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Artykuły w czasopismach na temat "Liquid holdups"
1
Seong, Yongho, Changhyup Park, Jinho Choi i Ilsik Jang. "Surrogate Model with a Deep Neural Network to Evaluate Gas–Liquid Flow in a Horizontal Pipe". Energies 13, nr 4 (21.02.2020): 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.
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, nr 2 (10.09.2013): 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.
3
Razzak, Shaikh A., Muhammad I. Hossain, Syed M. Rahman i 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, nr 1 (1.01.2014): 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.
4
Weiss, Jindřich. "Phase Inversion in Two-Phase Liquid Systems". Collection of Czechoslovak Chemical Communications 57, nr 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.
5
KIM, SANG DONE, YONG HO YU i POONG WOO HAN. "PHASE HOLDUPS AND LIQUID-LIQUID EXTRACTION IN THREE PHASE FLUIDIZED BEDS". Chemical Engineering Communications 68, nr 1 (czerwiec 1988): 57–68. http://dx.doi.org/10.1080/00986448808940397.
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Bensebia, Bensaber, Fatma-Zohra Chaouche, Ouahida Bensebia i Soumia Moustefaï. "Bed expansion in turbulent bed contactor: Experiments and prediction". Chemical Industry and Chemical Engineering Quarterly, nr 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.
7
Nematbakhsh, Gita, i 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, nr 1 (25.09.2015): 31–37. http://dx.doi.org/10.1080/15533174.2014.900629.
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Abid, Mohammad F., Zainab Y. Shanain i 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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Yamada, Hiroshi, i 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, nr 5 (1998): 813–17. http://dx.doi.org/10.1252/jcej.31.813.
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Wugeng, L. "The phase holdups in a gas-liquid-solid circulating fluidized bed". International Journal of Multiphase Flow 22 (grudzień 1996): 100. http://dx.doi.org/10.1016/s0301-9322(97)88183-9.
Pełny tekst źródłaRozprawy doktorskie na temat "Liquid holdups"
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Deshpande, Kiran B. "Studies On Phase Inversion". Thesis, Indian Institute of Science, 2001. https://etd.iisc.ac.in/handle/2005/285.
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Agitated dispersions of one liquid in another immiscible liquid are widely used in chemical industry in operations such as liquid-liquid extraction, suspension polymerisation, and blending of polymers. When holdup of the dispersed phase is increased, in an effort to increase the productivity, at a critical holdup, the dispersed phase catastrophically becomes the continuous phase and vice versa. This phenomenon is known as phase inversion.
Although the inversion phenomenon has been studied off and on over the past few decades, the mechanism of phase inversion (PI) has yet not become clear. These studies have however brought out many interesting aspects of PI, besides unravelling the effect of physical and operational variables on PL Experiments show that oil-in-water (o/w) and water-in-oil (w/o) dispersions behave very differently, e.g water drops in w/o dispersions contain oil droplets in them, but oil drops in o/w dispersions contain none, dispersed phase hold up at which inversion occurs increases with agitation speed for w/o dispersions but decreases for o/w dispersions.
A common feature of both types of dispersions however is that as agitation speed is increased to high values, inversion holdups reach a constant value. A further increase in agitation speed does not change inversion hold up. Although this finding was first reported a long time ago, the implications it may have not received any attentions. In fact, the work reported in the literature since then does not even mention it. The present work shows that this finding has profound implications. Starting with the finding that at high agitation speed inversion hold up does not change with agitation speed, the present work shows that inversion hold up also does not change with agitator diameter, type of agitator and vessel diameter. In these experiments, carried out in agitated vessel, energy was introduced as a point source. The experiments carried out with turbulent flow in annular region of two coaxial cylinders, inner one rotating, in which energy is introduced nearly uniformly throughout the system, show that the inversion holdup remains unchanged. These results indicate that constant values of inversion holdups for a given liquid-liquid systems (o/w and w/o) are properties of the liquid-liquid systems alone, independent of geometrical and operational parameters. A new hypothesis is proposed to explain the new findings.
Phase inversion is considered to occur as a result of imbalance between breakup and coalescence of drops. Electrolytes, which affect only coalescence of drops, were therefore added to the system to investigate the effect of altering coalescence of drops on phase inversion. The experiments performed in the presence of electrolyte KI at various concentrations indicate that addition of electrolyte increases the inversion holdup for both o/w and w/o dispersions for three types of systems: non polar-water, polar-water and immiscible organic-organic. Higher the concentration of electrolyte used, higher was the holdup required for phase inversion. These findings indicate that while the addition of electrolyte increases coalescence of drops in lean dispersions, it has exactly opposite effect on imbalance of breakage and coalescence of drops at high holdups near phase inversion point. The opposite effect of electrolytes in lean and concentrated dispersions could be explained qualitatively, but only in part in the light of a new theory, involving multi-particle interactions.
The phase inversion phenomenon is quantified in a simple manner by testing the
breakage and coalescence rate expressions available in literature. It has been found
that, equilibrium drop size (where breakage and coalescence events are in dynamic
equilibrium) approaches infinity near phase inversion holdup which is not an ex
perimentally observed fact. To capture the catastrophic nature of phase inversion,
two steady state approach is proposed. The two steady states namely the stable
steady state and unstable steady state, are achieved by modifying the expression
for coalescence frequency on the basis of (i) shear coalescence mechanism and, (ii)
recognising the fact that at high dispersed phase holdup the droplets are already in
contact with each other at all times and hence rendering the second order coales
cence process to a first order one. Using two steady states approach, catastrophic
phase inversion is shown to occur at finite drop size.
2
Deshpande, Kiran B. "Studies On Phase Inversion". Thesis, Indian Institute of Science, 2001. http://hdl.handle.net/2005/285.
Pełny tekst źródłaStreszczenie:
Agitated dispersions of one liquid in another immiscible liquid are widely used in chemical industry in operations such as liquid-liquid extraction, suspension polymerisation, and blending of polymers. When holdup of the dispersed phase is increased, in an effort to increase the productivity, at a critical holdup, the dispersed phase catastrophically becomes the continuous phase and vice versa. This phenomenon is known as phase inversion.
Although the inversion phenomenon has been studied off and on over the past few decades, the mechanism of phase inversion (PI) has yet not become clear. These studies have however brought out many interesting aspects of PI, besides unravelling the effect of physical and operational variables on PL Experiments show that oil-in-water (o/w) and water-in-oil (w/o) dispersions behave very differently, e.g water drops in w/o dispersions contain oil droplets in them, but oil drops in o/w dispersions contain none, dispersed phase hold up at which inversion occurs increases with agitation speed for w/o dispersions but decreases for o/w dispersions.
A common feature of both types of dispersions however is that as agitation speed is increased to high values, inversion holdups reach a constant value. A further increase in agitation speed does not change inversion hold up. Although this finding was first reported a long time ago, the implications it may have not received any attentions. In fact, the work reported in the literature since then does not even mention it. The present work shows that this finding has profound implications. Starting with the finding that at high agitation speed inversion hold up does not change with agitation speed, the present work shows that inversion hold up also does not change with agitator diameter, type of agitator and vessel diameter. In these experiments, carried out in agitated vessel, energy was introduced as a point source. The experiments carried out with turbulent flow in annular region of two coaxial cylinders, inner one rotating, in which energy is introduced nearly uniformly throughout the system, show that the inversion holdup remains unchanged. These results indicate that constant values of inversion holdups for a given liquid-liquid systems (o/w and w/o) are properties of the liquid-liquid systems alone, independent of geometrical and operational parameters. A new hypothesis is proposed to explain the new findings.
Phase inversion is considered to occur as a result of imbalance between breakup and coalescence of drops. Electrolytes, which affect only coalescence of drops, were therefore added to the system to investigate the effect of altering coalescence of drops on phase inversion. The experiments performed in the presence of electrolyte KI at various concentrations indicate that addition of electrolyte increases the inversion holdup for both o/w and w/o dispersions for three types of systems: non polar-water, polar-water and immiscible organic-organic. Higher the concentration of electrolyte used, higher was the holdup required for phase inversion. These findings indicate that while the addition of electrolyte increases coalescence of drops in lean dispersions, it has exactly opposite effect on imbalance of breakage and coalescence of drops at high holdups near phase inversion point. The opposite effect of electrolytes in lean and concentrated dispersions could be explained qualitatively, but only in part in the light of a new theory, involving multi-particle interactions.
The phase inversion phenomenon is quantified in a simple manner by testing the
breakage and coalescence rate expressions available in literature. It has been found
that, equilibrium drop size (where breakage and coalescence events are in dynamic
equilibrium) approaches infinity near phase inversion holdup which is not an ex
perimentally observed fact. To capture the catastrophic nature of phase inversion,
two steady state approach is proposed. The two steady states namely the stable
steady state and unstable steady state, are achieved by modifying the expression
for coalescence frequency on the basis of (i) shear coalescence mechanism and, (ii)
recognising the fact that at high dispersed phase holdup the droplets are already in
contact with each other at all times and hence rendering the second order coales
cence process to a first order one. Using two steady states approach, catastrophic
phase inversion is shown to occur at finite drop size.
3
Van, der Merwe Werner. "The Morphology of Trickle Flow Liquid Holdup". Diss., University of Pretoria, 2005. http://hdl.handle.net/2263/31385.
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Gravity driven trickle flow of a liquid over a fixed bed in the presence of a gaseous phase is widely encountered throughout the process industry. It is one of the most common ways of contacting multi-phase fluids for reaction or mass transfer purposes. The presence of three phases greatly complicates the mathematical modelling of trickle-bed reactors and makes a description from first principles difficult. Trickle flow performance is usually characterized in terms of hydrodynamic parameters. One such parameter is the liquid holdup. The value and morphology (shape or texture) of the holdup influences the catalyst contacting, wetting, mass transfer characteristics and ultimately the performance of the trickle flow unit. This study is limited to the air-water-glass spheres system with no gas flow. It is partitioned into three sections. An investigation into the nature of the residual liquid holdup in beds of spherical particles revealed that the general assumption that all residual liquid is held in the form of pendular rings at particle contact points proves to be untrue. Instead, indication is that 48 % of the residual holdup is present in the form of agglomerated liquid globules in interstices of low local porosity. Theoretical residual liquid holdup models and residual liquid holdup-based mass transfer models should include this phenomenon. In a subsequent section, the influence of the prewetting procedure on the operating holdup is investigated. Three distinct limiting cases are identified: Kan-wetted, Levec-wetted and non-wetted. A volumetric utilization coefficient that describes the extent to which the bed is irrigated is developed. It indicates that large fractions of the bed remain non-irrigated in the Levec- and non-wetted modes. A momentum balance-based model is adopted to predict the Kan-wetted mode holdup. This model was successfully extended to predicting the holdup in the Levec- and non-wetted modes by simple incorporation of the volumetric utilization coefficient. The predictive capability of this model is highly satisfactory, especially in light of it using only the classical Ergun constants and no fitted parameters (AARE = 9.6 %). The differences in the hysteresis behaviour of holdup and pressure drop in the different modes are attributed to differences in the morphology of the operating holdup. The existence of the three limiting prewetted modes is confirmed by residence time distribution (RTD) analysis of the stimulus-response behaviour of the system. This behaviour was quantified using a NaCl tracer and conductivity measurements at both the inlet and outlet of a bench scale bed. The analyses show that: · There are large fractions of the holdup that is inaccessible to the tracer in the Levec-wetted and non-wetted modes. · The mixedness in the three prewetted modes differ appreciably, with the Kan-wetted mode clearly less mixed than the Levec-wetted mode. The RTD analyses also confirm the existence of the three prewetting modes in a porous system (spherical a-alumina), with a large fraction of the holdup being inaccessible to the tracer in the Levec-wetted mode. This study emphasizes the role of the morphology of the various types of liquid holdup on the hydrodynamic performance of a trickle flow unit. It is apparent that aspects of the morphology depend strongly on phenomena like globule formation, hysteresis and flow and prewetting history that have not been adequately recognized to date. The visualization of the various modes of trickle flow is an intellectual platform from which future studies may be directed.Dissertation (MEng)--University of Pretoria, 2004.
Chemical Engineering
Unrestricted
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Hanstead, Alison Rae. "Measurement of static liquid holdup at low Eotvos numbers". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0034/MQ64222.pdf.
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Akor, Innocent Collins. "Liquid Holdup in Vertical Air/Water Multiphase Flow with Surfactant". University of Dayton / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1382076807.
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Barigou, Mostafa. "Bubble size, gas holdup and interfacial area distributions in mechanically agitated gas-liquid reactors". Thesis, University of Bath, 1987. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376338.
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Smith, Steven P. "Experimental investigation of multiple solutions for liquid holdup in upward inclined stratified flow". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0021/MQ49702.pdf.
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Maley, Lisa. "A study of slug flow characteristics in large diameter horizontal multiphase pipelines". Ohio : Ohio University, 1997. http://www.ohiolink.edu/etd/view.cgi?ohiou1177090588.
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Duran, Tibo. "Summary of Laboratory Multiphase Flow Studies in 2” Diameter Pipe at the University of Dayton and Comparison to OLGA Predictions". University of Dayton / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1430004871.
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Barrios, Evelyn. "Hydrodynamique des reacteurs a lit fixe avec ecoulement en co-courant ascendant de gaz et de liquide". Paris 6, 1987. http://www.theses.fr/1987PA066066.
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L'etude experimentale porte sur plusieurs systemes : 4 types de solides (3 supports de catalyseur et des billes de verres, 2 liquides (eau ou cyclohexane) et 2 gaz (air ou azote) ainsi que 2 tailles de colonne (5 ou 15 cm). On suit l'influence de ces parametres sur le regime d'ecoulement, la retenue liquide et gazeuse et sur les pertes de charges
Książki na temat "Liquid holdups"
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Ohio. Ohio liquor laws and rules: Relating to liquor permit holders. Columbus, Ohio (2323 W. 5th Ave., Columbus 43266-0701): Ohio Dept. of Liquor Control, 1988.
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Chris, Woffenden, red. Licensing course book (Scotland): Scottish Certificate for Personal Licence Holders (SCPLH). Wyd. 2. Doncaster: Highfield.co.uk, 2009.
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publisher, Lloyd Richards. Alcohol Glue That Holds This Shitshow Together Liquor: Daily NoteBooks - A5 Size, High Quality Paper Stock. Independently Published, 2020.
Znajdź pełny tekst źródłaCzęści książek na temat "Liquid holdups"
1
Shah, M., H. Zhao, R. Mohan i O. Shoham. "Variation of Zero-Net Liquid Holdup in Gas–Liquid Cylindrical Cyclone (GLCCⒸ)". W Integral Methods in Science and Engineering, 323–42. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-07171-3_22.
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Liu, Zilong, Ruiquan Liao, Yindi Zhang, Yubin Su i Xiaoya Feng. "Flow Pattern, Liquid Holdup and Pressure Drop of Gas-Liquid Two-Phase Flow with Different Liquid Viscosities". W Computational and Experimental Simulations in Engineering, 891–905. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-27053-7_77.
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Saraswathi, K. Swetha, i P. R. Naren. "Using Dimensional Analysis for Development of Empirical Correlations for Estimation of Liquid Holdup and Drop Size in Rotating Disc Contactor". W Lecture Notes in Mechanical Engineering, 137–43. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0698-4_15.
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Cottrell, Geoff. "3. Forms of matter". W Matter: A Very Short Introduction, 19–38. Oxford University Press, 2019. http://dx.doi.org/10.1093/actrade/9780198806547.003.0003.
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Solids, liquids, and gases are the great states of matter; a solid has a shape and a volume, a liquid has a volume but no shape, and a gas has neither shape nor volume. ‘Forms of matter’ explains how these different states arise from a competition between opposites: thermal motion driving particles apart and the attractive forces between atoms pulling them together, repulsion and attraction. The ‘glue’ that holds electrons to atoms, brings atoms together to form molecules, and draws molecules together to make solids and liquids, is electricity. Chemical bonds, crystals, intermediate states, and plasma—the fourth state of matter—are discussed.
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Abiev, Rufat. "Analysis of Hydrodynamics and Mass Transfer of Gas-Liquid and Liquid-Liquid Taylor Flows in Microchannels". W Process Analysis, Design, and Intensification in Microfluidics and Chemical Engineering, 1–49. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7138-4.ch001.
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Analysis of hydrodynamics and mass transfer Taylor flows in micro channels of both gas-liquid and liquid-liquid systems on the basis of classical theoretical approach with some simplifying assumptions was performed. Results of theoretical analysis for description of hydrodynamic parameters and mass transfer characteristics were confirmed by comparison with the author's own and available in literature experimental data. It was shown that the main parameters of two-phase Taylor flows could be quite precisely described theoretically: mean bubble/droplet velocity, liquid film thickness, real gas holdup (which is always smaller than so-called dynamic holdup), pressure drop. Peculiarities of liquid-liquid flows compared to gas-liquid Taylor flows in capillaries are discussed. Wettability effect on hydrodynamics was examined. Tools of mass transfer intensification of gas-liquid and liquid-liquid Taylor flow in micro channels are analyzed. Three-layer model for heat and mass transfer has been proposed and implemented for the case of solid-liquid mass transfer for gas-liquid Taylor flows; optimal process conditions for this process are found theoretically and discussed from physical point of view.
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Liu, Yunti, Xiaoxiao Zhu, Haoyue Wu, Yutao Wang i Shimin Zhang. "Simulation Analysis of Slug Dispersion Process During Bypass Pigging Process in Vertical Riser". W Advances in Transdisciplinary Engineering. IOS Press, 2023. http://dx.doi.org/10.3233/atde230017.
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In offshore riser systems, the slug flow can aggravate the instability of pipeline system during pigging processes, resulting in problems, such as increased pressure fluctuations and the excessive load of the slug catcher over a short period. Bypass pig can disperse the slug due to the highly velocity passing through the bypass hole, thus mitigating the impact of the slug flow on the pigging process. This paper established a two-dimensional CFD model to study the effect of different bypass rates and inlet gas velocities on the downstream slug dispersion process in vertical riser. The results showed that increasing the bypass rate and inlet gas velocity can improve the dissipation effect of the bypass pig to the slug, but it is necessary to comprehensively consider the pigging efficiency and the changes of outlet fluid mass flow and liquid holdup. The research results can contribute to preventing pigging accidents as well as determining the pigging technology parameters during pigging processes in marine pipelines.
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McFarland, Ben. "The Triple-Point Planet". W A World From Dust. Oxford University Press, 2016. http://dx.doi.org/10.1093/oso/9780190275013.003.0008.
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Let’s move to a vantage point a little quieter: the surface of the moon. It is so still that Neil Armstrong’s footprints remain undisturbed. The only reason the US flag there appears to “fly” is that a wire holds it up. The moon and Mercury stayed still as Mars, Venus, and Earth moved on down the road of geological development. The moon is a “steady” environment, a word whose Middle English roots are appropriately tangled with the word for “sterile.” Nothing moves on the moon, but in its sky Mars, Venus, and Earth move in their orbits, just as they moved on in complexity 4 billion years ago. Out of the whole solar system, Mars and Venus are the most like Earth in size, position, and composition. Mars is smaller, but Venus could be Earth’s twin in size. If Earth and Venus were separated at birth, then something happened to obscure the family resemblance: liquid water brought life. To chemists, liquid is the third phase of matter, between solid and gas, and its presence made all the difference. Mars gleams a bright blood red even to the naked eye, while Venus is choked with thick yellow bands of clouds. Mars is cold enough to have carbon dioxide snow, while Venus is hot enough to melt tin and boil water. Earth’s blue oceans and green continents provide a bright, primary contrast. These three siblings have drastically different fortunes. At first, they looked the same, colored with black mafic basalt and glowing red magma. The original planets were all so hot that their atmospheres were driven off into space. The oceans and the air came from within. Steam condensed into oceans on each planet’s cool basalt surface. Oceans changed the planet. Water is a transformative chemical, small yet highly charged, seeping into the smallest cracks, dissolving what it can and carrying those things long distances. Venus, Earth, and Mars do not look like the moon because they have been washed in water. Mars is dry now, but the Curiosity rover left no doubt that the red planet was first blue with water.
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Furbish, David Jon. "Conservation of Mass". W Fluid Physics in Geology. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195077018.003.0012.
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The concept of conservation of mass holds a fundamental role in most problems in fluid physics. For a given problem this concept is cast in the form of an equation of continuity. Such an equation describes a condition—conservation of mass—that must be satisfied in any formal analysis of a problem. Thus an equation of continuity often is one of several complementary equations that are solved simultaneously to arrive at a solution to a flow problem, for example, the flow velocity as a function of coordinate position in a flow field. (Typically these complementary equations, as we will see in later chapters, involve conservation of momentum or energy, or both.) Although we did not explicitly use this idea in analyzing the one-dimensional flow problems at the end of Chapter 3, it turns out that continuity was implicitly satisfied in setting up each problem. We will return to these problems to illustrate this point. We will develop equations of continuity for three general cases: purely fluid flow, saturated single-phase flow in porous media, and unsaturated flow in porous media. The most general of the three equations is that for unsaturated flow, where pores are partially filled with the fluid phase of interest, such that the degree of saturation with respect to that phase is less than one. We will then show that this equation reduces, in the special case in which the degree of saturation equals one, to a simpler form appropriate for saturated single-phase flow. Then, this equation for saturated flow could be reduced further, in the special case in which the porosity equals one, to a form appropriate for purely fluid flow. For pedagogical reasons, however, we shall reverse this order and consider purely fluid flow first. In addition we will consider conservation of a solid or gas dissolved in a liquid, and take this opportunity to introduce Fick’s law for molecular diffusion. For simplicity we will consider only species that do not react chemically with the liquid, nor with the solid phases of a porous medium. Most of the derivations below are based on the idea of a small control volume of specified dimensions embedded within a fluid or porous medium.
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Tupy, Isabela Carvalho, Gyzelle Pereira Vilhena do Nascimento, Alberto de Andrade Reis Mota i Simone Cruz Longatti. "Development of phytocosmetics based on the hydroalcoholic extract of Myrciaria cauliflora (jabuticaba)". W DEVELOPMENT AND ITS APPLICATIONS IN SCIENTIFIC KNOWLEDGE. Seven Editora, 2023. http://dx.doi.org/10.56238/devopinterscie-221.
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Brazil holds the largest reserves of natural resources in the world, being an international highlight in biological diversity, it is estimated that 20% of the total species already inventoried are in Brazil. However, the literature indicates that there are few studies related to the use and development of technologies from native plants, mainly in the cosmetic industry. This work aims to develop a cosmetic product based on the hydroalcoholic extract of the bark of Myrciaria Cauliflora (jabuticaba) and carry out its quality control. As an extraction methodology, cold maceration was used, with distilled water as the extracting liquid. Three different concentrations of extract incorporation were tested [1.5%], [3.5%] and [4.0%], in triplicate, and centrifugation tests, temperature stress, organoleptic assays, pH, density, and spreadability. All samples were stable in most tests, with changes being observed in centrifugation tests (creaming) in all samples, and temperature stress at 70°C, where there was flocculation of concentration samples [4.0%]. The moisturizer obtained from the hydroalcoholic extract of Myrciaria cauliflora bark has a potential cosmetological profile, being an economical alternative for the cosmetic industries due to the possible reuse of waste from the food industry, and encompasses the new market of consumers who value the ecological footprint of companies.
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Zhang, H. "Electrokinetic Properties". W Chemistry of Variable Charge Soils. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195097450.003.0010.
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Cations and anions adsorbed by soil particles carrying surface charges are not present totally on the surface of the particles. Actually, in a soil-water system, a portion of adsorbed ions is distributed near the surface, forming an electric double layer at the interface between the solid particle and the liquid phase. When the two phases have a relative movement in an electrical field or are affected by other forces, the system can exhibit certain electrical properties, called electrokinetic properties. Electrokinetic properties of soils are the overall reflection of the distribution of various kinds of ions in the electric double layer of a soil-water system. They are related to both the characteristics of the soil and the nature of ions. For variable charge soils, because they adsorb anions as well as cations and during the adsorption both electrostatic force and specific force are involved, their electrokinetic properties frequently manifest themselves in a complex manner. As shall be seen in the present chapter, the electrokinetic properties of variable charge soils exhibit certain characteristics different from those of constant charge soils, and these characteristics are of significance for further distinguishing soil types among these soils. All the electrokinetic phenomena occurring in any colloid system result from the existence of the electric double layer. The same holds true for soils. Therefore, in this section the theory of the electric double layer along with its relation to various electrokinetic properties will be introduced first, and then the complexities in soil systems in this respect will be examined. When two phases are in contact, owing to the difference in properties, a redistribution of electric charge will occur at the interface between the two phases, leading to the formation of two layers with charges equal in quantity but opposite in sign between the two sides of the interface. This pair of charged layers is called electric double layer. It is a microscopically charged system present in the interfacial region between the two phases. The electric potential may vary at different positions within the system, but the system as a whole is electrically neutral.
Streszczenia konferencji na temat "Liquid holdups"
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Asante, Ben. "Two Phase Flow: Accounting for the Presence of Liquids in Gas Pipeline Design". W 2004 International Pipeline Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ipc2004-0546.
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Multiphase flow of gas and low loads of liquids occurs frequently in natural gas gathering and transmission pipelines for both onshore and offshore operations. Literature and experimental investigations indicate that dispersed droplet and stratified flow patterns are obtained when gas and small quantities of liquids flow concurrently in a pipe. Very few correlations exist for the prediction of holdup and pressure drop for these systems and fewer still give satisfactory results. Experimental studies for air-oil and airwater systems flowing through small diameter plastic and steel horizontal pipes ranging in size from 1-inch to 3-inches were performed. The experiments were carried out at the multiphase flow laboratories of Imperial College in London and the University of Calgary in Canada. Data from actual operating gas pipeline systems transporting small amounts of hydrocarbon liquids were also evaluated. Based on the experimental results and the operating data, two approaches for modeling these systems are proposed: 1) A homogeneous approach for very low liquid loads (holdups up to 0.005), typical in gas transmission systems. A friction factor correlation based on the holdup has been developed for this flow regime. 2) A mechanistic stratified two-phase approach for higher liquid loads (holdups greater than 0.005) usually found in gas gathering systems with consideration given to: a) The reduction in the available flow area and extent of wetting of the pipe perimeter by the liquid film. The gas/liquid interface was observed to be either flat or curved. b) The interfacial friction factor between the liquid film and the gas. A new correlation based on the liquid and gas Reynolds numbers as well as the film thickens and hold up has been developed. This correlation has been successfully tested against both experimental and actual pipeline operating data.
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Warsito, W., i L. S. Fan. "Real Time and Quasi-3D Imaging of Gas-Liquid Flow Using Electrical Capacitance Tomography". W ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/fedsm2003-45552.
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In this study, an electrical capacitance tomography (ECT) adopted with neural-network based multi-criterion optimization image reconstruction technique (NN-MOIRT) for real time and quasi-3D imaging of gas-liquid flow system is developed. The technique reconstruct the permittivity distribution (tomography image) from capacitance data obtained using 12-electrode twin-plane capacitance sensor. A combined series and parallel capacitance model is used convert the permittivity distribution into gas holdup distribution. Comparison of the overall gas holdups obtained by the ECT with those obtained from the pressure measurements shows a good agreement, validating the model proposed. The ECT is applied to study the hydrodynamic characteristics of the gas-liquid flow system including the bubbly flow structures, gas holdup profiles, and gas holdup variations along with the effect of the gas velocity.
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Mazza, Ricardo A., i Fábio K. Suguimoto. "Experimental Study of Liquid-Liquid Flow Through Upward Vertical to Horizontal Transition". W ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-62409.
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This work consists of an experimental analysis of the liquid-liquid two-phase flow of water-kerosene through a vertical bend. The duct has diameter of 0.026 m, the bend radius is 0.125 m and the superficial velocities of the water and kerosene ranged from 0.1 to 1.0 m/s. The pressures drops were measured by differential pressure transducers SMAR LD301, the holdups were determined by the method of trapping fluid using quick-closing valves and the flow patterns was determined using a high-speed camera. The bend pressure gradient is increased with the superficial velocities of both phases. The bend coefficient has no correlation with the mixture Reynolds number, such as in single-flows. The modified Reynolds number proposed by [1] described accurately the bend flow pattern.
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Etminan, Amin, Yuri S. Muzychka i Kevin Pope. "CFD Modelling for Gas-Liquid and Liquid-Liquid Taylor Flows in the Entrance Region of Microchannels". W ASME 2021 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/fedsm2021-64172.
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Abstract This paper presents a CFD-based simulation method for air/water and water/dodecane Taylor flows through an axisymmetric microchannel with a circular cross-sectional area. A systematic analysis is conducted by exploring the effects of different superficial velocities and apparent viscosities on the hydrodynamics of a slug flow regime. A concentric junction is employed to make bubbles of air in a continuous flow of water and slugs of water in a continuous flow of dodecane oil. A time-history study is conducted to predict the air-bubble and water-slug evolution processes, in particular at the moment of slug breakup. The results show that the larger apparent viscosity ratio of phases involved in the liquid-liquid flow generates a more stable interface. However, the liquid slug length is less and film thickness is slightly larger in liquid-liquid compared to gas-liquid flow. Furthermore, variations in gas and liquid holdups are correlated by the superficial velocity ratio. The numerical analysis developed in this paper is in good agreement with the correlations and data in the literature.
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Hongli Li, Dengxin Li, Yangdong Li, Chunsheng Yin i Enqiang Wang. "Distribution characteristics of local phase holdups in gold concentrates gas-liquid-solid circulating fluidized bed". W 2011 International Conference on Remote Sensing, Environment and Transportation Engineering (RSETE). IEEE, 2011. http://dx.doi.org/10.1109/rsete.2011.5965692.
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Hewitt, G. F. "Multiphase Flows With Two Liquid Phases". W ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/htd-24202.
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Abstract Liquid-liquid two-phase flows and liquid-liquid-gas flows occur widely in industrial applications. A particularly important case is in hydrocarbon recovery where such flows occur in subsea pipelines carrying produced fluids (oil, water and natural gas) from subsea wells to on-shore or platform-based processing facilities. The presence of a second liquid phase makes gas-liquid flows even more complex. At higher gas velocities, the liquid phases tend to become inter-dispersed. The dispersions formed can either be of oil drops dispersed in water or water drops dispersed in oil. The transition between one form of dispersion and the other is called phase inversion and is accompanied by anomalous behaviour signalled by a large increase in pressure gradient. A similar inversion phenomenon occurs in liquid-liquid flows at high superficial velocity. In this presentation, recent Imperial College work on this class of flows will be presented. This includes studies of overall parameters such as pressure gradient and phase holdups (the latter being measured using dual energy gamma densitometry) and investigations of local phenomena and parameters (e.g. drop size and interfacial structure) using advanced optical and other techniques. Both steady state and transient flow have been studied. Progress on meeting the formidable challenges of modelling such flows is also reviewed.
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Porter, Kyle, Eduardo Pereyra, Jose Mesa i Cem Sarica. "Fluid-Pipe Interaction in Horizontal Gas-Liquid Flow". W SPE Annual Technical Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210424-ms.
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Abstract In recent years, internal, two-phase, flow-induced vibration (FIV) has received elevated attention in various fields while assessing piping system fatigue life. Regarding the oil and gas industry, in particular, assessing FIV impact is essential for ensuring the integrity of flow lines, both onshore and offshore. This study conducted a series of experimental tests at various superficial gas and liquid velocities to investigate the effects of flow parameters on the structural dynamics of a horizontal 6-inch ID polycarbonate test section. The relationship between flow characteristics and the structural response was examined in detail. A novel methodology was developed and implemented to achieve non-intrusive, simultaneous measurement of pipe motion and liquid distribution. The presented results reveal that downward deflection generally decreased with increasing superficial gas velocity and increased with increasing superficial liquid velocity. It was also found that as superficial gas velocity increased, the range of frequencies experienced by the test section increased, with increased participation from higher frequencies in the range. Film and slug body liquid holdups are strongly related to the observed deflection amplitudes.
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Ayala, Luis F., Eltohami S. Eltohami i Michael A. Adewumi. "A Unified Two-Fluid Model for Multiphase Flow in Natural Gas Pipelines". W ASME 2002 Engineering Technology Conference on Energy. ASMEDC, 2002. http://dx.doi.org/10.1115/etce2002/prod-29119.
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A unified two-fluid model for multiphase natural gas and condensate flow in pipelines is presented. The hydrodynamic model consists of steady-state one-dimensional mass and continuity balances for each phase and a combined energy equation to give a system of five first-order ordinary differential equations. The hydrodynamic model is coupled with a phase behavior model based on the Peng-Robinson equation of state to handle the vapor-/liquid equilibrium calculations and thermodynamic property predictions. The model handles single and two-phase flow conditions and is able to predict the transition between them. It also generates profiles for pressure, temperature, and the fluid velocities in both phases as well as their holdups. The expected flow patterns as well as their transitions are modeled with emphasis on the low liquid loading character of such systems. The expected flow regimes for this system are dispersed liquid, annular-mist, stratified smooth as well as stratified wavy.
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Lane, C. D., i A. A. Donaldson. "Flow Profiles and Gas/Liquid Separation in First and Second Generation Designs for Ebullated Reactors". W ASME/JSME/KSME 2015 Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/ajkfluids2015-03227.
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Ebullated bed reactor technology is found in the oil and gas industry as part of the hydrocracking process, within which heavy oils are cracked under elevated temperatures and pressures to produce increased fractions of refinable petroleum products. A unique feature of these types of reactors is the presence of an internal gas/liquid separation and liquid recycle line, through which 60 to 90% of the net liquid flow through the column is recycled to maintain fluidized conditions within the internal catalyst bed. The separation efficiency within these systems has a significant impact on overall unit profitability, whereby high levels of gas recirculation results in lower liquid throughput and increased potential of over-cracking of product gases and production of light ends [1]. These units typically operate at gas holdups above 30%, with even small reductions in gas entrainment potentially leading to significant increases in profitability. Due to the severe conditions present within operating units (several MPa pressures, >300°C), pilot-scale experimental systems exploring fluid flow phenomena have typically employed nitrogen and kerosene as analogous fluids[2]. Even within these systems, the ability to visualize flow patterns and parametrically evaluate the effects of separator modifications on gas recirculation has been limited. In an effort to provide strategic focus for future process improvements, Dalhousie University has been collaborating with Ottawa University and Syncrude Canada Ltd. to develop 3D CFD-based simulations of older generation designs to explore fundamental flow characteristics and sensitivity of gas-liquid separation efficiency to changes in geometry and process conditions. This work explores the sensitivity of gas separation efficiency to operational parameters (bubble size, processing rate, gas holdup), geometric design (two generations of separator designs), and computational model choices (drag correlations and packing limiters). Of particular note is the sensitivity of the predicted performance to drag models, for which there is limited empirical validation under the high gas fraction conditions present in this industrial unit, and the sensitivity to packing limiters, which reflect foam formation (an issue observed within operating units). The trends predicted within this work show significant similarities to current operational trends observed in commercial ebullated bed reactors, and provide a basis for predicting the effects of operational changes on the overall performance of these units.
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Fan, Yilin, Eissa Al-Safran, Eduardo Pereyra i Cem Sarica. "Modeling Liquid Holdup in Pseudo-Slugs". W International Petroleum Technology Conference. International Petroleum Technology Conference, 2020. http://dx.doi.org/10.2523/19769-abstract.
Pełny tekst źródłaRaporty organizacyjne na temat "Liquid holdups"
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Unknown, Author. L51393 A.G.A. Gas-Liquid Data Bank. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), styczeń 1990. http://dx.doi.org/10.55274/r0011062.
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The purposes of the Data Bank are to organize field (operating pipeline) data from a wide variety of gas and oil pipelines and make these data available in a convenient form to interested pipeline designers and operators. The Data Bank itself consists of a computer tape written in IBM Fortran and a User's Manual. The tape contains two computer programs, (one to enter data and one to read back the data), the files of the data, an index listing pipelines contained in the Data Bank, a bibliography for the data in the Data Bank, and a brief summary describing the data. The types of data of interest include: composition, pipe geometry, pressure drop and holdup data (obtained pigging or by measurements). Transient data during pigging operations or from rapid flow changes are also of interest.
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Johnson. L51582 Scaling of Multiphase Pipe Flow Behavior at High Gas Density. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), lipiec 1988. http://dx.doi.org/10.55274/r0010628.
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This report contains data that demonstrates the scaling of flow regime, pressure drop, and holdup multiphase flow with pipe diameter. In addition, entrance length effects, the onset of liquid entrainment, and interfacial shear modeling at high gas density were studied for purposes of validating multiphase flow design methods. Stratified, slug and annual flow regimes were observed in a 112-foot long 3.5-inch diameter test section. Air, freon, and water were used to represent pipeline fluids.
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Stafford, Robert B. Shielded open-circuited sample holders for dielectric and magnetic measurements of liquids and powders. Gaithersburg, MD: National Institute of Standards and Technology, 1993. http://dx.doi.org/10.6028/nist.ir.5001.
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Kiefner i Duffy. L51509 Two-Phase Flow in Horizontal and Inclined Pipes at Large Pipe Size and High Gas Density. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), luty 1986. http://dx.doi.org/10.55274/r0010275.
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Knowledge of flow regime, holdup and pressure drop is needed in order to design gas and oil pipelines confidently and to minimize construction and operating costs. Previous public studies of two-phase flow in inclined pipes have used small diameter pipes two inches in diameter or less, and have primarily used air and water as the working fluids at low pressure (near one atmosphere). Present design methods are based upon the results of these experiments. In most advanced analyses available today, the flow regime transition is governed by a Froude number, the balance between inertial and buoyancy forces. The primary objective of the work has been to obtain experimental data to challenge the present two-phase flow analysis methods for large pipe size, high gas density, and pipe inclination. Present analysis and design methods for two-phase flow in pipelines are based on correlations of data from small pipes of order 2-inches diameter or less, for air-water flows at pressures near one atmosphere. To achieve this objective, Creare performed experiments in an existing test facility with a special test section assembled for this project. Pipe diameter and gas density are closer to prototypical oil and gas pipeline conditions than previous experiments reported in the literature. The key experimental results include flow regime observations, pressure drops, and holdup measurements. The instrumentation in the test facility allows detailed characteristics of the flow such as slug velocity, slug frequency, liquid film velocity, and slug length to be measured in the slug flow regime.