International Journal of Multiphase Flow最新文献

{"title":"Direct numerical simulation of a rising CO2 bubble dissolving in quiescent water at high Schmidt number","authors":"Yating Wang ,&nbsp;Yohei Sato","doi":"10.1016/j.ijmultiphaseflow.2025.105566","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105566","url":null,"abstract":"<div><div>Three-dimensional direct numerical simulation (DNS) was performed to investigate mass transfer at high Schmidt numbers, focusing on a rising, dissolving gas bubble in a liquid. The objectives are (i) to develop a numerical method based on the volume-of-fluid (VOF) approach for simulating a dissolving gas bubble and (ii) to determine the mesh resolution required to accurately capture the underlying physical phenomena. A sharp-interface phase-change model is employed, in which the species concentration gradient at the gas–liquid interface is calculated using an irregular stencil that accounts for the local interface geometry. The method was first validated against benchmark cases at low Schmidt numbers, and then applied to a 9 mm CO₂ bubble rising in quiescent water. The simulation was performed on grids ranging from 128³ to 2048³, with the finest case using 8192 cores over 15 days. The total simulated physical time was 1.2 s, including the grid-refinement stages up to the finest resolution. The grid-dependence study indicates that the evaluated grid resolutions remain outside the fully asymptotic regime; nevertheless, the 2048³ grid result underestimates the Sherwood number by only about 7 % relative to the empirical correlation. The CO₂ concentration isosurface from the 2048³ case reveals a complex wake structure with elongated filaments and rolled-up sheets, indicative of shear-induced vortices and strong entrainment. The grid-dependence study suggests that even finer grids (e.g., 4096³) may be necessary, highlighting the need for future exascale computing to fully resolve mass transfer at a high Schmidt number (∼530).</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105566"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787064","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}

{"title":"Flow transition of liquid–liquid two-phase Taylor–Couette flow with axial flow","authors":"Hayato Masuda,&nbsp;Yuta Kikuchi,&nbsp;Hiroyuki Iyota","doi":"10.1016/j.ijmultiphaseflow.2025.105585","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105585","url":null,"abstract":"<div><div>A liquid–liquid two-phase Taylor–Couette flow is of fundamental and practical importance in multiphase flow systems. This study investigates the flow transitions in such a system with constant axial flow and gradually increased rotation of the inner cylinder. To clarify the effect of continuous-phase viscosity on flow transitions, several concentrations of glycerol–water solutions were employed as the continuous phase, while soybean oil was used as the dispersed phase. Visualization experiments revealed that the flow undergoes a cascade of transitions: stratified flow, disturbed stratified flow, transitional droplet flow, unstable banded flow, and stable banded flow. A flow map was constructed using two dimensionless parameters, rotational Reynolds number (<em>Re</em>_rot) and Weber number (<em>We</em>). The transitions from disturbed stratified to unstable banded flow (TR I) and from unstable to stable banded flow (TR II) were found to be approximately expressed by a power-law relation of the form <em>We</em> ∼ <em>Re</em>_rot^A, where <em>A</em> is a fitting exponent. For TR I, A showed no clear dependence on continuous-phase viscosity, suggesting that the transition is governed by the combined effects of inertia, viscosity, and interfacial tension. In contrast, <em>A</em> decreased with increasing viscosity in TR II, becoming nearly zero at high glycerol concentration. Furthermore, to clarify the mechanism of stable banded flow formation, the droplet inertia was evaluated using the Stokes number (<em>St</em>). It was revealed that the stable banded structure results from the loss of droplet inertia, associated with droplet fragmentation under higher rotation and the increasing inertia of the continuous phase.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105585"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836412","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}

{"title":"Bubble collapse near a wall: A numerical study on the impact of physical mechanisms for a bubble initially at rest","authors":"Zhidian Yang,&nbsp;Bo Wang,&nbsp;Francesco Romanò","doi":"10.1016/j.ijmultiphaseflow.2025.105567","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105567","url":null,"abstract":"<div><div>Cavitation near solid boundaries is a well-documented phenomenon due to its potential to damage surfaces and impair the performance of pumps, turbines, and similar machinery. This work numerically investigates the pressure exerted by a cavitation bubble collapsing near a rigid wall, with results compared against experimental measurements. The bubble is assumed to start from rest at its maximum equivalent radius. Simulations employ the All-Mach approach of Basilisk, using the VOF (Volume-of-Fluid) method to resolve interface dynamics. Our findings show that the maximum wall pressure during collapse depends strongly on the bubble stand-off ratio and the interior-to-exterior pressure ratio at maximum size. In contrast, the evolution of the equivalent radius shows a weak sensitivity to these parameters, despite significant effects on the detailed interface motion. Additional analyses assess the influence of viscosity, heat transfer, surface tension, and bubble sphericity, allowing identification of the leading-order mechanisms to reduce model complexity. Comparison with experiments and prior studies indicates that accounting for flow compressibility, while neglecting phase change during collapse, provides good agreement for interfacial dynamics, though notable discrepancies remain for the maximum wall pressure.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105567"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836920","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}

{"title":"Influence of dissolved gas concentration on the lifetime of surface bubbles in volatile liquids","authors":"Xin Li ,&nbsp;Yanshen Li","doi":"10.1016/j.ijmultiphaseflow.2025.105580","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105580","url":null,"abstract":"<div><div>Bubbles at the air–liquid interface are important for many natural and industrial processes. Factors influencing the lifetime of such surface bubbles have been investigated extensively, yet the impact of dissolved gas concentration remains unexplored. Here we investigate how the lifetime of surface bubbles in volatile liquids depends on the dissolved gas concentration. The bubble lifetime is found to decrease with the dissolved gas concentration. Larger microbubbles at increased gas concentration are found to trigger bubble bursting at earlier times. Combined with the thinning rate of the bubble cap thickness, a scaling law of the bubble lifetime is developed. The scaling is also found to be independent of factors like container type, liquid pool depth and bubble size. Our findings may provide new insight on surface bubble lifetime and foam stability.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105580"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836916","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}

{"title":"Phenomenological characterization of heat transfer and boiling crisis in churn liquid-vapor flows using high-resolution diagnostics","authors":"Mauricio Mani Marinheiro ,&nbsp;Gustavo Matana Aguiar ,&nbsp;Roman William Morse ,&nbsp;Gherhardt Ribatski ,&nbsp;Matteo Bucci","doi":"10.1016/j.ijmultiphaseflow.2025.105568","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105568","url":null,"abstract":"<div><div>This experimental investigation leverages high-speed shadowgraphy and infrared thermography to provide a phenomenological description of heat transfer and boiling crisis in the churn flow regime. In churn flow, intermittent cycles of overheating and cooling occur on the heated surface. The surface is cooled down by nucleating bubbles, liquid slugs, and backflow and descending liquid films. However, backflow and descending liquid films are not observed at high mass flow rates. The surface overheats when the liquid film in contact with the channel wall stagnates. Under high imposed heat fluxes, the stagnant film dries out, forming a high-temperature region that prevents liquid slugs and descending liquid films from effectively cooling the surface, thereby triggering a boiling crisis. Since the macroscale characteristics of the churn flow govern the onset of a boiling crisis, mass flux has a more dominant influence on the critical heat flux than surface wettability.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105568"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733885","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}

{"title":"Dynamic evolution of the mixing zone during diesel displacement of oil-water two-phase flow in multiphase pipelines","authors":"Ming Zhang ,&nbsp;Pengcheng Li ,&nbsp;Shengde Di ,&nbsp;Jinghua Chen ,&nbsp;Qi Xiang ,&nbsp;Xiaoming Luo","doi":"10.1016/j.ijmultiphaseflow.2025.105582","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105582","url":null,"abstract":"<div><div>Following the shutdown of deepwater oil–water multiphase pipelines, crude oil readily solidifies under low-temperature conditions, posing a serious risk of pipeline blockage. Diesel displacement is a critical technique for ensuring the safe shutdown and restart of subsea pipelines. However, the mechanisms governing the formation and evolution of the mixing zone and the reliable prediction of its length remain unclear. This study combines loop experiments with numerical simulations to systematically investigate the effects of flow velocity, water cut, pipe diameter, and pipeline inclination on the development of the mixing zone during diesel displacement of oil–water two-phase flow. The results demonstrate that flow velocity is the dominant factor controlling the mixing zone length, reducing the mixing zone length by 31–33% when the velocity increases from 0.5 to 1.0 m/s. Increasing velocity significantly enhances turbulence, accelerates diesel dissolution and scouring of wall-adhered crude oil, and strengthens water entrainment, thereby shortening the mixing zone and improving displacement efficiency. Larger pipe diameters and greater inclinations extend the mixing zone by approximately 20%, due to increased oil adhesion, water backflow in upward sections, and oil buoyancy or partial-flow effects in downward sections, while the impact of water cut is relatively minor. Meanwhile, numerical simulations can effectively reproduce the dynamic evolution of the mixing zone, but have difficulty in accurately characterizing crude oil adhesion effects, resulting in a MAPE of approximately 19.1% between the predicted and measured mixing zone lengths. This study elucidates the mechanisms underlying mixing zone formation and dynamic evolution, reveals the dissolution-scouring synergy governing the removal of wall-adhered crude oil and the roles of gravity-induced stratification and buoyancy, quantitatively assesses the effects of key parameters on mixing zone length, and provides a theoretical basis for optimizing shutdown displacement in deepwater multiphase pipelines.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105582"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787065","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}

{"title":"Nanoscale mapping of competitive cavitation nucleation: From surface to bulk","authors":"Yuhan Li ,&nbsp;Junhao Cai ,&nbsp;Yunqiao Liu ,&nbsp;Mingbo Li ,&nbsp;Benlong Wang","doi":"10.1016/j.ijmultiphaseflow.2025.105595","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105595","url":null,"abstract":"<div><div>The prevailing view that pits are more susceptible to cavitation nucleation than pillars has spurred extensive research on pit scenarios; however, competition among bulk, pit surface, or pillar surface nucleation under a broader range of wettability has received limited attention. Therefore, nanoscopic molecular dynamics simulations (MD) and classical nucleation theory (CNT) are employed to elucidate the competitive nucleation diagram across the three nucleation pathways. Results reveal that bulk nucleation can still out-compete surface nucleation provided the entire rough wall exhibits extreme super-wettability; however, achieving this wetting state is highly demanding. In contrast, pit-embedded surface nucleation dominates when the rough wall features uniformly weak wettability. The Blake threshold constitutes the metastable equilibrium of vapor bubbles confined within pits. Weakly wettable pillars on strongly hydrophilic substrates prevail in the competitive cavitation nucleation; however, they exert an insignificant influence when the substrate is also weakly hydrophilic, thereby allowing pit-embedded surface nucleation to dominate. The nucleation mode phase diagram establishes a universal framework for predicting the cavitation nucleation across a tailored wettability regime, offering fundamental significance to nucleation research.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105595"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836411","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}

{"title":"How substrate temperature shapes Salmonella Typhimurium deposition patterns and pathogenesis in evaporating droplets","authors":"Amey Nitin Agharkar ,&nbsp;Anmol Singh ,&nbsp;Kush Kumar Dewangan ,&nbsp;Dipshikha Chakravortty ,&nbsp;Saptarshi Basu","doi":"10.1016/j.ijmultiphaseflow.2025.105592","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105592","url":null,"abstract":"<div><div>Droplets expelled from infected hosts can deposit on surfaces and serve as fomites. Temperature‑controlled industrial equipment is also susceptible to such contamination. To test the hypothesis that substrate temperature influences droplet behaviour, we examined how temperatures from 25 °C to 70 °C affect evaporation dynamics, internal flows, deposition patterns, bacterial viability, and infectivity in <em>Salmonella</em> Typhimurium–laden droplets. Milli‑Q water, Luria broth (LB) medium, and meat extract were used as representative physiological fluids. Imaging and confocal microscopy techniques were used to study the evaporation dynamics and flow, whilst the morphology of dried precipitates was characterised using microscopy and profilometry. The classical “coffee-ring” deposition is exhibited at low temperatures for <em>S.</em> Typhimurium-Milli-Q water droplet. However, as the substrate temperature rises, thermal gradients generate strong inward Marangoni convection that competes with the capillary flow, producing thinner rings or central deposits for Milli-Q water and with dendritic structures for LB. Meanwhile, for meat extract, the patterns remained unchanged. The measured radial velocities at 50 °C were ten times higher than at 25 °C. Increased substrate temperatures resulted in a drastic reduction of the evaporation time and a decreased bacterial area of projection, keeping the bacterial aspect ratio intact. It depicted higher stress due to faster evaporation. The viability of <em>Salmonella</em> in precipitates was reduced with increasing substrate temperature, but infectivity remained unaltered across all base fluids.</div><div>Thus, the findings show that substrate temperature highly influences bacterial deposition and viability. The potential fomite-based infection risks from heated surfaces are outlined.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105592"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836918","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}

{"title":"Collision-induced breakup dynamics of binary equal-sized nanodroplets","authors":"Zongjun Yin,&nbsp;Chengbin Zhang,&nbsp;Yongping Chen","doi":"10.1016/j.ijmultiphaseflow.2025.105593","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105593","url":null,"abstract":"<div><div>The role of scale effects on binary nanodroplet collision dynamics is profound, as interfacial forces exhibit strong size dependence at the nanoscale. This study employs molecular dynamics simulations to investigate head-on collisions of equal-sized water nanodroplets, focusing on rupture mechanisms and interfacial dynamics at the nanoscale. The effect of disjoining pressure on nanoscale interfacial phenomena is elucidated, demonstrating a marked increase in surface energy density in thin films and nanodroplets. Four distinct outcomes are identified: regular coalescence, coalescence after perforation, limited splattering, and divergent splattering, and a regime map is constructed accordingly. The rupture instability of nanosheets formed during binary nanodroplet collisions is dictated by thermocapillary short-wave instabilities, which govern the selection of the critical wavenumber. These instabilities initiate perforation at the periphery of the spreading meniscus and subsequently propagate inward once a critical nanosheet thickness is reached. However, the relevant scaling arguments regarding the critical nanosheet thickness remain to be satisfactorily determined. Therefore, the critical nanosheet thickness is calculated semi-empirically to scale with the nanoscale critical wavelength, demonstrating that the critical thickness intriguingly becomes an invariant value for the range of Ohnesorge numbers considered. Based on the scaled critical nanosheet thickness for nanodroplet breakup, a theoretical model is developed for collision-induced breakup dynamics of binary equal-sized nanodroplets, explicitly incorporating nanoscale disjoining pressure effects. The proposed model is validated against extensive numerical simulations, and good agreement is achieved, demonstrating its predictive power for nanoscale free-flow dynamics where classical theories fail.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105593"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880107","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}

{"title":"Beyond the Cassie–Baxter model: New insights for predicting imbibition in complex systems","authors":"Mathis Fricke ,&nbsp;Lisanne Gossel ,&nbsp;Joël De Coninck","doi":"10.1016/j.ijmultiphaseflow.2025.105560","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105560","url":null,"abstract":"<div><div>We revisit the classical problem of liquid imbibition in a single tube with spatially varying wettability. Starting from the Lucas–Washburn equation, we derive analytical solutions for the imbibition time (crossing time) in systems where wettability alternates between different materials. For ordered arrangements, we demonstrate that the imbibition speed depends non-trivially on the spatial distribution, with the ”more hydrophobic-first” configuration being optimal. For disordered systems, where segment lengths follow a Gaussian distribution, we show that the classical Cassie–Baxter contact angle, originally derived for static wetting, fails to predict the dynamics of capillary-driven flow. To address this, we propose a new weighted harmonic averaging method for the contact angle, which accurately describes the viscous crossing time in such heterogeneous systems. Our findings reveal fundamental insights into the role of wettability heterogeneity in capillary-driven flow, offering a basis for understanding imbibition dynamics in complex heterogeneous systems.</div><div>The research data and the software supporting this study are openly available at <span><span>DOI:10.5281/zenodo.14537452</span><svg><path></path></svg></span>.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105560"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145610442","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}