and military industrial and engineering applications.

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