International Journal of Multiphase Flow最新文献_第10页

Effect of inflow velocity and liquid water content on icing and aerodynamic characteristics of the inertial separator blade in marine environment 海洋环境下入流速度和液态水含量对惯性分离器叶片结冰及气动特性的影响

IF 3.8 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2025-10-21 DOI: 10.1016/j.ijmultiphaseflow.2025.105492

Yongpeng Ren, Yanhua Wang, Xiaohu Chen, Zhongyi Wang, Haiou Sun

In polar or cold marine environments, icing of inertial separator blades in the air intake systems of ships and offshore platforms can obstruct the blade channels, severely compromising their stable operation. This study investigates the effects of varying inflow conditions and droplet salinity on the icing and aerodynamic characteristics of inertial separator blades by modifying the physical properties of droplets. The results indicate that droplet salinity and inflow conditions significantly affect the blade icing shape, particularly causing the icing region near the second vane to shift markedly downstream as inflow velocity increases. For saline droplets, higher inflow velocity and liquid water content exert a more pronounced effect on the icing characteristics of blades. At the second vane, as salinity increases from 0.00 % to 2.67%, the decay rate of maximum icing thickness reaches 0.131 under the inflow velocity of 7 m/s and liquid water content of 1.0 g/m³, whereas under lower inflow velocity and liquid water content, the decay rates are 0.079 and 0.110, respectively. Under the inflow velocity of 7 m/s and liquid water content of 1.0 g/m³, the total icing area decreases by approximately 22.24 % when salinity increases from 0.00 % to 2.67 %; the reduction is approximately 19.61 % under lower inflow velocity and about 11.62 % under lower liquid water content. With increasing droplet salinity, the total pressure loss induced by blade icing gradually decreases, and higher inflow velocity and liquid water content further amplify this effect.

在极地或寒冷的海洋环境中，船舶和海洋平台进气系统中的惯性分离器叶片结冰会阻塞叶片通道，严重影响叶片的稳定运行。通过改变液滴的物理性质，研究了不同入流条件和液滴盐度对惯性分离器叶片结冰和气动特性的影响。结果表明，液滴盐度和入流条件对叶片结冰形状有显著影响，特别是随着入流速度的增加，第二叶片附近的结冰区域明显向下游移动。对于盐水液滴，较高的流入速度和液态水含量对叶片结冰特性的影响更为显著。在第二叶片，当盐度从0.00 %增加到2.67%时，在7 m/s入流速度和1.0 g/m³液态水含量下，最大覆冰厚度衰减率为0.131，而在较低入流速度和液态水含量下，衰减率分别为0.079和0.110。在入流速度为7 m/s、液态水含量为1.0 g/m³的条件下，盐度从0.00 %增加到2.67%，总结冰面积减少约22.24%；在较低的流入速度下降低了约19.61%，在较低的液态水含量下降低了约11.62%。随着液滴盐度的增加，叶片结冰引起的总压损失逐渐减小，而更高的流入速度和液态水含量进一步放大了这一影响。

{"title":"Effect of inflow velocity and liquid water content on icing and aerodynamic characteristics of the inertial separator blade in marine environment","authors":"Yongpeng Ren, Yanhua Wang, Xiaohu Chen, Zhongyi Wang, Haiou Sun","doi":"10.1016/j.ijmultiphaseflow.2025.105492","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105492","url":null,"abstract":"<div><div>In polar or cold marine environments, icing of inertial separator blades in the air intake systems of ships and offshore platforms can obstruct the blade channels, severely compromising their stable operation. This study investigates the effects of varying inflow conditions and droplet salinity on the icing and aerodynamic characteristics of inertial separator blades by modifying the physical properties of droplets. The results indicate that droplet salinity and inflow conditions significantly affect the blade icing shape, particularly causing the icing region near the second vane to shift markedly downstream as inflow velocity increases. For saline droplets, higher inflow velocity and liquid water content exert a more pronounced effect on the icing characteristics of blades. At the second vane, as salinity increases from 0.00 % to 2.67%, the decay rate of maximum icing thickness reaches 0.131 under the inflow velocity of 7 m/s and liquid water content of 1.0 g/m³, whereas under lower inflow velocity and liquid water content, the decay rates are 0.079 and 0.110, respectively. Under the inflow velocity of 7 m/s and liquid water content of 1.0 g/m³, the total icing area decreases by approximately 22.24 % when salinity increases from 0.00 % to 2.67 %; the reduction is approximately 19.61 % under lower inflow velocity and about 11.62 % under lower liquid water content. With increasing droplet salinity, the total pressure loss induced by blade icing gradually decreases, and higher inflow velocity and liquid water content further amplify this effect.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105492"},"PeriodicalIF":3.8,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145414604","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}

引用次数: 0

CFD–DEM analysis of energy dissipation and erosion in solid–liquid multiphase flow dynamics through a pipe elbow 管道弯头固液多相流动耗散与冲蚀的CFD-DEM分析

IF 3.8 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2025-10-21 DOI: 10.1016/j.ijmultiphaseflow.2025.105493

Eman Yasser , Ling Zhou , Mahmoud A. El-Emam

Solid–liquid multiphase flows in pipeline systems often experience severe erosion and energy loss, particularly in regions of flow separation such as 90° elbows, where particle–fluid–wall interactions intensify momentum and energy exchange. This study employs a coupled Computational Fluid Dynamics–Discrete Element Method (CFD–DEM) to investigate the erosion mechanisms and hydraulic performance of a 90° elbow under particle-laden flow, explicitly resolving the translational and rotational dynamics of polyhedral particles to better represent real slurry conditions. Particle sizes (0.4, 0.8, and 1.2 mm) and volume fractions (15 %, 30 %, and 50 %) are systematically varied to quantify their effects on particle trajectories, interphase forces, local energy dissipation, and erosion patterns. Results show that larger particles induce stronger momentum transfer to the wall, causing localized, high-intensity erosion and higher hydraulic losses. Increased solid volume fractions amplify turbulence, drag fluctuations, and particle clustering, which collectively enhance energy dissipation and flow resistance. Analysis of particle kinetic energy distributions reveals that rotational irregularities at high concentrations significantly contribute to dissipation mechanisms. The numerical predictions demonstrate strong agreement with experimental measurements, validating the modeling approach. By integrating erosion assessment with a multiphase energy-loss framework and employing realistic particle morphologies, this work advances the predictive capability for slurry transport performance in energy-intensive industries. The findings provide a framework for optimizing solid–liquid multiphase transport systems across diverse industrial and energy applications, enhancing hydraulic efficiency, reducing erosion-related losses, and extending operational lifespan.

管道系统中的固液多相流经常经历严重的侵蚀和能量损失，特别是在90°弯头等流动分离区域，颗粒-流体-壁面相互作用加剧了动量和能量交换。本研究采用计算流体动力学-离散元耦合方法（CFD-DEM）研究了90°弯头在颗粒流作用下的侵蚀机制和水力性能，明确求解了多面体颗粒的平移和旋转动力学，以更好地反映真实的泥浆状态。颗粒尺寸（0.4、0.8和1.2 mm）和体积分数（15%、30%和50%）系统地变化，以量化它们对颗粒轨迹、相间力、局部能量耗散和侵蚀模式的影响。结果表明，颗粒越大，向壁面的动量传递越强，造成局部高强度侵蚀和更高的水力损失。固体体积分数的增加放大了湍流、阻力波动和颗粒聚集，这些因素共同增强了能量耗散和流动阻力。粒子动能分布分析表明，高浓度下的旋转不规则性对耗散机制有重要影响。数值预测结果与实验测量结果非常吻合，验证了模型方法的有效性。通过将侵蚀评估与多相能量损失框架相结合，并采用真实的颗粒形态，这项工作提高了能源密集型工业中泥浆输送性能的预测能力。研究结果为优化各种工业和能源应用中的固液多相输送系统提供了框架，提高了水力效率，减少了与侵蚀相关的损失，延长了使用寿命。

{"title":"CFD–DEM analysis of energy dissipation and erosion in solid–liquid multiphase flow dynamics through a pipe elbow","authors":"Eman Yasser , Ling Zhou , Mahmoud A. El-Emam","doi":"10.1016/j.ijmultiphaseflow.2025.105493","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105493","url":null,"abstract":"<div><div>Solid–liquid multiphase flows in pipeline systems often experience severe erosion and energy loss, particularly in regions of flow separation such as 90° elbows, where particle–fluid–wall interactions intensify momentum and energy exchange. This study employs a coupled Computational Fluid Dynamics–Discrete Element Method (CFD–DEM) to investigate the erosion mechanisms and hydraulic performance of a 90° elbow under particle-laden flow, explicitly resolving the translational and rotational dynamics of polyhedral particles to better represent real slurry conditions. Particle sizes (0.4, 0.8, and 1.2 mm) and volume fractions (15 %, 30 %, and 50 %) are systematically varied to quantify their effects on particle trajectories, interphase forces, local energy dissipation, and erosion patterns. Results show that larger particles induce stronger momentum transfer to the wall, causing localized, high-intensity erosion and higher hydraulic losses. Increased solid volume fractions amplify turbulence, drag fluctuations, and particle clustering, which collectively enhance energy dissipation and flow resistance. Analysis of particle kinetic energy distributions reveals that rotational irregularities at high concentrations significantly contribute to dissipation mechanisms. The numerical predictions demonstrate strong agreement with experimental measurements, validating the modeling approach. By integrating erosion assessment with a multiphase energy-loss framework and employing realistic particle morphologies, this work advances the predictive capability for slurry transport performance in energy-intensive industries. The findings provide a framework for optimizing solid–liquid multiphase transport systems across diverse industrial and energy applications, enhancing hydraulic efficiency, reducing erosion-related losses, and extending operational lifespan.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105493"},"PeriodicalIF":3.8,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145414607","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}

引用次数: 0

Droplet breakup by multimodal nonlinear Rayleigh Taylor instability 液滴的多模态非线性瑞利-泰勒不稳定性

IF 3.8 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2025-10-21 DOI: 10.1016/j.ijmultiphaseflow.2025.105490

Calvin J. Young , Andrew W. Cook , Jacob A. McFarland

A droplet impacted by a shock wave will undergo a process of fragmentation due to the development of interfacial hydrodynamic instabilities. The interface experiences variable acceleration and shear that result in the development of both inertial (Rayleigh–Taylor) and shear (Kelvin–Helmholtz) instabilities. These perturbations grow in time and drive the fragmentation and breakup of the deformed droplet. Experiments are performed on nominally 0.86 mm water droplet subjected to a Mach

7.6

detonation wave, resulting in a high Weber number (

\sim 36, 000

) breakup event. Perturbation growth is measured from a series of high-speed (

> 1 MHz

) shadowgraph images. It is proposed that, given the size of the large-scale perturbations observed in experiments, these instabilities are growing in the non-linear regime and can be described by bubble-merger models for nonlinear mixing. Calculations are performed for the growth rates and size of these instabilities using deformation and external flow models to establish the time-dependent boundary conditions. The concurrence of the measured perturbation widths and the predictions of the simple model lend credence to the theory. This novel approach serves to open a new avenue in the characterization of droplet breakup via hydrodynamic instabilities.

液滴在激波作用下，由于界面水动力不稳定性的发展，液滴将经历一个破碎过程。界面经历可变的加速度和剪切，导致惯性（瑞利-泰勒）和剪切（开尔文-亥姆霍兹）不稳定性的发展。这些扰动随着时间的推移而增长，并驱动变形液滴的破碎。实验在名义上0.86毫米的水滴上进行，受到7.6马赫的爆震波，导致高韦伯数（~ 36000）破裂事件。摄动增长是由一系列高速（>1MHz）阴影图像测量的。我们提出，考虑到实验中观察到的大尺度扰动的大小，这些不稳定性在非线性体系中增长，可以用非线性混合的气泡合并模型来描述。使用变形和外部流动模型计算这些不稳定性的增长率和大小，以建立随时间变化的边界条件。测量到的扰动宽度与简单模型的预测相一致，为理论提供了可信度。这种新方法为通过流体动力不稳定性表征液滴破碎开辟了一条新途径。

{"title":"Droplet breakup by multimodal nonlinear Rayleigh Taylor instability","authors":"Calvin J. Young , Andrew W. Cook , Jacob A. McFarland","doi":"10.1016/j.ijmultiphaseflow.2025.105490","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105490","url":null,"abstract":"<div><div>A droplet impacted by a shock wave will undergo a process of fragmentation due to the development of interfacial hydrodynamic instabilities. The interface experiences variable acceleration and shear that result in the development of both inertial (Rayleigh–Taylor) and shear (Kelvin–Helmholtz) instabilities. These perturbations grow in time and drive the fragmentation and breakup of the deformed droplet. Experiments are performed on nominally 0.86 mm water droplet subjected to a Mach <span><math><mrow><mspace></mspace><mn>7</mn><mo>.</mo><mn>6</mn></mrow></math></span> detonation wave, resulting in a high Weber number (<span><math><mrow><mo>∼</mo><mn>36</mn><mo>,</mo><mn>000</mn></mrow></math></span>) breakup event. Perturbation growth is measured from a series of high-speed (<span><math><mrow><mo>></mo><mn>1</mn><mspace></mspace><mi>MHz</mi></mrow></math></span>) shadowgraph images. It is proposed that, given the size of the large-scale perturbations observed in experiments, these instabilities are growing in the non-linear regime and can be described by bubble-merger models for nonlinear mixing. Calculations are performed for the growth rates and size of these instabilities using deformation and external flow models to establish the time-dependent boundary conditions. The concurrence of the measured perturbation widths and the predictions of the simple model lend credence to the theory. This novel approach serves to open a new avenue in the characterization of droplet breakup via hydrodynamic instabilities.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105490"},"PeriodicalIF":3.8,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145358063","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}

引用次数: 0

Numerical simulation of inorganic particle fouling in RO desalination channel using the discrete phase model 基于离散相模型的RO海水淡化通道无机颗粒污染数值模拟

IF 3.8 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2025-10-21 DOI: 10.1016/j.ijmultiphaseflow.2025.105491

Xiao Hu , Junjie Li , Zuchao Zhu , Peifeng Lin , Jianzhong Lin

The seawater desalination process involves the accumulation of salt ions, leading to the formation of particles. These particles accumulate and deposit on the membrane surface, presenting complex multiphase flow phenomena. This study proposes a three-dimensional inorganic particle fouling model for the spacer-equipped reverse osmosis (RO) membrane surface, aiming to investigate the impact and mechanisms of inorganic particle fouling in RO seawater desalination. The model focuses on calcium carbonate particles and integrates improved force-based discrete phase model (DPM), cake filtration model, and solute convection-diffusion model to simulate particle transport and deposition in membrane channel. Model validation against experimental data confirms its accuracy. Additionally, the effects of Reynolds number (Re_f) and particle concentration (ϕ) on permeate flux and membrane fouling index are examined. The results show that particles tend to deposit in low-velocity regions within the spacer unit. Additionally, particles are more likely to accumulate on spacer filaments with higher vorticity, especially on the upstream side. Modifying the spacer structure is essential for reducing particle fouling between the membranes. A predictive model is developed to estimate flux decline rate as a function of Re_f and ϕ. These findings contribute to the understanding of multiphase flow dynamics in the reverse osmosis seawater desalination process and provide theoretical guidance for optimizing system design and operation.

海水淡化过程涉及到盐离子的积累，导致颗粒的形成。这些颗粒在膜表面聚集沉积，呈现复杂的多相流现象。本研究针对反渗透（RO）膜表面建立了三维无机颗粒污染模型，旨在探讨无机颗粒污染对RO海水淡化的影响及其机理。该模型以碳酸钙颗粒为研究对象，结合改进的基于力的离散相模型（DPM）、滤饼过滤模型和溶质对流扩散模型，模拟了碳酸钙颗粒在膜通道中的迁移和沉积过程。模型与实验数据的对比验证了模型的准确性。此外，研究了雷诺数（Ref）和颗粒浓度（φ）对渗透通量和膜污染指数的影响。结果表明，颗粒倾向于在间隔单元内的低速区域沉积。此外，颗粒更容易积聚在高涡度的间隔丝上，特别是在上游。改变隔膜结构是减少膜间颗粒污染的关键。开发了一个预测模型来估计通量下降率作为Ref和ϕ的函数。这些研究结果有助于理解反渗透海水淡化过程中多相流动力学，并为优化系统设计和运行提供理论指导。

{"title":"Numerical simulation of inorganic particle fouling in RO desalination channel using the discrete phase model","authors":"Xiao Hu , Junjie Li , Zuchao Zhu , Peifeng Lin , Jianzhong Lin","doi":"10.1016/j.ijmultiphaseflow.2025.105491","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105491","url":null,"abstract":"<div><div>The seawater desalination process involves the accumulation of salt ions, leading to the formation of particles. These particles accumulate and deposit on the membrane surface, presenting complex multiphase flow phenomena. This study proposes a three-dimensional inorganic particle fouling model for the spacer-equipped reverse osmosis (RO) membrane surface, aiming to investigate the impact and mechanisms of inorganic particle fouling in RO seawater desalination. The model focuses on calcium carbonate particles and integrates improved force-based discrete phase model (DPM), cake filtration model, and solute convection-diffusion model to simulate particle transport and deposition in membrane channel. Model validation against experimental data confirms its accuracy. Additionally, the effects of Reynolds number (<em>Re<sub>f</sub></em>) and particle concentration (<em>ϕ</em>) on permeate flux and membrane fouling index are examined. The results show that particles tend to deposit in low-velocity regions within the spacer unit. Additionally, particles are more likely to accumulate on spacer filaments with higher vorticity, especially on the upstream side. Modifying the spacer structure is essential for reducing particle fouling between the membranes. A predictive model is developed to estimate flux decline rate as a function of <em>Re<sub>f</sub></em> and <em>ϕ</em>. These findings contribute to the understanding of multiphase flow dynamics in the reverse osmosis seawater desalination process and provide theoretical guidance for optimizing system design and operation.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105491"},"PeriodicalIF":3.8,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145358064","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}

引用次数: 0

Cavitation onset in transient pressure fields 瞬态压力场中出现空化现象

IF 3.8 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2025-10-18 DOI: 10.1016/j.ijmultiphaseflow.2025.105489

Pierre Coulombel, Fabian Denner

While it is well known that cavitation occurs in liquids under tension, no universally accepted criterion for its onset in transient pressure fields exists. We propose a precise definition of the critical tension for cavitation in transient pressure fields that bridges the gap between quasi-static and dynamic regimes, identifying cavitation as the transition of the bubble radius to a dynamically unstable state. This threshold depends on the instantaneous state of the gas–liquid system and, when combined with an appropriate set of dimensionless parameters, yields a self-similar description of cavitation onset. Phase maps for different liquids reveal a minimum tension required for the onset of cavitation, determined by the duration of the tension event and the initial bubble size, whereby the well-known Blake threshold is the lower bound for cavitation across all conditions.

众所周知，液体在张力作用下会发生空化现象，但对于瞬态压力场中空化现象的发生尚无普遍接受的判据。我们提出了瞬态压力场中空化的临界张力的精确定义，该定义弥合了准静态和动态状态之间的差距，将空化确定为气泡半径向动态不稳定状态的过渡。该阈值取决于气液系统的瞬时状态，当与一组适当的无量纲参数相结合时，可以产生自相似的空化开始描述。不同液体的相图揭示了空化发生所需的最小张力，由张力事件的持续时间和初始气泡大小决定，由此众所周知的布莱克阈值是所有条件下空化的下限。

引用次数: 0

Effect of thixotropy on primary jet breakup – A DNS study 触变性对初级射流破裂影响的DNS研究

IF 3.8 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2025-10-17 DOI: 10.1016/j.ijmultiphaseflow.2025.105486

Marianne Abdelsayed, Markus Klein

In the current study, round thixotropic jets injected into stagnant gas are investigated using direct numerical simulations (DNS). The Volume-of-Fluid (VOF) method is employed to capture the interface between the two phases. The thixotropic flow behavior is modeled by a kinetic rate equation for the microstructural integrity. The advection of the structural parameter

λ

is carried out in a flux-consistent manner, that is, the VOF fluxes are used to calculate the fluxes of

λ

, as recently proposed in the literature. A parametric study is conducted to determine the effect of thixotropy on the primary breakup mechanism. Starting from a thixotropic baseline configuration, the destruction parameter

β

and the thixotropic time scale

τ_{θ}

are varied. The results are also compared with two Newtonian cases. The findings indicate that the thixotropic flow behavior has a significant effect on the instantaneous viscosity and therefore, the extent of breakup. However, the first- and second-order statistics of the velocity and the liquid phase volume fraction exhibit only slight differences. In addition, the viscosity of the liquid phase at the gas–liquid interface influences the number of droplets produced.

本文采用直接数值模拟（DNS）方法研究了注入停滞气体中的圆形触变射流。采用流体体积法（VOF）捕获两相之间的界面。触变流动行为用微观结构完整性的动力学速率方程来模拟。结构参数λ的平流以通量一致的方式进行，即使用VOF通量来计算λ的通量，如最近在文献中提出的那样。通过参数研究确定触变性对初始破碎机制的影响。从触变基线构型出发，破坏参数β和触变时间尺度τθ发生变化。结果还与两种牛顿情形进行了比较。研究结果表明，触变流动行为对瞬时粘度有显著影响，因此对破裂程度也有显著影响。然而，速度和液相体积分数的一阶和二阶统计量只有微小的差异。此外，气液界面处液相的粘度影响液滴的产生。

{"title":"Effect of thixotropy on primary jet breakup – A DNS study","authors":"Marianne Abdelsayed, Markus Klein","doi":"10.1016/j.ijmultiphaseflow.2025.105486","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105486","url":null,"abstract":"<div><div>In the current study, round thixotropic jets injected into stagnant gas are investigated using direct numerical simulations (DNS). The Volume-of-Fluid (VOF) method is employed to capture the interface between the two phases. The thixotropic flow behavior is modeled by a kinetic rate equation for the microstructural integrity. The advection of the structural parameter <span><math><mi>λ</mi></math></span> is carried out in a flux-consistent manner, that is, the VOF fluxes are used to calculate the fluxes of <span><math><mi>λ</mi></math></span>, as recently proposed in the literature. A parametric study is conducted to determine the effect of thixotropy on the primary breakup mechanism. Starting from a thixotropic baseline configuration, the destruction parameter <span><math><mi>β</mi></math></span> and the thixotropic time scale <span><math><msub><mrow><mi>τ</mi></mrow><mrow><mi>θ</mi></mrow></msub></math></span> are varied. The results are also compared with two Newtonian cases. The findings indicate that the thixotropic flow behavior has a significant effect on the instantaneous viscosity and therefore, the extent of breakup. However, the first- and second-order statistics of the velocity and the liquid phase volume fraction exhibit only slight differences. In addition, the viscosity of the liquid phase at the gas–liquid interface influences the number of droplets produced.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105486"},"PeriodicalIF":3.8,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145358062","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}

引用次数: 0

Spherical bubble moving through a flowing liquid 在流动的液体中运动的球形气泡

IF 3.8 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2025-10-16 DOI: 10.1016/j.ijmultiphaseflow.2025.105476

Giorgio Riccardi , Enrico De Bernardis

The dynamics of a vapor/gas bubble moving through a flowing inviscid liquid is investigated by developing simplified analytical models, based on the assumption that the bubble remains spherical during its motion. Effects of viscosity are neglected, and the carrier flow is assumed to be potential. Equations are derived for the time evolution of the bubble radius and the position of its center of mass. The radial motion equation can be interpreted as a member of a large family of formulations that derive from the fundamental Rayleigh–Plesset equation and include the overall bubble motion among the factors that influence radial oscillation. The equation governing the center-of-mass motion is compared with the Maxey–Riley equation, which describes the motion of a rigid spherical particle in a moving liquid. The formulation is validated through several numerical experiments that demonstrate different aspects of how the bubble interacts with a sample flow. It is found that the material time derivative of the carrier flow velocity, as well as the corresponding strain field, plays a crucial role in the bubble dynamics.

基于气泡在运动过程中保持球形的假设，通过建立简化的分析模型，研究了蒸汽/气泡在流动的无粘液体中的动力学。忽略粘度的影响，假设载流为势流。推导了气泡半径和质心位置的时间演化方程。径向运动方程可以被解释为源自基本瑞利-普莱塞特方程的一大族公式的成员，这些公式包括影响径向振荡的因素中的整体气泡运动。将控制质心运动的方程与描述刚性球形粒子在运动液体中的运动的Maxey-Riley方程进行了比较。通过几个数值实验验证了该公式，这些实验展示了气泡如何与样品流相互作用的不同方面。发现载流速度的材料时间导数以及相应的应变场在气泡动力学中起着至关重要的作用。

{"title":"Spherical bubble moving through a flowing liquid","authors":"Giorgio Riccardi , Enrico De Bernardis","doi":"10.1016/j.ijmultiphaseflow.2025.105476","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105476","url":null,"abstract":"<div><div>The dynamics of a vapor/gas bubble moving through a flowing inviscid liquid is investigated by developing simplified analytical models, based on the assumption that the bubble remains spherical during its motion. Effects of viscosity are neglected, and the carrier flow is assumed to be potential. Equations are derived for the time evolution of the bubble radius and the position of its center of mass. The radial motion equation can be interpreted as a member of a large family of formulations that derive from the fundamental Rayleigh–Plesset equation and include the overall bubble motion among the factors that influence radial oscillation. The equation governing the center-of-mass motion is compared with the Maxey–Riley equation, which describes the motion of a rigid spherical particle in a moving liquid. The formulation is validated through several numerical experiments that demonstrate different aspects of how the bubble interacts with a sample flow. It is found that the material time derivative of the carrier flow velocity, as well as the corresponding strain field, plays a crucial role in the bubble dynamics.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105476"},"PeriodicalIF":3.8,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320965","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}

引用次数: 0

Oil droplet from blowouts: Role of gas and dispersant 井喷产生的油滴：气体和分散剂的作用

IF 3.8 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2025-10-15 DOI: 10.1016/j.ijmultiphaseflow.2025.105488

Ruixue Liu , Subhamoy Gupta , Cosan Daskiran , Changyang Tan , Diego Muriel , Joseph Katz , Zhaonian Qu , Kenneth Lee , Michel Boufadel

Oil and gas often emanate jointly during a subsea oil blowout. Based on the proportions of the two phases, the hydraulic regime within the pipe could be bubbly, churn, slug, annular, and dispersed. We hypothesized herein that the regime impacts the oil droplet size distribution (DSD) in the blowout in the absence and presence of chemical dispersant (essentially surfactant). In this paper, we conducted oil and air jet releases in a 0.6 m diameter, and 2.6 m vertical water tank. The results showed that the churn flow caused a decrease of oil droplet sizes under the condition of same effective momentum, demonstrating that extra turbulence was introduced in the flow compared to bubbly flow. The application of dispersant significantly decreased the droplet sizes for both oil-only flow and oil-air jets. The phenomena of compound droplets were also identified for both oil only jets and oil-air jets. Generally, this work can contribute both experimental benchmarks for model validation and practical guidance for optimizing response decisions during deepwater oil spill events.

在海底石油井喷过程中，石油和天然气通常是共同排放的。根据两相的比例，管道内的水力状态可以是气泡状、搅拌状、段塞状、环空和分散状。我们在此假设，在没有和存在化学分散剂（主要是表面活性剂）的情况下，这种状态会影响井喷中油滴尺寸分布（DSD）。在本文中，我们在直径0.6 m，垂直2.6 m的水箱中进行了油气喷射释放。结果表明，在相同有效动量的条件下，搅拌流导致油滴尺寸减小，表明与气泡流相比，搅拌流中引入了额外的湍流。分散剂的应用显著减小了纯油射流和油气射流的液滴尺寸。在纯油射流和油气射流中也发现了复合液滴现象。总的来说，这项工作既可以为模型验证提供实验基准，也可以为深水溢油事件中优化响应决策提供实际指导。

{"title":"Oil droplet from blowouts: Role of gas and dispersant","authors":"Ruixue Liu , Subhamoy Gupta , Cosan Daskiran , Changyang Tan , Diego Muriel , Joseph Katz , Zhaonian Qu , Kenneth Lee , Michel Boufadel","doi":"10.1016/j.ijmultiphaseflow.2025.105488","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105488","url":null,"abstract":"<div><div>Oil and gas often emanate jointly during a subsea oil blowout. Based on the proportions of the two phases, the hydraulic regime within the pipe could be bubbly, churn, slug, annular, and dispersed. We hypothesized herein that the regime impacts the oil droplet size distribution (DSD) in the blowout in the absence and presence of chemical dispersant (essentially surfactant). In this paper, we conducted oil and air jet releases in a 0.6 m diameter, and 2.6 m vertical water tank. The results showed that the churn flow caused a decrease of oil droplet sizes under the condition of same effective momentum, demonstrating that extra turbulence was introduced in the flow compared to bubbly flow. The application of dispersant significantly decreased the droplet sizes for both oil-only flow and oil-air jets. The phenomena of compound droplets were also identified for both oil only jets and oil-air jets. Generally, this work can contribute both experimental benchmarks for model validation and practical guidance for optimizing response decisions during deepwater oil spill events.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105488"},"PeriodicalIF":3.8,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145358060","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}

引用次数: 0

Waveform-modulated inertial focusing for deformable particles 可变形粒子的波形调制惯性聚焦

IF 3.8 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2025-10-15 DOI: 10.1016/j.ijmultiphaseflow.2025.105487

Jingyu Cui , Xiang Zhu , Haoming Wang , Yuzhen Jin , Zuchao Zhu

While inertial focusing has been widely adopted for particle manipulation in microfluidics, its efficiency deteriorates for small particles due to weak inertial lift forces and long focusing lengths. Although oscillatory flows offer a promising strategy to overcome these limitations by enhancing shear-driven migration, a clear understanding of how flow unsteadiness and particle deformability jointly influence focusing behavior remains lacking. This study conducts a three-dimensional numerical investigation of a deformable particle's inertial migration in oscillatory channel flows using an immersed boundary–lattice Boltzmann method. The effects of oscillating waveform types, Laplace number (La) and Womersley number (Wo) are systematically examined. The results reveal that the waveform type and oscillation frequency fundamentally govern particle migration and focusing outcomes: at low Wo, square waveforms mimic quasi-steady Poiseuille flow and stabilize off-diagonal equilibria, whereas sinusoidal waveforms enhance particle deformation and yield a unique diagonal equilibrium, accompanied by larger post-focusing oscillations. Mapping in the La–Wo parameter space identifies three focusing modes—diagonal, short-range axial, and long-range axial—with clear transitions as particle deformability decreases or oscillation frequency increases. Oscillatory forcing significantly reduces focusing length, especially for highly deformable particles. A dimensionless performance index is proposed to quantify focusing efficiency, which highlights an optimal frequency window (4.38≤Wo≤6.86) where focusing efficiency is maximized, with square waveforms generally outperforming sinusoidal ones. The best performance is achieved at La=5 and Wo=5.6, representative of highly deformable particles such as biological cells and vesicles, underscoring the potential of oscillatory microflows as a tunable platform for precision cell manipulation and microfluidic separation.

惯性聚焦在微流体中被广泛应用于粒子操纵，但由于惯性升力较弱和聚焦长度较长，其效率下降。尽管振荡流动提供了一种很有希望的策略，通过增强剪切驱动的迁移来克服这些限制，但对流动不稳定性和颗粒可变形性如何共同影响聚焦行为的清晰理解仍然缺乏。本文采用浸入式边界晶格玻尔兹曼方法对振动通道流动中可变形粒子的惯性迁移进行了三维数值研究。系统地考察了振荡波形类型、拉普拉斯数（La）和沃默斯利数（Wo）的影响。结果表明，波形类型和振荡频率从根本上控制了粒子的迁移和聚焦结果：在低Wo时，方波波形模拟准稳态泊泽维尔流并稳定非对角平衡，而正弦波波形增强粒子变形并产生独特的对角平衡，并伴有较大的聚焦后振荡。在La-Wo参数空间中映射出三种聚焦模式：对角线聚焦模式、近程轴向聚焦模式和远程轴向聚焦模式，随着粒子变形能力的降低或振荡频率的增加，聚焦模式发生了明显的转变。振荡强迫显着减少聚焦长度，特别是对于高度变形的颗粒。提出了一种量化聚焦效率的无量纲性能指标，该指标突出了聚焦效率最大化的最佳频率窗（4.38≤Wo≤6.86），方波的表现普遍优于正弦波。在La=5和Wo=5.6时达到最佳性能，代表了高度可变形的颗粒，如生物细胞和囊泡，强调了振荡微流作为精密细胞操作和微流体分离的可调平台的潜力。

{"title":"Waveform-modulated inertial focusing for deformable particles","authors":"Jingyu Cui , Xiang Zhu , Haoming Wang , Yuzhen Jin , Zuchao Zhu","doi":"10.1016/j.ijmultiphaseflow.2025.105487","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105487","url":null,"abstract":"<div><div>While inertial focusing has been widely adopted for particle manipulation in microfluidics, its efficiency deteriorates for small particles due to weak inertial lift forces and long focusing lengths. Although oscillatory flows offer a promising strategy to overcome these limitations by enhancing shear-driven migration, a clear understanding of how flow unsteadiness and particle deformability jointly influence focusing behavior remains lacking. This study conducts a three-dimensional numerical investigation of a deformable particle's inertial migration in oscillatory channel flows using an immersed boundary–lattice Boltzmann method. The effects of oscillating waveform types, Laplace number (<em>La</em>) and Womersley number (<em>Wo</em>) are systematically examined. The results reveal that the waveform type and oscillation frequency fundamentally govern particle migration and focusing outcomes: at low <em>Wo</em>, square waveforms mimic quasi-steady Poiseuille flow and stabilize off-diagonal equilibria, whereas sinusoidal waveforms enhance particle deformation and yield a unique diagonal equilibrium, accompanied by larger post-focusing oscillations. Mapping in the <em>La</em>–<em>Wo</em> parameter space identifies three focusing modes—diagonal, short-range axial, and long-range axial—with clear transitions as particle deformability decreases or oscillation frequency increases. Oscillatory forcing significantly reduces focusing length, especially for highly deformable particles. A dimensionless performance index is proposed to quantify focusing efficiency, which highlights an optimal frequency window (4.38≤<em>Wo</em>≤6.86) where focusing efficiency is maximized, with square waveforms generally outperforming sinusoidal ones. The best performance is achieved at <em>La</em>=5 and <em>Wo</em>=5.6, representative of highly deformable particles such as biological cells and vesicles, underscoring the potential of oscillatory microflows as a tunable platform for precision cell manipulation and microfluidic separation.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105487"},"PeriodicalIF":3.8,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145358061","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}

引用次数: 0

Interaction of droplets and carbon particles exposed to a high-temperature air counterflow 暴露在高温空气逆流中的液滴和碳颗粒的相互作用

IF 3.8 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2025-10-12 DOI: 10.1016/j.ijmultiphaseflow.2025.105485

A.G. Islamova, S.S. Kropotova, A. Klimenko, S.A. Shulyaev

The removal of dispersed solid particles, such as dust, from gas and liquid flows is a critical objective due to its significant implications for the environment and human health. This study reports on the interaction of water droplets (1–1.6 mm in size) and solid particles (0.4–1.6 mm in size) exposed to a counterflow of air. This research is the first to investigate the collisions of water droplets with coal particles and coal combustion products, when varying the ambient conditions (the flow temperature and velocity) in ranges typical of real industrial processes. Particles of coal and its combustion products were the kind of solid particles chosen for research. The temperature and counterflow velocity were 50 to 100 °С and 1 to 2 m/s, respectively. Two regimes of droplet-particle interaction were identified. They were agglomeration and separation. The drag coefficient of droplets and particles exposed to an airflow was calculated. In the collisions of droplets with coal combustion products, the critical Weber number decreased on average by 51%, while the drag coefficient increased by about 29%, compared to the case of droplets colliding with coal particles. A relationship between the drag coefficient and dimensionless Reynolds, Froude, Stokes and capillary numbers was obtained. The energy balance was calculated in the zone of occurrence of different droplet-particle collision regimes. At We <50 and linear impact parameter equaling 0, the surface energy of droplets exceeds their kinetic energy and accounts for more than 50% of the total initial energy of the droplet. The ranges of the Stokes number in which the droplet settles on the particle were determined. Approximations describing the interaction of water droplets with solid particles and demonstrating the transition boundary between regimes were derived. The research findings can be applied in dust collection and dust removal technologies.

从气体和液体流动中去除分散的固体颗粒（如灰尘）是一项关键目标，因为它对环境和人类健康有重大影响。本研究报告了暴露在逆流空气中的水滴（1-1.6毫米大小）和固体颗粒（0.4-1.6毫米大小）的相互作用。这项研究首次调查了在实际工业过程中典型的环境条件（流动温度和速度）变化范围内，水滴与煤颗粒和煤燃烧产物的碰撞。煤及其燃烧产物的颗粒是研究的固体颗粒。温度为50 ~ 100°С，逆流速度为1 ~ 2m /s。确定了液滴-粒子相互作用的两种机制。它们是团聚和分离。计算了水滴和颗粒在气流中的阻力系数。液滴与煤燃烧产物碰撞时，临界韦伯数比与煤颗粒碰撞时平均降低51%，阻力系数提高约29%。得到了阻力系数与无因次雷诺数、弗劳德数、斯托克斯数和毛细数之间的关系。在不同的液滴-粒子碰撞区计算了能量平衡。在We <；50，线性冲击参数为0时，液滴的表面能超过其动能，占液滴总初始能量的50%以上。测定了液滴落在粒子上的斯托克斯数范围。近似描述了水滴与固体颗粒的相互作用，并证明了过渡边界之间的制度。研究成果可应用于集尘除尘技术。

{"title":"Interaction of droplets and carbon particles exposed to a high-temperature air counterflow","authors":"A.G. Islamova, S.S. Kropotova, A. Klimenko, S.A. Shulyaev","doi":"10.1016/j.ijmultiphaseflow.2025.105485","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105485","url":null,"abstract":"<div><div>The removal of dispersed solid particles, such as dust, from gas and liquid flows is a critical objective due to its significant implications for the environment and human health. This study reports on the interaction of water droplets (1–1.6 mm in size) and solid particles (0.4–1.6 mm in size) exposed to a counterflow of air. This research is the first to investigate the collisions of water droplets with coal particles and coal combustion products, when varying the ambient conditions (the flow temperature and velocity) in ranges typical of real industrial processes. Particles of coal and its combustion products were the kind of solid particles chosen for research. The temperature and counterflow velocity were 50 to 100 °С and 1 to 2 m/s, respectively. Two regimes of droplet-particle interaction were identified. They were agglomeration and separation. The drag coefficient of droplets and particles exposed to an airflow was calculated. In the collisions of droplets with coal combustion products, the critical Weber number decreased on average by 51%, while the drag coefficient increased by about 29%, compared to the case of droplets colliding with coal particles. A relationship between the drag coefficient and dimensionless Reynolds, Froude, Stokes and capillary numbers was obtained. The energy balance was calculated in the zone of occurrence of different droplet-particle collision regimes. At We <50 and linear impact parameter equaling 0, the surface energy of droplets exceeds their kinetic energy and accounts for more than 50% of the total initial energy of the droplet. The ranges of the Stokes number in which the droplet settles on the particle were determined. Approximations describing the interaction of water droplets with solid particles and demonstrating the transition boundary between regimes were derived. The research findings can be applied in dust collection and dust removal technologies.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105485"},"PeriodicalIF":3.8,"publicationDate":"2025-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320968","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}

引用次数: 0