International Journal of Multiphase Flow最新文献_第2页

Sensitivity to added mass closure models on predictions of supersonic jet-induced cratering in a particle bed 添加质量闭合模型对超音速喷流诱发颗粒床破碎预测的敏感性

IF 3.6 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2024-11-13 DOI: 10.1016/j.ijmultiphaseflow.2024.105050

Kaushik Balakrishnan , Josette Bellan

A recent formulation describing supersonic-plume impingement on a granular bed has been shown to have the desirable property of being hyperbolic, thus permitting the physical propagation of pressure waves. This property stemmed from the inclusion of a model for the added mass and a model for the fluid-mediated particle pressure. These models are semi-empirical, and thus the present study is devoted to exploring the sensitivity of the results to the pivotal model of the added mass contributing to hyperbolicity of the equations. Several added-mass models are explored and are first evaluated with available shock tube experimental data that reports the global pressure evolution as function of time. The results show that this type of data cannot discriminate among the different models investigated. Therefore, the remaining of the study is dedicated to exploring the type of data that would allow to differentiate among models. To this end, because the situation of supersonic jet-induced cratering in particle beds is complex and its multifacets are well suited to a variety of measurements, the effect of added-mass models on the spatial multidimensional dynamics of crater formation and evolution is then investigated. Particularly, cratering dynamics, ejecta formation and dispersion, and other aspects crucial to avoiding potential disasters during spacecraft controlled landing on planetary bodies are comparatively assessed to understand the range of predictions corresponding to the added-mass models. The analysis of the results crucially focusses on the identification of experimental results that would discriminate among models for the purpose of only retaining the model encapsulating the correct physics. For the selected initial conditions that are in the range of Earth or Mars atmospheres, it is found that the choice of the added-mass model only slightly affects the crater topography, primarily modifying the shape of the crater floor, the crater depth at which same macroscopic features are found and the shape of the crater walls. The models influence the predictions of the ejecta only at intermediary crater depths, with no influence in other spatial regions.

最近，一种描述超音速水流撞击颗粒床的公式被证明具有双曲线的理想特性，从而允许压力波的物理传播。这一特性源于加入了附加质量模型和流体介导的颗粒压力模型。这些模型都是半经验模型，因此本研究致力于探索结果对造成方程双曲性的关键附加质量模型的敏感性。研究探讨了几种附加质量模型，并首先用现有的冲击管实验数据进行了评估，这些数据报告了全球压力随时间的演变。结果表明，这类数据无法区分所研究的不同模型。因此，研究的其余部分致力于探索能够区分不同模型的数据类型。为此，由于超音速射流在颗粒床中诱发的陨石坑情况复杂，且其多面体非常适合各种测量，因此研究了添加质量模型对陨石坑形成和演变的空间多维动态的影响。特别是对陨石坑动力学、喷出物的形成和弥散以及对避免航天器在行星体上受控着陆时可能发生的灾难至关重要的其他方面进行了比较评估，以了解添加质量模型相应的预测范围。对结果的分析主要集中在确定能够区分不同模型的实验结果，以便只保留包含正确物理原理的模型。对于所选择的地球或火星大气范围内的初始条件，研究发现，附加质量模型的选择只对陨石坑地形产生轻微影响，主要是改变陨石坑底部的形状、发现相同宏观特征的陨石坑深度以及陨石坑壁的形状。这些模型只对中间陨石坑深度的喷出物预测产生影响，对其他空间区域没有影响。

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引用次数: 0

A simple and efficient finite difference scheme to the Cahn–Hilliard–Navier–Stokes system equations 卡恩-希利亚德-纳维尔-斯托克斯系统方程的简单高效有限差分方案

IF 3.6 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2024-11-10 DOI: 10.1016/j.ijmultiphaseflow.2024.105061

Mingguang Shen , Ben Q. Li

Central difference schemes are usually not suited to convective terms in a transport equation due to its oscillation nature when convection effect is pronounced. However, this work found that applying the standard central difference scheme to the convective term along with another central difference scheme to the fourth order diffusive term in the Cahn–Hilliard equation can realize nearly an order of magnitude speed rise, in the framework of a fully explicit finite difference scheme. The discretization was done on a semi-staggered grid where pressure was stored at the cell center and other variables were stored at the cell corners. To accelerate computation, a simple parallelism based on OpenMP was used. The scheme was tested in a number of cases and was compared with both analytical and experimental outcomes. The results showed that the scheme is efficient compared with a previous fully explicit finite difference scheme for the Cahn–Hilliard equation, and that a time step more than five times larger can be employed.

由于对流效应明显时会产生振荡，中心差分方案通常不适用于输运方程中的对流项。然而，这项工作发现，在完全显式有限差分方案框架内，将标准中心差分方案应用于对流项，同时将另一种中心差分方案应用于卡恩-希利亚德方程中的四阶扩散项，可以实现近一个数量级的速度提升。离散化是在半交错网格上进行的，压力存储在单元中心，其他变量存储在单元角落。为了加速计算，使用了基于 OpenMP 的简单并行计算。该方案在多种情况下进行了测试，并与分析和实验结果进行了比较。结果表明，与之前用于 Cahn-Hilliard 方程的完全显式有限差分方案相比，该方案是高效的，而且可以采用比其大五倍以上的时间步长。

引用次数: 0

A simple explicit thermodynamic closure for multi-fluid simulations including complex vapor–liquid equilibria: Application to NH3 H2O mixtures 用于包括复杂汽液平衡在内的多流体模拟的简单显式热力学封闭：在 NH3 H2O 混合物中的应用

IF 3.6 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2024-11-09 DOI: 10.1016/j.ijmultiphaseflow.2024.105044

J. Carmona , I. Raspo , V. Moureau , P. Boivin

This paper presents a new thermodynamic closure formulation appropriate for the simulation of subcritical multiphase flows, where two liquid/vapor components need to be considered, in addition of an arbitrary number of perfect gas non-condensable components. Assuming each component to follow the Noble-Abel Stiffened Gas (NASG) equation of state allows to derive a fully explicit formulation for the mixture pressure. A matching phase transition solver is then proposed to compute efficiently and accurately the thermochemical equilibrium of the said mixture. The model capabilities are then illustrated through a two-dimensional simulation of a liquid ammonia tank leak into 80%-saturated humid air, where water is found to significantly condensate when interacting with the ammonia jet.

本文提出了一种适用于亚临界多相流模拟的新热力学闭合公式，在亚临界多相流中，除了需要考虑两个液体/蒸汽组分外，还需要考虑任意数量的完全气体不可冷凝组分。假定每种成分都遵循诺贝尔-阿贝尔僵化气体（NASG）状态方程，就可以推导出完全明确的混合物压力公式。然后提出一个匹配的相变求解器，以高效、准确地计算上述混合物的热化学平衡。然后，通过对液氨罐泄漏到 80% 饱和潮湿空气中的二维模拟来说明模型的能力。

引用次数: 0

Study on aerodynamic breakup of non-Newtonian liquid droplets and the distribution characteristics of their sub-droplets 非牛顿流体液滴的空气动力破裂及其子液滴分布特征研究

IF 3.6 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2024-11-07 DOI: 10.1016/j.ijmultiphaseflow.2024.105039

Lijuan Qian , Lijun Cheng , Chengbin Sun , Li Lv

In industrial applications, the secondary breakup of droplets and the size distribution of their sub-droplets are crucial for atomization performance indicators. In this work, a high-speed digital camera is utilized to experimentally and theoretically study the secondary breakup process of xanthan gum (XG) droplets and the size distribution changes of resulting sub-droplets in continuous airflow by changing the Weber number and effective Ohnesorge number. In addition, a detailed study is conducted on the liquid ring with the highest liquid content. The results show that at low Weber numbers, the number of nodes generated at the XG droplet ring is the same as that of the water droplet, following “the combined R-T/aerodynamic drag” mechanism. However, the final diameter of the nodes differs significantly from that of the water droplet. The particle size of XG liquid ring nodes is not only affected by the Weber number but also decreases with the increase of the effective Ohnesorge number. The particle size of the remaining broken sub-droplets in the liquid ring decreases with the increase of the effective Ohnesorge number. Finally, the spatial range of droplet breakup under different parameters is described by using the liquid ring breakup angle, and it is found that the breakup angle of the liquid ring is mainly related to the breakup mode.

在工业应用中，液滴的二次破裂及其子液滴的粒度分布是雾化性能指标的关键。本研究利用高速数码相机，通过改变韦伯数和有效奥氏数，对连续气流中黄原胶（XG）液滴的二次破裂过程及其产生的子液滴的粒度分布变化进行了实验和理论研究。此外，还对液体含量最高的液环进行了详细研究。结果表明，在低韦伯数时，XG 液滴环产生的节点数量与水滴相同，遵循 "R-T/气动阻力组合 "机制。但是，节点的最终直径与水滴的直径有很大不同。XG 液环节点的粒径不仅受韦伯数的影响，而且随着有效奥氏数的增加而减小。液环中剩余破碎子液滴的粒径随着有效奥涅索尔格数的增加而减小。最后，利用液环破裂角描述了不同参数下液滴破裂的空间范围，发现液环破裂角主要与破裂模式有关。

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引用次数: 0

CFD unified approach under Eulerian–Lagrangian framework for methanol and gasoline direct injection sprays in evaporative and flash boiling conditions 蒸发和闪沸条件下甲醇和汽油直喷喷雾的欧拉-拉格朗日框架下的 CFD 统一方法

IF 3.6 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2024-11-04 DOI: 10.1016/j.ijmultiphaseflow.2024.105048

Francesco Duronio , Hao-Pin Lien , Angelo De Vita

Innovative synthetic fuels for advanced propulsion systems, such as methanol and ammonia, and synthetic blended fuels (E00, E10, and E30), known for their high volatility, are often injected directly into combustion chambers. It follows that Eulerian–Lagrangian spray models need to accurately capture the spray collapse as a consequence of flash boiling onset and be capable of proficiently handling the preferential evaporation of multi-component fuels in evaporative scenarios.

So, we performed the assessment of an Eulerian–Lagrangian CFD code for simulating methanol and E00 gasoline blend sprays in both early and late injection conditions involving flash boiling conditions and preferential evaporation. The adoption of an effervescent breakup model and of a non-equilibrium phase transition model for the discrete phase allows the adoption of a setup that is almost completely free from specific constant tuning, especially for what concerns the breakup model. We validated the simulations using experimental PLV maps of methanol and E00 sprays issued from the ECN Spray M injector. The results highlight a significantly different morphology of the methanol spray compared to the E00 one under late injection conditions. Under stratified combustion, low-volatile fuels are likely to be ignited first, and the flame propagates toward the high-volatile fuels. The spray collapse was also correctly reproduced, inducing the presence of a low-pressure zone and modifying the spray morphology.

用于先进推进系统的创新合成燃料，如甲醇和氨，以及合成混合燃料（E00、E10 和 E30），以其高挥发性而著称，通常直接注入燃烧室。因此，我们对欧拉-拉格朗日喷雾模型进行了评估，以模拟甲醇和 E00 汽油混合物在早期和晚期喷射条件下的喷雾，包括闪沸条件和优先蒸发。由于采用了泡腾破裂模型和离散相的非平衡相变模型，因此几乎完全不需要对特定常数进行调整，尤其是在破裂模型方面。我们使用从 ECN Spray M 喷射器喷出的甲醇和 E00 喷雾的实验 PLV 图验证了模拟结果。结果表明，在后期喷射条件下，甲醇喷雾与 E00 喷雾的形态明显不同。在分层燃烧条件下，低挥发性燃料可能首先被点燃，火焰向高挥发性燃料蔓延。喷雾塌陷也得到了正确再现，导致低压区的存在并改变了喷雾形态。

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引用次数: 0

Thin liquid film stability in the presence of bottom topography and surfactant 底部地形和表面活性剂作用下的薄液膜稳定性

IF 3.6 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2024-11-02 DOI: 10.1016/j.ijmultiphaseflow.2024.105043

Eugene Zivkov, Jean-Paul Pascal

We consider gravity-driven fluid flow down a wavy inclined surface in the presence of surfactant. The periodicity of the bottom topography allows us to leverage Floquet theory to determine the form of the solution to the linearized governing partial differential equations. The result is that perturbations from steady state are wavelike, and a dispersion relation is identified which relates the wavenumber of an initial perturbation,

κ

, to its complex frequency,

ω

. The real part of

ω

provides a criterion for determining linear flow stability. We observe that the addition of surfactant generally has a stabilizing effect on the flow, but has a destabilizing effect for small wavenumbers. These results are compared and validated against numerical simulations of the nonlinear system. The linear and nonlinear analyses show good agreement, except at small wavenumbers, where the linear results could not be replicated.

我们考虑了在表面活性剂存在的情况下，重力驱动流体沿波浪形倾斜表面向下流动的问题。底部地形的周期性使我们能够利用 Floquet 理论来确定线性化控制偏微分方程的解的形式。结果表明，从稳态开始的扰动是波浪式的，并且确定了一种分散关系，它将初始扰动的波数 κ 与其复频 ω 联系起来。ω的实部提供了确定线性流动稳定性的标准。我们观察到，添加表面活性剂通常会对流动产生稳定作用，但在小波数情况下会产生不稳定作用。这些结果与非线性系统的数值模拟进行了比较和验证。线性分析和非线性分析结果显示出良好的一致性，除了在小波数时，线性分析结果无法复制。

引用次数: 0

An analytical gradient method to model interfacial heat and mass transfer in multi-field CFD codes 多场 CFD 代码中模拟界面传热和传质的分析梯度法

IF 3.6 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2024-11-02 DOI: 10.1016/j.ijmultiphaseflow.2024.105045

Clément Loiseau , Stéphane Mimouni , Didier Colmont , Stéphane Vincent

Phase change at the interface between a liquid and a gas, commonly referred to as bulk condensation/boiling or interface condensation/boiling, is often overshadowed by wall condensation/boiling. However, interfacial phase change plays a critical role in various industrial applications, including boiling flows in microchannels and boiling liquid metal flows. In this article, we introduce a novel analytical model based on the gradient method. This model accounts for interfacial phase change within multi-field codes. It is validated against both analytical and experimental cases involving bulk boiling, demonstrating excellent agreement. Notably, the mesh convergence aligns with the methods employed in single-fluid codes. Additionally, we propose a hybrid approach that combines the high accuracy of this model with the computational efficiency of dispersed methods.

液体和气体界面上的相变，通常被称为块状凝结/沸腾或界面凝结/沸腾，往往被壁状凝结/沸腾所掩盖。然而，界面相变在各种工业应用中起着至关重要的作用，包括微通道中的沸腾流和沸腾液态金属流。本文介绍了一种基于梯度法的新型分析模型。该模型在多场代码中考虑了界面相变。该模型与分析和实验中的块状沸腾案例进行了验证，结果表明两者非常吻合。值得注意的是，网格收敛与单流体代码中采用的方法一致。此外，我们还提出了一种混合方法，将该模型的高精度与分散方法的计算效率相结合。

引用次数: 0

Void drift in narrow rectangular channels for highly advective bubbly flows: A macroscopic drift-flux model derived from two-fluid local simulations 高平流气泡流在窄矩形水道中的空隙漂移：从双流体局部模拟中得出的宏观漂移-流动模型

IF 3.6 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2024-10-28 DOI: 10.1016/j.ijmultiphaseflow.2024.105038

G. Bois, R. Barbera, M. Amate-Vignon

This article addresses the issue of reduced models to describe turbulent two-phase flows in industrial applications. This work is an application based on Bois (2021) theoretical derivations to connect the spatially-averaged drift-flux model (DFM) to the local Reynolds-averaged two-fluid model (TFM). It presents new opportunities to calibrate closure laws or propose new models based on finer-scale descriptions. Highly convective steady bubbly flows with wall-peaking void fraction profiles are considered. Dispersed bubbles are weakly deformable. A new model dedicated to void fraction dispersion in flat rectangular channels is developed for application into the DFM. The model is calibrated based on reference local Euler–Euler two-fluid simulations of pressurised water and steam mono-dispersed bubbles, in adiabatic conditions. 64 conditions are considered to cover regularly the 3D parameter space in void fraction, Reynolds and Eötvös numbers. The new formulation proposed shows a very good fit with the post-processed predictions of local CFD simulations along with a substantial reduction in grid requirement. The model contains sub-filter correlations between vapour concentration and mixture or relative velocities. This model derived from local simulations is validated a posteriori in an industrial component scale code where the full space-filtered DFM is implemented and resolved. This work proves the benefits and feasibility of one-by-one model development and calibration based on two-fluid simulations.

本文探讨了在工业应用中描述湍流两相流的简化模型问题。这项工作是基于 Bois（2021 年）理论推导的应用，将空间平均漂移-流动模型（DFM）与局部雷诺平均双流体模型（TFM）连接起来。它为校准闭合定律或基于更精细尺度描述提出新模型提供了新的机会。研究考虑了具有壁面空隙率剖面的高对流稳定气泡流。分散气泡的变形能力很弱。为应用于 DFM，开发了一个专门用于扁平矩形通道中空隙率分散的新模型。该模型根据绝热条件下加压水和蒸汽单分散气泡的参考局部欧拉-欧拉双流体模拟进行校准。考虑了 64 种条件，定期覆盖空隙率、雷诺数和 Eötvös 数的三维参数空间。所提出的新公式与本地 CFD 模拟的后处理预测结果非常吻合，同时大大减少了网格需求。该模型包含蒸汽浓度与混合物或相对速度之间的子过滤器相关性。这个从局部模拟中得出的模型在一个工业组件规模的代码中进行了后验，在该代码中实施并解决了完整的空间滤波 DFM。这项工作证明了基于双流体模拟的逐一模型开发和校准的优点和可行性。

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引用次数: 0

Investigation of the GCI main injection: experimental-numerical analysis of gasoline spray impact at reference engine conditions GCI 主喷射系统研究：参考发动机工况下汽油喷雾影响的实验-数值分析

IF 3.6 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2024-10-28 DOI: 10.1016/j.ijmultiphaseflow.2024.105034

Davide Viscione , Valerio Mariani , Gian Marco Bianchi , Stefania Falfari , Vittorio Ravaglioli , Giacomo Silvagni , Luigi Allocca , Giovanni Meccariello , Alessandro Montanaro

This work deals with the experimental and numerical investigation of ultra-high pressure gasoline injection against heated walls in order to characterize the fuel evaporation and distribution in gasoline compression ignition combustion chambers. Spray-wall impingement tests have been conducted in a quiescent vessel and recorded by means of the Mie scattering technique. The test conditions have been set in line with those of a reference benched GCI engine, leading to 500 bar and 700 bar for the injection pressure, 298 K, 423 K, 493 K for the wall temperature, 20 mm and 30 mm for the injector-wall distance. The same test matrix has been reproduced by means of CFD three-dimensional simulations using a proper setting of the wall-impingement model and the joint use of CFD-FEM approaches for the vapour-wall heat exchange. The time evolution of the rebound spray has been recorded and then postprocessed leading to the width and the thickness of the cloud. The CFD results are in line with the experimental ones both in terms of the overall time evolution and punctual values, proving a good accuracy of the simulation in predicting the rebound/adhered fuel mass split and the local distribution of the fuel after the impingement. Given the reliability of the simulations, insights on the numerical wall film mass and evaporated mass have been provided in order to clarify the effect of increasing pressure, temperature, and distance.

这项工作涉及超高压汽油喷射对加热壁的实验和数值研究，以确定汽油压燃燃烧室中燃料蒸发和分布的特征。在静态容器中进行了喷壁撞击试验，并通过米氏散射技术进行了记录。试验条件与参考台架 GCI 发动机的条件一致，喷射压力分别为 500 巴和 700 巴，壁温分别为 298 K、423 K 和 493 K，喷射器与壁的距离分别为 20 毫米和 30 毫米。通过 CFD 三维模拟再现了相同的测试矩阵，采用了适当的壁面阻碍模型设置和联合使用 CFD-FEM 方法进行蒸汽-壁面热交换。反弹喷雾的时间演变被记录下来，然后进行后处理，从而得出云的宽度和厚度。CFD 结果与实验结果在整体时间演变和精确值方面都相吻合，证明模拟在预测反弹/粘附燃料质量分布和撞击后燃料的局部分布方面具有很高的准确性。鉴于模拟的可靠性，我们对数值壁膜质量和蒸发质量进行了深入分析，以阐明压力、温度和距离增加的影响。

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引用次数: 0

3D numerical investigation of bubble upflow condensation behaviors during subcooled flow boiling in mini-channel with VOSET 利用 VOSET 对微型通道中过冷流沸腾时的气泡上升流冷凝行为进行三维数值研究

IF 3.6 2区工程技术 Q1 MECHANICS

International Journal of Multiphase Flow

Pub Date : 2024-10-28 DOI: 10.1016/j.ijmultiphaseflow.2024.105040

Shuqi Jin , Yujie Chen , Kong Ling , Weidong Xu , Wen-Quan Tao

In the subcooled flow boiling process, bubble condensation is an inevitable basic phenomenon. This paper studies the condensation phenomenon of the single, double vertical/horizontal saturated bubbles rising in a three-dimensional mini-rectangular channel based on the interface capture method VOSET (coupled volume-of-fluid and level set method) and the phase transition model. Bubble condensation behaviors are investigated at different initial diameters, inlet velocity distributions, subcooling temperatures, bubble gaps, and arrangement for the two-bubble condensing system especially. The effects of these parametric on bubble motion trajectory, shape evolution, volume variation, and condensation rate are presented. The numerical results indicated that the initial bubble size and liquid subcooling play an important role in influencing the shape and volume variation of condensing bubble behaviors significantly, while the inlet velocity distribution only affects bubble motion trajectory. Furthermore, the interaction and coalescence between the bubbles will affect the bubble behaviors and the condensation rate. Finally, the condensation heat transfer coefficients at the bubble surfaces for different cases simulated in this paper are presented, seemingly first in the literature.

在过冷流动沸腾过程中，气泡凝结是不可避免的基本现象。本文基于界面捕获法 VOSET（流体容积和液面集耦合法）和相变模型，研究了在三维微型矩形通道中上升的单、双垂直/水平饱和气泡的凝结现象。研究了不同初始直径、入口速度分布、过冷温度、气泡间隙和排列方式下的气泡冷凝行为，特别是双气泡冷凝系统。这些参数对气泡运动轨迹、形状演变、体积变化和冷凝速率的影响得到了展示。数值结果表明，初始气泡大小和液体过冷度对冷凝气泡的形状和体积变化有重要影响，而入口速度分布只影响气泡的运动轨迹。此外，气泡之间的相互作用和凝聚也会影响气泡行为和冷凝速率。最后，本文给出了模拟不同情况下气泡表面的冷凝传热系数，这在文献中尚属首次。

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引用次数: 0