Pub Date : 2026-01-15Epub Date: 2025-10-22DOI: 10.1016/j.ijmultiphaseflow.2025.105497
Jiajun Jiao , Yunhui Sun , Menghan Pan , Pengfei Lv , Junli He , Qingquan Liu , Yi An , Xiaoliang Wang
This study experimentally investigated the dense particle-liquid open channel flows over smooth and rough inclined beds using the refractive index matching (RIM) technique. The internal flow profiles of the granular phase, including velocity, shear rate, granular temperature, and solid concentration, were reconstructed through image processing techniques. The vertical stratification behavior of dense particle-liquid channel flows under various inclination angles and inflow heights was examined. Results indicated that four fundamental local flow states exist in dense particle-liquid channel flows: plug flow, ordered friction flow, disordered friction flow, and collision flow. These flow states can be combined to construct the stratification flow in the granular phase of two-phase dense granular flows. There are three flowing superimposed modes on the smooth bed: plug flow, disordered friction flow + plug flow, and disordered friction flow. We identified three typical superimposed flow modes on the rough bed: ordered friction flow + disordered friction flow (OF-DF flow), collision flow + disordered friction flow (C-DF flow), and collision flow + disordered friction flow + plug flow (C-DF-P flow). The complex flow structure observed under various operating conditions is simplified through the superposition of the fundamental local flow states. This study significantly advances the understanding of the intricate internal flow behavior and structure of dense particle-liquid two-phase flows.
{"title":"Vertical stratification and local flow states of dense particle-liquid inclined open channel flow based on internal observation","authors":"Jiajun Jiao , Yunhui Sun , Menghan Pan , Pengfei Lv , Junli He , Qingquan Liu , Yi An , Xiaoliang Wang","doi":"10.1016/j.ijmultiphaseflow.2025.105497","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105497","url":null,"abstract":"<div><div>This study experimentally investigated the dense particle-liquid open channel flows over smooth and rough inclined beds using the refractive index matching (RIM) technique. The internal flow profiles of the granular phase, including velocity, shear rate, granular temperature, and solid concentration, were reconstructed through image processing techniques. The vertical stratification behavior of dense particle-liquid channel flows under various inclination angles and inflow heights was examined. Results indicated that four fundamental local flow states exist in dense particle-liquid channel flows: plug flow, ordered friction flow, disordered friction flow, and collision flow. These flow states can be combined to construct the stratification flow in the granular phase of two-phase dense granular flows. There are three flowing superimposed modes on the smooth bed: plug flow, disordered friction flow + plug flow, and disordered friction flow. We identified three typical superimposed flow modes on the rough bed: ordered friction flow + disordered friction flow (OF-DF flow), collision flow + disordered friction flow (C-DF flow), and collision flow + disordered friction flow + plug flow (C-DF-P flow). The complex flow structure observed under various operating conditions is simplified through the superposition of the fundamental local flow states. This study significantly advances the understanding of the intricate internal flow behavior and structure of dense particle-liquid two-phase flows.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105497"},"PeriodicalIF":3.8,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145414608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
<div><div>Convection-driven separation in binary fluid mixtures is crucial in applications ranging from geothermal energy to chemical processing. However, prior studies have largely neglected the combined influence of the Soret and Dufour effects on species redistribution. This paper investigates convection-driven separation in a binary fluid mixture within a porous medium, incorporating the Soret effect and, for the first time, systematically evaluating the influence of the Dufour effect. Using a combination of analytical and numerical methods, this study assesses the impact of the Dufour parameter on both the onset of convection and the resulting species separation within a shallow porous cavity. Linear and nonlinear analyses are employed to determine thresholds for stationary, oscillatory, and subcritical bifurcations with respect to key parameters: the Dufour number (<span><math><mrow><mi>D</mi><mi>f</mi></mrow></math></span>), the separation ratio (<span><math><mi>φ</mi></math></span>), the Lewis number (<span><math><mrow><mi>L</mi><mi>e</mi></mrow></math></span>), the thermal Rayleigh number (<span><math><msub><mi>R</mi><mi>T</mi></msub></math></span>), and the Darcy number (<span><math><mrow><mi>D</mi><mi>a</mi></mrow></math></span>). An analytical solution based on the parallel flow approximation is developed and validated numerically using a finite-difference method to evaluate species separation and heat transfer characteristics. Three regimes are examined: Darcy, Brinkman, and pure fluid media. The analysis spans a wide range of Lewis numbers (<span><math><mrow><mi>L</mi><mi>e</mi></mrow></math></span> = 0.1 to 100), covering gases, hydrocarbon fuels, and salt-water solutions. Results show that the Dufour effect significantly influences species separation in gaseous mixtures, while its impact on liquid mixtures is negligible. The findings demonstrate that within the Darcy regime, low permeability effectively suppresses convective flows, thereby enhancing species separation more effectively than in the Brinkman or pure fluid regimes, where higher permeability promotes stronger convection and reduces separation efficiency. Moreover, a low-permeability Darcy medium, combined with a negative Dufour number and minimal thermal gradients, provides the most favorable conditions for maximizing species separation. Results show that for <span><math><mrow><mi>L</mi><mi>e</mi><mo>=</mo><mn>2</mn></mrow></math></span>, 10 and 100, increasing <span><math><mrow><mi>D</mi><mi>f</mi></mrow></math></span> from -0.2 to 0.2 reduces species separation by <span><math><mrow><mn>23.15</mn><mo>%</mo><mo>,</mo></mrow></math></span> <span><math><mrow><mn>9</mn><mo>%</mo></mrow></math></span> and <span><math><mrow><mn>0.00</mn><mo>%</mo><mo>,</mo></mrow></math></span> respectively. This confirms the minimal impact of the Dufour effect on liquid mixtures (high <span><math><mrow><mi>L</mi><mi>e</mi></mrow></math></span>). Negative <span><math><mrow><mi>D</mi><mi>f</
{"title":"Influence of the dufour effect on soret-driven species separation in binary mixtures: A comparative numerical and analytical study across porous flow regimes","authors":"Ismail Filahi , Layla Foura , Mohamed Bourich , Youssef Dahani , Safae Hasnaoui , Abdelfattah El Mansouri , Abdelkhalek Amahmid , Mohammed Hasnaoui","doi":"10.1016/j.ijmultiphaseflow.2025.105501","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105501","url":null,"abstract":"<div><div>Convection-driven separation in binary fluid mixtures is crucial in applications ranging from geothermal energy to chemical processing. However, prior studies have largely neglected the combined influence of the Soret and Dufour effects on species redistribution. This paper investigates convection-driven separation in a binary fluid mixture within a porous medium, incorporating the Soret effect and, for the first time, systematically evaluating the influence of the Dufour effect. Using a combination of analytical and numerical methods, this study assesses the impact of the Dufour parameter on both the onset of convection and the resulting species separation within a shallow porous cavity. Linear and nonlinear analyses are employed to determine thresholds for stationary, oscillatory, and subcritical bifurcations with respect to key parameters: the Dufour number (<span><math><mrow><mi>D</mi><mi>f</mi></mrow></math></span>), the separation ratio (<span><math><mi>φ</mi></math></span>), the Lewis number (<span><math><mrow><mi>L</mi><mi>e</mi></mrow></math></span>), the thermal Rayleigh number (<span><math><msub><mi>R</mi><mi>T</mi></msub></math></span>), and the Darcy number (<span><math><mrow><mi>D</mi><mi>a</mi></mrow></math></span>). An analytical solution based on the parallel flow approximation is developed and validated numerically using a finite-difference method to evaluate species separation and heat transfer characteristics. Three regimes are examined: Darcy, Brinkman, and pure fluid media. The analysis spans a wide range of Lewis numbers (<span><math><mrow><mi>L</mi><mi>e</mi></mrow></math></span> = 0.1 to 100), covering gases, hydrocarbon fuels, and salt-water solutions. Results show that the Dufour effect significantly influences species separation in gaseous mixtures, while its impact on liquid mixtures is negligible. The findings demonstrate that within the Darcy regime, low permeability effectively suppresses convective flows, thereby enhancing species separation more effectively than in the Brinkman or pure fluid regimes, where higher permeability promotes stronger convection and reduces separation efficiency. Moreover, a low-permeability Darcy medium, combined with a negative Dufour number and minimal thermal gradients, provides the most favorable conditions for maximizing species separation. Results show that for <span><math><mrow><mi>L</mi><mi>e</mi><mo>=</mo><mn>2</mn></mrow></math></span>, 10 and 100, increasing <span><math><mrow><mi>D</mi><mi>f</mi></mrow></math></span> from -0.2 to 0.2 reduces species separation by <span><math><mrow><mn>23.15</mn><mo>%</mo><mo>,</mo></mrow></math></span> <span><math><mrow><mn>9</mn><mo>%</mo></mrow></math></span> and <span><math><mrow><mn>0.00</mn><mo>%</mo><mo>,</mo></mrow></math></span> respectively. This confirms the minimal impact of the Dufour effect on liquid mixtures (high <span><math><mrow><mi>L</mi><mi>e</mi></mrow></math></span>). Negative <span><math><mrow><mi>D</mi><mi>f</","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105501"},"PeriodicalIF":3.8,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145414687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study presents an experimental investigation of hydrodynamic cavitation (HC) in two microfluidic chips (microscale HC chips) under varying flow patterns (upstream pressure and local temperature), with and without dissolved CO₂. High-speed imaging and spectral analysis were used to characterize cavitation inception, vapor cloud formation, void fraction, and bubble dynamics (frequency spectra) under the effect of the dissolved gas in micro domains. The results show that higher upstream pressure substantially intensifies cavitation, while the presence of dissolved CO₂ lowers the pressure threshold for cavitation inception and amplifies cavitation activity. The micro-step chip (Reactor 1) presented more intense cavitation and a greater vapor void fraction than the long-diaphragm chip (Reactor 2) across all conditions. Notably, dissolved CO₂ suppressed high-frequency bubble-collapse fluctuations and induced a transition from violent cloud-shedding cavitation to a stable, continuous bubbly flow regime. Additionally, cavitation facilitated significant CO₂ degassing, removing up to ∼30% of the dissolved gas in Reactor 1 (versus ∼11% in Reactor 2) under the similar conditions. The results also show that temperature significantly influenced CO₂ removal efficiency, with the highest elimination (52%) occurring at 25°C, where high gas solubility and low vapor pressure were optimally balanced. These findings highlight the coupled influence of pressure, temperature, and dissolved gas on “HC on a chip” concept and provide fundamental insights into multiphase flow dynamics and bubble–fluid interactions, offering guidance for controlling microscale cavitation and bubble-mediated transport phenomena.
{"title":"Role of dissolved CO2 in hydrodynamic cavitation on a chip","authors":"Mohammad Imanzadeh , Rokhsareh Bakhtiari , Shahriyar Rahbarshahlan , Mohammadamin Maleki , Salar Heyat Davoudian , Morteza Ghorbani","doi":"10.1016/j.ijmultiphaseflow.2025.105526","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105526","url":null,"abstract":"<div><div>This study presents an experimental investigation of hydrodynamic cavitation (HC) in two microfluidic chips (microscale HC chips) under varying flow patterns (upstream pressure and local temperature), with and without dissolved CO₂. High-speed imaging and spectral analysis were used to characterize cavitation inception, vapor cloud formation, void fraction, and bubble dynamics (frequency spectra) under the effect of the dissolved gas in micro domains. The results show that higher upstream pressure substantially intensifies cavitation, while the presence of dissolved CO₂ lowers the pressure threshold for cavitation inception and amplifies cavitation activity. The micro-step chip (Reactor 1) presented more intense cavitation and a greater vapor void fraction than the long-diaphragm chip (Reactor 2) across all conditions. Notably, dissolved CO₂ suppressed high-frequency bubble-collapse fluctuations and induced a transition from violent cloud-shedding cavitation to a stable, continuous bubbly flow regime. Additionally, cavitation facilitated significant CO₂ degassing, removing up to ∼30% of the dissolved gas in Reactor 1 (versus ∼11% in Reactor 2) under the similar conditions. The results also show that temperature significantly influenced CO₂ removal efficiency, with the highest elimination (52%) occurring at 25°C, where high gas solubility and low vapor pressure were optimally balanced. These findings highlight the coupled influence of pressure, temperature, and dissolved gas on “HC on a chip” concept and provide fundamental insights into multiphase flow dynamics and bubble–fluid interactions, offering guidance for controlling microscale cavitation and bubble-mediated transport phenomena.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105526"},"PeriodicalIF":3.8,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15Epub Date: 2025-11-15DOI: 10.1016/j.ijmultiphaseflow.2025.105543
Marc Vacher , Tullio Traverso , Christophe Josserand , Stéphane Perrard , Sophie Ramananarivo
We present an image processing method to track and characterize the motion of air–liquid interfaces occurring in aerated liquid baths. In a rectangular tank filled with water, an immersed sparger injects air vertically at a constant flow rate and creates well-defined sloshing oscillations of the free surface. The phenomenon is referred to as self-induced sloshing.
We retrieve the positions of both the surface and the jet position using a tailored image processing method based on shadowgraphy. Using Complex Orthogonal Decomposition (COD), we reveal the main spatial and temporal dynamics of the oscillations.
{"title":"Shadowgraphy measurements of bubble jet coupled with surface oscillations","authors":"Marc Vacher , Tullio Traverso , Christophe Josserand , Stéphane Perrard , Sophie Ramananarivo","doi":"10.1016/j.ijmultiphaseflow.2025.105543","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105543","url":null,"abstract":"<div><div>We present an image processing method to track and characterize the motion of air–liquid interfaces occurring in aerated liquid baths. In a rectangular tank filled with water, an immersed sparger injects air vertically at a constant flow rate and creates well-defined sloshing oscillations of the free surface. The phenomenon is referred to as self-induced sloshing.</div><div>We retrieve the positions of both the surface and the jet position using a tailored image processing method based on shadowgraphy. Using Complex Orthogonal Decomposition (COD), we reveal the main spatial and temporal dynamics of the oscillations.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105543"},"PeriodicalIF":3.8,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15Epub Date: 2025-11-17DOI: 10.1016/j.ijmultiphaseflow.2025.105550
Jonas Görtz, Andreas Jupke
Gas-evolving electrochemical processes, such as water-splitting, are heavily affected by the presence of gas bubbles. Detached electrogenerated bubbles alter electrolyte conductivity, and attached bubbles reduce the active electrode surface area. However, due to the complex interaction between gas bubbles and electrolyte flow, estimating gas phase fractions and flow patterns within membrane-separated parallel plate electrolyzers is challenging. Utilizing a partially transparent electrolyzer equipped with a 5k high-speed camera, this work applies particle image velocimetry (PIV) to capture time-averaged detailed flow fields across different current densities, superficial electrolyte velocities, heights, and electrode-membrane gaps. The findings reveal distinct flow regimes transforming from quasi-steady segregated flows under no net flow conditions into pseudo-turbulent flows with increased forced convection. Moreover, variations in current density, superficial electrolyte velocity, and electrode-membrane gap are shown to critically define the upward flow regime’s width and turbulence levels. Out of all studied parameters, we found the superficial electrolyte velocity to be the predominant factor for the width of the bubble curtain. The presented findings support understanding bubble-electrolyte interactions, flow patterns, and gas phase distribution in parallel-plate electrolyzers.
{"title":"Exploring the bubble-electrolyte interplay in membrane electrolyzers: PIV measurement of electrolyte flow regimes","authors":"Jonas Görtz, Andreas Jupke","doi":"10.1016/j.ijmultiphaseflow.2025.105550","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105550","url":null,"abstract":"<div><div>Gas-evolving electrochemical processes, such as water-splitting, are heavily affected by the presence of gas bubbles. Detached electrogenerated bubbles alter electrolyte conductivity, and attached bubbles reduce the active electrode surface area. However, due to the complex interaction between gas bubbles and electrolyte flow, estimating gas phase fractions and flow patterns within membrane-separated parallel plate electrolyzers is challenging. Utilizing a partially transparent electrolyzer equipped with a 5k high-speed camera, this work applies particle image velocimetry (PIV) to capture time-averaged detailed flow fields across different current densities, superficial electrolyte velocities, heights, and electrode-membrane gaps. The findings reveal distinct flow regimes transforming from quasi-steady segregated flows under no net flow conditions into pseudo-turbulent flows with increased forced convection. Moreover, variations in current density, superficial electrolyte velocity, and electrode-membrane gap are shown to critically define the upward flow regime’s width and turbulence levels. Out of all studied parameters, we found the superficial electrolyte velocity to be the predominant factor for the width of the bubble curtain. The presented findings support understanding bubble-electrolyte interactions, flow patterns, and gas phase distribution in parallel-plate electrolyzers.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105550"},"PeriodicalIF":3.8,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145568897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15Epub Date: 2025-11-20DOI: 10.1016/j.ijmultiphaseflow.2025.105539
C. Gadal , J. Schneider , C. Bonamy , J. Chauchat , Y. Dossmann , S. Kiesgen de Richter , M.J. Mercier , F. Naaim-Bouvet , M. Rastello , L. Lacaze
This study investigates the early slumping regime of particle-laden gravity currents from full-depth dam-break releases, combining laboratory experiments and two-fluid simulations. By systematically exploring the parameter space, it highlights the influence of the bottom slope, particle volume fraction and particle settling velocity on the flow dynamics.
{"title":"Particle-laden gravity currents: The lock-release slumping regime at the laboratory scale","authors":"C. Gadal , J. Schneider , C. Bonamy , J. Chauchat , Y. Dossmann , S. Kiesgen de Richter , M.J. Mercier , F. Naaim-Bouvet , M. Rastello , L. Lacaze","doi":"10.1016/j.ijmultiphaseflow.2025.105539","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105539","url":null,"abstract":"<div><div>This study investigates the early slumping regime of particle-laden gravity currents from full-depth dam-break releases, combining laboratory experiments and two-fluid simulations. By systematically exploring the parameter space, it highlights the influence of the bottom slope, particle volume fraction and particle settling velocity on the flow dynamics.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105539"},"PeriodicalIF":3.8,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145615324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15Epub Date: 2025-11-19DOI: 10.1016/j.ijmultiphaseflow.2025.105553
Eric R. Upchurch , Yaxin Liu , Evren M. Ozbayoglu
An experimental investigation into Taylor bubble countercurrent behavior in an eccentric 0.1524 m x 0.1016 m (6 in. x 4 in.) annulus using non-Newtonian fluids is presented. This annulus configuration and the fluids tested are commonly used in oil, gas and geothermal drilling operations, but are not reflected in the existing research literature. Fluid rheology, annulus inclination, and internal pipe rotational speed are varied to provide an understanding of Taylor bubble physics under countercurrent flow and its implications for effectively managing unwanted upward gas migration that can occur in a wellbore during drilling operations in fractured or vugular rock formations.
Water and Bingham plastic fluids of ever-increasing plastic viscosity (μp) and yield point (τy) are tested to determine the minimum average downward fluid velocity (i.e., ) that each requires to halt Taylor bubble migration. Increases in μp and τy do not monotonically reduce . Instead, moderate increases up to μp = 31 cP and τy = 40 lb/100 ft2 increase – while further increases in μp and τy reduce , but at the cost of increased friction pressures in the wellbore. Accepting a larger reduces friction pressures but requires using larger fluid volumes during the drilling process. Conversely, minimizing induces higher friction pressure on the wellbore. Determining the appropriate balance of these factors, and others, when planning drilling operations requires integrating the findings of our low-pressure experiments with that of recently published high-pressure Taylor bubble migration experiments. A discussion of the various considerations in such planning is presented.
实验研究了偏心0.1524 m x 0.1016 m (6 in。介绍了使用非牛顿流体的x4英寸)环空。这种环空结构和测试的流体通常用于石油、天然气和地热钻井作业，但在现有的研究文献中没有反映出来。流体流变学、环空倾斜度和管内旋转速度的变化，提供了对逆流作用下泰勒气泡物理特性的理解，以及它对有效管理压裂或空化岩层钻井作业期间井筒中可能出现的有害向上运移的影响。测试了不断增加的塑性粘度（μp）和屈服点（τy）的水和宾厄姆塑性流体，以确定最小的平均向下流体速度（即V - min），每个流体都需要停止泰勒气泡迁移。μp和τy的增加不会单调地减少V的最小值。相反，适度增加到μp = 31 cP和τy = 40 lb/100 ft2会增加V的min，而μp和τy的进一步增加会减少V的min，但代价是增加井筒中的摩擦压力。接受较大的V - min可以减少摩擦压力，但在钻井过程中需要使用较大的流体体积。相反，最小化V - min会在井筒上产生更高的摩擦压力。在规划钻井作业时，需要将我们的低压实验结果与最近发表的高压Taylor气泡迁移实验结果相结合，以确定这些因素以及其他因素的适当平衡。讨论了这种规划中的各种考虑因素。
{"title":"Controlling Taylor bubble migration in a non-concentric annulus: full-scale experiments applied to well drilling operations","authors":"Eric R. Upchurch , Yaxin Liu , Evren M. Ozbayoglu","doi":"10.1016/j.ijmultiphaseflow.2025.105553","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105553","url":null,"abstract":"<div><div>An experimental investigation into Taylor bubble countercurrent behavior in an eccentric 0.1524 m x 0.1016 m (6 in. x 4 in.) annulus using non-Newtonian fluids is presented. This annulus configuration and the fluids tested are commonly used in oil, gas and geothermal drilling operations, but are not reflected in the existing research literature. Fluid rheology, annulus inclination, and internal pipe rotational speed are varied to provide an understanding of Taylor bubble physics under countercurrent flow and its implications for effectively managing unwanted upward gas migration that can occur in a wellbore during drilling operations in fractured or vugular rock formations.</div><div>Water and Bingham plastic fluids of ever-increasing plastic viscosity (<em>μ<sub>p</sub></em>) and yield point (<em>τ<sub>y</sub></em>) are tested to determine the minimum average downward fluid velocity (i.e., <span><math><msub><mover><mrow><mi>V</mi></mrow><mo>‾</mo></mover><mi>min</mi></msub></math></span>) that each requires to halt Taylor bubble migration. Increases in <em>μ<sub>p</sub></em> and <em>τ<sub>y</sub></em> do not monotonically reduce <span><math><msub><mover><mrow><mi>V</mi></mrow><mo>‾</mo></mover><mi>min</mi></msub></math></span>. Instead, moderate increases up to <em>μ<sub>p</sub></em> = 31 cP and <em>τ<sub>y</sub></em> = 40 lb/100 ft<sup>2</sup> increase <span><math><msub><mover><mrow><mi>V</mi></mrow><mo>‾</mo></mover><mi>min</mi></msub></math></span> – while further increases in <em>μ<sub>p</sub></em> and <em>τ<sub>y</sub></em> reduce <span><math><msub><mover><mrow><mi>V</mi></mrow><mo>‾</mo></mover><mi>min</mi></msub></math></span>, but at the cost of increased friction pressures in the wellbore. Accepting a larger <span><math><msub><mover><mrow><mi>V</mi></mrow><mo>‾</mo></mover><mi>min</mi></msub></math></span> reduces friction pressures but requires using larger fluid volumes during the drilling process. Conversely, minimizing <span><math><msub><mover><mrow><mi>V</mi></mrow><mo>‾</mo></mover><mi>min</mi></msub></math></span> induces higher friction pressure on the wellbore. Determining the appropriate balance of these factors, and others, when planning drilling operations requires integrating the findings of our low-pressure experiments with that of recently published high-pressure Taylor bubble migration experiments. A discussion of the various considerations in such planning is presented.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105553"},"PeriodicalIF":3.8,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145615311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study explores the influence of rectangular cavity wettability and size on explosive boiling through nonequilibrium molecular dynamics (MD) simulations. Hybrid wettability rectangular cavity nanostructured surfaces (HWRN) were constructed. Among them, surfaces HWRN-A1 to HWRN-A6 represent a gradual decrease in cavity wettability, while surfaces HWRN-B1 to HWRN-B6 correspond to a gradual increase in the area ratio of the superhydrophobic cavity surface. The atomic energy distribution of the argon liquid film was analyzed to investigate the mechanism of surface wettability on bubble nucleation. The heated surface temperature increased from 90 K to 180 K in 15 ns (6K/ns). The simulation results indicate that reducing the wettability of the rectangular cavities on the HWRN-A surface shortens the time for both bubble nucleation and explosive boiling. The explosive boiling time of HWRN-A6 (superhydrophobic cavity) is 225 ps earlier than that of HWRN-A1 (superhydrophilic cavity). The bubble nucleation time demonstrates a decreasing then increasing trend with the expansion of HWRN-B's cavity area. Under the conditions of this study, the optimal area ratio of HWRN-B was 8% (B3). The surfaces with the largest CHF in the HWRN-A and HWRN-B groups of studies were HWRN-A6 (5.4 × 10–4eV/(nm2·ps)) and HWRN-B3 (5.7 × 10–4 eV/(nm2·ps)), respectively.
{"title":"Molecular dynamics study of boiling on the surface of hybrid wettability rectangular cavity nanostructures","authors":"Dongling Liu, Xiaoping Luo, Yijie Fan, Jinxin Zhang","doi":"10.1016/j.ijmultiphaseflow.2025.105555","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105555","url":null,"abstract":"<div><div>This study explores the influence of rectangular cavity wettability and size on explosive boiling through nonequilibrium molecular dynamics (MD) simulations. Hybrid wettability rectangular cavity nanostructured surfaces (HWRN) were constructed. Among them, surfaces HWRN-A1 to HWRN-A6 represent a gradual decrease in cavity wettability, while surfaces HWRN-B1 to HWRN-B6 correspond to a gradual increase in the area ratio of the superhydrophobic cavity surface. The atomic energy distribution of the argon liquid film was analyzed to investigate the mechanism of surface wettability on bubble nucleation. The heated surface temperature increased from 90 K to 180 K in 15 ns (6K/ns). The simulation results indicate that reducing the wettability of the rectangular cavities on the HWRN-A surface shortens the time for both bubble nucleation and explosive boiling. The explosive boiling time of HWRN-A6 (superhydrophobic cavity) is 225 ps earlier than that of HWRN-A1 (superhydrophilic cavity). The bubble nucleation time demonstrates a decreasing then increasing trend with the expansion of HWRN-B's cavity area. Under the conditions of this study, the optimal area ratio of HWRN-B was 8% (B3). The surfaces with the largest CHF in the HWRN-A and HWRN-B groups of studies were HWRN-A6 (5.4 × 10<sup>–4</sup>eV/(nm<sup>2</sup>·ps)) and HWRN-B3 (5.7 × 10<sup>–4</sup> eV/(nm<sup>2</sup>·ps)), respectively.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105555"},"PeriodicalIF":3.8,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145615310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15Epub Date: 2025-10-27DOI: 10.1016/j.ijmultiphaseflow.2025.105499
Faraz Salimnezhad, Metin Muradoglu
Evaporation of a deformable droplet under convection is investigated and performance of the classical and Abramzon–Sirignano (A–S) models is evaluated. Using the Immersed Boundary/Front-Tracking (IB/FT) method, interface-resolved simulations are performed to examine droplet evaporation dynamics over a wide range of Reynolds (), Weber (), and mass transfer () numbers. It is shown that flow in the wake region is greatly influenced by the Stefan flow as higher evaporation rates leads to an earlier flow separation and a larger recirculation zone behind the droplet. Under strong convection, the models fail to capture the evaporation rate especially in the wake region, which leads to significant discrepancies compared to interface-resolved simulations. Droplet deformation greatly influences the flow field around the droplet and generally enhances evaporation but the evaporation rate remains well correlated with the surface area. The A–S model exhibits a reasonably good performance for a nearly spherical droplet but its performance deteriorates significantly and generally underpredicts evaporation rate as droplet deformation increases. The A–S model is overall found to outperform the classical model in the presence of significant convection.
{"title":"Computational investigation of deformable droplet evaporation under forced convection","authors":"Faraz Salimnezhad, Metin Muradoglu","doi":"10.1016/j.ijmultiphaseflow.2025.105499","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105499","url":null,"abstract":"<div><div>Evaporation of a deformable droplet under convection is investigated and performance of the classical and Abramzon–Sirignano (A–S) models is evaluated. Using the Immersed Boundary/Front-Tracking (IB/FT) method, interface-resolved simulations are performed to examine droplet evaporation dynamics over a wide range of Reynolds (<span><math><mrow><mn>20</mn><mo>≤</mo><mi>R</mi><mi>e</mi><mo>≤</mo><mn>200</mn></mrow></math></span>), Weber (<span><math><mrow><mn>0</mn><mo>.</mo><mn>65</mn><mo>≤</mo><mi>W</mi><mi>e</mi><mo>≤</mo><mn>9</mn></mrow></math></span>), and mass transfer (<span><math><mrow><mn>1</mn><mo>≤</mo><msub><mrow><mi>B</mi></mrow><mrow><mi>M</mi></mrow></msub><mo>≤</mo><mn>15</mn></mrow></math></span>) numbers. It is shown that flow in the wake region is greatly influenced by the Stefan flow as higher evaporation rates leads to an earlier flow separation and a larger recirculation zone behind the droplet. Under strong convection, the models fail to capture the evaporation rate especially in the wake region, which leads to significant discrepancies compared to interface-resolved simulations. Droplet deformation greatly influences the flow field around the droplet and generally enhances evaporation but the evaporation rate remains well correlated with the surface area. The A–S model exhibits a reasonably good performance for a nearly spherical droplet but its performance deteriorates significantly and generally underpredicts evaporation rate as droplet deformation increases. The A–S model is overall found to outperform the classical model in the presence of significant convection.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105499"},"PeriodicalIF":3.8,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145414605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15Epub Date: 2025-11-13DOI: 10.1016/j.ijmultiphaseflow.2025.105541
Jinho Oh , Hyunduk Seo , Kyung Chun Kim
This study investigated a time-resolved three-dimensional morphology reconstruction of a deforming single bubble and visualization of velocity field, vortical structures and pressure field around the bubble.
本文研究了单气泡变形的时间分辨三维形态重建，以及气泡周围的速度场、旋涡结构和压力场的可视化。
{"title":"Three-dimensional time-resolved morphology of a deformable bubble and associated vortex structures","authors":"Jinho Oh , Hyunduk Seo , Kyung Chun Kim","doi":"10.1016/j.ijmultiphaseflow.2025.105541","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105541","url":null,"abstract":"<div><div>This study investigated a time-resolved three-dimensional morphology reconstruction of a deforming single bubble and visualization of velocity field, vortical structures and pressure field around the bubble.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105541"},"PeriodicalIF":3.8,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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