Joelle Aubin | University of Toulouse (original) (raw)
Papers by Joelle Aubin
Chemical Engineering Research and Design, Nov 1, 2000
Chemical Engineering Technology, Aug 1, 2012
Chemical Engineering & Technology, 2015
From Concepts to Industrial Applications, 2015
Green Processing and Synthesis, 2014
A Comprehensive Handbook, 2009
... a combination of classical solutions of the Navier-Stokes equations, coupled with ad hoc mode... more ... a combination of classical solutions of the Navier-Stokes equations, coupled with ad hoc models of ... They concluded that central differencing and the Crank-Nicholson schemes performed the best and that ... This is a very efficient way to solve the problem for straight channels but ...
Industrial & Engineering Chemistry Research, 2003
Chemical Engineering Research and Design, 2001
Taylor flow is a gas-liquid two-phase flow pattern which appears in microchannels and capillaries... more Taylor flow is a gas-liquid two-phase flow pattern which appears in microchannels and capillaries over a wide range of flow rates. It is characterized by elongated bubbles separated form each other by liquid slugs (Figure 1). The bubbles themselves are separated from the channel wall by a liquid film. A particular feature of Taylor flow is the velocity field within the liquid slugs; two symmetrical vortices are created at both sides of the channel centre line. This behavior is considered as advantageous for mass transfer and turns the Taylor flow regime into an interesting operating condition for gas-liquid or gas-liquid-solid microreactors (solid catalyst deposited on the channel walls) [1]. Figure 1: Example image of Taylor flow through a rectangular microchannels used in the frame of the present study (lS = slug length, lB = bubble length). In order to provide sufficient residence time for a reactive system, typically long microchannels are needed. Since one of the design require...
Chemical Engineering Science, 2005
Experimental Thermal and Fluid Science
Single phase turbulent flow in a tank stirred by a down- and an up-pumping pitched blade turbine ... more Single phase turbulent flow in a tank stirred by a down- and an up-pumping pitched blade turbine has been simulated using CFD. The effect of the modeling approach, discretization scheme and turbulence model on mean velocities, turbulent kinetic energy and global quantities, such as the power and circulation numbers, has been investigated. The results have been validated by LDV data. The stationary and time-dependent modeling approaches were found to have little effect on the turbulent flow, however the choice of the numerical scheme was found to be important, especially for the predicted turbulent kinetic energy. A first order method was found to highly underestimate LDV data compared with higher order methods. The type of the turbulence model was limited to the k-e and RNG models due to convergence difficulties encountered with a Reynolds Stress Model (RSM) and there was found to be little effect of these models on the mean flow and turbulent kinetic energy. This latter quantity wa...
ABSTRACT Vortex Structure and Mixing in Meandering Microchannels
Chemical Engineering Science, 2006
Chemical Engineering Science, 2010
Chemical Engineering & Technology, 2003
Journal of Computational Physics
This paper deals with the comparison of Eulerian methods to take into account the capillary contr... more This paper deals with the comparison of Eulerian methods to take into account the capillary contribution in the vicinity of a fluid–fluid interface. Eulerian methods are well-known to produce additional vorticity close to the interface that leads to non-physical spurious currents. Numerical equilibrium between pressure gradient and capillary force for the static bubble test case within a VOF framework has been reached in [35] with the height-function technique [14] and [35]. However, once the bubble is translated in a uniform flow, spurious currents are maintained by slight errors induced by translation schemes. In this work, two main points are investigated: the ability of Volume of Fluid and Level Set methods to accurately calculate the curvature, and the magnitude of spurious currents due to errors in the calculation of the curvature after advection in both translating and rotating flows. The spurious currents source term is expressed from the vorticity equation and used to discu...
Although a number of definitions of mixing have been proposed in the literature, no single defini... more Although a number of definitions of mixing have been proposed in the literature, no single definition accurately and clearly describes the full range of problems in the field of industrial mixing. An alternate approach is proposed which defines segregation as being composed of three separate dimensions. The first dimension is the intensity of segregation quantified by the normalized concentration variance (CoV); the second dimension is clustering or the scale of segregation; and the last dimension is the exposure or the potential to reduce segregation. The first dimension focuses on the instantaneous concentration variance; the second on the instantaneous length scales in the mixing field; and the third on the driving force for change, i.e. the mixing time scale, or the instantaneous rate of reduction in segregation. With these three dimensions in hand, it is possible to speak more clearly about what is meant by the control of segregation in industrial mixing processes. In this pape...
Microractor for catalytic oxidation of voc : characterisation and efficiency
Microfluidics and Nanofluidics
The effect of fluid properties and operating conditions on the generation of gas–liquid Taylor fl... more The effect of fluid properties and operating conditions on the generation of gas–liquid Taylor flow in microchannels has been investigated experimentally and numerically. Visualisation experiments and 2D numerical simulations have been performed to study bubble and slug lengths, liquid film hold-up and bubble velocities. The results show that the bubble and slug lengths increase as a function of the gas and liquid flow rate ratios. The bubble and slug lengths follow the model developed by Garstecki et al. (Lab chip 6:437–446, 2006) and van Steijn et al. (Chem Eng Sci 62:7505–7514, 2007), however, the model coefficients appear to be dependent on the liquid properties and flow conditions in some cases. The ratio of the bubble velocity to superficial two-phase velocity is close to unity, which confirms a thin liquid film under the assumption of a stagnant liquid film. Numerical simulations confirm the hypothesis of a stagnant liquid film and provide information on the thickness of the ...
Chemical Engineering Research and Design, Nov 1, 2000
Chemical Engineering Technology, Aug 1, 2012
Chemical Engineering & Technology, 2015
From Concepts to Industrial Applications, 2015
Green Processing and Synthesis, 2014
A Comprehensive Handbook, 2009
... a combination of classical solutions of the Navier-Stokes equations, coupled with ad hoc mode... more ... a combination of classical solutions of the Navier-Stokes equations, coupled with ad hoc models of ... They concluded that central differencing and the Crank-Nicholson schemes performed the best and that ... This is a very efficient way to solve the problem for straight channels but ...
Industrial & Engineering Chemistry Research, 2003
Chemical Engineering Research and Design, 2001
Taylor flow is a gas-liquid two-phase flow pattern which appears in microchannels and capillaries... more Taylor flow is a gas-liquid two-phase flow pattern which appears in microchannels and capillaries over a wide range of flow rates. It is characterized by elongated bubbles separated form each other by liquid slugs (Figure 1). The bubbles themselves are separated from the channel wall by a liquid film. A particular feature of Taylor flow is the velocity field within the liquid slugs; two symmetrical vortices are created at both sides of the channel centre line. This behavior is considered as advantageous for mass transfer and turns the Taylor flow regime into an interesting operating condition for gas-liquid or gas-liquid-solid microreactors (solid catalyst deposited on the channel walls) [1]. Figure 1: Example image of Taylor flow through a rectangular microchannels used in the frame of the present study (lS = slug length, lB = bubble length). In order to provide sufficient residence time for a reactive system, typically long microchannels are needed. Since one of the design require...
Chemical Engineering Science, 2005
Experimental Thermal and Fluid Science
Single phase turbulent flow in a tank stirred by a down- and an up-pumping pitched blade turbine ... more Single phase turbulent flow in a tank stirred by a down- and an up-pumping pitched blade turbine has been simulated using CFD. The effect of the modeling approach, discretization scheme and turbulence model on mean velocities, turbulent kinetic energy and global quantities, such as the power and circulation numbers, has been investigated. The results have been validated by LDV data. The stationary and time-dependent modeling approaches were found to have little effect on the turbulent flow, however the choice of the numerical scheme was found to be important, especially for the predicted turbulent kinetic energy. A first order method was found to highly underestimate LDV data compared with higher order methods. The type of the turbulence model was limited to the k-e and RNG models due to convergence difficulties encountered with a Reynolds Stress Model (RSM) and there was found to be little effect of these models on the mean flow and turbulent kinetic energy. This latter quantity wa...
ABSTRACT Vortex Structure and Mixing in Meandering Microchannels
Chemical Engineering Science, 2006
Chemical Engineering Science, 2010
Chemical Engineering & Technology, 2003
Journal of Computational Physics
This paper deals with the comparison of Eulerian methods to take into account the capillary contr... more This paper deals with the comparison of Eulerian methods to take into account the capillary contribution in the vicinity of a fluid–fluid interface. Eulerian methods are well-known to produce additional vorticity close to the interface that leads to non-physical spurious currents. Numerical equilibrium between pressure gradient and capillary force for the static bubble test case within a VOF framework has been reached in [35] with the height-function technique [14] and [35]. However, once the bubble is translated in a uniform flow, spurious currents are maintained by slight errors induced by translation schemes. In this work, two main points are investigated: the ability of Volume of Fluid and Level Set methods to accurately calculate the curvature, and the magnitude of spurious currents due to errors in the calculation of the curvature after advection in both translating and rotating flows. The spurious currents source term is expressed from the vorticity equation and used to discu...
Although a number of definitions of mixing have been proposed in the literature, no single defini... more Although a number of definitions of mixing have been proposed in the literature, no single definition accurately and clearly describes the full range of problems in the field of industrial mixing. An alternate approach is proposed which defines segregation as being composed of three separate dimensions. The first dimension is the intensity of segregation quantified by the normalized concentration variance (CoV); the second dimension is clustering or the scale of segregation; and the last dimension is the exposure or the potential to reduce segregation. The first dimension focuses on the instantaneous concentration variance; the second on the instantaneous length scales in the mixing field; and the third on the driving force for change, i.e. the mixing time scale, or the instantaneous rate of reduction in segregation. With these three dimensions in hand, it is possible to speak more clearly about what is meant by the control of segregation in industrial mixing processes. In this pape...
Microractor for catalytic oxidation of voc : characterisation and efficiency
Microfluidics and Nanofluidics
The effect of fluid properties and operating conditions on the generation of gas–liquid Taylor fl... more The effect of fluid properties and operating conditions on the generation of gas–liquid Taylor flow in microchannels has been investigated experimentally and numerically. Visualisation experiments and 2D numerical simulations have been performed to study bubble and slug lengths, liquid film hold-up and bubble velocities. The results show that the bubble and slug lengths increase as a function of the gas and liquid flow rate ratios. The bubble and slug lengths follow the model developed by Garstecki et al. (Lab chip 6:437–446, 2006) and van Steijn et al. (Chem Eng Sci 62:7505–7514, 2007), however, the model coefficients appear to be dependent on the liquid properties and flow conditions in some cases. The ratio of the bubble velocity to superficial two-phase velocity is close to unity, which confirms a thin liquid film under the assumption of a stagnant liquid film. Numerical simulations confirm the hypothesis of a stagnant liquid film and provide information on the thickness of the ...