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Lev Shemer - One of the best experts on this subject based on the ideXlab platform.

  • Spatial distribution of void fraction in the Liquid Slug in the whole range of pipe inclinations
    International Journal of Multiphase Flow, 2013
    Co-Authors: Dvora Barnea, E. Roitberg, Lev Shemer
    Abstract:

    Abstract A wire mesh sensor was used to detect the local instantaneous cross-sectional distribution of the phases in gas-Liquid Slug flow. Data were obtained for a wide range of flow rates and for pipe inclinations ranging from shallow to vertical. Processing of the wire mesh sensor data yielded detailed information of the 3D void fraction distribution in the Liquid Slug. These results shed additional light on the hydrodynamics of Slug flow, in particular, regarding the formation and distribution of dispersed bubbles in the Liquid Slug. Comparison with available data was carried out. The present results compared favorably with model predictions.

  • hydrodynamic characteristics of gas Liquid Slug flow in a downward inclined pipe
    Chemical Engineering Science, 2008
    Co-Authors: E. Roitberg, Lev Shemer, Dvora Barnea
    Abstract:

    Abstract Gas–Liquid Slug flow in a downward inclined pipe was studied experimentally by employing a wire-mesh sensor that enables quantitative measurements of the cross-sectional void fraction distribution. Processing of the wire-mesh sensor data was applied to carry out a statistical analysis of characteristic parameters of downward Slug flow, such as bubble and Liquid Slug length distributions, as well as to determine the ensemble-averaged shapes of the bubble nose, Liquid film and bubble tail. It was found that the pipe inclination affects mainly the bubble length, while variation in the gas flow rate affects both bubble and Slug length. The bubble nose shape is more sensitive to the flow conditions than the bubble tail. The 3D structure of an elongated bubble in downward Slug flow was reconstructed from the wire-mesh sensor data.

  • Hydrodynamic characteristics of gas–Liquid Slug flow in a downward inclined pipe
    Chemical Engineering Science, 2008
    Co-Authors: E. Roitberg, Lev Shemer, Dvora Barnea
    Abstract:

    Abstract Gas–Liquid Slug flow in a downward inclined pipe was studied experimentally by employing a wire-mesh sensor that enables quantitative measurements of the cross-sectional void fraction distribution. Processing of the wire-mesh sensor data was applied to carry out a statistical analysis of characteristic parameters of downward Slug flow, such as bubble and Liquid Slug length distributions, as well as to determine the ensemble-averaged shapes of the bubble nose, Liquid film and bubble tail. It was found that the pipe inclination affects mainly the bubble length, while variation in the gas flow rate affects both bubble and Slug length. The bubble nose shape is more sensitive to the flow conditions than the bubble tail. The 3D structure of an elongated bubble in downward Slug flow was reconstructed from the wire-mesh sensor data.

  • Evolution of hydrodynamic and statistical parameters of gas-Liquid Slug flow along inclined pipes
    Chemical Engineering Science, 2003
    Co-Authors: R. Van Hout, Lev Shemer, Dvora Barnea
    Abstract:

    The development of Slug $ow along two 10 m long inclined pipes (2–90 ◦ from the horizontal) with internal diameters of 0.024 and 0:054 m was measured bythree optical 4ber probes. The probes were located in a measurement module at axial distances of 0 :020 m between the 4ber tips. To measure the evolution of Slug $ow, the module was placed at di6erent positions along the pipe. Instantaneous elongated bubble velocities and corresponding elongated bubble and Liquid Slug lengths were determined byprocessing the optical probe signals. The evolution of the Liquid Slug and elongated bubble length distributions along the pipes is characterized bya gradual growth of the mean and mode values. The growth rate decreases with decreasing inclination. Mean elongated bubble lengths have a minimum at about 60 ◦ , while mean Liquid Slug lengths decrease slowlywith decreasing inclination angle. The coalescence rate, de4ned as the decrease in the ensemble size, becomes almost negligible at x=D ? 60, independent of pipe diameter, $ow rates and inclination angle. The Slug frequencyhas a maximum at about 60 ◦ inclination.

  • evolution of statistical parameters of gas Liquid Slug flow along vertical pipes
    International Journal of Multiphase Flow, 2001
    Co-Authors: R. Van Hout, Dvora Barnea, Lev Shemer
    Abstract:

    Abstract The evolution of hydrodynamic and statistical parameters along the pipe was studied experimentally in gas–Liquid Slug flow for various flow conditions and two pipe diameters. The measuring modules comprise a set of three adjacent optical fiber probes and could be easily transferred to various positions along the pipes. The probes detect the passage of the gas–Liquid interface. This technique enables one to measure the instantaneous velocities of nose and tail of elongated (Taylor) bubbles simultaneously with the Slug length ahead of each bubble. The Liquid Slug and Taylor bubble length distributions along the pipe, together with the dependence of the Taylor bubble velocity on the Liquid Slug length ahead of it, are presented at various locations along the pipe. Empirical correlations relating the Taylor bubble velocity with the bubble separation distance are suggested. These correlations are used as an input to a model for Slug length distribution. The model results are compared with the experiments.

David W Agar - One of the best experts on this subject based on the ideXlab platform.

  • experimental investigation of wall film renewal in Liquid Liquid Slug flow
    International Journal of Multiphase Flow, 2016
    Co-Authors: Linda Arsenjuk, Florian Kaske, Joachim Franzke, David W Agar
    Abstract:

    Abstract Liquid–Liquid Slug flow offers the unique characteristics of high heat and mass transfer combined with a narrow residence time distribution in continuous flow and has thus attracted considerable attention in the field of microfluidics. To exploit its advantages in the successful design and operation of micro-reactors, a precise understanding of the mass transfer processes is essential. In the present work, the role of the thin continuous Liquid film formed on the capillary wall in mass transfer is investigated. Fluorescence microscopy is used to determine the exchange between wall film and continuous phase segments to determine if the film is continuously renewed and can therefore be considered to contribute interfacial area available for mass transfer. The distinct wetting properties of different capillary materials are utilized in the experimental set-up to achieve a reproducible and non-invasive release of tracer. The degree of wall film mass transfer as a function of velocity, interfacial area and wall-film thickness is established.

  • hydrodynamic studies of Liquid Liquid Slug flows in circular microchannels
    Chemical Engineering Science, 2011
    Co-Authors: Aras Ghaini, Axel Mescher, David W Agar
    Abstract:

    Abstract The aim of the work presented was to clarify the existence of a wall film and its influence on the hydrodynamics of Liquid–Liquid Slug flow capillary microreactor. The methodology of the laser induced fluorescence (LIF) was adopted for visualisation purposes. The measurement of the light intensity profiles revealed a fully developed wall film for a variety of aqueous–organic two-phase systems in glass and PTFE capillaries of 1 mm internal diameter. In addition an acid as a quenching agent enabled the observation of the internal circulation patterns within the Liquid Slugs, as the fluorescent dye was deactivated by the acid diffusing in from the dye-free phase. A well-defined internal circulation pattern was always present in the wetting phase, i.e. that forming the wall film, leading to uniform mixing in the Slugs of this phase. Stagnant zones and local circulation vortices, indicated by variations in the concentrations of the quenched dye, were observed in the non-wetting dispersed phase. These more complex flow structures varied little with the Slug velocity, but were strongly dependent on the physical properties of the Liquid–Liquid system. To predict Slug shape and hydrodynamics within the Liquid Slugs, CFD simulations were carried out using the volume-of-fluid method (VOF) based on the incompressible Navier–Stokes equation with appropriate boundary conditions between the two phases. The Slug generation process was studied in a T-junction with 1 mm internal diameter inlets. The implementation of the wetting contact angle, measured in the visualisation experiments for the various systems, led to realistic Slug lengths and shapes. The velocity vector plot indicated a fully developed internal circulation pattern within the simulated Slugs. Calculations for a single Slug with a non-wetting condition gave rise to a wall film in the simulated system. The results obtained demonstrate the significance of the wall film in the hydrodynamics and mass transfer Liquid–Liquid Slug flow and reveal the presence of hitherto unsuspected complex patterns in place of simple single Taylor vortex flow assumed in the past.

  • Liquid Liquid Slug flow capillary microreactor
    Chemical Engineering & Technology, 2011
    Co-Authors: Andreas Ufer, Matthias Mendorf, Aras Ghaini, David W Agar
    Abstract:

    The Liquid-Liquid Slug flow capillary microreactor offers an excellent mass transfer performance for extraction and biphasic reactions. In combination with a simple phase separator based on wettability discrimination between the two Liquids, it provides a powerful tool for process intensification and microscale processing. By new visualization techniques, the interfacial surface and Slug vortex structures dictating inter- and intraphase mass transfer have been revealed to be more complex than previously assumed. Suspending fine catalyst particles in one phase of a two-phase Slug flow is an effective technique for using heterogeneous catalysts in microreactors, owing to the very good mass transfer characteristics and because catalyst recovery becomes simply a matter of separating the catalyst carrier phase from the reaction medium. To exploit the performance attributes of capillary microreactors at higher throughputs, distributor and control strategies for parallelisation were developed to provide a flow distribution uniform to within 1 % or less.

  • Liquid/Liquid Slug Flow Capillary Microreactor
    Chemical Engineering & Technology, 2011
    Co-Authors: Andreas Ufer, Matthias Mendorf, Aras Ghaini, David W Agar
    Abstract:

    The Liquid-Liquid Slug flow capillary microreactor offers an excellent mass transfer performance for extraction and biphasic reactions. In combination with a simple phase separator based on wettability discrimination between the two Liquids, it provides a powerful tool for process intensification and microscale processing. By new visualization techniques, the interfacial surface and Slug vortex structures dictating inter- and intraphase mass transfer have been revealed to be more complex than previously assumed. Suspending fine catalyst particles in one phase of a two-phase Slug flow is an effective technique for using heterogeneous catalysts in microreactors, owing to the very good mass transfer characteristics and because catalyst recovery becomes simply a matter of separating the catalyst carrier phase from the reaction medium. To exploit the performance attributes of capillary microreactors at higher throughputs, distributor and control strategies for parallelisation were developed to provide a flow distribution uniform to within 1 % or less.

  • Hydrodynamic studies of Liquid–Liquid Slug flows in circular microchannels
    Chemical Engineering Science, 2011
    Co-Authors: Aras Ghaini, Axel Mescher, David W Agar
    Abstract:

    Abstract The aim of the work presented was to clarify the existence of a wall film and its influence on the hydrodynamics of Liquid–Liquid Slug flow capillary microreactor. The methodology of the laser induced fluorescence (LIF) was adopted for visualisation purposes. The measurement of the light intensity profiles revealed a fully developed wall film for a variety of aqueous–organic two-phase systems in glass and PTFE capillaries of 1 mm internal diameter. In addition an acid as a quenching agent enabled the observation of the internal circulation patterns within the Liquid Slugs, as the fluorescent dye was deactivated by the acid diffusing in from the dye-free phase. A well-defined internal circulation pattern was always present in the wetting phase, i.e. that forming the wall film, leading to uniform mixing in the Slugs of this phase. Stagnant zones and local circulation vortices, indicated by variations in the concentrations of the quenched dye, were observed in the non-wetting dispersed phase. These more complex flow structures varied little with the Slug velocity, but were strongly dependent on the physical properties of the Liquid–Liquid system. To predict Slug shape and hydrodynamics within the Liquid Slugs, CFD simulations were carried out using the volume-of-fluid method (VOF) based on the incompressible Navier–Stokes equation with appropriate boundary conditions between the two phases. The Slug generation process was studied in a T-junction with 1 mm internal diameter inlets. The implementation of the wetting contact angle, measured in the visualisation experiments for the various systems, led to realistic Slug lengths and shapes. The velocity vector plot indicated a fully developed internal circulation pattern within the simulated Slugs. Calculations for a single Slug with a non-wetting condition gave rise to a wall film in the simulated system. The results obtained demonstrate the significance of the wall film in the hydrodynamics and mass transfer Liquid–Liquid Slug flow and reveal the presence of hitherto unsuspected complex patterns in place of simple single Taylor vortex flow assumed in the past.

Dvora Barnea - One of the best experts on this subject based on the ideXlab platform.

  • Spatial distribution of void fraction in the Liquid Slug in the whole range of pipe inclinations
    International Journal of Multiphase Flow, 2013
    Co-Authors: Dvora Barnea, E. Roitberg, Lev Shemer
    Abstract:

    Abstract A wire mesh sensor was used to detect the local instantaneous cross-sectional distribution of the phases in gas-Liquid Slug flow. Data were obtained for a wide range of flow rates and for pipe inclinations ranging from shallow to vertical. Processing of the wire mesh sensor data yielded detailed information of the 3D void fraction distribution in the Liquid Slug. These results shed additional light on the hydrodynamics of Slug flow, in particular, regarding the formation and distribution of dispersed bubbles in the Liquid Slug. Comparison with available data was carried out. The present results compared favorably with model predictions.

  • hydrodynamic characteristics of gas Liquid Slug flow in a downward inclined pipe
    Chemical Engineering Science, 2008
    Co-Authors: E. Roitberg, Lev Shemer, Dvora Barnea
    Abstract:

    Abstract Gas–Liquid Slug flow in a downward inclined pipe was studied experimentally by employing a wire-mesh sensor that enables quantitative measurements of the cross-sectional void fraction distribution. Processing of the wire-mesh sensor data was applied to carry out a statistical analysis of characteristic parameters of downward Slug flow, such as bubble and Liquid Slug length distributions, as well as to determine the ensemble-averaged shapes of the bubble nose, Liquid film and bubble tail. It was found that the pipe inclination affects mainly the bubble length, while variation in the gas flow rate affects both bubble and Slug length. The bubble nose shape is more sensitive to the flow conditions than the bubble tail. The 3D structure of an elongated bubble in downward Slug flow was reconstructed from the wire-mesh sensor data.

  • Hydrodynamic characteristics of gas–Liquid Slug flow in a downward inclined pipe
    Chemical Engineering Science, 2008
    Co-Authors: E. Roitberg, Lev Shemer, Dvora Barnea
    Abstract:

    Abstract Gas–Liquid Slug flow in a downward inclined pipe was studied experimentally by employing a wire-mesh sensor that enables quantitative measurements of the cross-sectional void fraction distribution. Processing of the wire-mesh sensor data was applied to carry out a statistical analysis of characteristic parameters of downward Slug flow, such as bubble and Liquid Slug length distributions, as well as to determine the ensemble-averaged shapes of the bubble nose, Liquid film and bubble tail. It was found that the pipe inclination affects mainly the bubble length, while variation in the gas flow rate affects both bubble and Slug length. The bubble nose shape is more sensitive to the flow conditions than the bubble tail. The 3D structure of an elongated bubble in downward Slug flow was reconstructed from the wire-mesh sensor data.

  • Evolution of hydrodynamic and statistical parameters of gas-Liquid Slug flow along inclined pipes
    Chemical Engineering Science, 2003
    Co-Authors: R. Van Hout, Lev Shemer, Dvora Barnea
    Abstract:

    The development of Slug $ow along two 10 m long inclined pipes (2–90 ◦ from the horizontal) with internal diameters of 0.024 and 0:054 m was measured bythree optical 4ber probes. The probes were located in a measurement module at axial distances of 0 :020 m between the 4ber tips. To measure the evolution of Slug $ow, the module was placed at di6erent positions along the pipe. Instantaneous elongated bubble velocities and corresponding elongated bubble and Liquid Slug lengths were determined byprocessing the optical probe signals. The evolution of the Liquid Slug and elongated bubble length distributions along the pipes is characterized bya gradual growth of the mean and mode values. The growth rate decreases with decreasing inclination. Mean elongated bubble lengths have a minimum at about 60 ◦ , while mean Liquid Slug lengths decrease slowlywith decreasing inclination angle. The coalescence rate, de4ned as the decrease in the ensemble size, becomes almost negligible at x=D ? 60, independent of pipe diameter, $ow rates and inclination angle. The Slug frequencyhas a maximum at about 60 ◦ inclination.

  • evolution of statistical parameters of gas Liquid Slug flow along vertical pipes
    International Journal of Multiphase Flow, 2001
    Co-Authors: R. Van Hout, Dvora Barnea, Lev Shemer
    Abstract:

    Abstract The evolution of hydrodynamic and statistical parameters along the pipe was studied experimentally in gas–Liquid Slug flow for various flow conditions and two pipe diameters. The measuring modules comprise a set of three adjacent optical fiber probes and could be easily transferred to various positions along the pipes. The probes detect the passage of the gas–Liquid interface. This technique enables one to measure the instantaneous velocities of nose and tail of elongated (Taylor) bubbles simultaneously with the Slug length ahead of each bubble. The Liquid Slug and Taylor bubble length distributions along the pipe, together with the dependence of the Taylor bubble velocity on the Liquid Slug length ahead of it, are presented at various locations along the pipe. Empirical correlations relating the Taylor bubble velocity with the bubble separation distance are suggested. These correlations are used as an input to a model for Slug length distribution. The model results are compared with the experiments.

João B. L. M. Campos - One of the best experts on this subject based on the ideXlab platform.

  • review on vertical gas Liquid Slug flow
    International Journal of Multiphase Flow, 2016
    Co-Authors: A.o. Morgado, João M. Miranda, José D. P. Araújo, João B. L. M. Campos
    Abstract:

    Abstract Vertical Slug flow is characterized by the rise of long bullet-shaped gas bubbles with a diameter almost matching that of the tube - Taylor bubbles. Liquid Slugs separate consecutive Taylor bubbles, which may interact and coalesce if the distance between them is small. Slug flow has numerous industrial applications, being also observed on physiological and geological systems. In spite of the contribution of the development of non-intrusive experimental techniques to a deeper understanding of Slug flow features, the complexity of this flow pattern requires the combined use of numerical approaches to overcome some of the optical problems reported in experimental methods, and other limitations related to the flow aperiodic behavior. The need to systematize the large amount of data published on the subject and to understand the limitations of the techniques employed constitutes the motivation for this review. In the present work, literature on vertical gas–Liquid Slug flow, with Newtonian fluids, from 1943 to 2015, covering theoretical, experimental and numerical approaches, is reviewed. Focus is given to single and trains of Taylor bubbles rising through stagnant and co-current Liquids. It should be emphasized, however, that further research still needs to be conducted in some particular areas, namely the hydrodynamics of the Liquid film surrounding the Taylor bubbles, the interaction between consecutive bubbles, and a more detailed approach to the flow of Taylor bubbles through co-current Liquids.

  • Review on vertical gas–Liquid Slug flow
    International Journal of Multiphase Flow, 2016
    Co-Authors: A.o. Morgado, João M. Miranda, José D. P. Araújo, João B. L. M. Campos
    Abstract:

    Abstract Vertical Slug flow is characterized by the rise of long bullet-shaped gas bubbles with a diameter almost matching that of the tube - Taylor bubbles. Liquid Slugs separate consecutive Taylor bubbles, which may interact and coalesce if the distance between them is small. Slug flow has numerous industrial applications, being also observed on physiological and geological systems. In spite of the contribution of the development of non-intrusive experimental techniques to a deeper understanding of Slug flow features, the complexity of this flow pattern requires the combined use of numerical approaches to overcome some of the optical problems reported in experimental methods, and other limitations related to the flow aperiodic behavior. The need to systematize the large amount of data published on the subject and to understand the limitations of the techniques employed constitutes the motivation for this review. In the present work, literature on vertical gas–Liquid Slug flow, with Newtonian fluids, from 1943 to 2015, covering theoretical, experimental and numerical approaches, is reviewed. Focus is given to single and trains of Taylor bubbles rising through stagnant and co-current Liquids. It should be emphasized, however, that further research still needs to be conducted in some particular areas, namely the hydrodynamics of the Liquid film surrounding the Taylor bubbles, the interaction between consecutive bubbles, and a more detailed approach to the flow of Taylor bubbles through co-current Liquids.

  • hydrodynamics of gas Liquid Slug flow along vertical pipes in turbulent regime an experimental study
    International Journal of Heat and Fluid Flow, 2008
    Co-Authors: T.s. Mayor, Alexandra M.f.r. Pinto, V. Ferreira, João B. L. M. Campos
    Abstract:

    Abstract An experimental study on free-bubbling gas–Liquid (air–water) vertical Slug flow was developed using a non-intrusive image analysis technique. The flow pattern in the near-wake of the bubbles and in the main Liquid between bubbles was turbulent. A single correlation for the bubble-to-bubble interaction is proposed, relating the trailing bubble velocity to the length of the Liquid Slug ahead of the bubble. The proposed correlation is shown to be independent of column diameter, column vertical coordinate, superficial Liquid and gas velocities and the velocity and length of the leading bubble. Frequency distribution curves, averages, modes and standard deviations are reported, for distributions of bubble velocity, bubble length and Liquid Slug length, for each experimental condition studied. Good agreement was found between theoretical predictions and experimental results regarding the upward velocity of undisturbed bubbles, in a 0.032 m internal diameter column. A considerable discrepancy was found, though, for a 0.052 m internal diameter column. The acquired experimental data are crucial for the development and validation of a robust Slug flow simulator.

  • Hydrodynamics of gas–Liquid Slug flow along vertical pipes in turbulent regime–An experimental study
    International Journal of Heat and Fluid Flow, 2008
    Co-Authors: T.s. Mayor, Alexandra M.f.r. Pinto, V. Ferreira, João B. L. M. Campos
    Abstract:

    Abstract An experimental study on free-bubbling gas–Liquid (air–water) vertical Slug flow was developed using a non-intrusive image analysis technique. The flow pattern in the near-wake of the bubbles and in the main Liquid between bubbles was turbulent. A single correlation for the bubble-to-bubble interaction is proposed, relating the trailing bubble velocity to the length of the Liquid Slug ahead of the bubble. The proposed correlation is shown to be independent of column diameter, column vertical coordinate, superficial Liquid and gas velocities and the velocity and length of the leading bubble. Frequency distribution curves, averages, modes and standard deviations are reported, for distributions of bubble velocity, bubble length and Liquid Slug length, for each experimental condition studied. Good agreement was found between theoretical predictions and experimental results regarding the upward velocity of undisturbed bubbles, in a 0.032 m internal diameter column. A considerable discrepancy was found, though, for a 0.052 m internal diameter column. The acquired experimental data are crucial for the development and validation of a robust Slug flow simulator.

  • an image analysis technique for the study of gas Liquid Slug flow along vertical pipes associated uncertainty
    Flow Measurement and Instrumentation, 2007
    Co-Authors: T.s. Mayor, Alexandra M.f.r. Pinto, João B. L. M. Campos
    Abstract:

    Abstract An image analysis technique for the study of continuous co-current gas–Liquid Slug flow, in vertical columns, is reported. The technique comprises the automatic analysis of a sequence of video frames with the purpose of object (bubbles) tracking and characterization (dimension, velocity, distance). Its applicability to continuous Slug flow conditions (even for very large number of bubbles) and the high accuracy of the results are the main added value of the proposed technique. The evaluation of the uncertainty associated with the parameters measured is performed (following the general uncertainty analysis approach ). Partial uncertainties are acknowledged in bubble boundary definition, time measurement and calibration procedure. Expressions are derived for the computation of the overall uncertainty of bubble velocity, bubble length and Liquid Slug length. Global relative uncertainties of 5%, 2.5% and 7%, were found, for these parameters. The uncertainty estimation supports the ongoing trend for the implementation of image analysis techniques for the study of Slug flow patterns.

R. Van Hout - One of the best experts on this subject based on the ideXlab platform.

  • Evolution of hydrodynamic and statistical parameters of gas-Liquid Slug flow along inclined pipes
    Chemical Engineering Science, 2003
    Co-Authors: R. Van Hout, Lev Shemer, Dvora Barnea
    Abstract:

    The development of Slug $ow along two 10 m long inclined pipes (2–90 ◦ from the horizontal) with internal diameters of 0.024 and 0:054 m was measured bythree optical 4ber probes. The probes were located in a measurement module at axial distances of 0 :020 m between the 4ber tips. To measure the evolution of Slug $ow, the module was placed at di6erent positions along the pipe. Instantaneous elongated bubble velocities and corresponding elongated bubble and Liquid Slug lengths were determined byprocessing the optical probe signals. The evolution of the Liquid Slug and elongated bubble length distributions along the pipes is characterized bya gradual growth of the mean and mode values. The growth rate decreases with decreasing inclination. Mean elongated bubble lengths have a minimum at about 60 ◦ , while mean Liquid Slug lengths decrease slowlywith decreasing inclination angle. The coalescence rate, de4ned as the decrease in the ensemble size, becomes almost negligible at x=D ? 60, independent of pipe diameter, $ow rates and inclination angle. The Slug frequencyhas a maximum at about 60 ◦ inclination.

  • evolution of statistical parameters of gas Liquid Slug flow along vertical pipes
    International Journal of Multiphase Flow, 2001
    Co-Authors: R. Van Hout, Dvora Barnea, Lev Shemer
    Abstract:

    Abstract The evolution of hydrodynamic and statistical parameters along the pipe was studied experimentally in gas–Liquid Slug flow for various flow conditions and two pipe diameters. The measuring modules comprise a set of three adjacent optical fiber probes and could be easily transferred to various positions along the pipes. The probes detect the passage of the gas–Liquid interface. This technique enables one to measure the instantaneous velocities of nose and tail of elongated (Taylor) bubbles simultaneously with the Slug length ahead of each bubble. The Liquid Slug and Taylor bubble length distributions along the pipe, together with the dependence of the Taylor bubble velocity on the Liquid Slug length ahead of it, are presented at various locations along the pipe. Empirical correlations relating the Taylor bubble velocity with the bubble separation distance are suggested. These correlations are used as an input to a model for Slug length distribution. The model results are compared with the experiments.

  • Evolution of statistical parameters of gas–Liquid Slug flow along vertical pipes
    International Journal of Multiphase Flow, 2001
    Co-Authors: R. Van Hout, Dvora Barnea, Lev Shemer
    Abstract:

    Abstract The evolution of hydrodynamic and statistical parameters along the pipe was studied experimentally in gas–Liquid Slug flow for various flow conditions and two pipe diameters. The measuring modules comprise a set of three adjacent optical fiber probes and could be easily transferred to various positions along the pipes. The probes detect the passage of the gas–Liquid interface. This technique enables one to measure the instantaneous velocities of nose and tail of elongated (Taylor) bubbles simultaneously with the Slug length ahead of each bubble. The Liquid Slug and Taylor bubble length distributions along the pipe, together with the dependence of the Taylor bubble velocity on the Liquid Slug length ahead of it, are presented at various locations along the pipe. Empirical correlations relating the Taylor bubble velocity with the bubble separation distance are suggested. These correlations are used as an input to a model for Slug length distribution. The model results are compared with the experiments.

  • SPATIAL DISTRIBUTION OF VOID FRACTION WITHIN A Liquid Slug AND SOME OTHER RELATED Slug PARAMETERS
    International Journal of Multiphase Flow, 1992
    Co-Authors: R. Van Hout, Lev Shemer, Dvora Barnea
    Abstract:

    The structure of vertical upward Slug flow in a pipe is studied. The distribution of the phases in the Taylor bubble zone and the Liquid Slug zone is investigated by simultaneous measurements with two optical fiber probes. In the Taylor bubble zone the shape of the Taylor bubble and the distribution of the bubble length is reported. In the Liquid Slug region, the distribution of the void fraction is obtained over a dense grid in both the axial and radial directions. These experimental results shed some light on the hydrodynamics of the two-phase Slug flow, in particular regarding the production of the dispersed bubbles and their distribution along the Liquid Slug.