Pub Date : 2026-03-01Epub Date: 2026-01-16DOI: 10.1016/j.ijmultiphaseflow.2026.105620
Haifu Huang, Hervé Mutelle
This study investigates the impact of cladding ballooning on dispersed droplet flow during Loss of Coolant Accidents (LOCA), integrating experimental insights from COAL and MASCARA campaigns with advanced CFD simulations using Neptune_CFD. The work validates carrier gas flow, analyzes droplet dynamics in highly blocked subchannels, and assesses peak cladding temperature behavior under disperse droplet conditions. Handling complex balloons with a discrete forcing Immersed Boundary Methods (IBM), results highlight the critical influence of blockage ratio, blockage length, and droplet size on flow redistribution and hotspot formation. By combining detailed experiments with multiphase modeling, the study could advance understanding of coolability margins in ballooned fuel assemblies and supports the development of more predictive multiscale safety codes.
{"title":"CFD investigation of ballooning effects for dispersed droplet flow during LOCA","authors":"Haifu Huang, Hervé Mutelle","doi":"10.1016/j.ijmultiphaseflow.2026.105620","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105620","url":null,"abstract":"<div><div>This study investigates the impact of cladding ballooning on dispersed droplet flow during Loss of Coolant Accidents (LOCA), integrating experimental insights from COAL and MASCARA campaigns with advanced CFD simulations using Neptune_CFD. The work validates carrier gas flow, analyzes droplet dynamics in highly blocked subchannels, and assesses peak cladding temperature behavior under disperse droplet conditions. Handling complex balloons with a discrete forcing Immersed Boundary Methods (IBM), results highlight the critical influence of blockage ratio, blockage length, and droplet size on flow redistribution and hotspot formation. By combining detailed experiments with multiphase modeling, the study could advance understanding of coolability margins in ballooned fuel assemblies and supports the development of more predictive multiscale safety codes.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105620"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023323","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}
The effect of viscoelasticity on drop deformation in the presence of an electric field is investigated using both analytical and numerical methods. The study focuses on two configurations, namely, a viscoelastic drop suspended in a Newtonian fluid and a Newtonian drop suspended in a viscoelastic medium. Oldroyd-B constitutive equation is employed to model the constant viscosity viscoelasticity. Effect of Deborah number (ratio of polymer relaxation time to convective time scale) on drop deformation is studied by examining the electric, elastic and viscous stresses at the interface. For small deformations, we apply the method of domain perturbations, and show that the viscoelastic properties of the drop significantly influence its deformation more than when the surrounding fluid is viscoelastic. Numerical computations are performed using a finite volume framework for larger drop deformations. The transient dynamics of the drops show distinct oscillatory patterns before eventually stabilizing at a steady deformation value. We observe a trend of decreased deformation in both configurations as the Deborah number increases. Relative magnitude of normal and tangential stresses plays a crucial role in drop deformation.
{"title":"Effect of viscoelasticity on electrohydrodynamic drop deformation","authors":"Santanu Kumar Das , Sarika Shivaji Bangar , Amaresh Dalal , Gaurav Tomar","doi":"10.1016/j.ijmultiphaseflow.2026.105633","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105633","url":null,"abstract":"<div><div>The effect of viscoelasticity on drop deformation in the presence of an electric field is investigated using both analytical and numerical methods. The study focuses on two configurations, namely, a viscoelastic drop suspended in a Newtonian fluid and a Newtonian drop suspended in a viscoelastic medium. Oldroyd-B constitutive equation is employed to model the constant viscosity viscoelasticity. Effect of Deborah number (ratio of polymer relaxation time to convective time scale) on drop deformation is studied by examining the electric, elastic and viscous stresses at the interface. For small deformations, we apply the method of domain perturbations, and show that the viscoelastic properties of the drop significantly influence its deformation more than when the surrounding fluid is viscoelastic. Numerical computations are performed using a finite volume framework for larger drop deformations. The transient dynamics of the drops show distinct oscillatory patterns before eventually stabilizing at a steady deformation value. We observe a trend of decreased deformation in both configurations as the Deborah number increases. Relative magnitude of normal and tangential stresses plays a crucial role in drop deformation.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105633"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074277","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}
Heat transfer in porous fiber-reinforced composite cylinders is critical for enhancing thermal system performance in applications such as material drying, atomization devices, and aerospace engineering. However, the influence of compressible fluid flow within porous structures remains insufficiently understood due to limited experimental data and incomplete theoretical models. This study establishes a transient heat and mass transfer model for a multilayer porous composite cylinder containing hygroscopic moisture. The model incorporates Darcy-based flow and local thermal non-equilibrium (LTNE) assumptions. It accounts for critical water saturation, gravitational effects, and gas compressibility. Solved using the finite volume method, the model predicts unsteady thermal and mass transport behavior. Its accuracy is validated via a custom experimental platform. Finally, the effects of thermal conductivity, porosity, and moisture saturation on heat and mass transfer characteristics are analyzed. The proposed model provides a reliable tool for predicting transient thermal behavior in porous composite systems, offering concrete guidance for the design and performance optimization of advanced thermal equipment such as insulation sleeves, drying cylinders, and thermal storage components.
{"title":"Unsteady heat and mass transfer in composite cylinders with water-containing hygroscopic porous media and compressible gas phase","authors":"Yu-Cheng Wei , Zheng-Wei Huang , Hong-Liang Dai, Zhi-Wei Sun, Jian Xu","doi":"10.1016/j.ijmultiphaseflow.2026.105632","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105632","url":null,"abstract":"<div><div>Heat transfer in porous fiber-reinforced composite cylinders is critical for enhancing thermal system performance in applications such as material drying, atomization devices, and aerospace engineering. However, the influence of compressible fluid flow within porous structures remains insufficiently understood due to limited experimental data and incomplete theoretical models. This study establishes a transient heat and mass transfer model for a multilayer porous composite cylinder containing hygroscopic moisture. The model incorporates Darcy-based flow and local thermal non-equilibrium (LTNE) assumptions. It accounts for critical water saturation, gravitational effects, and gas compressibility. Solved using the finite volume method, the model predicts unsteady thermal and mass transport behavior. Its accuracy is validated via a custom experimental platform. Finally, the effects of thermal conductivity, porosity, and moisture saturation on heat and mass transfer characteristics are analyzed. The proposed model provides a reliable tool for predicting transient thermal behavior in porous composite systems, offering concrete guidance for the design and performance optimization of advanced thermal equipment such as insulation sleeves, drying cylinders, and thermal storage components.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105632"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074269","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}
The two-fluid model (TFM) is foundational for modelling and simulation of dispersed-regime multiphase flows which are pervasive in natural and industrial processes. The TFM provides a coarse-grained representation of complex multiphase flows without explicitly capturing interfaces between phases through the use of volume-, time-, or ensemble-averaging. This results in the benefit of significantly reduced computational complexity but at the cost of increased approximation requiring accurate interphase transfer closures, compared to interface-capturing models. The choice of interphase transfer closures for TFM accuracy has been one of the main foci of past research, which is expansive due to the various multiphase system combinations (e.g. gas dispersed in liquid and liquid dispersed in gas). Recent research using detailed interface-capturing models has shown that the inclusion of a laminar dispersion force in the TFM when modelling bubbly flows both improves physical fidelity and mathematical completeness. In this work, a simulation-based study is performed to determine the effects of including different recently proposed laminar dispersion force models on both numerical stability and physical fidelity of a TFM formulation for gas dispersed in liquid multiphase flows. It includes a formulation of a TFM based on Brennen’s canonical formulation incorporating various recently developed laminar dispersion force closures. Overall, it is shown that inclusion of a laminar dispersion force both improves numerical stability and physical fidelity through validation with past experimental results.
{"title":"Laminar dispersion force effects on two-fluid modelling and simulation of bubble column hydrodynamics","authors":"Arshia Fazeli , Sander Rhebergen , Nasser Mohieddin Abukhdeir","doi":"10.1016/j.ijmultiphaseflow.2025.105590","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105590","url":null,"abstract":"<div><div>The two-fluid model (TFM) is foundational for modelling and simulation of dispersed-regime multiphase flows which are pervasive in natural and industrial processes. The TFM provides a coarse-grained representation of complex multiphase flows without explicitly capturing interfaces between phases through the use of volume-, time-, or ensemble-averaging. This results in the benefit of significantly reduced computational complexity but at the cost of increased approximation requiring accurate interphase transfer closures, compared to interface-capturing models. The choice of interphase transfer closures for TFM accuracy has been one of the main foci of past research, which is expansive due to the various multiphase system combinations (e.g. gas dispersed in liquid and liquid dispersed in gas). Recent research using detailed interface-capturing models has shown that the inclusion of a laminar dispersion force in the TFM when modelling bubbly flows both improves physical fidelity and mathematical completeness. In this work, a simulation-based study is performed to determine the effects of including different recently proposed laminar dispersion force models on both numerical stability and physical fidelity of a TFM formulation for gas dispersed in liquid multiphase flows. It includes a formulation of a TFM based on Brennen’s canonical formulation incorporating various recently developed laminar dispersion force closures. Overall, it is shown that inclusion of a laminar dispersion force both improves numerical stability and physical fidelity through validation with past experimental results.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105590"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974413","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 : 2026-03-01Epub Date: 2026-01-08DOI: 10.1016/j.ijmultiphaseflow.2026.105610
Abderraouf Arabi, Youssef Stiriba, Jordi Pallares
Accurately predicting flow regime transitions remains one of the key challenges in multiphase flow systems, with significant implications for design, safety, and operational reliability. In this study, novel models are introduced to predict the bubbly-to-slug flow transition in vertical downward gas–liquid flows. The transition to bubbly flow is defined in such a way that it reflects the disappearance of slug-like flow structures, offering a more intuitive physical interpretation of the underlying mechanisms. Two independent and physically meaningful criteria are proposed: (i) the onset of homogeneous flow behavior and (ii) the vanishing of the Taylor bubble. Based on these criteria, analytical expressions are derived using recent correlations for global and slug liquid holdups.
The resulting transition lines are nearly identical, underscoring the internal consistency and robustness of the proposed methodology. The models’ performances were validated against an extensive experimental database from the literature and covering a broad range of pipe diameters (9.53 mm ≤ D≤ 80 mm). They showed excellent agreement with observed transitions in most cases, confirming their predictive accuracy.
{"title":"Physically-based models for predicting the bubbly-to-slug flow transition in vertical downward gas–liquid two-phase flow","authors":"Abderraouf Arabi, Youssef Stiriba, Jordi Pallares","doi":"10.1016/j.ijmultiphaseflow.2026.105610","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105610","url":null,"abstract":"<div><div>Accurately predicting flow regime transitions remains one of the key challenges in multiphase flow systems, with significant implications for design, safety, and operational reliability. In this study, novel models are introduced to predict the bubbly-to-slug flow transition in vertical downward gas–liquid flows. The transition to bubbly flow is defined in such a way that it reflects the disappearance of slug-like flow structures, offering a more intuitive physical interpretation of the underlying mechanisms. Two independent and physically meaningful criteria are proposed: (i) the onset of homogeneous flow behavior and (ii) the vanishing of the Taylor bubble. Based on these criteria, analytical expressions are derived using recent correlations for global and slug liquid holdups.</div><div>The resulting transition lines are nearly identical, underscoring the internal consistency and robustness of the proposed methodology. The models’ performances were validated against an extensive experimental database from the literature and covering a broad range of pipe diameters (9.53 mm ≤ <em>D</em>≤ 80 mm). They showed excellent agreement with observed transitions in most cases, confirming their predictive accuracy.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105610"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974415","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 : 2026-03-01Epub Date: 2026-01-24DOI: 10.1016/j.ijmultiphaseflow.2026.105631
A. Madhav Sai Kumar , A. Hari Govindha , Ranajit Mondal , Kirti Chandra Sahu
The drying of colloidal suspensions leads to complex deposition patterns, accompanied by instabilities such as cracking and delamination. In this study, we experimentally investigate the coupled influence of particle surface charge and substrate wettability on the evaporation dynamics, final deposition morphology, and crack patterns of sessile droplets containing silica nanoparticles. We examine the dynamics of two types of colloids, namely the negatively charged colloidal silica nanoparticles (Ludox TM50) and the positively charged silica nanoparticle (Ludox CL30), at concentrations ranging from 0.1 wt% to 5.0 wt%, deposited on glass, polystyrene, and polytetrafluoroethylene (PTFE) substrates with distinct wettability. Side and top-view imaging techniques are employed to capture the evaporation process and analyze the resulting cracks. Our results reveal that the nature of the particle charge and substrate wettability significantly affect the evaporation mode, with transitions observed between constant contact radius (CCR), constant contact angle (CCA), and mixed modes. TM50-laden droplets consistently exhibit radial cracks, whereas CL30 droplets display more randomly oriented and irregular cracks. At higher particle concentrations, TM50 suspensions form thicker deposits that undergo delamination, particularly on highly wettable substrates like glass. Quantitative analysis reveals that crack spacing and length follow power-law relationships with particle concentration. Additionally, the delamination behavior is strongly influenced by both the particle concentration and the type of substrate. We propose a mechanistic framework to explain the role of particle–substrate interactions in governing the observed cracking and delamination behaviors.
{"title":"Instabilities in drying colloidal films: Role of surface charge and substrate wettability","authors":"A. Madhav Sai Kumar , A. Hari Govindha , Ranajit Mondal , Kirti Chandra Sahu","doi":"10.1016/j.ijmultiphaseflow.2026.105631","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105631","url":null,"abstract":"<div><div>The drying of colloidal suspensions leads to complex deposition patterns, accompanied by instabilities such as cracking and delamination. In this study, we experimentally investigate the coupled influence of particle surface charge and substrate wettability on the evaporation dynamics, final deposition morphology, and crack patterns of sessile droplets containing silica nanoparticles. We examine the dynamics of two types of colloids, namely the negatively charged colloidal silica nanoparticles (Ludox TM50) and the positively charged silica nanoparticle (Ludox CL30), at concentrations ranging from 0.1 wt% to 5.0 wt%, deposited on glass, polystyrene, and polytetrafluoroethylene (PTFE) substrates with distinct wettability. Side and top-view imaging techniques are employed to capture the evaporation process and analyze the resulting cracks. Our results reveal that the nature of the particle charge and substrate wettability significantly affect the evaporation mode, with transitions observed between constant contact radius (CCR), constant contact angle (CCA), and mixed modes. TM50-laden droplets consistently exhibit radial cracks, whereas CL30 droplets display more randomly oriented and irregular cracks. At higher particle concentrations, TM50 suspensions form thicker deposits that undergo delamination, particularly on highly wettable substrates like glass. Quantitative analysis reveals that crack spacing and length follow power-law relationships with particle concentration. Additionally, the delamination behavior is strongly influenced by both the particle concentration and the type of substrate. We propose a mechanistic framework to explain the role of particle–substrate interactions in governing the observed cracking and delamination behaviors.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105631"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074276","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 : 2026-03-01Epub Date: 2026-01-14DOI: 10.1016/j.ijmultiphaseflow.2026.105619
Guilherme Rosário dos Santos
Slug flow is a commonly encountered flow pattern in systems within the nuclear and petroleum industries. Slug length is a critical parameter for predicting pressure drop and in designing processing equipment and slug catchers. This study proposes a new correlation for slug length prediction based on an extensive experimental dataset obtained from the literature. The correlation accounts for liquid viscosity, pipe inner diameter, gas and liquid superficial velocities, gravity, gas-to-liquid density ratio, and pipe inclination. It was established using the Buckingham Pi theorem, and the resulting model was expressed in terms of Reynolds and Froude numbers, defined using liquid properties and superficial velocity, with an additional function to incorporate pipe inclination effects. When evaluated against the extensive experimental dataset across upward vertical, inclined, and horizontal pipe configurations, existing correlations performed poorly, whereas the proposed correlation demonstrated substantially improved performance. For vertical flow, 88% of 98 data points fell within a ± 30% relative error band; for inclined flow, 61–79% of 127 data points were within a ± 10% band; and for horizontal flow, 65% of 450 data points fell within a ± 30% band. Sensitivity analysis confirmed the robustness of the proposed correlation with respect to liquid viscosity and other flow parameters. The upper applicability limit of liquid viscosity was 100 mPa·s for small- and large-diameter pipes at inclinations of 90°–45° and 0°, respectively, and increased to 1000 mPa·s for nearly and fully horizontal flows.
{"title":"New correlation for slug length prediction in upward vertical, inclined, and horizontal slug flows","authors":"Guilherme Rosário dos Santos","doi":"10.1016/j.ijmultiphaseflow.2026.105619","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105619","url":null,"abstract":"<div><div>Slug flow is a commonly encountered flow pattern in systems within the nuclear and petroleum industries. Slug length is a critical parameter for predicting pressure drop and in designing processing equipment and slug catchers. This study proposes a new correlation for slug length prediction based on an extensive experimental dataset obtained from the literature. The correlation accounts for liquid viscosity, pipe inner diameter, gas and liquid superficial velocities, gravity, gas-to-liquid density ratio, and pipe inclination. It was established using the Buckingham Pi theorem, and the resulting model was expressed in terms of Reynolds and Froude numbers, defined using liquid properties and superficial velocity, with an additional function to incorporate pipe inclination effects. When evaluated against the extensive experimental dataset across upward vertical, inclined, and horizontal pipe configurations, existing correlations performed poorly, whereas the proposed correlation demonstrated substantially improved performance. For vertical flow, 88% of 98 data points fell within <em>a</em> ± 30% relative error band; for inclined flow, 61–79% of 127 data points were within <em>a</em> ± 10% band; and for horizontal flow, 65% of 450 data points fell within <em>a</em> ± 30% band. Sensitivity analysis confirmed the robustness of the proposed correlation with respect to liquid viscosity and other flow parameters. The upper applicability limit of liquid viscosity was 100 mPa·s for small- and large-diameter pipes at inclinations of 90°–45° and 0°, respectively, and increased to 1000 mPa·s for nearly and fully horizontal flows.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105619"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023353","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 : 2026-03-01Epub Date: 2026-01-10DOI: 10.1016/j.ijmultiphaseflow.2026.105614
Anastasia Islamova, Andrey Klimenko, Stanislav Shulyaev, Pavel Strizhak
With a variety of industrial applications involving the collisions of droplets and particles in gas, it is important to explore processes during their agglomeration and separation, as well as their classification. By recording the characteristics of droplet-particle interaction in aerosol flows, it will be possible to significantly optimize processes in abundance of systems for dust collection, liquid filtration, fine spraying, etc. The purpose of this research was to experimentally study the characteristics of interaction between water droplets and particles of coal and sand, when varying the ambient temperature from 25 to 300°С. A high-speed camera was employed to obtain shadow images of interaction of droplets and particles, with their respective velocities varying from 0.2 to 15.1 m/s and from 0.4 to 33.8 m/s. The obtained data were plotted as curves taking account of dimensionless numbers (the Weber, Reynolds, Froude and Stokes numbers). Predictive equations were derived on the basis of the experimental findings. With a temperature increase from 25°С to 300°С, the number of child droplets rose by almost 30 %. The interaction outcome was found to be mainly affected by the shape and size of solid particles, as well as their impact velocity.
{"title":"Interaction of droplets and particles in the airflow under various ambient conditions","authors":"Anastasia Islamova, Andrey Klimenko, Stanislav Shulyaev, Pavel Strizhak","doi":"10.1016/j.ijmultiphaseflow.2026.105614","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105614","url":null,"abstract":"<div><div>With a variety of industrial applications involving the collisions of droplets and particles in gas, it is important to explore processes during their agglomeration and separation, as well as their classification. By recording the characteristics of droplet-particle interaction in aerosol flows, it will be possible to significantly optimize processes in abundance of systems for dust collection, liquid filtration, fine spraying, etc. The purpose of this research was to experimentally study the characteristics of interaction between water droplets and particles of coal and sand, when varying the ambient temperature from 25 to 300°С. A high-speed camera was employed to obtain shadow images of interaction of droplets and particles, with their respective velocities varying from 0.2 to 15.1 m/s and from 0.4 to 33.8 m/s. The obtained data were plotted as curves taking account of dimensionless numbers (the Weber, Reynolds, Froude and Stokes numbers). Predictive equations were derived on the basis of the experimental findings. With a temperature increase from 25°С to 300°С, the number of child droplets rose by almost 30 %. The interaction outcome was found to be mainly affected by the shape and size of solid particles, as well as their impact velocity.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105614"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974420","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 : 2026-02-01Epub Date: 2025-11-28DOI: 10.1016/j.ijmultiphaseflow.2025.105556
Davide Picchi , Valentina Ciriello
The success of CCS technologies relies on the effectiveness and safety of the infrastructure for the transport of carbon dioxide in pressurized pipelines. Unlike natural gas networks, long-distance carbon dioxide transport presents critical design challenges, such as the need for repressurization to prevent two-phase flow conditions and potential freezing. To address this, we propose a comprehensive assessment framework that combines high-fidelity numerical simulations with a stochastic approach based on the Polynomial Chaos Expansion (PCE). Specifically, we employ the Homogeneous Equilibrium Model (HEM) to compute key quantities of interest (QoIs) — related to pressure drop and the maximum distance before repressurization is required — under a design scenario inspired by the Cortez pipeline (Colorado, USA). Based on PCE surrogates, we then perform global sensitivity analyses and uncertainty quantification to evaluate how variability in inlet parameters influences these QoIs, mapping results across a range of realistic operating conditions. Our results provide critical insight into the risks connected with CO2 transport and support the optimal design of operating conditions. Moreover, the proposed methodology is general and easily applicable to other CO2 transport facilities.
{"title":"Impact of variability in inlet operating conditions on CO2 transport in pipelines","authors":"Davide Picchi , Valentina Ciriello","doi":"10.1016/j.ijmultiphaseflow.2025.105556","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105556","url":null,"abstract":"<div><div>The success of CCS technologies relies on the effectiveness and safety of the infrastructure for the transport of carbon dioxide in pressurized pipelines. Unlike natural gas networks, long-distance carbon dioxide transport presents critical design challenges, such as the need for repressurization to prevent two-phase flow conditions and potential freezing. To address this, we propose a comprehensive assessment framework that combines high-fidelity numerical simulations with a stochastic approach based on the Polynomial Chaos Expansion (PCE). Specifically, we employ the Homogeneous Equilibrium Model (HEM) to compute key quantities of interest (QoIs) — related to pressure drop and the maximum distance before repressurization is required — under a design scenario inspired by the Cortez pipeline (Colorado, USA). Based on PCE surrogates, we then perform global sensitivity analyses and uncertainty quantification to evaluate how variability in inlet parameters influences these QoIs, mapping results across a range of realistic operating conditions. Our results provide critical insight into the risks connected with CO<sub>2</sub> transport and support the optimal design of operating conditions. Moreover, the proposed methodology is general and easily applicable to other CO<sub>2</sub> transport facilities.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105556"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682954","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}
The design of large-scale multiphase reactors, such as fluidized beds for methanation, requires numerical methods that are both computationally efficient and physically accurate. This study addresses the limitations of existing approaches, where traditional DEM–CFD solvers are often computationally expensive and computationally less expensive methods typically fail to capture crucial physical phenomena such as finite-speed acoustic waves. We present a novel DEM–CFD framework for low-Mach number flows that couples the Discrete Element Method (DEM) with a non-iterative, weakly-compressible fractional-step method for the gas phase. This approach combines the particle-scale accuracy of DEM with a gas solver that efficiently handles both density variations and acoustic wave propagation. As a fundamental step before simulating reactive flows, this paper validates the framework’s hydrodynamic and acoustic capabilities using non-reactive test cases. First, simulations of pressure drop across a fixed bed show excellent agreement with the Ergun equation, validating the momentum exchange model. Second, the complex dynamics of a spout-fluidized bed are shown to reproduce experimental trends, while also highlighting the simulation’s sensitivity to particle contact parameters like restitution and friction coefficients. Finally, speed of sound measurements in various gases (Dry Air, CO, H) within a particle bed confirm the framework’s ability to accurately capture finite sound speed and species-dependent properties, with results aligning well with pure-gas theory. The framework’s flexibility was further demonstrated by successfully reproducing an alternative ”frozen” two-phase sound speed. These comprehensive validations demonstrate the framework’s capability as a robust and efficient tool for investigating complex reactive multiphase flows.
{"title":"A weakly-compressible DEM–CFD framework for dense gas–solid multiphase flows: Foundations consistent with reactive coupling","authors":"Yuki Yakata , Kimiaki Washino , Masaya Muto , Ryoichi Kurose , Takuya Tsuji","doi":"10.1016/j.ijmultiphaseflow.2025.105558","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105558","url":null,"abstract":"<div><div>The design of large-scale multiphase reactors, such as fluidized beds for methanation, requires numerical methods that are both computationally efficient and physically accurate. This study addresses the limitations of existing approaches, where traditional DEM–CFD solvers are often computationally expensive and computationally less expensive methods typically fail to capture crucial physical phenomena such as finite-speed acoustic waves. We present a novel DEM–CFD framework for low-Mach number flows that couples the Discrete Element Method (DEM) with a non-iterative, weakly-compressible fractional-step method for the gas phase. This approach combines the particle-scale accuracy of DEM with a gas solver that efficiently handles both density variations and acoustic wave propagation. As a fundamental step before simulating reactive flows, this paper validates the framework’s hydrodynamic and acoustic capabilities using non-reactive test cases. First, simulations of pressure drop across a fixed bed show excellent agreement with the Ergun equation, validating the momentum exchange model. Second, the complex dynamics of a spout-fluidized bed are shown to reproduce experimental trends, while also highlighting the simulation’s sensitivity to particle contact parameters like restitution and friction coefficients. Finally, speed of sound measurements in various gases (Dry Air, CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>) within a particle bed confirm the framework’s ability to accurately capture finite sound speed and species-dependent properties, with results aligning well with pure-gas theory. The framework’s flexibility was further demonstrated by successfully reproducing an alternative ”frozen” two-phase sound speed. These comprehensive validations demonstrate the framework’s capability as a robust and efficient tool for investigating complex reactive multiphase flows.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105558"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682497","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号