International Journal of Multiphase Flow最新文献

{"title":"Experimental study on multi-scale characteristics of cavitating flows with holographic imaging measurement","authors":"Beichen Tian,&nbsp;Yuntian Wang,&nbsp;Biao Huang,&nbsp;Chao Liu,&nbsp;Yue Wu","doi":"10.1016/j.ijmultiphaseflow.2025.105569","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105569","url":null,"abstract":"<div><div>Cavitating flows are characterized by multi-phase and multi-scale features, with evolutionary processes involving coupled interactions between the convection evolution of macroscale vapor structures and the growth and motion of microbubbles. The quantitative information and intrinsic physical mechanism are poorly understood, due to limitations of traditional methods in quantitatively measuring the three-dimensional distribution of microbubbles within cavity structures. In the present work, an experimental study integrating high-speed imaging of macroscale cavity convection evolution and quantitative digital in-line holography (DIH) measurement of microbubbles is conducted to investigate multiscale characteristics of cavitating flows. Results demonstrate that cavitation morphology progresses through inception, sheet, and cloud stages with decreasing cavitation numbers, accompanied by gradual increases in maximum attached cavity length and significant growth in discrete bubble quantities. Mesoscale bubbles are predominantly distributed at vapor-liquid interfaces of macroscale cavities, surrounding shedding cloud cavities, and within wake regions of turbulent cavitating flows. Meanwhile, the Sauter mean diameter of microbubbles progressively decreases along the streamwise direction. As the cavitation number decreases, within the cavity-shedding region, shed cavities gradually manifest as large scale cavities, the time-averaged number density of discrete microbubbles first increases and then paradoxically decreases. In contrast, within the wake flow region, shed cavities undergo complete fragmentation into discrete bubbles, resulting in a persistent increase in detectable mesoscale discrete bubbles with decreasing cavitation number. Across all cavitation regimes and the holographic measurement zone, the number of discrete bubbles initially increased then decreased with increasing bubble diameter, with spectral peaks in bubble size distribution (BSD) at 30-40 μm. Turbulent flow structures significantly affect bubble dynamic evolution. Consequently, dual power-law scaling governs the microbubble size distribution, relative to the Hinze scale at approximately 55–65 μm. Sub-Hinze-scale bubbles follow <em>a</em> − 4/3 scaling exponent, whereas super-Hinze-scale bubbles obey <em>a</em> − 10/3 scaling law.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105569"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733816","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":"Impact boiling in real liquids under intense heating rates","authors":"H.D. Haustein ,&nbsp;E. Elias","doi":"10.1016/j.ijmultiphaseflow.2025.105581","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105581","url":null,"abstract":"<div><div>This study examines the phenomenon of impact boiling in a uniformly heated liquid containing nucleation sites. This extreme phenomenon may occur in applications with intense heating, as is encountered in lasers and nuclear reactors. Present theoretical analysis couples the energy equation with a non-equilibrium vapor formation model, to describe the crucial competition between rapid volumetric heating and thermal relaxation by latent heat absorption. The pre-existence of nucleation sites limits the heat-up rates to 10⁶ [K/s], and to the thermal bubble growth regime. This balance then yields a criterion for maximum achievable liquid superheat, expressed as a function of the ratio of heating rate to the density of existing vapor embryos. Exceeding this threshold triggers unwanted <em>explosive</em> boiling, characterized by intense vapor generation driven by homogeneous nucleation. The model’s dimensionless formulation allows for generalization to other liquids, beyond water and methanol examined here.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105581"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836919","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":"Numerical study of particle rolling entrainment in wall turbulence on rough bed","authors":"Yicong Zhu,&nbsp;Yan Zhang,&nbsp;Ping Wang","doi":"10.1016/j.ijmultiphaseflow.2025.105548","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105548","url":null,"abstract":"<div><div>The transport of sediment particles in turbulent flow is widespread in nature. The entrainment of bed particle represents the first step in forming and developing multiphase flow. According to the observed fact that the duration of fluid force acting on the particles is equally significant as its magnitude, event-based entrainment criterions have been developed to analyze the dynamical interactions between the particles and turbulence. However, these models, mainly based on wind tunnel or water channel experiments, only focus on the fluid forces and particle motions in two-dimensional plane (streamwise and vertical). Recent studies highlight the importance of spanwise fluid action, which depends on particle bed arrangement. In this work, the semi-resolved particle Lagrangian tracking method and direct numerical simulation of wall turbulence four-way coupled with particles are employed to simulate the rolling entrainment of individual particles for different bed arrangement and various Shields numbers. The simulation results illustrate that on specific bed arrangement, the spanwise fluid effect cannot be neglected and will lead to none-streamwise rolling entrainment. The fluid structures surrounding the particles during the entrainment process were analyzed, revealing that at lower Shields numbers, sweep events are the primary driving force for particle entrainment. Furthermore, for particles initiating motion in the spanwise direction, the conditional surrounding spanwise velocity field is asymmetrical and the spanwise structures are according the direction of motion. After simplifying the complex three-dimensional force/torque analysis by a projection method, a three-dimensional impulse criterion for particle entrainment was developed and validated by the numerical simulation results.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105548"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145610440","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":"Segmenting the complex and irregular in two-phase flows: A real-world empirical Study with SAM2","authors":"Semanur Küçük,&nbsp;Cosimo Della Santina,&nbsp;Angeliki Laskari","doi":"10.1016/j.ijmultiphaseflow.2025.105557","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105557","url":null,"abstract":"<div><div>Segmenting gas bubbles in multiphase flows is a critical yet unsolved challenge in numerous industrial settings, from metallurgical processing to maritime drag reduction. Traditional approaches — and most recent learning-based methods — assume near-spherical shapes, limiting their effectiveness in regimes where bubbles undergo deformation, coalescence, or breakup. This complexity is particularly evident in air lubrication systems, where coalesced bubbles form amorphous and topologically diverse patches. In this work, we revisit the problem through the lens of modern vision foundation models. We cast the task as a transfer learning problem and demonstrate, for the first time, that a fine-tuned Segment Anything Model (SAM v2.1) can accurately segment highly non-convex, irregular bubble structures using as few as 100 annotated images.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105557"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145622979","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":"Data-Free physics-informed neural networks for modeling compressible multiphase flows","authors":"Rui Liu ,&nbsp;Zitong Zhao ,&nbsp;Jili Rong","doi":"10.1016/j.ijmultiphaseflow.2025.105589","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105589","url":null,"abstract":"<div><div>Physics-informed neural networks (PINNs), which formulate loss functions based on the residuals of governing equations, have gained increasing attention for modeling fluid mechanics. However, in compressible flows, the differential form of hyperbolic conservation laws breaks down near discontinuities due to the absence of derivatives. This limitation presents a significant challenge for data-free PINN frameworks. The challenge is further intensified in multiphase flows, where contact discontinuities exhibit more complex structures and interactions, and relevant studies remain limited. To address these challenges, this study proposes a multiphase PINN model incorporating an encoder-decoder convolutional long short-term memory (ConvLSTM) deep learning framework to enable deep feature extraction and global residual computation. A multiphase Godunov-type finite volume method (FVM) loss function is developed based on a highly robust five-equation model. By employing a Godunov-type discretization derived from the weak form of the conservation laws, the framework circumvents the limits associated with strong-form discontinuities. This approach ensures entropy consistency while achieving high-resolution shock capturing in discontinuous regions. Due to the inherent dissipation of the modeling approach, the interface thickness tends to increase over time during flow evolution, which degrades the prediction accuracy of the model. To address this limitation, an improved loss function with interface anti-diffusion properties is proposed to effectively suppress interface smearing and enhance prediction fidelity. Through training and extrapolative prediction on various one-dimensional Riemann problems and high-dimensional shock cases, the proposed multiphase PINN model demonstrates accurate interface tracking and high precision in discontinuous regions. The multiphase PINN model developed in this study offers a novel predictive framework for a broad range of compressible multiphase flow problems.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105589"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836413","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":"Hybrid Eulerian–Lagrangian approach for direct numerical simulations of elastic turbulence","authors":"F. Serafini","doi":"10.1016/j.ijmultiphaseflow.2025.105587","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105587","url":null,"abstract":"<div><div>Direct Numerical Simulation (DNS) is a fundamental tool for studying elastic turbulence (ET), as the polymer stresses that trigger ET are not directly accessible experimentally. We discuss a hybrid Eulerian–Lagrangian approach for DNS, and we show that the main ET features can be consistently observed in a wide range of concentrations and Weissenberg numbers. The hybrid approach does not require a larger resolution compared to fully Eulerian simulations, with the advantage of more accurate predictions of the polymer stress, and a clear link between model parameters and real polymer properties. Furthermore, a Lagrangian description of the polymer phase allows to explore the limiting, but realistic, conditions of small concentration and large Weissenberg number.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105587"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836917","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":"Free-spray characteristics and spray-wall interactions of methanol on a gasoline direct injector under flash-boiling and non-flash-boiling conditions","authors":"Hao-Pin Lien ,&nbsp;Rafael Clemente-Mallada ,&nbsp;Meghna Dhanji ,&nbsp;Roberto Torelli ,&nbsp;Lyle M. Pickett","doi":"10.1016/j.ijmultiphaseflow.2025.105562","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105562","url":null,"abstract":"<div><div>Methanol is considered a promising alternative fuel for internal combustion engines (ICEs) due to its high-octane number, fast laminar flame speed, and elevated latent heat of vaporization, all of which support higher compression ratios and improved thermal efficiency. However, its substantial latent heat of vaporization also poses cold-start challenges, such as misfire and fuel film deposition. This study aims to investigate methanol spray morphology and spray-wall interaction using the Spray M injector from the Engine Combustion Network within a constant-pressure flow vessel. A recently developed unified numerical framework capable of modeling both flash and non-flash boiling sprays is validated against experimental liquid volume fraction data acquired via 3-D computed tomography. The results reveal that flash boiling significantly alters the spray morphology, leading to smaller droplets and spray collapse due to enhanced air-entrainment-induced turbulence. Quantitative agreement between experiments and simulations confirms this behavior. Coupled 0-D equilibrium and 3-D computational fluid dynamics analyses show that flash boiling accelerates evaporation and reduces fuel residence time, while non-flash conditions maintain a persistent liquid core more susceptible to wall wetting. Wall temperature diagnostics reveal that spray collapse alters heat transfer patterns by shifting cooling effects. Mixture fraction analysis indicates that evaporation is primarily governed by shear-layer turbulence, though deviations from adiabatic equilibrium mixing emerge under low-turbulence conditions. Finally, increasing fuel, ambient, and wall temperatures reduces wall wetting and film thickness, mitigating cold-start risks. These findings enhance the understanding of methanol sprays’ behavior and support its adoption as a viable, alternative fuel for ICEs.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105562"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733814","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":"Numerical study of spray cooling: The effect of nozzle arrangement on heat transfer performance","authors":"Qingshan Chen ,&nbsp;Qinrui Zhang ,&nbsp;Cong Wang ,&nbsp;Kailun Guo ,&nbsp;Mingjun Wang ,&nbsp;Xiaoyan Wang ,&nbsp;Wenxi Tian ,&nbsp;Suizheng Qiu ,&nbsp;Guanghui Su","doi":"10.1016/j.ijmultiphaseflow.2025.105561","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105561","url":null,"abstract":"<div><div>Spray cooling technology, known for its high heat transfer efficiency, is widely applied in high heat flux scenarios. However, existing studies often lack efficient model transition strategies for simulating droplet impingement, liquid film formation, and evaporative heat and mass transfer processes, resulting in high computational costs and limited applicability to large-scale fields. This study proposes an innovative numerical spray cooling method called DPM-VOF-LEE. It integrates Volume of Fluid (VOF) and Discrete Phase Model (DPM) with an evaporative heat transfer model through a transition strategy. The DPM model is employed for efficient droplet tracking in the far-field region. In contrast, the VOF model is applied near the wall to resolve liquid film morphology and heat transfer accurately. This model transition method significantly reduces mesh requirements and improves scalability. It is especially suitable for large-area or multi-nozzle spray cooling systems. Results indicate that vertical single-nozzle spraying exhibits the best cooling performance. In dual-nozzle configurations, interference regions enhance heat transfer. Cooling efficiency increases by more than 78 % compared with non-interference cases. For triple-nozzle configurations, the staggered layout achieves faster average temperature reduction on aluminum plates, with cooling efficiency 8.32 % higher than the inline layout.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105561"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145622980","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":"Engineered surface-fluid interactions: bubble dynamics and heat transfer with different fluid thermophysical properties","authors":"Niloy Laskar ,&nbsp;Asmita Bhaumik ,&nbsp;Sali Snigdha ,&nbsp;Mihir K. Das","doi":"10.1016/j.ijmultiphaseflow.2025.105565","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105565","url":null,"abstract":"<div><div>Engineered surfaces are widely recognized for enhancing pool boiling heat transfer (PBHT), yet the role of bubble dynamics across different fluids on a common platform has not been fully explored. This study presents a comprehensive experimental investigation of the coupled effects of surface morphology and fluid thermophysical properties on bubble dynamics and PBHT performance. Bare, copper-coated, DLC-coated, and micro-structure tubes were tested with distilled water, acetone, and isopropanol under PBHT conditions. Bubble dynamics parameters, including departure diameter, frequency, and nucleation site density, were quantified to understand their role in PBHT performance. The findings reveal a consistent trend across all fluids, with engineered surfaces producing smaller bubbles that depart more rapidly and exhibit a higher active nucleation sites compared to conventional bare surfaces. Among the tested surfaces, micro-structure tubes delivered the highest HTC and the lowest wall superheat, followed by copper- and DLC-coated surfaces. Fluid properties also significantly influenced PBHT performance, with isopropanol initiating the earliest onset of nucleate boiling, while water exhibited a delayed onset. Despite larger bubbles, lower frequency, and fewer nucleation sites, distilled water achieved the highest HTC due to its high latent heat and thermal conductivity. Additionally, the peak HTC enhancements observed on micro-structure surfaces were 96 % for distilled water, 134 % for acetone, and 161 % for isopropanol compared to bare tubes. The study highlights that optimal PBHT performance is achieved through a synergistic combination of surface engineering and appropriate fluid selection. The results provide actionable insights for designing next-generation heat exchangers that can achieve superior thermal performance.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"196 ","pages":"Article 105565"},"PeriodicalIF":3.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733815","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}