International Journal of Heat and Mass Transfer最新文献_第6页

A new prediction model on the effective thermal conductivity of fluid saturated consolidated rock media via the pore-scale numerical study 基于孔隙尺度数值研究的流体饱和固结岩石介质有效导热系数预测新模型

IF 5.8 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2026-06-01 Epub Date: 2026-02-10 DOI: 10.1016/j.ijheatmasstransfer.2026.128491

Dongxing Du, Zhongwen Zhang, Guoyang Song, Dong Wang, Yingge Li

Accurate prediction of the Effective Thermal Conductivity (ETC) of fluid-saturated consolidated rock is essential in geo-energy development and CCUS applications. The present empirical models are usually derived based on ideal or simplified geometries, and vary significantly on the prediction results. With help of digital rock technology, 3D matrix-pore integrated porous domains are reconstructed and the pore-scale numerical studies are carried out on the solid‒fluid coupled heat conduction processes. First, the methodology is validated on the basis of satisfactory agreements between the numerical and reported measurement ETC results for water-, oil- and air-saturated rock samples. Then, comprehensive simulation studies are performed at various rock porosities ranging from 14.5% to 27.2%, various matrix thermal conductivities ranging from 2.7 to 7.7 W/(m·K), and various saturated fluid types of water, hydrogen, oil and air. Evaluation of some classical empirical ETC models is performed, and the widely scattered model estimations, especially under high rock/fluid thermal conductivity ratio (k_s/k_f) conditions, demonstrates the key role of the precise description of the porous internal geometry on accurate ETC predictions. Finally, a new ETC model is proposed on the basis of the pore-scale numerical results. The new model shows a proper applicability across multiple fluid and rock types, covering a k_s/k_f range of 4.5-320.8.

流体饱和固结岩有效热导率（ETC）的准确预测在地能开发和CCUS应用中至关重要。目前的经验模型通常基于理想或简化的几何形状，预测结果差异很大。借助数字岩石技术，重构了三维基质-孔隙一体化孔隙域，对固-流耦合热传导过程进行了孔隙尺度数值研究。首先，在水、油和空气饱和岩石样品的数值和报告的测量ETC结果令人满意的基础上，验证了该方法。在岩石孔隙度14.5% ~ 27.2%、基质导热系数2.7 ~ 7.7 W/（m·K）、饱和流体类型水、氢、油、空气等条件下进行了综合模拟研究。对一些经典的经验ETC模型进行了评价，结果表明，在高岩石/流体导热系数（ks/kf）条件下，模型估计非常分散，证明了孔隙内部几何形状的精确描述对ETC预测的准确性至关重要。最后，在孔隙尺度数值模拟结果的基础上，提出了新的ETC模型。新模型显示了对多种流体和岩石类型的适当适用性，覆盖4.5-320.8 ks/kf范围。

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引用次数: 0

Time-spectral BEM for dynamics analysis of 2D ultra-thin-layered coating structures 二维超薄层状涂层结构动力学分析的时谱边界元法

IF 5.8 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2026-06-01 Epub Date: 2026-02-11 DOI: 10.1016/j.ijheatmasstransfer.2026.128501

Wenbin Sun , Juan Wang , Yan Gu , Shengdong Zhao , Zhiyu Hu

Ultra-thin coatings play a critical role in advanced engineering applications. However, their extremely small thickness relative to in-plane dimensions introduces substantial difficulties for dynamic numerical simulation. This study proposes a high-efficiency numerical framework that integrates a time-spectral integration strategy with a scaled coordinate transformation boundary element method (SCT-BEM) to overcome these challenges in two-dimensional (2D) composite ultra-thin coating systems. The framework achieves a complete decoupling of temporal and spatial discretization by converting time derivatives into equivalent domain integrals. For the temporal dimension, a time-spectral integration scheme based on Gaussian quadrature and Legendre polynomials is employed, thereby eliminating the restrictive time-step requirements that typically hinder traditional finite-difference approaches. For the spatial domain, SCT techniques are used to transform domain integrals into boundary integrals, ensuring that the classical boundary-only discretization property of the BEM is preserved. Moreover, a sinh-based nonlinear coordinate transformation is introduced to effectively regularize the near-singular integrals produced by the highly slender coating geometry. Four representative numerical examples, including both transient thermal loading and dynamic wave excitation, are presented to demonstrate the accuracy, robustness, and computational efficiency of the proposed approach. The results confirm that the integrated time-spectral SCT-BEM framework provides a powerful and reliable numerical tool for long-time dynamic analysis of composite ultra-thin coating structures.

超薄涂层在先进的工程应用中起着至关重要的作用。然而，它们的厚度相对于面内尺寸非常小，这给动态数值模拟带来了很大的困难。本研究提出了一种高效的数值框架，该框架将时间谱积分策略与缩放坐标变换边界元方法（SCT-BEM）相结合，以克服二维（2D）复合超薄涂层系统中的这些挑战。该框架通过将时间导数转换为等价的域积分，实现了时间和空间离散化的完全解耦。对于时间维度，采用基于高斯正交和勒让德多项式的时谱积分方案，从而消除了通常阻碍传统有限差分方法的限制性时间步长要求。对于空间域，利用SCT技术将域积分转换为边界积分，保证边界元的经典仅限边界的离散性。此外，引入了一种基于sinh的非线性坐标变换，有效地正则化了由高细长涂层几何形状产生的近奇异积分。以瞬态热载荷和动态波激励为例，验证了该方法的准确性、鲁棒性和计算效率。结果表明，集成时谱SCT-BEM框架为复合材料超薄涂层结构的长时间动力学分析提供了一个强大而可靠的数值工具。

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引用次数: 0

Coupled thermo–electrochemical performance of proton exchange membrane fuel cells with micro-encapsulated phase change material suspension: A 3D multiphysics simulation study 微封装相变材料悬浮液质子交换膜燃料电池热电化学耦合性能的三维多物理场模拟研究

IF 5.8 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2026-06-01 Epub Date: 2026-02-11 DOI: 10.1016/j.ijheatmasstransfer.2026.128465

Hao Hu , Jie Xu , Jinsong Liu , Yang Qiu , Qihao Deng , Ke Chen , Ben Chen

Efficient thermal management is crucial for maintaining the durability and electrochemical stability of proton exchange membrane fuel cells (PEMFCs). A three-dimensional (3D) multiphysics model was developed to investigate the coupled heat–fluid–electrochemical behavior of PEMFCs using a micro-encapsulated phase change material suspension (MePCS) as coolant. The effects of micro-encapsulated phase change material (MePCM) volume fraction (

φ_{v}

), coolant velocity (

V_{coolant}

), and inlet temperature (

T_{i n}

) on thermal and electrochemical performance were systematically analyzed. Results show that incorporating MePCS effectively enhances temperature uniformity and suppresses local overheating. Compared with pure water, the maximum membrane temperature difference (

Δ T_{m a x}

) and temperature uniformity index (TUI) decreased by 68.2% and 42.3%, respectively. The optimal operating parameters were identified as

φ_{v}

= 15%,

V_{coolant}

= 0.05 m/s, and

T_{i n}

= 340.15 K, achieving a net power density of 0.518

W \cdot c m^{- 2}

. Moreover, the co-flow configuration of the reaction gas and coolant improved power density by 1.41% over counter-flow, attributed to better heat–water–gas coupling. These findings demonstrate that MePCS based coolants provide an effective approach to improving PEMFCs water and thermal uniformity and overall efficiency.

高效的热管理对于维持质子交换膜燃料电池（pemfc）的耐久性和电化学稳定性至关重要。采用微封装相变材料悬浮液（MePCS）作为冷却剂，建立了三维多物理场模型，研究了PEMFCs的热-流-电化学耦合行为。系统分析了微封装相变材料（MePCM）体积分数（φv）、冷却剂速度（Vcoolant）和进口温度（Tin）对热学和电化学性能的影响。结果表明，加入MePCS可以有效地提高温度均匀性，抑制局部过热。与纯水相比，最大膜温差（ΔTmax）和温度均匀度指数（TUI）分别降低了68.2%和42.3%。优化后的运行参数为φv = 15%, Vcoolant = 0.05 m/s, Tin = 340.15 K，净功率密度为0.518 W·cm−2。此外，反应气和冷却剂的共流配置比逆流配置提高了1.41%的功率密度，这是由于更好的热-水-气耦合。这些发现表明，基于MePCS的冷却剂为改善pemfc的水和热均匀性以及整体效率提供了有效的方法。

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引用次数: 0

Synergistic enhancement of cryogenic quenching using porous low-thermal-conductivity coatings 多孔低导热涂层协同增强低温淬火性能

IF 5.8 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2026-06-01 Epub Date: 2026-01-23 DOI: 10.1016/j.ijheatmasstransfer.2026.128393

Chunkai Guo, Peng Zhang

Applying a porous low-thermal-conductivity coating layer on the surface is an effective method to enhance cryogenic quenching process. However, existing studies have not thoroughly explored the mechanisms of quenching enhancement by the porous structures, nor have they systematically optimized the structural parameters of porous coating for cryogenic quenching process. Therefore, in this study, an effective method of cryogenic quenching enhancement employing a porous low-thermal-conductivity coating is proposed. The pool quenching experiments are carried out using a pristine rodlet, eight rodlets coated with pure Teflon layers of varying thicknesses, and fifteen rodlets coated with porous Teflon layers of different thicknesses and porosities. It is found that the chilldown time of the rodlets with porous Teflon coating layer is reduced by approximately 56.3 %–82.8 % relative to the bare rodlet. By comparing the boiling curves of the rodlets with pure Teflon coating layers and porous Teflon coating layers, the mechanism of synergistic enhancement of cryogenic quenching by porous low-thermal-conductivity coatings is revealed. Furthermore, it can be found that the porous Teflon coating layer with a porosity greater than 45 % exhibits a higher heat flux across the entire cryogenic quenching process compared with the pure Teflon coating layer under the condition of similar thermal resistance. This work paves a new design strategy to enhance cryogenic quenching performance across the entire regime of quenching process.

在表面涂敷多孔低导热涂层是提高低温淬火性能的有效方法。然而，现有的研究并没有深入探索多孔结构增强淬火的机理，也没有系统地优化多孔涂层低温淬火工艺的结构参数。因此，本研究提出了一种利用多孔低导热涂层进行低温淬火强化的有效方法。池淬实验采用一个原始棒、8个棒涂覆不同厚度的纯聚四氟乙烯层和15个棒涂覆不同厚度和孔隙率的多孔聚四氟乙烯层进行。结果表明，多孔聚四氟乙烯涂层的结晶器冷却时间比裸结晶器冷却时间缩短56.3% ~ 82.8%。通过对比纯聚四氟乙烯涂层和多孔聚四氟乙烯涂层的小棒沸腾曲线，揭示了多孔低导热涂层协同增强低温淬火的机理。在相同的热阻条件下，孔隙率大于45%的多孔Teflon涂层比纯Teflon涂层在整个低温淬火过程中表现出更高的热流密度。这项工作为在整个淬火过程中提高低温淬火性能奠定了新的设计策略。

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引用次数: 0

Unidirectional flow and heat transfer optimization of pin-fin cold plates for power battery thermal management: Integrated experimental, simulation and multi-objective optimization study 动力电池热管理用针翅冷板单向流动与传热优化：实验、仿真与多目标优化集成研究

IF 5.8 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2026-06-01 Epub Date: 2026-02-06 DOI: 10.1016/j.ijheatmasstransfer.2026.128482

Shuai Feng , Xingyan Dong , Ziqiang He , Chenguang Lai , Jie Song , Lijuan Fu , Ranran Fang , Weiping Li , Zhanxiao Kang

To address the thermal management challenges of high-power battery packs, a novel hybrid cold plate integrating straight channels and pin fins is proposed in this study. The structural and operational parameters of the cold plate are systematically optimized through a combined approach incorporating multi-objective optimization, numerical simulations, and experimental validation. Results indicate that the circular pin-fin (C-Pin-fin) configuration achieves the optimal thermo-hydraulic performance. At a mass flow rate of 0.03 kg/s, compared with conventional straight-channel designs, the maximum temperature is reduced by 2.9 K and the temperature difference is decreased by 0.7 K. Sensitivity analysis shows that channel height is the dominant factor affecting pressure drop (with a sensitivity of 44.2%), while mass flow rate primarily influences temperature uniformity (with a sensitivity of 53 %). Compared to the baseline model, the optimized design improves temperature uniformity by 23.1 %, reduces pressure drop by 43.2 %, achieves a maximum reduction in thermal resistance of 16 %, and attains a maximum cooling efficiency factor of 15,452. Furthermore, a channel height of 1.5 mm is identified as optimal for balancing performance and structural compactness. The superior performance of the proposed design is experimentally validated, demonstrating its potential for application in advanced battery thermal management systems.

为了解决大功率电池组的热管理挑战，本研究提出了一种集成直通道和针翅的新型混合冷板。采用多目标优化、数值模拟和实验验证相结合的方法，对冷板的结构参数和运行参数进行了系统优化。结果表明，圆形pin-fin （C-Pin-fin）结构获得了最佳的热工性能。在质量流量为0.03 kg/s时，与传统直通道设计相比，最高温度降低了2.9 K，温差减小了0.7 K。灵敏度分析表明，通道高度是影响压降的主要因素（灵敏度为44.2%），而质量流量主要影响温度均匀性（灵敏度为53%）。与基准模型相比，优化后的温度均匀性提高了23.1%，压降降低了43.2%，热阻最大降低了16%，最大冷却效率系数达到了15,452。此外，1.5毫米的通道高度被认为是平衡性能和结构紧凑性的最佳选择。实验验证了该设计的优越性能，证明了其在先进电池热管理系统中的应用潜力。

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引用次数: 0

Thermal-hydraulic performance assessment of a micro shell-and-tube heat exchanger operating under part-load conditions in the NET Power cycle recuperator 微管壳式换热器部分负荷工况下的热工性能评价

IF 5.8 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2026-06-01 Epub Date: 2026-01-28 DOI: 10.1016/j.ijheatmasstransfer.2026.128419

Iván Velázquez , Frederiek Demeyer , Miriam Reyes

This paper numerically investigates the thermal-hydraulic performance of a micro shell-and-tube heat exchanger (MSTHE) for application in the thermal recuperator of the innovative oxy-combustion-based NET Power cycle, operating under cycle-relevant part-load conditions. The aim is to support the technological transition from the established printed circuit heat exchangers (PCHE) to MSTHE, which offer a lower inertia, cost-effective, and maintenance-friendly high-performance alternative. To this end, a thermal-hydraulic computational model of the MSTHE was developed, capable of capturing the rapid variation of the supercritical CO₂ (scCO₂) properties and the partial filmwise condensation of the turbine exhaust gases. Results show that the MSTHE must contain at least 60,000 tubes so that the pressure drop on the tube-side is lower than 1 bar at nominal conditions. The MSTHE effectiveness decreases from 89.2% to 65.1% as the cycle load is reduced from 100% to 20%. The overall heat transfer coefficient decreases gradually between 100% and 40% cycle load, drops sharply between 40% and 30%, and then stabilizes between 30% and 20% cycle load. This stabilization is attributed to the abrupt local increase of the heat capacity on the scCO₂-side during the pseudo-critical phase transition, which also enhances local condensation heat release and thickens the condensate film on the shell-side. However, it was found that this phenomenon induces strong axial temperature gradients that may induce thermal stresses, representing a trade-off to the proposed compact design. While the floating microtube bundle of MSTHEs can accommodate these thermal stresses, the rigid compact block structure of PCHE is more prone to damage, revealing an additional key advantage of MSTHEs.

本文对应用于新型全氧燃烧净动力循环热回收器的微型管壳式换热器（MSTHE）在循环相关部分负荷条件下的热工性能进行了数值研究。其目的是支持从已建立的印刷电路热交换器（PCHE）到MSTHE的技术转型，提供更低的惯性，成本效益和维护友好的高性能替代方案。为此，开发了MSTHE的热水力计算模型，能够捕捉超临界CO2 （scCO2）特性的快速变化和涡轮废气的部分膜状冷凝。结果表明，MSTHE必须包含至少60,000根管，以使管侧的压降在标称条件下低于1bar。当循环负荷从100%降低到20%时，MSTHE效率从89.2%降低到65.1%。总换热系数在100% ~ 40%循环负荷之间逐渐减小，在40% ~ 30%循环负荷之间急剧下降，在30% ~ 20%循环负荷之间趋于稳定。这种稳定是由于在拟临界相变过程中scco2侧局部热容的突然增加，这也增加了局部冷凝热释放，使壳侧冷凝膜变厚。然而，人们发现这种现象会引起强烈的轴向温度梯度，从而可能引起热应力，这是对所提出的紧凑设计的一种权衡。虽然MSTHEs的浮动微管束可以适应这些热应力，但PCHE的刚性致密块结构更容易损坏，这揭示了MSTHEs的另一个关键优势。

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引用次数: 0

Experimental investigation of mixed convection in a horizontal tube for a liquid metal flow 金属液流水平管内混合对流的实验研究

IF 5.8 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2026-06-01 Epub Date: 2026-02-11 DOI: 10.1016/j.ijheatmasstransfer.2026.128495

Linda Elmlinger, Tim Laube, Benjamin Dietrich, Thomas Wetzel

An experimental study of the heat transfer on mixed convection in a turbulent liquid metal flow with azimuthally inhomogeneous heat flux distribution is presented. A horizontal nickel tube is heated in different sections to investigate the influence of heat flux orientation relative to gravity on heat transfer in a liquid metal flow. Four semi-circumferential heat flux distributions (top, bottom, right and bottom right half) are examined. These configurations emulate the azimuthally inhomogeneous heat flux profile that is characteristic of receiver tubes in concentrated solar power plants. The working fluid is a near eutectic alloy of gallium, indium, and tin (GaInSn,

P r = 0.03

,

ϑ_{melt} = 11^{\circ} C

). The Péclet number is varied within a range of

2.4 \times 10^{2} < P e < 3 \times 10^{3}

, while the Rayleigh number is

1.6 \times 10^{3} < R a_{q} < 8.2 \times 10^{3}

. For all four heat flux distributions, the correlation for the azimuthally averaged Nusselt number

〈 N u 〉

can be confirmed. The temperature difference along the circumference of the tube reveals mixed convection for heating directions opposing the direction of gravitational acceleration for

P e < 7.2 \times 10^{2}

. Based on this quotient, the applicability of the Rayleigh number, the Buhr parameter, the Buoyancy parameter, and the Richardson number as criteria for the determination of mixed convection in liquid metals is discussed. New correlations for the critical Rayleigh number and limits for the Buhr parameter are established.

本文对热通量分布不均匀的金属液态湍流混合对流换热进行了实验研究。在不同截面上加热水平镍管，研究了相对于重力的热流取向对液态金属流动传热的影响。研究了四种半周热通量分布（上、下、右和右下半部分）。这些结构模拟了聚光太阳能电站中接收管的方位不均匀热流分布。工作流体是镓、铟和锡的近共晶合金（GaInSn, Pr=0.03， ϑmelt=11°C）。p;Pe<3×103， Rayleigh号为1.6×103<Raq<8.2×103。对于所有四种热通量分布，都可以证实方位平均努塞尔数< Nu >的相关性。沿管周长的温差揭示了与Pe<；7.2×102重力加速度方向相反的加热方向的混合对流。在此基础上，讨论了瑞利数、布尔参数、浮力参数和理查德森数作为判定液态金属混合对流的判据的适用性。建立了临界瑞利数和布尔参数极限的新关系式。

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引用次数: 0

Modeling of flow and mass transfer dynamics in spacer-filled channels of membrane processes using direct numerical simulations 用直接数值模拟方法模拟膜过程中间隔器填充通道的流动和传质动力学

IF 5.8 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2026-06-01 Epub Date: 2026-02-11 DOI: 10.1016/j.ijheatmasstransfer.2026.128512

Santiago Cespedes, Bastiaan Blankert, Cristian Picioreanu

This study evaluates the effect of different flow regimes on the local and global mass transfer coefficient for feed spacer-filled channels in membrane separation processes using Direct Numerical Simulation (DNS). The computational domain was built with arrangements of multiple spacer units based on accurate three-dimensional CT scan of a commercial reverse osmosis feed-spacer. Hydrodynamics was coupled with solute transport and a permeable membrane. Computations were performed in two membrane/spacer configurations: (i) spacer “floating” within the feed channel and (ii) spacer “touching” the membrane, both in a wide range of inlet channel velocities (2 – 60 cm/s). The observed flow-regime was categorized based on dynamics (steady vs. periodic vs. unsteady), subdividing the laminar steady regime based on spatial distribution (regular vs irregular), resulting in four observed regimes: regular laminar-steady, irregular laminar-steady, periodic and unstable, depending on velocity and position. Transition from laminar-steady to unsteady flow occurred for Re > 950 (“floating”) and 720 (“touching”). When more than four spacer cells are considered, different flow-regimes can occur simultaneously at different locations in the channel. Instabilities within the flow arising from external perturbation can trigger unstable flow only at high velocities (40 cm/s), indicating that at industrial conditions (velocity < 16 cm/s) it would be difficult to perturb the flow in a meaningful way. Vortex analysis showed how the spacer works as a static mixer, promoting the splitting and rotation of flow. Furthermore, in the unsteady flow, the presence of vortices traveling within the feed channel assists the transport of solute from the membrane to the bulk, renewing the polarization layer. Finally, the effect of each flow regime on the mass transfer coefficient was shown in the traditional Sh-Re power law (

S h = a R e^{b} S c^{c}

), where the exponent b varied from the expected 1/3 in the laminar-steady flow to ca. 0.9 in the transitional regime.

本研究利用直接数值模拟（DNS）方法评估了不同流动形式对膜分离过程中填料通道局部和整体传质系数的影响。基于商用反渗透进料间隔器的精确三维CT扫描，建立了多个间隔单元的计算域。流体力学与溶质输运和可渗透膜相结合。在两种膜/间隔器配置下进行了计算：(i)间隔器“漂浮”在进料通道内，（ii）间隔器“接触”在膜上，两者都在很大的入口通道速度范围内（2 - 60 cm/s）。观察到的流型根据动力学（稳定、周期性和非定常）进行分类，并根据空间分布（规则与不规则）对层流稳定进行细分，根据速度和位置，得出四种观察到的流型：规则层流稳定、不规则层流稳定、周期性和不稳定。Re > 950（“漂浮”）和720（“接触”）发生了从层流稳定到非定常流的转变。当考虑四个以上的间隔单元时，不同的流态可能同时发生在通道的不同位置。由外部扰动引起的流动不稳定只能在高速（40 cm/s）下触发不稳定流动，这表明在工业条件下（速度<； 16 cm/s），很难以有意义的方式扰动流动。旋涡分析显示了隔离器如何作为静态混合器，促进气流的分裂和旋转。此外，在非定常流中，进料通道内涡流的存在有助于溶质从膜向体的运输，从而更新极化层。最后，在传统的Sh- re幂律（Sh=aRebScc）中显示了每种流型对传质系数的影响，其中指数b从层流稳定流的预期1/3变化到过渡流态的约0.9。

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引用次数: 0

Interaction between soil freezing-thawing process and heat extraction by ground heat exchangers: modeling of thermal-hydrological-mechanical coupling in unsaturated soil 土壤冻融过程与地下换热器抽热的相互作用：非饱和土壤热-水-力耦合模型

IF 5.8 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2026-06-01 Epub Date: 2026-02-11 DOI: 10.1016/j.ijheatmasstransfer.2026.128499

Fuqiang Xu , Yu Shi , Can Ji , Qiang Wang , Fenghua Duan , Cong Wang

The ground heat exchanger (GHE) is a cost-effective and efficient technology for utilizing shallow geothermal resources, which provides both cooling in summer and heating in winter. In many regions, soil undergoes seasonal freezing in winter. The operation of heat exchangers affects the soil freezing-thawing process, while the ice-water phase transition conversely impacts the performance of the heat exchangers. To explore these interactions, a thermal-hydrological-mechanical (T-H-M) coupling model is developed at the experimental scale, considering the freezing-thawing dynamics in unsaturated soil and the heat exchange between GHEs and the surrounding formation. The results indicate that the ice-water phase transition can delay changes in soil temperature. Heat extraction by GHEs not only forms a frozen zone in their vicinity but also accelerates the freezing process and inhibits the thawing of the overlying frozen soil layer. Moreover, the ice-water phase transition increases the outlet temperature of GHEs during the freezing process and decreases it during the thawing process. Specifically, under lower temperature gradients, the displacement induced by the soil freezing-thawing process is significantly larger than that caused by other factors. And heat extraction exerts a notable effect: a displacement difference of up to 0.58 mm is observed at the upper boundary after 168 h when comparing scenarios with and without heat extraction. Furthermore, the periodic operation of the system expands both the low-temperature zone and the frozen zone. Notably, the ice-water phase transition affects reservoir properties such as relative saturation, thermal conductivity, volumetric heat capacity, and diffusion coefficient, which in turn influence subsequent phase transitions and heat exchange processes. This study provides insights for improving heat exchange efficiency and mitigating soil freezing-thawing risks.

地下换热器（GHE）是一种经济高效的利用浅层地热资源的技术，它可以提供夏季制冷和冬季供暖。在许多地区，土壤在冬季经历季节性冻结。换热器的运行影响土壤冻融过程，而冰水相变反过来影响换热器的性能。为了探索这些相互作用，在实验尺度上建立了一个热-水文-力学（T-H-M）耦合模型，考虑了非饱和土壤的冻融动力学以及GHEs与周围地层之间的热交换。结果表明，冰-水相变可以延缓土壤温度的变化。温室气体的抽热不仅在其附近形成冻结区，而且加速冻结过程，抑制上覆冻土层的融化。冰-水相变使温室气体的出口温度在冻结过程中升高，在解冻过程中降低。具体而言，在较低温度梯度下，土壤冻融过程引起的位移明显大于其他因素引起的位移。抽热效果显著，在抽热和不抽热情况下，168 h后上界位移差达0.58 mm。此外，系统的周期性运行扩大了低温区和冻结区。值得注意的是，冰-水相变会影响储层的性质，如相对饱和度、导热系数、体积热容量和扩散系数，进而影响随后的相变和热交换过程。该研究为提高土壤热交换效率，降低土壤冻融风险提供了参考。

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引用次数: 0

A novel transformation-driven SBFEM framework for time-domain coupled heat conduction and stress analysis in 3D layered half-spaces 三维层状半空间中热传导与应力耦合分析的转换驱动SBFEM框架

IF 5.8 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2026-06-01 Epub Date: 2026-01-28 DOI: 10.1016/j.ijheatmasstransfer.2026.128400

Chuhao Huang , Jun Liu , Lei Gan , Tugen Feng , Haibo Wang , Jie Ren , Wenbin Ye , Peiqing Wang , Zhen Zhang , Xi Lu

This study develops a novel transformation-driven scaled boundary finite element method (SBFEM) framework for the sequentially coupled, time-domain analysis of heat conduction and thermal stress in 3D semi-infinite media. The framework employs a domain partitioning strategy where the unbounded far-field is modeled using scaling surface-based SBFEM. A new coordinate transformation based on geometric similarity between a scaling surface (ξ=0) and boundary surface (ξ=1) is introduced. Departing from traditional point-scaling approaches, this framework introduces a methodological innovation by rigorously handling non-separable Jacobian matrices through a variational derivation, enabling accurate capture of spatial non-uniformity and complex topological features. The transient system is solved by formulating the heat conduction matrix via continued-fraction expansion and integrating in the time domain using the modified precise time step integration method (MPTSIM). The method’s accuracy is validated through benchmarks, demonstrating near-perfect agreement with semi-analytical and FEM results. Critically, this high accuracy is achieved with significantly greater computational efficiency, showing a substantial reduction in both DOFs and CPU time compared to the FEM model. The validated framework is applied to layered thermoelastic half-spaces, revealing that the induced stress field is not linearly proportional to the temperature gradient. Instead, the results demonstrate that the mechanical constraint of the surface layer plays a dominant role in shaping the thermal stress distribution. This finding elucidates a fundamental engineering trade-off between minimizing displacement and reducing stress, underscoring the framework’s capability to capture the intrinsic coupling between thermal and mechanical responses in complex layered media.

本研究开发了一种新的转换驱动的尺度边界有限元（SBFEM）框架，用于三维半无限介质中热传导和热应力的时序耦合时域分析。该框架采用了一种领域划分策略，其中无界远场采用基于尺度表面的SBFEM建模。提出了一种基于尺度曲面（ξ=0）与边界曲面（ξ=1）几何相似性的坐标变换方法。与传统的点尺度方法不同，该框架引入了一种方法创新，通过变分推导严格处理不可分雅可比矩阵，从而能够准确捕获空间非均匀性和复杂的拓扑特征。采用连续分式展开构造热传导矩阵，并采用改进的精确时间步长积分法（MPTSIM）在时域内进行积分，求解了瞬态系统。通过基准测试验证了该方法的准确性，与半解析和有限元结果几乎完全吻合。至关重要的是，与FEM模型相比，这种高精度以更高的计算效率实现，显示出自由度和CPU时间的大幅减少。将验证的框架应用于层状热弹性半空间，发现诱发应力场与温度梯度不是线性正比的。相反，结果表明，表面层的机械约束在形成热应力分布方面起主导作用。这一发现阐明了最小化位移和减小应力之间的基本工程权衡，强调了框架在复杂层状介质中捕捉热响应和机械响应之间固有耦合的能力。

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引用次数: 0