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Christophe Gourdon - One of the best experts on this subject based on the ideXlab platform.
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Local investigations on the gas-liquid mass transfer around Taylor bubbles flowing in a meandering millimetric Square Channel
Chemical Engineering Science, 2017Co-Authors: Lixia Yang, Nicolas Dietrich, Karine Loubiere, Christophe Gourdon, Claude Le Men, Gilles HébrardAbstract:Gas-liquid mass transfer around Taylor bubbles moving in a meandering millimetric Square Channel was locally visualized and characterized in the present study. For that, the colorimetric technique proposed by Dietrich et al. (2013) was implemented. With this technique, the evolution of equivalent oxygen concentration fields in the liquid slugs passing through one and several bends was firstly described. In particular, it was observed how the flow structure (recirculation zones) inside the liquid slugs were twisted and split by the periodic bends (centrifugal effect), until reaching, after several bends, a uniform O-2 concentration inside the liquid slugs. The influence of the "turning point", joining two "straight" sections of meandering Channel was also highlighted: a slowing down of the gas-liquid mass transfer was clearly shown. Volumetric mass transfer coefficients were determined at last by fitting the experimental axial profiles of averaged oxygen concentrations in the liquid slugs (before the turning point) with the ones predicted by a classical plug-flow model.
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A new direct technique for visualizing and measuring gas-liquid mass transfer around bubbles moving in a straight millimetric Square Channel
Chemical Engineering Science, 2013Co-Authors: Nicolas Dietrich, Karine Loubiere, Miguel Angel Jiménez, Gilles Hébrard, Christophe GourdonAbstract:The present paper focuses on the local characterization of gas-liquid mass transfer in a straight millimetric Square Channel, as constituting the preliminary step required for performing gas-liquid reactions in such devices. For this purpose, a new colourimetric technique using an oxygen sensitive dye was developed. It was based on the reduction of a colourimetric indicator in presence of oxygen, this reduction being catalysed by sodium hydroxide and glucose. In this study, resazurin was selected as the colourimetric indicator as it offered various reduced forms, the colours of which ranged from colourless (without oxygen) to pink (when oxygen was present). Thus the mass transfer around bubbles flowing in a straight millimetric Square Channel could be visualized in space and time. Some pictures were recorded by a monochromatic CCD high speed camera and, after post-processing, the shape, size and velocity of the bubbles, and the grey-level maps around them were measured. A calculation method was also developed to determine the transferred oxygen fluxes around the bubbles and the associated liquid-side mass transfer coefficients. The results compared satisfactorily with global measurements made using oxygen microsensors (Roudet et al., 2011. Hydrodynamics and mass transfer in inertial gas-liquid flow regimes through straigth and meandering millimetric Square Channels. Chem. Eng. Sci. 66, 2974-2990). This study constitutes a striking example of how interesting a tool this new colourimetric method could be for investigating gas-liquid mass transfer in transparent fluids with a view to quick millireactor design.
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A new direct technique for visualizing and measuring gas–liquid mass transfer around bubbles moving in a straight millimetric Square Channel
Chemical Engineering Science, 2013Co-Authors: Nicolas Dietrich, Karine Loubiere, Miguel Angel Jiménez, Gilles Hébrard, Christophe GourdonAbstract:The present paper focuses on the local characterization of gas–liquid mass transfer in a straight millimetric Square Channel, as constituting the preliminary step required for performing gas–liquid reactions in such devices. For this purpose, a new colourimetric technique using an oxygen sensitive dye was developed. It was based on the reduction of a colourimetric indicator in presence of oxygen, this reduction being catalysed by sodium hydroxide and glucose. In this study, resazurin was selected as the colourimetric indicator as it offered various reduced forms, the colours of which ranged from colourless (without oxygen) to pink (when oxygen was present). Thus the mass transfer around bubbles flowing in a straight millimetric Square Channel could be visualized in space and time. Some pictures were recorded by a monochromatic CCD high speed camera and, after post-processing, the shape, size and velocity of the bubbles, and the grey-level maps around them were measured. A calculation method was also developed to determine the transferred oxygen fluxes around the bubbles and the associated liquid-side mass transfer coefficients. The results compared satisfactorily with global measurements made using oxygen microsensors (Roudet et al., 2011. Hydrodynamics and mass transfer in inertial gas–liquid flow regimes through straigth and meandering millimetric Square Channels. Chem. Eng. Sci. 66, 2974–2990). This study constitutes a striking example of how interesting a tool this new colourimetric method could be for investigating gas–liquid mass transfer in transparent fluids with a view to quick millireactor design.
Nicolas Dietrich - One of the best experts on this subject based on the ideXlab platform.
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Local investigations on the gas-liquid mass transfer around Taylor bubbles flowing in a meandering millimetric Square Channel
Chemical Engineering Science, 2017Co-Authors: Lixia Yang, Nicolas Dietrich, Karine Loubiere, Christophe Gourdon, Claude Le Men, Gilles HébrardAbstract:Gas-liquid mass transfer around Taylor bubbles moving in a meandering millimetric Square Channel was locally visualized and characterized in the present study. For that, the colorimetric technique proposed by Dietrich et al. (2013) was implemented. With this technique, the evolution of equivalent oxygen concentration fields in the liquid slugs passing through one and several bends was firstly described. In particular, it was observed how the flow structure (recirculation zones) inside the liquid slugs were twisted and split by the periodic bends (centrifugal effect), until reaching, after several bends, a uniform O-2 concentration inside the liquid slugs. The influence of the "turning point", joining two "straight" sections of meandering Channel was also highlighted: a slowing down of the gas-liquid mass transfer was clearly shown. Volumetric mass transfer coefficients were determined at last by fitting the experimental axial profiles of averaged oxygen concentrations in the liquid slugs (before the turning point) with the ones predicted by a classical plug-flow model.
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A new direct technique for visualizing and measuring gas-liquid mass transfer around bubbles moving in a straight millimetric Square Channel
Chemical Engineering Science, 2013Co-Authors: Nicolas Dietrich, Karine Loubiere, Miguel Angel Jiménez, Gilles Hébrard, Christophe GourdonAbstract:The present paper focuses on the local characterization of gas-liquid mass transfer in a straight millimetric Square Channel, as constituting the preliminary step required for performing gas-liquid reactions in such devices. For this purpose, a new colourimetric technique using an oxygen sensitive dye was developed. It was based on the reduction of a colourimetric indicator in presence of oxygen, this reduction being catalysed by sodium hydroxide and glucose. In this study, resazurin was selected as the colourimetric indicator as it offered various reduced forms, the colours of which ranged from colourless (without oxygen) to pink (when oxygen was present). Thus the mass transfer around bubbles flowing in a straight millimetric Square Channel could be visualized in space and time. Some pictures were recorded by a monochromatic CCD high speed camera and, after post-processing, the shape, size and velocity of the bubbles, and the grey-level maps around them were measured. A calculation method was also developed to determine the transferred oxygen fluxes around the bubbles and the associated liquid-side mass transfer coefficients. The results compared satisfactorily with global measurements made using oxygen microsensors (Roudet et al., 2011. Hydrodynamics and mass transfer in inertial gas-liquid flow regimes through straigth and meandering millimetric Square Channels. Chem. Eng. Sci. 66, 2974-2990). This study constitutes a striking example of how interesting a tool this new colourimetric method could be for investigating gas-liquid mass transfer in transparent fluids with a view to quick millireactor design.
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A new direct technique for visualizing and measuring gas–liquid mass transfer around bubbles moving in a straight millimetric Square Channel
Chemical Engineering Science, 2013Co-Authors: Nicolas Dietrich, Karine Loubiere, Miguel Angel Jiménez, Gilles Hébrard, Christophe GourdonAbstract:The present paper focuses on the local characterization of gas–liquid mass transfer in a straight millimetric Square Channel, as constituting the preliminary step required for performing gas–liquid reactions in such devices. For this purpose, a new colourimetric technique using an oxygen sensitive dye was developed. It was based on the reduction of a colourimetric indicator in presence of oxygen, this reduction being catalysed by sodium hydroxide and glucose. In this study, resazurin was selected as the colourimetric indicator as it offered various reduced forms, the colours of which ranged from colourless (without oxygen) to pink (when oxygen was present). Thus the mass transfer around bubbles flowing in a straight millimetric Square Channel could be visualized in space and time. Some pictures were recorded by a monochromatic CCD high speed camera and, after post-processing, the shape, size and velocity of the bubbles, and the grey-level maps around them were measured. A calculation method was also developed to determine the transferred oxygen fluxes around the bubbles and the associated liquid-side mass transfer coefficients. The results compared satisfactorily with global measurements made using oxygen microsensors (Roudet et al., 2011. Hydrodynamics and mass transfer in inertial gas–liquid flow regimes through straigth and meandering millimetric Square Channels. Chem. Eng. Sci. 66, 2974–2990). This study constitutes a striking example of how interesting a tool this new colourimetric method could be for investigating gas–liquid mass transfer in transparent fluids with a view to quick millireactor design.
Gilles Hébrard - One of the best experts on this subject based on the ideXlab platform.
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Local investigations on the gas-liquid mass transfer around Taylor bubbles flowing in a meandering millimetric Square Channel
Chemical Engineering Science, 2017Co-Authors: Lixia Yang, Nicolas Dietrich, Karine Loubiere, Christophe Gourdon, Claude Le Men, Gilles HébrardAbstract:Gas-liquid mass transfer around Taylor bubbles moving in a meandering millimetric Square Channel was locally visualized and characterized in the present study. For that, the colorimetric technique proposed by Dietrich et al. (2013) was implemented. With this technique, the evolution of equivalent oxygen concentration fields in the liquid slugs passing through one and several bends was firstly described. In particular, it was observed how the flow structure (recirculation zones) inside the liquid slugs were twisted and split by the periodic bends (centrifugal effect), until reaching, after several bends, a uniform O-2 concentration inside the liquid slugs. The influence of the "turning point", joining two "straight" sections of meandering Channel was also highlighted: a slowing down of the gas-liquid mass transfer was clearly shown. Volumetric mass transfer coefficients were determined at last by fitting the experimental axial profiles of averaged oxygen concentrations in the liquid slugs (before the turning point) with the ones predicted by a classical plug-flow model.
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A new direct technique for visualizing and measuring gas-liquid mass transfer around bubbles moving in a straight millimetric Square Channel
Chemical Engineering Science, 2013Co-Authors: Nicolas Dietrich, Karine Loubiere, Miguel Angel Jiménez, Gilles Hébrard, Christophe GourdonAbstract:The present paper focuses on the local characterization of gas-liquid mass transfer in a straight millimetric Square Channel, as constituting the preliminary step required for performing gas-liquid reactions in such devices. For this purpose, a new colourimetric technique using an oxygen sensitive dye was developed. It was based on the reduction of a colourimetric indicator in presence of oxygen, this reduction being catalysed by sodium hydroxide and glucose. In this study, resazurin was selected as the colourimetric indicator as it offered various reduced forms, the colours of which ranged from colourless (without oxygen) to pink (when oxygen was present). Thus the mass transfer around bubbles flowing in a straight millimetric Square Channel could be visualized in space and time. Some pictures were recorded by a monochromatic CCD high speed camera and, after post-processing, the shape, size and velocity of the bubbles, and the grey-level maps around them were measured. A calculation method was also developed to determine the transferred oxygen fluxes around the bubbles and the associated liquid-side mass transfer coefficients. The results compared satisfactorily with global measurements made using oxygen microsensors (Roudet et al., 2011. Hydrodynamics and mass transfer in inertial gas-liquid flow regimes through straigth and meandering millimetric Square Channels. Chem. Eng. Sci. 66, 2974-2990). This study constitutes a striking example of how interesting a tool this new colourimetric method could be for investigating gas-liquid mass transfer in transparent fluids with a view to quick millireactor design.
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A new direct technique for visualizing and measuring gas–liquid mass transfer around bubbles moving in a straight millimetric Square Channel
Chemical Engineering Science, 2013Co-Authors: Nicolas Dietrich, Karine Loubiere, Miguel Angel Jiménez, Gilles Hébrard, Christophe GourdonAbstract:The present paper focuses on the local characterization of gas–liquid mass transfer in a straight millimetric Square Channel, as constituting the preliminary step required for performing gas–liquid reactions in such devices. For this purpose, a new colourimetric technique using an oxygen sensitive dye was developed. It was based on the reduction of a colourimetric indicator in presence of oxygen, this reduction being catalysed by sodium hydroxide and glucose. In this study, resazurin was selected as the colourimetric indicator as it offered various reduced forms, the colours of which ranged from colourless (without oxygen) to pink (when oxygen was present). Thus the mass transfer around bubbles flowing in a straight millimetric Square Channel could be visualized in space and time. Some pictures were recorded by a monochromatic CCD high speed camera and, after post-processing, the shape, size and velocity of the bubbles, and the grey-level maps around them were measured. A calculation method was also developed to determine the transferred oxygen fluxes around the bubbles and the associated liquid-side mass transfer coefficients. The results compared satisfactorily with global measurements made using oxygen microsensors (Roudet et al., 2011. Hydrodynamics and mass transfer in inertial gas–liquid flow regimes through straigth and meandering millimetric Square Channels. Chem. Eng. Sci. 66, 2974–2990). This study constitutes a striking example of how interesting a tool this new colourimetric method could be for investigating gas–liquid mass transfer in transparent fluids with a view to quick millireactor design.
Withada Jedsadaratanachai - One of the best experts on this subject based on the ideXlab platform.
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Forced convective heat transfer and thermal efficiency assessment in Square Channel equipped with 10° wavy thin rib:
Advances in Mechanical Engineering, 2020Co-Authors: Amnart Boonloi, Withada JedsadaratanachaiAbstract:Forced convective heat transfer and thermo-hydraulic efficiency in the heat exchanger Square Channel (HESC) inserted with 10° wavy thin rib (WTR) are reported numerically. The effects of rib height...
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Effect of Flow Attack Angle on Heat Transfer, Friction Loss and Thermal Performance in Square Channel with Inclined Wavy Surface
Asian Journal of Applied Sciences, 2017Co-Authors: Amnart Boonloi, Withada JedsadaratanachaiAbstract:Effects of flow attack angles for inclined wavy surface on heat transfer rate, friction loss and thermal performance in a Square Channel are investigated numerically. The inclined wavy surface with Square profile is inserted in the middle of the Square Channel to increase heat transfer rate and performance. The current study is solved by finite volume method with SIMPLE algorithm. The convective heat transfer in turbulent regime, Re = 3000 – 10,000, is considered. The flow structure and heat transfer behavior in the test section are presented in the numerical results. The thermal performance is also analyzed in terms of Nusselt number ratio (Nu/Nu 0 ), friction factor ratio (f/f 0 ) and thermal enhancement factor (TEF). The maximum heat transfer rate is detected at the flow attack angle of 45 o , while the extreme pressure loss is found at the flow attack angle of 60 o . The optimum TEF are found at the flow attack angle of 30 o and 45 o around 1.9.
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Laminar Flow and Heat Transfer in a Square Channel Installed with Inclined Wavy Surface
Journal of Mathematics and Statistics, 2017Co-Authors: Amnart Boonloi, Withada JedsadaratanachaiAbstract:Laminar flow and heat transfer characteristic in a Square Channel heat exchanger installed with inclined wavy surface are investigated numerically. The inclined wavy surface is designed with the main the aim to help the installation, production and maintenance when using the inclined wavy surface in the heat exchanger. The finite volume method with SIMPLE algorithm is selected to solve the present problem. The effects of flow attack angle (α = 15°-60°) and Reynolds number (Re = 100-1200) on heat transfer, friction loss and thermal performance are considered. The numerical model is validated with the smooth Channel. The grid independence of the computational domain is checked. The numerical results show that the heat transfer enhancement is around 1.9-7.5 times above the smooth Channel. The optimum thermal performance is found at the flow attack angle of 45° around 2.35 at Re = 1200.
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Flow and Heat Transfer Profiles in a Square Channel with 45? V-Downstream Orifices
Journal of Mathematics and Statistics, 2016Co-Authors: Withada Jedsadaratanachai, Amnart BoonloiAbstract:Flow and heat transfer profiles in a Square Channel heat exchanger inserted with 45d V-orifices are presented. The influences of Reynolds number (Re = 3000-10,000) and blockage ratio (BR = 0.05, 0.10, 0.15, 0.20 and 0.25) on periodic concepts are investigated numerically. The computational domain is solved with the finite volume method and SIMPLE algorithm. As the numerical results, the periodic profiles on flow and heat transfer are found when inserted the 45d V-orifices in the Square duct. The configurations on flow and heat transfer in the heating section can separated into two sections; periodic profile and fully developed periodic profile. The patterns on flow and heat transfer are similar, but the values are not equal, called qperiodic profilesq, while the identical on both profiles and values, called qfully developed periodic profilesq. In addition, the periodic structures depends on the parameters of the vortex generator, position in the Channel and Reynolds number.
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turbulent forced convection in a heat exchanger Square Channel with wavy ribs vortex generator
Chinese Journal of Chemical Engineering, 2015Co-Authors: Amnart Boonloi, Withada JedsadaratanachaiAbstract:Abstract Turbulent forced convective heat transfer and flow configurations in a Square Channel with wavy-ribs inserted diagonally are examined numerically. The influences of the 30° and 45° flow attack angles for wavy-ribs, blockage ratio, R B = b / H = 0.05–0.25 with single pitch ratio, R P = P / H = 1 are investigated for the Reynolds number based on the hydraulic diameter of the Square Channel, Re = 3000–20000. The use of the wavy-ribs, which inserted diagonal in the Square Channel, is aimed to help to improve the thermal performance in heat exchange systems. The finite volume method and SIMPLE algorithm are applied to the present numerical simulation. The results are presented on the periodic flow and heat transfer profiles, flow configurations, heat transfer characteristics and the performance evaluations. The mathematical results reveal that the use of wavy-ribs leads to a higher heat transfer rate and friction loss over the smooth Channel. The heat transfer enhancements are around 1.97–5.14 and 2.04–5.27 times over the smooth Channel for 30° and 45° attack angles, respectively. However, the corresponding friction loss values for 30° and 45° are around 4.26–86.55 and 5.03–97.98 times higher than the smooth Square Channel, respectively. The optimum thermal enhancement factor on both cases is found at R B = 0.10 and the lowest Reynolds number, Re = 3000, to be about 1.47 and 1.52, respectively, for 30° and 45° wavy-ribs.
Karine Loubiere - One of the best experts on this subject based on the ideXlab platform.
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Local investigations on the gas-liquid mass transfer around Taylor bubbles flowing in a meandering millimetric Square Channel
Chemical Engineering Science, 2017Co-Authors: Lixia Yang, Nicolas Dietrich, Karine Loubiere, Christophe Gourdon, Claude Le Men, Gilles HébrardAbstract:Gas-liquid mass transfer around Taylor bubbles moving in a meandering millimetric Square Channel was locally visualized and characterized in the present study. For that, the colorimetric technique proposed by Dietrich et al. (2013) was implemented. With this technique, the evolution of equivalent oxygen concentration fields in the liquid slugs passing through one and several bends was firstly described. In particular, it was observed how the flow structure (recirculation zones) inside the liquid slugs were twisted and split by the periodic bends (centrifugal effect), until reaching, after several bends, a uniform O-2 concentration inside the liquid slugs. The influence of the "turning point", joining two "straight" sections of meandering Channel was also highlighted: a slowing down of the gas-liquid mass transfer was clearly shown. Volumetric mass transfer coefficients were determined at last by fitting the experimental axial profiles of averaged oxygen concentrations in the liquid slugs (before the turning point) with the ones predicted by a classical plug-flow model.
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A new direct technique for visualizing and measuring gas-liquid mass transfer around bubbles moving in a straight millimetric Square Channel
Chemical Engineering Science, 2013Co-Authors: Nicolas Dietrich, Karine Loubiere, Miguel Angel Jiménez, Gilles Hébrard, Christophe GourdonAbstract:The present paper focuses on the local characterization of gas-liquid mass transfer in a straight millimetric Square Channel, as constituting the preliminary step required for performing gas-liquid reactions in such devices. For this purpose, a new colourimetric technique using an oxygen sensitive dye was developed. It was based on the reduction of a colourimetric indicator in presence of oxygen, this reduction being catalysed by sodium hydroxide and glucose. In this study, resazurin was selected as the colourimetric indicator as it offered various reduced forms, the colours of which ranged from colourless (without oxygen) to pink (when oxygen was present). Thus the mass transfer around bubbles flowing in a straight millimetric Square Channel could be visualized in space and time. Some pictures were recorded by a monochromatic CCD high speed camera and, after post-processing, the shape, size and velocity of the bubbles, and the grey-level maps around them were measured. A calculation method was also developed to determine the transferred oxygen fluxes around the bubbles and the associated liquid-side mass transfer coefficients. The results compared satisfactorily with global measurements made using oxygen microsensors (Roudet et al., 2011. Hydrodynamics and mass transfer in inertial gas-liquid flow regimes through straigth and meandering millimetric Square Channels. Chem. Eng. Sci. 66, 2974-2990). This study constitutes a striking example of how interesting a tool this new colourimetric method could be for investigating gas-liquid mass transfer in transparent fluids with a view to quick millireactor design.
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A new direct technique for visualizing and measuring gas–liquid mass transfer around bubbles moving in a straight millimetric Square Channel
Chemical Engineering Science, 2013Co-Authors: Nicolas Dietrich, Karine Loubiere, Miguel Angel Jiménez, Gilles Hébrard, Christophe GourdonAbstract:The present paper focuses on the local characterization of gas–liquid mass transfer in a straight millimetric Square Channel, as constituting the preliminary step required for performing gas–liquid reactions in such devices. For this purpose, a new colourimetric technique using an oxygen sensitive dye was developed. It was based on the reduction of a colourimetric indicator in presence of oxygen, this reduction being catalysed by sodium hydroxide and glucose. In this study, resazurin was selected as the colourimetric indicator as it offered various reduced forms, the colours of which ranged from colourless (without oxygen) to pink (when oxygen was present). Thus the mass transfer around bubbles flowing in a straight millimetric Square Channel could be visualized in space and time. Some pictures were recorded by a monochromatic CCD high speed camera and, after post-processing, the shape, size and velocity of the bubbles, and the grey-level maps around them were measured. A calculation method was also developed to determine the transferred oxygen fluxes around the bubbles and the associated liquid-side mass transfer coefficients. The results compared satisfactorily with global measurements made using oxygen microsensors (Roudet et al., 2011. Hydrodynamics and mass transfer in inertial gas–liquid flow regimes through straigth and meandering millimetric Square Channels. Chem. Eng. Sci. 66, 2974–2990). This study constitutes a striking example of how interesting a tool this new colourimetric method could be for investigating gas–liquid mass transfer in transparent fluids with a view to quick millireactor design.