International Communications in Heat and Mass Transfer最新文献_第2页

Numerical study of squeezed Sutterby nanomaterial flow configured by parallel magnetized plates: Application of generalized heat-mass fluxes 平行磁化板配置的挤压萨特比纳米材料流的数值研究：广义热质通量的应用

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2024-09-26 DOI: 10.1016/j.icheatmasstransfer.2024.108054

Optimizing the thermal aspects of working liquid is a realistic procedure to boost heat transference effectiveness. Nanoliquids (including nano-particles adjourned in a base liquid) appear as a favorable aspirant. These cutting-edge liquids could function as both emergency and primary coolants in nuclear reactors contributing improved performance under critical conditions. This research accounts magnetically driven Sutterby nanomaterial squeezed flow configured by parallel convective walls. Convective squeezed flow subject to thermo-solutal buoyancy forces is formulated. Heat-mass transportation features are addressed through Cattaneo-Christov (CC) dual diffusive models. The expressions governing the nonlinear flow together with heat-mass transportation are derived by deploying lower magnetized Reynolds number and negligible dissipation assumptions, and then converted to dimensionless expressions by delineating the apposite similarity variables. Numerical solutions through shooting scheme are acquired. Results are outlined and physical elaboration is comprehensively addressed for sundry flow factors. Variations in dimensionless profiles is analyzed graphically and arithmetically. To ensure the accuracy of deployed solution scheme, the results obtained are compared with available limiting cases and found that our deployed scheme has good agreement with existing outcomes. It is inspected that Brownian diffusive factor intensifies the nano-particles concentration while thermophoresis variable exhibits reduction in concentration. Larger thermal-solutal relaxation factors yield lower temperature and nano-particles concentration.

优化工作液体的热性能是提高热传导效率的现实步骤。纳米液体（包括在基础液体中加入纳米颗粒）似乎是一个有利的选择。这些尖端液体可作为核反应堆的应急冷却剂和主冷却剂，有助于提高临界状态下的性能。本研究介绍了由平行对流壁配置的磁驱动萨特比纳米材料挤压流。研究提出了受热固性浮力影响的对流挤压流。通过卡塔尼奥-克里斯托夫（CC）双扩散模型解决了热质传输问题。通过使用较低的磁化雷诺数和可忽略的耗散假设，推导出了非线性流动和热质传输的表达式，然后通过划分相应的相似变量转换为无量纲表达式。通过射击方案获得数值解。对结果进行了概述，并对各种流动因素进行了全面的物理阐述。以图形和算术方式分析了无量纲曲线的变化。为确保所部署的求解方案的准确性，将所获得的结果与现有的极限案例进行了比较，发现我们所部署的方案与现有结果具有良好的一致性。结果表明，布朗扩散因子提高了纳米粒子的浓度，而热泳变量则降低了浓度。较大的热固性弛豫因子会降低温度和纳米粒子浓度。

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引用次数: 0

Is it time to move on from the Bohart-Adams model for column adsorption? 是时候放弃柱吸附的 Bohart-Adams 模型了吗？

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2024-09-26 DOI: 10.1016/j.icheatmasstransfer.2024.108062

The Bohart-Adams model provides a standard expression for the breakthrough curve of contaminant at the outlet of a packed column. It is a basic building block for analysis and computations in the field. In this paper we demonstrate that this model can provide highly inaccurate results and that its well-documented success is shown to be a result of using known system parameters as unknown fitting parameters, permitting constant values to vary, permitting unphysical values (such as negative adsorption sites) and an acceptance of poor fits. Using correct system parameters we provide examples where the Bohart-Adams prediction for the breakthrough time is more than double the experimentally observed value. It is shown that the symmetric exponential form is an inevitable consequence of a mathematical model consisting of a balance between advection and a mass sink, where the sink is of the Langmuir form. Finally, we briefly mention a model that fits a wider range of experimental data without resorting to unphysical and inconsistent parameter values.

Bohart-Adams 模型提供了填料塔出口污染物突破曲线的标准表达式。它是现场分析和计算的基本构件。在本文中，我们证明了该模型可以提供非常不准确的结果，并证明了其有据可查的成功是将已知系统参数作为未知拟合参数、允许常数变化、允许非物理值（如负吸附位点）和接受不良拟合的结果。通过使用正确的系统参数，我们举例说明了 Bohart-Adams 预测的突破时间是实验观测值的两倍多。结果表明，对称指数形式是由吸附和质量汇平衡组成的数学模型的必然结果，其中质量汇是朗缪尔形式。最后，我们简要地提到了一个模型，该模型可以拟合更广泛的实验数据，而无需采用非物理的、不一致的参数值。

引用次数: 0

Impact of heat transfer in a duct composed of anisotropic porous material: A non-linear Brinkman-Forchheimer extended Darcy's model: A computational study 各向异性多孔材料组成的管道中传热的影响：非线性布林克曼-福克海默扩展达西模型：计算研究

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2024-09-26 DOI: 10.1016/j.icheatmasstransfer.2024.108111

Forced convective heat transport in a rectangular porous channel with anisotropic permeability is investigated in this study. A fully developed flow field is assumed, and the Brinkman-Forchheimer extended Darcy's equation is adopted to model the fluid flow. The thermal field is developing. A weak formulation of the momentum equation has been obtained. The existence and uniqueness of the solution for the weak momentum equation are proved using the Browder-Minty theorem. The finite difference approach has been utilized to solve these coupled differential equations. Non-equidistant grids are implemented in the axial direction to reduce computational time and space. The effect of anisotropic parameters, such as permeability ratio and orientation angle, on the hydrodynamic and thermal characteristics of the flow has been discussed. An increase in the permeability ratio (K) causes an increase in the local Nusselt number. Anisotropy has been identified as crucial in heat transmission for the Darcy numbers less than 0.75. The anisotropic phenomenon of the channel contributed to a more than 13 % increase in the heat transmission rate compared to the isotropic scenario. Also, as the anisotropic parameters increase, the amount of heat transferred from the walls to the fluid up to any desired axial distance increases. Validation of numerical solutions is done using existing literature.

本研究探讨了具有各向异性渗透性的矩形多孔通道中的强制对流热传输。假定流场充分发展，并采用布林克曼-福克海默扩展达西方程来模拟流体流动。热场正在发展。研究获得了动量方程的弱公式。利用布劳德-明蒂定理证明了弱动量方程解的存在性和唯一性。利用有限差分法求解了这些耦合微分方程。在轴向采用了非等距网格，以减少计算时间和空间。讨论了各向异性参数（如渗透率和取向角）对流动的流体力学和热学特性的影响。渗透率（K）的增加会导致局部努塞尔特数的增加。各向异性被认为是达西数小于 0.75 时热量传递的关键。与各向同性的情况相比，通道的各向异性使热传导率增加了 13%。此外，随着各向异性参数的增加，在任何所需的轴向距离内从壁面向流体传递的热量也会增加。利用现有文献对数值解决方案进行了验证。

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引用次数: 0

Pancake bouncing of impacting nanodroplets on smooth and nanopillared surfaces 冲击纳米液滴在光滑表面和纳米柱面上的薄饼反弹

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2024-09-25 DOI: 10.1016/j.icheatmasstransfer.2024.108108

Reducing the contact time of impacting droplets on solid surfaces has become a research focus due to its promising application prospects in self-cleaning, anti-erosion, and anti-icing. In this study, the pancake bouncing of nanodroplets is investigated through molecular dynamics simulations, achieving a remarkable reduction in contact time. Two distinct patterns of pancake bouncing are identified when nanodroplets impact smooth and nanopillared surfaces with different bouncing mechanisms. The first pancake bouncing pattern with holes on smooth surfaces is attributed to internal-flow collision induced by multiple retraction centers. The second pancake bouncing pattern on nanopillared surfaces results from the storage and release of sufficient surface energy due to liquid penetration and requires satisfying both the timescale and energy criterion. Subsequently, theoretical models for two criteria are developed, which promote two parameter groups (−(s² + 2ws)h(wcosθ₀)⁻¹ and We^–1/3Re^–1/3R₀²) corresponding to the surface and droplet. Based on these two parameter groups, a phase diagram is established and indicates the triggering conditions for the second pancake bouncing patterns. Finally, it is further revealed that by increasing the pillar height from smooth to nanopillared surfaces, the bouncing regime is transformed from the first pancake bouncing pattern, regular bouncing, to the second pancake bouncing pattern.

由于在自清洁、防侵蚀和防结冰方面具有广阔的应用前景，缩短撞击液滴在固体表面的接触时间已成为研究重点。本研究通过分子动力学模拟研究了纳米液滴的薄饼弹跳，从而显著缩短了接触时间。当纳米液滴以不同的弹跳机制撞击光滑表面和纳米柱状表面时，可识别出两种截然不同的薄饼弹跳模式。光滑表面上第一种带孔的薄饼弹跳模式归因于多个回缩中心引起的内流碰撞。纳米柱表面上的第二种薄饼弹跳模式是由于液体渗透储存并释放了足够的表面能量，需要同时满足时间尺度和能量标准。随后，建立了两个标准的理论模型，促进了与表面和液滴相对应的两个参数组（-(s2 + 2ws)h(wcosθ0)-1 和 We-1/3Re-1/3R02）。根据这两个参数组，建立了相图，并指出了第二种薄饼弹跳模式的触发条件。最后，研究进一步揭示了通过增加从光滑表面到纳米柱状表面的柱状高度，弹跳机制从第一种薄饼弹跳模式（常规弹跳）转变为第二种薄饼弹跳模式。

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引用次数: 0

A comprehensive review of air-cooled heat sinks for thermal management of electronic devices 用于电子设备热管理的风冷散热器综合评述

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2024-09-25 DOI: 10.1016/j.icheatmasstransfer.2024.108055

Heat sinks are important for efficient heat dissipation in electronic devices. Continuous heat dissipation is of utmost importance to keep the electronic devices below the maximum operating temperature. Several thermal management solutions for electronics cooling have been studied in the past, however, air-cooled heat sinks are one of the most widely adopted thermal management techniques employed in the industry. The recent past has shown the evolution of several other thermal management techniques such as liquid cooling and phase change material-based cooling for electronic devices. Despite the introduction of newer thermal management techniques mentioned above, the air-cooled heat sink is still considered to be an effective device because of its compatibility with a broad range of electronic components. The present review is an attempt to discuss major research contributions on air-cooled heat sinks. A detailed discussion on various heat sink geometries available in the open literature, heat transfer mechanism (active, passive, and radiation heat transfer) and effect of modifications on the thermo-hydraulic performance of air-cooled heat sinks has been presented.

散热器对于电子设备的高效散热非常重要。要使电子设备保持在最高工作温度以下，持续散热至关重要。过去曾研究过多种用于电子设备冷却的热管理解决方案，但风冷散热器是业内最广泛采用的热管理技术之一。近年来，其他一些热管理技术也在不断发展，如液体冷却和基于相变材料的电子设备冷却技术。尽管引入了上述较新的热管理技术，但风冷散热器仍被认为是一种有效的设备，因为它与各种电子元件兼容。本综述试图讨论有关风冷散热器的主要研究成果。本综述详细讨论了公开文献中的各种散热片几何形状、传热机制（主动、被动和辐射传热）以及对风冷散热片热液压性能的修改效果。

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引用次数: 0

Stokes-type conjugate heat transfer and thermoelasticity analysis of a hollow spherical particle in a slip flow 滑移流中空心球质点的斯托克斯型共轭传热和热弹性分析

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2024-09-25 DOI: 10.1016/j.icheatmasstransfer.2024.108110

Conjugate heat transfer around a spherical particle submerged in a viscous heat-conducting fluid at very low Reynolds numbers is analytically investigated. The cases of spherically symmetric and axisymmetric temperature fields are solved. The temperature jump condition of dilute gas dynamics is assumed. The induced thermal stresses in the sphere in the case of spherical symmetry are analytically solved as well. The effect of temperature jump, heat conductivity ratio between the solid and fluid media, the heat generation and the inner radius of the sphere on the temperature, displacement, radial stress and circumferential stresses are studied. Furthermore, an exact correlation is proposed between the Reynolds, Knudsen and Nusselt numbers as well as the drag coefficient of the sphere, which is valid for slip flow at the Stokes limit. Whether it is accurate at higher Reynolds numbers would need further research.

对浸没在粘性导热流体中的球形颗粒周围在极低雷诺数条件下的共轭传热进行了分析研究。求解了球面对称和轴对称温度场的情况。假设了稀释气体动力学的温度跃迁条件。同时还分析了球面对称情况下球体中的诱导热应力。研究了温度跃迁、固体介质和流体介质之间的导热比、发热量和球体内部半径对温度、位移、径向应力和圆周应力的影响。此外，还提出了雷诺数、努森数和努塞尔特数以及球体阻力系数之间的精确相关性，该相关性适用于斯托克斯极限的滑移流。至于在更高的雷诺数下是否准确，还需要进一步研究。

引用次数: 0

Dynamic and equilibrate MD measurements of disjoining pressure according to its original definition 根据原始定义对分离压力进行动态和平衡 MD 测量

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2024-09-25 DOI: 10.1016/j.icheatmasstransfer.2024.108061

The concept of disjoining pressure has drawn attention since its first appearance in colloidal chemistry in the 1930s. Almost every scenario with liquid nano and sub-nano film is considered to be related to or even dominated by disjoining pressure. However, debates also last for years. Recently, researchers have explored the physical essence behind it computationally, while few computational works reproduced the discontinuity i.e. the pressure jump in experiments. In this study, a dynamic simulation with a large reservoir according to the very original definition of disjoining pressure by B. V. Derjaguin based on the experiment is conducted and the pressure jump is observed. The disjoining pressure isotherm is found to vary in four dynamic stages, and the liquid re-ordering stage corresponds to the disjoining pressure jumps. The understanding of disjoining pressure based on liquid molecular packing structure could pave the way to a predictive modeling of disjoining pressure.

自 20 世纪 30 年代首次出现在胶体化学中以来，脱节压力的概念就一直备受关注。几乎所有涉及纳米级和亚纳米级液体薄膜的情况都被认为与分界面压力有关，甚至由分界面压力主导。然而，争论也持续了多年。最近，研究人员通过计算探索了其背后的物理本质，但很少有计算工作能再现实验中的不连续性，即压力跃迁。在本研究中，根据 B. V. Derjaguin 在实验基础上对脱节压力的原创定义，对大型储层进行了动态模拟，并观察到了压力跃变。发现脱节压力等温线在四个动态阶段发生变化，而液体重新排序阶段与脱节压力跃变相对应。基于液体分子填料结构对脱节压力的理解可为脱节压力的预测建模铺平道路。

引用次数: 0

Flow and heat transfer analysis of submerged multiple synthetic jet impingement in a square channel with forced-flow 方形水道中浸没式多合成射流强制撞击的流动与传热分析

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2024-09-25 DOI: 10.1016/j.icheatmasstransfer.2024.108103

This study experimentally and numerically investigated the flow and heat transfer of submerged multiple synthetic jet impingement in forced crossflow in a square-section channel with a constant heat flux on the bottom surface. In the forced channel flow, effects on heat transfer of six synthetic jets placed diagonally in the main flow have four different amplitudes and six different frequencies at various Reynolds numbers (6000 ≤ Re ≤ 40000) were examined. Jets were submerged vertically into the main flow and their effects on heat transfer in the turbulent regime of the main flow were analyzed. Temperature measurements were made using thermocouples placed at the channel entrances and exits on the target surface. The Nusselt numbers (Nu) were calculated using the measured temperatures. The results indicate that at Re = 6000, the target surface temperature decreases significantly with increasing amplitude and frequency, and the effects of amplitude and frequency on surface temperatures decreased at increasing Reynolds numbers. It was observed that the THP values increased with increasing amplitude and frequency for all Reynolds numbers tested. For a constant jet parameter (A_o = 0.88 and Wo = 27), the highest THP was determined as 2.06 at Re = 6000.

本研究通过实验和数值方法研究了在底面热通量恒定的情况下，方形截面通道中强制横流中浸没式多合成射流撞击的流动和传热。在强制通道流中，研究了在不同雷诺数（6000 ≤ Re ≤ 40000）条件下，主流中对角放置的六个合成射流的四种不同振幅和六种不同频率对传热的影响。喷流被垂直浸没到主流中，并分析了它们对主流湍流状态下传热的影响。使用放置在目标表面通道入口和出口处的热电偶测量温度。通过测量温度计算出了努塞尔特数（Nu）。结果表明，在 Re = 6000 时，目标表面温度随振幅和频率的增加而显著降低，而振幅和频率对表面温度的影响随雷诺数的增加而减小。据观察，在所有测试的雷诺数下，THP 值都随着振幅和频率的增加而增加。对于恒定的射流参数（Ao = 0.88 和 Wo = 27），在 Re = 6000 时，最高 THP 值为 2.06。

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引用次数: 0

Heat transfer behavior and formation mechanism of stainless steel cladding carbon steel plate during horizontal continuous liquid-solid composite casting 水平连续液固复合铸造过程中不锈钢包覆碳钢板的传热行为和形成机理

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2024-09-25 DOI: 10.1016/j.icheatmasstransfer.2024.108105

Stainless steel/carbon steel laminated composites have a wide application demand, nevertheless, traditional preparation methods are still insufficient in terms of performance and efficiency. In this paper, a novel technique and new equipment of horizontal continuous liquid-solid composite casting was developed. The heat transfer behavior during the continuous composite casting process was investigated by a verified 3D model, and the influences of processing parameters on the microstructure and properties were analyzed via experiments. Heat transfer strongly affects the bonding and solidification process, initial inverse solidification, remelting, inverse and forward solidification of the cladding layer occur successively, resulting in a strong metallurgical bonding interface and a high-quality cladding layer. The maximum temperature of the substrate surface and the cooling rate of the cladding layer increase with increasing melt temperature and inverse solidification mold exit temperature. Additionally, an increased continuous casting speed reduces the maximum temperature and improves the cooling rate. Finally, stainless steel cladding carbon steel plates with average dimension error less than 3.4 % were successfully fabricated, and had an excellent interfacial shear strength of 412 MPa and an ultimate tensile strength of 577 MPa due to the formation of carbides and elimination of the decarburization layer and oxides at the interface.

不锈钢/碳钢层压复合材料具有广泛的应用需求，但传统的制备方法在性能和效率方面仍存在不足。本文开发了一种新型水平液固复合材料连铸技术和设备。通过验证三维模型研究了复合材料连铸过程中的传热行为，并通过实验分析了加工参数对微观结构和性能的影响。热传递强烈影响了结合和凝固过程，熔覆层的初始反向凝固、重熔、反向凝固和正向凝固相继发生，形成了牢固的冶金结合界面和高质量的熔覆层。随着熔体温度和反向凝固出模温度的升高，基体表面的最高温度和熔覆层的冷却速度也会增加。此外，提高连铸速度可降低最高温度并提高冷却速度。最后，成功制造出了平均尺寸误差小于 3.4 % 的不锈钢覆层碳钢板，由于碳化物的形成以及界面脱碳层和氧化物的消除，该钢板具有 412 兆帕的优异界面剪切强度和 577 兆帕的极限抗拉强度。

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引用次数: 0

Weak nonlinear thermo bioconvection: Heat transfer via artificial neural network 弱非线性热生物对流：通过人工神经网络传热

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2024-09-25 DOI: 10.1016/j.icheatmasstransfer.2024.108090

The present study undertakes an analytical exploration of the onset of regular and chaotic thermo-bioconvection in a suspension of gravitactic microorganisms. Additionally, it employs a machine learning approach for numerical computation and prediction of heat transfer rates. The two-dimensional flow governing dynamics are modeled using the Hamilton-Crosser model for microorganisms. The amplitude of convection is determined by solving the cubic Ginzburg-Landau equation derived by applying the Lorenz technique. Stationary curves are plotted with thermal Rayleigh number and wave number, while Nusselt numbers are depicted over a range of time. The onset of chaotic motion is briefly discussed through Lyapunov plots and a bifurcation diagram. Further, to predict the heat transfer rate with multiple interconnected parameters, an artificial neural network is trained with the Levenberg-Marquardt algorithm to understand the underlying patterns of simulated data. The trained neural network is then employed to estimate the Nusselt number for various values of bioconvection Rayleigh number, bioconvection Lewis number, and bioconvection Péclet number. The values obtained from the artificial neural network models are compared with numerical data for validation and are found to be in good agreement. The findings of weak non-linear stability indicate that chaotic motion emerges in the system at the Hopf-Rayleigh number of 24.635, and fast-swimming microorganisms significantly increase the heat transfer rate. The coefficient of correlation is higher than 0.99, supporting the accuracy of developed ANN models to predict the Nusselt number with high accuracy. This observation supports the potential utilization of microbes in heat transfer applications.

本研究对重力微生物悬浮液中规则和混乱热生物对流的发生进行了分析探索。此外，研究还采用机器学习方法对传热速率进行数值计算和预测。采用汉密尔顿-克罗瑟微生物模型对二维流动控制动力学进行建模。对流振幅是通过求解应用洛伦兹技术推导出的立方金兹堡-朗道方程确定的。根据热雷利数和波数绘制了静态曲线，同时在一定时间范围内描绘了努塞尔特数。通过 Lyapunov 图和分岔图简要讨论了混沌运动的开始。此外，为了预测具有多个相互关联参数的传热率，使用 Levenberg-Marquardt 算法训练了一个人工神经网络，以了解模拟数据的基本模式。然后，利用训练好的神经网络来估算生物对流雷利数、生物对流路易斯数和生物对流佩克莱特数的不同值的努塞尔特数。将人工神经网络模型得出的数值与数值数据进行比较验证，发现两者非常吻合。弱非线性稳定性的研究结果表明，在霍普夫-雷利数为 24.635 时，系统中出现了混沌运动，快速游动的微生物显著提高了传热速率。相关系数大于 0.99，证明所开发的 ANN 模型能准确预测努塞尔特数。这一观察结果支持了微生物在传热应用中的潜在用途。

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引用次数: 0