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Journal articles on the topic 'Liquid holdups'

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Author: Grafiati

Published: 6 September 2023

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1

Seong, Yongho, Changhyup Park, Jinho Choi, and Ilsik Jang. "Surrogate Model with a Deep Neural Network to Evaluate Gas–Liquid Flow in a Horizontal Pipe." Energies 13, no. 4 (February 21, 2020): 968. http://dx.doi.org/10.3390/en13040968.

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This study developed a data-driven surrogate model based on a deep neural network (DNN) to evaluate gas–liquid multiphase flow occurring in horizontal pipes. It estimated the liquid holdup and pressure gradient under a slip condition and different flow patterns, i.e., slug, annular, stratified flow, etc. The inputs of the surrogate modelling were related to the fluid properties and the dynamic data, e.g., superficial velocities at the inlet, while the outputs were the liquid holdup and pressure gradient observed at the outlet. The case study determined the optimal number of hidden neurons by considering the processing time and the validation error. A total of 350 experimental data were used: 279 for supervised training, 31 for validating the training performance, and 40 unknown data, not used in training and validation, were examined to forecast the liquid holdup and pressure gradient. The liquid holdups were estimated within less than 8.08% of the mean absolute percentage error, while the error of the pressure gradient was 23.76%. The R2 values confirmed the reliability of the developed model, showing 0.89 for liquid holdups and 0.98 for pressure gradients. The DNN-based surrogate model can be applicable to estimate liquid holdup and pressure gradients in a more realistic manner with a small amount of computating resources.

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2

Razzak, Shaikh A. "Study of Phase Distribution of a Liquid-Solid Circulating Fluidized Bed Reactor Using Abductive Network Modeling Approach." Chemical Product and Process Modeling 8, no. 2 (September 10, 2013): 77–91. http://dx.doi.org/10.1515/cppm-2013-0008.

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Abstract This communication deals with the Abductive Network modeling approach to investigate the phase holdup distributions of a liquid–solid circulating fluidized bed (LSCFB) system. The Abductive Network model is developed/trained using experimental data collected from a pilot scale LSCFB reactor involving 500-μm size glass beads and water as solid and liquid phases, respectively. The trained Abductive Network model successfully predicted experimental phase holdups of the LSCFB riser under different operating parameters. It is observed that the model predicted cross-sectional average of solids holdups in the axial directions and radial flow structure are well agreement with the experimental values. The statistical performance indicators including the mean absolute error (~4.67%) and the correlation coefficient (0.992) also show favorable indications of the suitability of Abductive Network modeling approach in predicting the solids holdup of the LSCFB system.

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3

Razzak, Shaikh A., Muhammad I. Hossain, Syed M. Rahman, and Mohammad M. Hossain. "Application of Support Vector Machine Modeling on Phase Distribution in the Riser of an LSCFB Reactor." International Journal of Chemical Reactor Engineering 12, no. 1 (January 1, 2014): 123–34. http://dx.doi.org/10.1515/ijcre-2013-0122.

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Abstract Support vector machine (SVM) modeling approach is applied to predict the solids holdups distribution of a liquid–solid circulating fluidized bed (LSCFB) riser. The SVM model is developed/trained using experimental data collected from a pilot-scale LSCFB reactor. Two different size glass bead particles (500 μm (GB-500) and 1,290 μm (GB-1290)) are used as solid phase, and water is used as liquid phase. The trained model successfully predicted the experimental solids holdups of the LSCFB riser under different operating parameters. It is observed that the model predicted cross-sectional average of solids holdups in the axial directions and radial flow structure are well agreement with the experimental values. The goodness of the model prediction is verified by using different statistical performance indicators. For the both sizes of particles, the mean absolute error is found to be less than 5%. The correlation coefficients (0.998 for GB-500 and 0.994 for GB-1290) also show favorable indications of the suitability of SVM approach in predicting the solids holdup of the LSCFB system.

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4

Weiss, Jindřich. "Phase Inversion in Two-Phase Liquid Systems." Collection of Czechoslovak Chemical Communications 57, no. 7 (1992): 1419–23. http://dx.doi.org/10.1135/cccc19921419.

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New data on critical holdups of dispersed phase were measured at which the phase inversion took place. The systems studied differed in the ratio of phase viscosities and interfacial tension. A weak dependence was found of critical holdups on the impeller revolutions and on the material contactor; on the contrary, a considerable effect of viscosity was found out as far as the viscosity of continuous phase exceeded that of dispersed phase.

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5

KIM, SANG DONE, YONG HO YU, and POONG WOO HAN. "PHASE HOLDUPS AND LIQUID-LIQUID EXTRACTION IN THREE PHASE FLUIDIZED BEDS." Chemical Engineering Communications 68, no. 1 (June 1988): 57–68. http://dx.doi.org/10.1080/00986448808940397.

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6

Bensebia, Bensaber, Fatma-Zohra Chaouche, Ouahida Bensebia, and Soumia Moustefaï. "Bed expansion in turbulent bed contactor: Experiments and prediction." Chemical Industry and Chemical Engineering Quarterly, no. 00 (2023): 10. http://dx.doi.org/10.2298/ciceq230304010b.

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In this work, the hydrodynamics of the turbulent bed contractor (TBC) have been studied in terms of bed expansion (Hd/Hst) using a particular approach for the prediction of this important property for the design of such equipment. The study is based on 1604 sets of experimental data of the bed expansion, obtained by varying the operating variables (gas velocity, liquid spray, packing characteristics, static bed height and free opening of the supporting grid. The prediction of the bed expansion necessitates the estimation of gas and liquid holdups. To achieve this, we employed a variety of correlations derived from existing literature, comprising six equations for gas holdup and twenty equations for liquid holdup estimation. Out of a total of 120 cases, bed expansion was estimated, and the accuracy of the model was evaluated by calculating the mean absolute error in percentage (MAPE), root mean square error (RMSE), correlation coefficient (?XY), and explained variance (VECV). This study enabled the identification of suitable correlations for gas and liquid holdups, leading to predictions with acceptable errors. Furthermore, statistical analysis was employed in a subsequent phase of the study to determine the most appropriate correlations for predicting bed expansion among those proposed by various authors.

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7

Nematbakhsh, Gita, and Ahmad Rahbar Kelishami. "The Effect of Nanoparticles on Liquid Holdups in a Randomly Packed Liquid-Liquid Extraction Column." Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry 46, no. 1 (September 25, 2015): 31–37. http://dx.doi.org/10.1080/15533174.2014.900629.

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8

Abid, Mohammad F., Zainab Y. Shanain, and Kadhim N. Abed. "Experimental and analysis study on dispersion of phases in an Ebullated Bed Reactor." Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 74 (2019): 20. http://dx.doi.org/10.2516/ogst/2018103.

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The effectiveness and performance of industrial hydro-processing Ebullated Bed Reactors (EBRs) are highly dependent on the bed hydrodynamics and operating conditions. In present work, hydrodynamics of EBRs was studied in a cold model experimental setup using air–water–solid particles system. Pressure gradient method and Residence Time Distribution (RTD) technique were used to estimate the individual holdups, and dispersion coefficients in the lab-scale ebullated bed column. System Hydraulic Efficiency (HEF) was also estimated. The results showed that liquid internal recycle ratio, which characterized the EBRs, has a predominant effect on the individual holdups and dispersion coefficients. Empirical correlations were developed for prediction of phase holdups, and dispersion coefficients with good accuracy.

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9

Yamada, Hiroshi, and Shigeo Goto. "Gas and Liquid Holdups in Multi-Stage Bubble Columns for Gas-Liquid-Liquid-Solid Four-Phase System." JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 31, no. 5 (1998): 813–17. http://dx.doi.org/10.1252/jcej.31.813.

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10

Wugeng, L. "The phase holdups in a gas-liquid-solid circulating fluidized bed." International Journal of Multiphase Flow 22 (December 1996): 100. http://dx.doi.org/10.1016/s0301-9322(97)88183-9.

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11

Liang, Wugeng, Zhiging Yu, Yong Jin, Zhangwen Wang, and Qunwei Wu. "The phase holdups in a gas—liquid—solid circulating fluidized bed." Chemical Engineering Journal and the Biochemical Engineering Journal 58, no. 3 (August 1995): 259–64. http://dx.doi.org/10.1016/0923-0467(94)02889-i.

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12

Wang, Feng, Zai-Sha Mao, Yuefa Wang, and Chao Yang. "Measurement of phase holdups in liquid–liquid–solid three-phase stirred tanks and CFD simulation." Chemical Engineering Science 61, no. 22 (November 2006): 7535–50. http://dx.doi.org/10.1016/j.ces.2006.08.046.

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13

Lee, Donghyun, Arturo Macchi, Norman Epstein, and John R. Grace. "Transition velocities and phase holdups at minimum fluidization in gas-liquid-solid systems." Canadian Journal of Chemical Engineering 79, no. 4 (August 2001): 579–83. http://dx.doi.org/10.1002/cjce.5450790416.

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14

Pallapothu, Surya K., and Adel M. Al Taweel. "Effect of Contaminants on the Gas Holdup and Mixing in Internal Airlift Reactors Equipped with Microbubble Generator." International Journal of Chemical Engineering 2012 (2012): 1–15. http://dx.doi.org/10.1155/2012/569463.

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The impact of contaminants on the gas holdup and mixing characteristics encountered in internal airlift reactors was investigated using a 200 L pilot scale unit equipped with a two-phase transonic sparger capable of generating microbubbles. Small dosages of a cationic surfactant (0–50 ppm of sodium dodecyl sulfonate (SDS)) were used to simulate the coalescence-retarding effect encountered in most industrial streams and resulted in the formation of bubbles that varied in size between 280 and 1,900 μm. Gas holdups as high as 0.14 were achieved in the riser under homogeneous flow regime when slowly coalescent systems were aerated at the relatively low superficial velocity of 0.02 ms−1, whereas liquid circulation velocities as high as 1.3 ms−1were achieved in conjunction with rapidly coalescent systems at the same superficial velocity. This excellent hydrodynamic performance represents a 5-fold improvement in the riser gas holdup and up to 8-fold enhancement in the liquid circulation velocity and is expected to yield good mixing and mass transfer performance at low energy dissipation rates.

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15

Choi, Jinho, Eduardo Pereyra, Cem Sarica, Changhyup Park, and Joe Kang. "An Efficient Drift-Flux Closure Relationship to Estimate Liquid Holdups of Gas-Liquid Two-Phase Flow in Pipes." Energies 5, no. 12 (December 14, 2012): 5294–306. http://dx.doi.org/10.3390/en5125294.

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16

Ahmed, Salem K. Brini, Aliyu M. Aliyu, Yahaya D. Baba, Mukhtar Abdulkadir, Rahil Omar Abdulhadi, Liyun Lao, and Hoi Yeung. "Comparative Analysis of Riser Base and Flowline Gas Injection on Vertical Gas-Liquid Two-Phase Flow." Energies 15, no. 19 (October 10, 2022): 7446. http://dx.doi.org/10.3390/en15197446.

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Gas injection is a frequently used method for artificial lift and flow regime rectification in offshore production and transportation flowlines. The flow behaviour in such flowlines is complex and a better understanding of flow characteristics, such as flow patterns, void fraction/hold up distributions and pressure gradient is always required for efficient and optimal design of downstream handling facilities. Injection method and location have been shown to strongly affect downstream fluid behaviour that can have important implications for pumping and downstream facility design, especially if the development length between pipeline and downstream facility is less than L/D = 50 as reported by many investigators. In this article, we provide the results of an experimental investigation into the effects of the gas injection position on the characteristics of the downstream upwards vertical gas flow using a vertical riser with an internal diameter of 52 mm and a length of 10.5 m. A horizontal 40-m-long section connected at the bottom provides options for riser base or horizontal flow line injection of gas. The flowline gas injection is performed 40 m upstream of the riser base. A 16 by 16 capacitance wire mesh sensor and a gamma densitometer were used to measure the gas-liquid phase cross-sectional distribution at the riser top. A detailed analysis of the flow characteristics is carried out based on the measurements. These include flow regimes, cross-sectional liquid holdup distributions and peaking patterns as well as analysis of the time series data. Our findings show that flow behaviours differences due to different gas injection locations were persisting after a development length of 180D in the riser. More specifically, core-peaking liquid holdup occurred at the lower gas injection rates through the flowline, while wall-peaking holdup profiles were established at the same flow conditions for riser base injection. Wall peaking was associated with dispersed bubbly flows and hence non-pulsating as against core-peaking was associated with Taylor bubbles and slug flows. Furthermore, it was found that the riser base injection generally produced lower holdups. It was noted that the circumferential injector used at the riser base promoted high void fraction and hence low liquid holdups. Due to the bubbly flow structure, the slip velocity is smaller than for larger cap bubbles and hence the void fraction is higher. The measurements and observations presented in the paper provides valuable knowledge on riser base/flowline gas introduction that can directly feed into the design of downstream facilities such as storage tanks, slug catchers and separators.

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17

Padmavathi, G., and K. Remananda Rao. "Effect of liquid viscosity on gas holdups in a reversed flow jet loop reactor." Canadian Journal of Chemical Engineering 70, no. 4 (August 1992): 800–802. http://dx.doi.org/10.1002/cjce.5450700426.

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18

Carraretto, I. M., L. P. M. Colombo, and M. Guilizzoni. "Liquid holdup measurement for gas-liquid stratified flows by means of resistive probes and image processing." Journal of Physics: Conference Series 2177, no. 1 (April 1, 2022): 012034. http://dx.doi.org/10.1088/1742-6596/2177/1/012034.

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Abstract Flow patterns exert a fundamental influence on the behaviour of multiphase flows, and they must be brought into play when dealing with their modelling. This is usually done by means of summarizing quantities as the phase holdups and the interfacial area concentration. Many techniques have been designed during the years to measure them, among which the use of probes relying on electrical resistance is one of the simplest and less expensive. While having these points of strength, resistive probes are intrusive devices. This work is therefore devoted to a comparison between liquid height (and derived quantities) measurements – for stratified and stratified-wavy air-water flows – performed using a conventional resistive probe and by means of an image-based technique. Validation of the latter was performed using computer-generated flow images. Then, an experimental campaign was carried out for flows with liquid superficial velocities in the range 0.03 ÷ 0.06 m/s and gas superficial velocities in the range 0.77 ÷ 2.31 m/s. Results showed that the two methods give answers within very few percent of difference, which is more than satisfactory in this field. The results are also in good agreement with some of the most credited literature models and correlations.

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19

Basavaraj, M. G., G. S. Gupta, K. Naveen, V. Rudolph, and R. Bali. "Local liquid holdups and hysteresis in a 2-D packed bed using X-ray radiography." AIChE Journal 51, no. 8 (2005): 2178–89. http://dx.doi.org/10.1002/aic.10481.

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20

Zhang, Xi, Ping Zhu, Shuaichao Li, Wenyuan Fan, and Jingyan Lian. "CFD-PBM simulation of hydrodynamics of microbubble column with shear-thinning fluid." International Journal of Chemical Reactor Engineering 19, no. 2 (February 1, 2021): 125–38. http://dx.doi.org/10.1515/ijcre-2020-0172.

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Abstract A numerical simulation was performed to study the hydrodynamics of micro-bubble swarm in bubble column with polyacrylamide (PAM) aqueous solution by using computational fluid dynamics coupled with population balance models (CFD-PBM). By considering rheological characteristics of fluid, this approach was able to accurately predict the features of bubble swarm, and validated by comparing with the experimental results. The gas holdup, turbulent kinetic energy and liquid velocity of bubble column have been elucidated by considering the influences of superficial gas velocity and gas distributor size respectively. The results show that with the rise of the superficial gas velocity, the gas holdup and its peak width increase significantly. Especially, the curve peak corresponding to high gas velocity tends to drift obviously toward the right side. Except for the occurrence of a smooth holdup peak at the column center under the condition of the moderate distributor size, the gas holdups for the small and large distributor sizes become flat in the radial direction respectively. The distribution of turbulent kinetic energy presents an increasingly asymmetrical feature in the radial direction and also its variation amplitude enhances obviously with the rise of gas velocity. The increase in gas distributor size can enhance markedly turbulent kinetic energy as well as its overall influenced width. At the low and moderate superficial gas velocity, the curves of the liquid velocity in radial direction present the Gaussian distributions, whereas the perfect distribution always is broken in the symmetry for high gas velocity. Both liquid velocities around the bubble column center and the ones near both column walls go up consistently with the gas distributor size, especially near the walls at the large distributor size condition.

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21

Lim, Dae Ho, Ji Hwa Jang, Yong Kang, and Ki Won Jun. "Effects of Column Diameter on the Holdups of Bubble, Wake and Continuous Liquid Phase in Bubble Columns with Viscous Liquid Medium." Korean Chemical Engineering Research 49, no. 5 (October 1, 2011): 582–87. http://dx.doi.org/10.9713/kcer.2011.49.5.582.

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22

Zheng, Shi-qing, Yun Yao, Fang-fei Guo, Rong-shan Bi, and Jing-ya Li. "Local bubble size distribution, gas–liquid interfacial areas and gas holdups in an up-flow ejector." Chemical Engineering Science 65, no. 18 (September 2010): 5264–71. http://dx.doi.org/10.1016/j.ces.2010.06.027.

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23

Kobayashi, Nobuya, Shun Adomi, Ryo Kurimoto, Kosuke Hayashi, and Akio Tomiyama. "EFFECTS OF INITIAL LIQUID HEIGHT ON TOTAL AND LOCAL GAS HOLDUPS IN AN AIR-WATER BUBBLE COLUMN." Multiphase Science and Technology 33, no. 2 (2021): 87–101. http://dx.doi.org/10.1615/multscientechn.2021039046.

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24

Liu, Jianhua, Mingyan Liu, and Zongding Hu. "Fractal Structure in Gas–Liquid–Solid Circulating Fluidized Beds with Low Solid Holdups of Macroporous Resin Particles." Industrial & Engineering Chemistry Research 52, no. 33 (March 12, 2013): 11404–13. http://dx.doi.org/10.1021/ie3030906.

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25

Cao, Changqing, Mingyan Liu, and Qingjie Guo. "Experimental Investigation into the Radial Distribution of Local Phase Holdups in a Gas−Liquid−Solid Fluidized Bed." Industrial & Engineering Chemistry Research 46, no. 11 (May 2007): 3841–48. http://dx.doi.org/10.1021/ie060798g.

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26

AKITA, KIYOMI, TATSUYA OKAZAKI, and HIROSHI KOYAMA. "Gas holdups and friction factors of gas-liquid two-phase flow in an air-lift bubble column." Journal of Chemical Engineering of Japan 21, no. 5 (1988): 476–82. http://dx.doi.org/10.1252/jcej.21.476.

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27

Li, Xiangnan, Mingyan Liu, Yongli Ma, Tingting Dong, and Dong Yao. "Experiments and meso-scale modeling of phase holdups and bubble behavior in gas-liquid-solid mini-fluidized beds." Chemical Engineering Science 192 (December 2018): 725–38. http://dx.doi.org/10.1016/j.ces.2018.08.005.

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28

Laakkonen, Marko, Markus Honkanen, Pentti Saarenrinne, and Juhani Aittamaa. "Local bubble size distributions, gas–liquid interfacial areas and gas holdups in a stirred vessel with particle image velocimetry." Chemical Engineering Journal 109, no. 1-3 (May 2005): 37–47. http://dx.doi.org/10.1016/j.cej.2005.03.002.

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29

Iliuta, I., and F. C. Thyrion. "Flow regimes, liquid holdups and two-phase pressure drop for two-phase cocurrent downflow and upflow through packed beds: air/Newtonian and non-Newtonian liquid systems." Chemical Engineering Science 52, no. 21-22 (November 1997): 4045–53. http://dx.doi.org/10.1016/s0009-2509(97)00247-9.

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30

Razzak, S. A., J. X. Zhu, and S. Barghi. "Radial Distributions of Phase Holdups and Phase Propagation Velocities in a Three-Phase Gas−Liquid−Solid Fluidized Bed (GLSCFB) Riser." Industrial & Engineering Chemistry Research 48, no. 1 (January 7, 2009): 281–89. http://dx.doi.org/10.1021/ie800299w.

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31

HIBINO, Tsutomu, and Masao SUDOH. "Effects of Holdups of Gas and Liquid Phases in Packed-bed Electrode on Current Efficiency of Electrochemical Production of Hydrogen Peroxide." Denki Kagaku oyobi Kogyo Butsuri Kagaku 65, no. 12 (December 5, 1997): 1091–96. http://dx.doi.org/10.5796/kogyobutsurikagaku.65.1091.

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32

Dohi, Naoki, Takanori Takahashi, Kimio Minekawa, and Yoshinori Kawase. "GAS-LIQUID MASS TRANSFER CHARACTERISTICS OF LARGE-SCALE IMPELLERS: EMPIRICAL CORRELATIONS OF GAS HOLDUPS AND VOLUMETRIC MASS TRANSFER COEFFICIENTS IN STIRRED TANKS." Chemical Engineering Communications 193, no. 6 (June 2006): 689–701. http://dx.doi.org/10.1080/00986440500265885.

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33

Razzak, S. A., J.-X. Zhu, and S. Barghi. "Effects of Particle Shape, Density, and Size on a Distribution of Phase Holdups in a Gas−Liquid−Solid Circulating Fluidized Bed Riser." Industrial & Engineering Chemistry Research 49, no. 15 (August 4, 2010): 6998–7007. http://dx.doi.org/10.1021/ie901704d.

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34

Shah, Imran Ali, Xiang Gou, and Jinxiang Wu. "Simulation Study of an Oxy-Biomass-Based Boiler for Nearly Zero Emission Using Aspen Plus." Energies 12, no. 10 (May 21, 2019): 1949. http://dx.doi.org/10.3390/en12101949.

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Bioenergy integrated CO2 capture is considered to be one of the viable options to reduce the carbon footprint in the atmosphere, as well as to lower dependability on the usage of fossil fuels. The present simulation-based study comprises the oxy bio-CCS technique with the objective of bringing about cleaner thermal energy production with nearly zero emissions, CO2 capture and purification, and with the ability to remove NOx and SO2 from the flue gas and to generate valuable byproducts, i.e., HNO3 and H2SO4. In the present work, a simulation on utilization of biomass resources by applying the oxy combustion technique was carried out, and CO2 sequestration through pressurized reactive distillation column (PRDC) was integrated into the boiler. Based on our proposed laboratory scale bio-CCS plant with oxy combustion technique, the designed thermal load was kept at 20 kWth using maize stalk as primary fuel. With the objective of achieving cleaner production with near zero emissions, CO2 rich flue gas and moisture generated during oxy combustion were hauled in PRDC for NOx and SO2 absorption and CO2 purification. The oxy combustion technique is unique due to its characteristic low output of NO sourced by fuel inherent nitrogen. The respective mechanisms of fuel inherent nitrogen conversion to NOx, and later, the conversion of NOx and SO2 to HNO3 and H2SO4 respectively, involve complex chemistry with the involvement of N–S intermediate species. Based on the flue gas composition generated by oxy biomass combustion, the focus was given to the fuel NOx, whereby different rates of NO formation from fuel inherent nitrogen were studied to investigate the optimum rates of conversion of NOx during conversion reactions. The rate of conversion of NOx and SO2 were studied under fixed temperature and pressure. The factors affecting the rate of conversion were optimized through sensitivity analysiês to get the best possible operational parameters. These variable factors include ratios of liquid to gas feed flow, vapor-liquid holdups and bottom recycling. The results obtained through optimizing the various factors of the proposed system have shown great potential in terms of maximizing productivity. Around 88.91% of the 20 kWth boiler’s efficiency was obtained. The rate of conversion of NOx and SO2 were recorded at 98.05% and 87.42% respectively under parameters of 30 °C temperature, 3 MPa pressure, 10% feed stream holdup, liquid/gaseous feed stream ratio of 0.04 and a recycling rate of the bottom product of 20%. During the simulation process, production of around four kilograms per hour of CO2 with 94.13% purity was achieved.

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35

Corvaro, Sara, and Maurizio Brocchini. "A Novel Two-fluid Model for the Identification of Possible Multiple Solutions in Slightly Inclined Pipelines." International Journal of Nonlinear Sciences and Numerical Simulation 14, no. 1 (February 21, 2013): 45–59. http://dx.doi.org/10.1515/ijnsns-2012-0127.

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Abstract A novel mechanistic two-fluid model (CB model) similar, in spirit, to the Taitel and Dukler [1, 2] (TD model), for the identification of possible multiple solutions of a multi-phase (gas-liquid) stratified flow in slightly inclined pipelines, is proposed. While Blasius-type closures are used in the TD model to represent the wall friction coefficients, the newly-implemented CB model makes use of Colebrook-White-type closures. Moreover, different closures for the interfacial shear are also employed in the CB models. The predictive capabilities of the CB model have been tested by using several experimental data, finding a better agreement between measured and calculated data than that existing when the TD model is used. The region of multiple solutions is influenced by the closures in use, such a dependence is more evident when different interfacial friction factors are used. Moreover, for the CB model also the fluid mixture in use influences the boundaries of the non-uniqueness region, while by using the TD model the multiple-solution region is unchanged. The choice of closures for the interfacial friction strongly influences the holdups, the Andritsos and Hanratty [10] correlation significantly shifting the non-uniqueness region to small values of the inclination parameter. Such a behaviour is more and more significant with the increase of the superficial gas velocity, even if for values of the inclination parameter within the range of inclinations for stratified flows (i.e. less than about 30° from the horizontal [11]), multiple solutions were not found. Finally, for the fluid mixture and flow conditions analyzed, multivalued solutions are obtained only for upward flows. Moreover, the portion of multiple-solution region interested by co-current flow (that occurs for slightly upward and downward pipes) is rather small, so that the operational point unlikely falls within such a region in the case of the studied hydrocarbon gas-liquid mixture.

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36

Spille, Claas, Vaishakh Prasannan Tholan, Benjamin Straiton, Monika Johannsen, Marko Hoffmann, Qussai Marashdeh, and Michael Schlüter. "Electrical Capacitance Volume Tomography (ECVT) for Characterization of Additively Manufactured Lattice Structures (AMLS) in Gas-Liquid Systems." Fluids 6, no. 9 (September 8, 2021): 321. http://dx.doi.org/10.3390/fluids6090321.

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Against the background of current and future global challenges, such as climate change, process engineering requires increasingly specific solutions adapted to the respective problem or application, especially in gas–liquid contact apparatuses. One possibility to adjust the conditions in this kind of apparatuses is an intelligent and customized structuring, which leads to consistent fluid properties and flow characteristics within the reactor. In the course of this, the interfacial area for mass transfer, as well as residence times, have to be adjusted and optimized specifically for the respective application. In order to better understand and advance the research on intelligent customized additively manufactured lattice structures (AMLS), the phase distributions and local gas holdups that are essential for mass transfer are investigated for different structures and flow conditions. For the first time a tomographic measurement technique is used, the Electrical Capacitance Volume Tomography (ECVT), and validated with the volume expansion method and a fiber optical needle probe (A2PS-B-POP) for an air-water system for different modes of operation (with or without co-current liquid flow in empty or packed state). The ECVT proved to be particularly useful for both in the empty tube and the packed state and provided new insights into the phase distributions occurring within structured packings, which would have led to significantly underestimated results based on the visual reference measurements, especially for a densely packed additively manufactured lattice structure (5 mm cubic on the tip). Particularly for the modified structures, which were supposed to show local targeted differences, the ECVT was able to resolve the changes locally. The additional use of a pump for co-current flow operation resulted in slightly higher fluctuations within the ECVT data, although local events could still be resolved sufficiently. The final comparison of the empty tube at rest data with a fiber optical needle probe showed that the results were in good agreement and that the local deviations were due to general differences in the respective measurement techniques.

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37

Abukhalifeh, H., M. E. Fayed, and R. Dhib. "Hydrodynamics of TBC with non-Newtonian liquids: Liquid holdup." Chemical Engineering and Processing: Process Intensification 48, no. 7 (July 2009): 1222–28. http://dx.doi.org/10.1016/j.cep.2009.04.007.

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38

Setyawan, Andriyanto, Indarto, Deendarlianto, and Apip Badarudin. "Effects of Liquid Viscosity on the Wave Velocity and Wave Frequency in Horizontal Annular Flow." Applied Mechanics and Materials 758 (April 2015): 7–12. http://dx.doi.org/10.4028/www.scientific.net/amm.758.7.

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An investigation on the liquid holdup, wave velocity, and wave frequency in horizontal annular flow has been experimentally conducted through the measurement of liquid holdup using constant electric current method (CECM) sensors. To investigate the effect of viscosity, water and glycerin were used as working liquid, using superficial liquid velocity and superficial gas velocity of 0.05 to 0.2 m/s and 12 to 40 m/s, respectively. Liquids with higher viscosity give the higher liquid holdup, lower wave velocity, and lower wave frequency. Correlations for liquid holdup and mean film thickness, wave velocity, and wave frequency have been developed with mean average errors (MAE) of 13.5%, 9.2%, and 8.6%, respectively.

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39

Nedeltchev, Stoyan. "Prediction of Small Bubble Holdups in Bubble Columns Operated with Various Organic Liquids at Both Ambient and Elevated Pressures and Temperatures." Fluids 8, no. 6 (May 24, 2023): 163. http://dx.doi.org/10.3390/fluids8060163.

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This article focuses on the prediction of the small bubble holdups (assuming the existence of two major bubble classes) in two bubble columns (0.289 m in ID and 0.102 m in ID), operated with organic liquids under various conditions (including high temperature and pressure). A new correction factor has been established in the existing model for the prediction of the gas holdups in the homogeneous regime. The correction parameter is a single function of the Eötvös number (gravitational forces to surface tension forces), which characterizes the bubble shape. In addition, the behavior of small bubble holdups in 1-butanol (selected as a frequently researched alcohol) aerated with nitrogen, in a smaller BC (0.102 m in ID), at various operating pressures, is presented and discussed. The ratio of small bubble holdup to overall gas holdup, as a function of superficial gas velocity and operating pressure, has been investigated. All small bubble holdups in this work have been measured by means of the dynamic gas disengagement technique.

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40

Naseva, Olivera, Ivica Stamenkovic, Ivana Bankovic-Ilic, Miodrag Lazic, Vlada Veljkovic, and Dejan Skala. "Gas holdup in a reciprocating plate bioreactor: Non-Newtonian - liquid phase." Chemical Industry 56, no. 5 (2002): 198–203. http://dx.doi.org/10.2298/hemind0205198n.

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The gas holdup was studied in non-newtonian liquids in a gas-liquid and gas-liquid-solid reciprocating plate bioreactor. Aqueous solutions of carboxy methyl cellulose (CMC; Lucel, Lucane, Yugoslavia) of different degrees of polymerization (PP 200 and PP 1000) and concentration (0,5 and 1%), polypropylene spheres (diameter 8.3 mm; fraction of spheres: 3.8 and 6.6% by volume) and air were used as the liquid, solid and gas phase. The gas holdup was found to be dependent on the vibration rate, the superficial gas velocity, volume fraction of solid particles and Theological properties of the liquid ohase. Both in the gas-liquid and gas-liquid-solid systems studied, the gas holdup increased with increasing vibration rate and gas flow rate. The gas holdup was higher in three-phase systems than in two-phase ones under otter operating conditions being the same. Generally the gas holdup increased with increasing the volume fraction of solid particles, due to the dispersion action of the solid particles, and decreased with increasing non-Newtonian behaviour (decreasing flow index) i.e. with increasing degree of polymerization and solution concentration of CMC applied, as a result of gas bubble coalescence.

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41

Anabtawi, Mohammed Zohdi. "Gas Holdup in Highly Viscous Liquids in Gas-Liquid Spouted Beds." JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 28, no. 6 (1995): 684–88. http://dx.doi.org/10.1252/jcej.28.684.

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42

Stamenkovic, Ivica, Olivera Stamenkovic, Ivana Bankovic-Ilic, Miodrag Lazic, Vlada Veljkovic, and Dejan Skala. "The gas holdup in a multiphase reciprocating plate column filled with carboxymethylcellulose solutions." Journal of the Serbian Chemical Society 70, no. 12 (2005): 1533–44. http://dx.doi.org/10.2298/jsc0512533s.

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Gas holdup was investigated in a gas-liquid and gas-liquid-solid reciprocating plate column (RPC) under various operation conditions. Aqueous carboxymethyl cellulose (sodium salt, CMC) solutions were used as the liquid phase, the solid phase was spheres placed into interplate spaces, and the gas phase was air. The gas holdup in the RPC was influenced by: the vibration intensity, i.e., the power consumption, the superficial gas velocity, the solids content and the rheological properties of the liquid phase. The gas holdup increased with increasing vibration intensity and superficial gas velocity in both the two- and three-phase system. With increasing concentration of the CMC PP 50 solution (Newtonian fluid), the gas holdup decreased, because the coalescence of the bubbles was favored by the higher liquid viscosity. In the case of the CMC PP 200 solutions (non-Newtonian liquids), the gas holdup depends on the combined influence of the rheological properties of the liquid phase, the vibration intensity and the superficial gas velocity. The gas holdup in the three-phase systems was greater than that in the two-phase ones under the same operating conditions. Increasing the solids content has little influence on the gas holdup. The gas holdup was correlated with the power consumption (either the time-averaged or total power consumption) and the superficial gas velocity.

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43

Setyawan, Andriyanto, Indarto, Deendarlianto, and Prasetyo. "Effects of Surface Tension on the Liquid Holdup and Wave Characteristics in Horizontal Annular Two-Phase Flow." Applied Mechanics and Materials 771 (July 2015): 248–51. http://dx.doi.org/10.4028/www.scientific.net/amm.771.248.

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The wave characteristics of horizontal annular two-phase flow in 16 mm diameter pipe were experimentally investigated using flush-mounted constant electric current method (CECM) sensors and visual observations. To examine the effect of surface tension on the wave velocity and frequency, air and three kinds of liquids with different surface tension were used, i.e., water, 2%-butanol solution, and 5%-butanol solution. The gas and liquid superficial velocities were varied from 12 to 40 m/s and 0.05 to 0.2 m/s, respectively. The liquid holdup was measured directly using CECM, while the wave velocity and frequency were determined using cross correlation and power spectral density functions of liquid holdup signals. Generally, combination of air and liquid with the highest surface tension gives the highest liquid holdup and wave frequency. Simple correlations for wave velocity and wave frequency were also developed.

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44

Venkatachalam, Sivakumar, Akilamudhan Palaniappan, Senthilkumar Kandasamy, and Kannan Kandasamy. "Prediction of gas holdup in a combined loop air lift fluidized bed reactor using Newtonian and non-Newtonian liquids." Chemical Industry and Chemical Engineering Quarterly 17, no. 3 (2011): 375–83. http://dx.doi.org/10.2298/ciceq110401024v.

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Many experiments have been conducted to study the hydrodynamic characteristics of column reactors and loop reactors. In this present work a novel combined loop airlift fluidized bed reactor was developed to study, the effect of superficial gas and liquid velocities, particle diameter, fluid properties on gas holdup by using Newtonian and non-Newtonian liquids. Compressed air was used as gas phase. Water, 5% n-butanol, various concentrations of glycerol (60 % and 80 %) were used as Newtonian liquids, different concentrations of Carboxy Methyl Cellulose (0.25 %, 0.6 % and 1.0 %) aqueous solutions were used as non-Newtonian liquids. Different sizes of Spheres, Bearl saddles and Raschig rings were used as solid phases. From the experimental results it was found that the increase in superficial gas velocity increases the gas holdup, but it decreases with increase in superficial liquid velocity and viscosity of liquids. Based on the experimental results a correlation was developed to predict the gas holdup for Newtonian and non-Newtonian liquids for a wide range of operating conditions at a homogeneous flow regime where the superficial gas velocity is approximately less than 5 cm/s.

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45

Rajarajan, J., D. Pollard, A. P. Ison, and P. Ayazi Shamlou. "Gas holdup and liquid velocity in airlift bioreactors containing viscous newtonian liquids." Bioprocess Engineering 14, no. 6 (May 1996): 311–15. http://dx.doi.org/10.1007/bf00369475.

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46

Carpenter, Chris. "Modeling Liquid Holdup in Pseudoslugs." Journal of Petroleum Technology 72, no. 11 (November 1, 2020): 72–73. http://dx.doi.org/10.2118/1120-0072-jpt.

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47

Maley, L. C., and W. P. Jepson. "Liquid Holdup in Large-Diameter Horizontal Multiphase Pipelines." Journal of Energy Resources Technology 120, no. 3 (September 1, 1998): 185–91. http://dx.doi.org/10.1115/1.2795033.

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This paper studies the liquid holdup within the mixing zone of the slug. The results of the study show that the liquid holdup begins at the liquid holdup of the liquid film before the slug and then increases until the end of the mixing zone is reached. Once past the mixing zone of the slug, the average liquid holdup becomes constant. As the height of the liquid film and/or viscosity increases, so does the liquid holdup at any given film Froude number. Since the liquid holdup becomes constant once past the mixing zone of the slug, the mixing zone length was determined for the film Froude numbers studied. The results show that the mixing zone length increases linearly with film Froude number and is independent of the viscosity of the liquid in the slug for a viscosity range of 1 to 16.6 cP.

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48

Hart, J., P. J. Hamersma, and J. M. H. Fortuin. "Correlations predicting frictional pressure drop and liquid holdup during horizontal gas-liquid pipe flow with a small liquid holdup." International Journal of Multiphase Flow 15, no. 6 (November 1989): 947–64. http://dx.doi.org/10.1016/0301-9322(89)90023-2.

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49

Minami, K., and J. P. Brill. "Liquid Holdup in Wet-Gas Pipelines." SPE Production Engineering 2, no. 01 (February 1, 1987): 36–44. http://dx.doi.org/10.2118/14535-pa.

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50

Eddie Setekleiv, A., Thomas Helsør, and Hallvard F. Svendsen. "Liquid holdup in wire-mesh pads." Chemical Engineering Research and Design 88, no. 11 (November 2010): 1523–31. http://dx.doi.org/10.1016/j.cherd.2010.03.009.

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