Liquid Taylor Bubbles Rising in a Vertical Column of a Heavier Liquid: An Approximate Analysis

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
T. K. Mandal ◽  
G. Das ◽  
P. K. Das
Keyword(s):  
Empirical Equation ◽  
Flow Analysis ◽  
Rise Velocity ◽  
Vertical Column ◽  
Taylor Bubble ◽  
Two Fluids ◽  
Viscosity Effects ◽  
Semi Empirical ◽  
Theoretical Analyses ◽  
Taylor Bubbles

It has been noted that a volume of lighter liquid when injected into a stationary column of a heavier liquid, it rises up as a simple elongated Taylor bubble. In the present study, experimental and theoretical analyses have been performed to understand the rise of liquid Taylor bubbles. The experiments have been performed with different liquid pairs with their viscosities ranging from 0.71mPas to 1.75mPas and conduit sizes ranging from 0.012 m to 0.0461 m. The bubble shape has been predicted using a potential flow analysis and validated from photographic measurements. This analysis has been further modified to predict the rise velocity. The modified analysis accounts for the density difference between the two liquids, viscosity effects of the primary liquid, and interfacial tension of two fluids. A semi-empirical equation has been developed, which gives satisfactory results for most of the cases.

scholarly journals Computational simulation of a single Taylor bubble rising in a vertical column with stagnant liquid

2021 ◽  
Vol 9 (2B) ◽  
Author(s):  
Francisco Rogerio Teixeira Nascimento
Keyword(s):  
Open Source Software ◽  
Numerical Solutions ◽  
Stokes Equations ◽  
Computational Simulation ◽  
Navier Stokes ◽  
Vertical Column ◽  
Navier Stokes Equations ◽  
Taylor Bubble ◽  
Two Fluids ◽  
Bubble Rising

This work presents a computational simulation of a single Taylor bubble rising in a vertical column of stagnant liquid. The computational simulation was based on the Navier-Stokes equations for isothermal, incompressible, and laminar flow, solved by using the open source software OpenFOAM. The two fluids were assumed immiscible. The governing equations were discretized by the volume-of-fluid (VOF) method and solved using the Gauss iteration method. Parametric mesh was used in order to improve the modeling of curvilinear geometry. Numerical solutions were obtained for the rise velocities and shapes of the bubbles which are in excellent agreement with experimental data and correlations from literature.

A new semi-empirical equation for compressed liquid densities ofn-alkanes

2012 ◽  
Vol 8 (3) ◽  
pp. 425-432
Author(s):  
Yanjun Sun ◽  
Xiaopo Wang ◽  
Zhigang Liu
Keyword(s):  
Empirical Equation ◽  
Compressed Liquid ◽  
Semi Empirical

Rise velocity of a Taylor bubble through concentric annulus

1998 ◽  
Vol 53 (5) ◽  
pp. 977-993 ◽  
Author(s):  
G. Das ◽  
P.K. Das ◽  
N.K. Purohit ◽  
A.K. Mitra
Keyword(s):  
Rise Velocity ◽  
Taylor Bubble ◽  
Concentric Annulus

scholarly journals Overpotential evaluation of PEMFC using semi-empirical equation and SEM

2018 ◽  
Vol 67 ◽  
pp. 01015 ◽  
Author(s):  
Yutaro Akimoto ◽  
Shin-nosuke Suzuki
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Fault Diagnosis ◽  
Wind Power ◽  
Power Supply ◽  
Empirical Equation ◽  
Independent Power Supply ◽  
Diagnosis Method ◽  
Degradation Diagnosis ◽  
Semi Empirical

Fuel cells are a clean and weather-independent power supply. Solar and wind power are widespread in islands that are difficult to supply power. If problems are solved in the future, fuel cells are also expected to become popular. The widespread commercialization of PEMFC stacks depends on their reliability and fault diagnosis. In this study, we developed a degradation diagnosis method for the purpose of improving reliability. The output reduction of the fuel cell is separated into reduction factors called overpotentials. And the factor of the decrease is specified. In this paper, we show the proposed method and the degradation factors, and the effectiveness of the method.

Pressure Corrections for the Potential Flow Analysis of Kelvin-Helmholtz Instability

2011 ◽  
Vol 110-116 ◽  
pp. 4628-4635 ◽  
Author(s):  
Mukesh Kumar Awasthi ◽  
Rishi Asthana ◽  
G.S. Agrawal
Keyword(s):  
Normal Stress ◽  
Potential Flow ◽  
Energy Equation ◽  
Mechanical Energy ◽  
Flow Analysis ◽  
Helmholtz Instability ◽  
Viscous Potential Flow ◽  
Two Fluids ◽  
Tangential Stresses ◽  
Viscous Pressure

The present paper deals with the study of viscous contribution to the pressure for the viscous potential flow analysis of Kelvin-Helmholtz instability of two viscous fluids. Viscosity enters through normal stress balance in the viscous potential flow theory and tangential stresses for two fluids are not continuous at the interface. Here we have considered viscous pressure in the normal stress balance along with the irrotational pressure and it is assumed that the addition of this viscous pressure will resolve the discontinuity between the tangential stresses and the tangential velocities at the interface. The viscous pressure is derived by mechanical energy equation and this pressure correction applied to compute the growth rate of Kelvin-Helmholtz instability. A dispersion relation is obtained and a stability criterion is given in the terms of critical value of relative velocity. It has been observed that the inclusion of irrotational shearing stresses stabilizes the system.

scholarly journals Solution selection of axisymmetric Taylor bubbles

2018 ◽  
Vol 843 ◽  
pp. 518-535 ◽  
Author(s):  
A. Doak ◽  
J.-M. Vanden-Broeck
Keyword(s):  
Surface Tension ◽  
Constant Velocity ◽  
Numerical Scheme ◽  
Solution Space ◽  
Selection Mechanism ◽  
Small Surface ◽  
Taylor Bubble ◽  
Solution Selection ◽  
Selection Of ◽  
Taylor Bubbles

A finite difference scheme is proposed to solve the problem of axisymmetric Taylor bubbles rising at a constant velocity in a tube. A method to remove singularities from the numerical scheme is presented, allowing accurate computation of the bubbles with the inclusion of both gravity and surface tension. This paper confirms the long-held belief that the solution space of the axisymmetric Taylor bubble for small surface tension is qualitatively similar to that of the plane Taylor bubble. Furthermore, evidence suggesting that the solution selection mechanism associated with plane bubbles also occurs in the axisymmetric case is presented.

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