International Journal of Heat and Fluid Flow最新文献

Performance evaluation of dovetail fin variants derived from a rectangular fin for laptop heat sinks 笔记本电脑散热器用矩形翅片衍生的燕尾翅的性能评价

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-01-15 DOI: 10.1016/j.ijheatfluidflow.2026.110256

Yogesh Chouksey, Nitin Shrivastava, Sunil Kumar

Cooling compact electronics, such as laptops, is challenging due to strict size limitations and the low thermal capacity of air. While rectangular fins are commonly used, dovetail fins with tip clearance may offer improved thermal performance. This study investigates the thermal–hydraulic behaviour of rectangular and dovetail fin heat sinks under these constraints. Initially, a rectangular channel heat sink was designed and later modified to a channel heat sink incorporating a rectangular fin with tip clearance. This fin was further adapted into three dovetail fin variants by varying the root and tip thicknesses to evaluate the feasibility of replacing rectangular fins. CFD analyses were conducted in ANSYS Fluent for inlet air velocities ranging from 1 to 6 m/s (corresponding Reynolds number varies from 2054–12323), with the top surface of the heat sink maintained at a constant temperature of 360 K. Temperature distribution, heat transfer, pressure drop, and effectiveness were evaluated, considering weight in the performance comparison. Dovetail fins outperformed the rectangular fin, enhancing heat convection by up to 20.6% but with a 66.7% increase in weight and substantially higher pressure drops. The dovetail variant with weight equal to the rectangular fin achieved up to 2.2% higher performance with only a marginal increase in pressure drop, indicating its potential as a promising alternative.

由于严格的尺寸限制和空气的低热容量，冷却小型电子产品，如笔记本电脑，是具有挑战性的。虽然通常使用矩形翅片，但带尖端间隙的燕尾翅片可以提供更好的热性能。本文研究了矩形和燕尾翼散热器在这些约束条件下的热水力特性。最初，设计了矩形通道散热器，后来修改为包含矩形翅片的通道散热器。通过改变尾鳍根部和尾鳍的厚度，进一步将其改造成三种燕尾鳍，以评估替代矩形鳍的可行性。在进口风速为1 ~ 6m /s（对应的雷诺数为2054 ~ 12323）的条件下，在ANSYS Fluent中进行CFD分析，散热器顶面温度保持在360 K恒定。温度分布，传热，压降和有效性进行了评估，考虑重量在性能比较。燕尾翼的性能优于矩形翅片，增加了20.6%的热对流，但重量增加了66.7%，压降也高得多。重量与矩形翅片相同的燕尾型的性能提高了2.2%，而压降仅略有增加，这表明它是一种有前途的替代方案。

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引用次数: 0

The flow and heat transfer performance of a novel double-spiral heat sink for processing unit cooling 一种新型双螺旋散热器的流动和传热性能

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-02-06 DOI: 10.1016/j.ijheatfluidflow.2026.110299

Feiyu Chen , Chenghao Liu , Xin Wu , Shida Yao , Wenguang Liu , Wei Chang

The escalating thermal power of processors demands advanced cooling solutions. This study proposes a novel double-spiral heat sink (DSHS) with dual inlets and outlets to address this challenge. First, experiments were conducted to test the performance of different inlet methods. When cooling water flows in from the end with a larger radius of curvature, the temperature difference of the CPU can be 49.3% lower than other methods. A decrease in the radius of curvature enhances the disturbance of the fluid, mitigating the negative impact of rising water temperature on the temperature difference. The simulation results show good consistency with the experimental data. The optimal spiral dimensions are determined to be r = 3 mm and R = 15 mm based on the geometric parameter analysis. Compared with single spiral heat sink (SSHS), DSHS can reduce the pressure drop by 48.3% and temperature difference by 64.1%. In addition, the DSHS is compared with the serpentine heat sink (SHS) to prove its advantages. The results show that the average temperature of the DSHS is slightly lower than that of the SHS, while the pressure drop, temperature difference, and performance evaluation criterion are all significantly better than those of the SHS. DSHS can dissipate a maximum heat of 438 W. The varying radius of curvature of DSHS can continuously disrupt the boundary layer and enhance heat transfer. Furthermore, by slotting the wall surface, the pressure drop is reduced by 10% without affecting the heat dissipation. The DSHS maintains its performance benefits across different working fluids such as ethylene glycol solution and transformer oil, showing its advantage of wide applicability. The proposed DSHS provides a promising alternative design of heat sinks for the processing unit cooling applications.

处理器不断升级的热功率需要先进的冷却解决方案。为了解决这一问题，本研究提出了一种具有双入口和双出口的新型双螺旋散热器（DSHS）。首先，通过实验对不同进气道的性能进行了测试。当冷却水从曲率半径较大的一端流入时，CPU的温度差可比其他方式降低49.3%。曲率半径的减小增强了流体的扰动，减轻了水温升高对温差的负面影响。仿真结果与实验数据吻合较好。通过几何参数分析，确定了最佳螺旋尺寸r = 3mm和r = 15mm。与单螺旋散热器（SSHS）相比，DSHS可将压降降低48.3%，温差降低64.1%。此外，还将DSHS与蛇形散热器（SHS）进行了比较，证明了其优点。结果表明：DSHS的平均温度略低于SHS，而压降、温差、性能评价指标均明显优于SHS。DSHS的最大散热功率为438w。DSHS曲率半径的变化可以不断破坏边界层，增强传热。此外，通过开槽壁面，在不影响散热的情况下，压降降低了10%。DSHS在不同的工作流体（如乙二醇溶液和变压器油）中保持其性能优势，显示出其广泛适用性的优势。所提出的DSHS为处理装置的冷却应用提供了一种有前途的散热器替代设计。

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引用次数: 0

Cavitation and associated entropy production characteristic of a pump turbine in pumping mode based on a modified Zwart-Gerber-Belamri model 基于改进Zwart-Gerber-Belamri模型的泵水轮机抽运模式空化及相关熵产特性

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-01-31 DOI: 10.1016/j.ijheatfluidflow.2026.110288

Xiuli Mao , Jiaren Hu , Pengju Zhong , Tong Mu , Zhiping Zhang , Shenggen Li

This study develops a modified Zwart-Gerber-Belamri (MZGB) cavitation model in which the saturation vapor pressure is defined dynamically. The proposed model is then applied to investigate the cavitation evolution and entropy production characteristics of a pump turbine under multiple pumping conditions. Numerical predictions based on the MZGB model show closer agreement with experimental data than those from the ZGB model, with an accuracy of 96.17% for pressure variation. With decreasing flow rate and cavitation number, the cavitation region extends along the blade suction surface, and coupled cavitation-vortex structures form within the runner, increasing both cavitation and vortex volume. The precipitation of cavitation bubbles, accompanied by energy absorption, weakens the pressure pulsations within the cavitation region. By contrast, in the non-cavitation region at 0.8 times of the flow rate at the best efficiency point (0.8Q_BEP), the maximum amplitude is 12 times that at 1.0Q_BEP and 1.9 times that at 0.6Q_BEP. Due to vortex development and flow separation in the runner, the dominant frequency of pressure pulsations corresponds to the runner rotating frequency (f_n) at 1.0Q_BEP, while that at 0.8Q_BEP is dominated by 3f_n. In contrast, 0.6Q_BEP exhibits multiple pressure pulsation peaks within f/f_n ≤ 5. Furthermore, as C_σ and flow rate decrease, the primary entropy production region extends to both the runner and guide vane domains, while the dominant mechanism of entropy production transfers from the wall shear dissipation to the turbulent dissipation. These findings provide a theoretical guidance for the cavitation risk assessment and the energy loss mitigation in pump turbines.

本文建立了一种改进的Zwart-Gerber-Belamri （MZGB）空化模型，其中饱和蒸汽压是动态定义的。将该模型应用于水泵水轮机多工况下的空化演化和熵产特性研究。与ZGB模型相比，基于MZGB模型的数值预测与实验数据的吻合度更高，对压力变化的预测精度为96.17%。随着流量和空化数的减小，空化区域沿叶片吸力面扩展，在转道内形成耦合空化-涡结构，空化和涡体积均增大。空化气泡的析出，伴随着能量的吸收，减弱了空化区域内的压力脉动。而在非空化区域，当流量为最佳效率点（0.8 qbep）的0.8倍时，最大振幅是1.0QBEP时的12倍，是0.6QBEP时的1.9倍。由于流道内的涡流发展和流动分离，压力脉动的主导频率对应于1.0QBEP时的流道旋转频率（fn），而0.8QBEP时的压力脉动以3fn为主。相比之下，0.6QBEP在f/fn≤5范围内出现多个压力脉动峰。此外，随着Cσ和流量的减小，初级熵产生区域扩展到流道和导叶区域，主要熵产生机制由壁面剪切耗散转变为湍流耗散。研究结果为水泵水轮机汽蚀风险评估和能量损失降低提供了理论指导。

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引用次数: 0

Mechanism of cycloidal trailing-edge blades in suppressing pressure pulsation and vibration in centrifugal pumps 摆线尾缘叶片抑制离心泵压力脉动和振动的机理

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-02-11 DOI: 10.1016/j.ijheatfluidflow.2026.110305

Yahui Hu , Qinyang Li , Jian Chen , Guanghua Gan , Chengyi Yi

To suppress pressure pulsation and flow-induced vibration in a fire-fighting centrifugal pump, cycloidal trailing-edge blades are designed according to the cycloidal principle, and three variants are assessed using transient CFD, combined with time–frequency analysis and coherent-structure identification based on the Q-criterion. The results show that cycloidal shaping reorganises the impeller-exit wake by weakening shear-layer roll-up and wake intermittency, thereby alleviating the tongue-adjacent impeller–volute interaction and reducing the broadband disturbance level. Consequently, pressure fluctuations are reduced in both the impeller passage and the volute, with a pronounced attenuation of low-frequency components below 50 Hz. Among the three designs, the B2 configuration achieves the best overall suppression, reducing impeller pressure-coefficient fluctuations by 42–55 percent and attenuating the oscillations of radial and axial loads, while producing smoother force waveforms. These findings link the effectiveness of the cycloidal trailing edge to wake reorganisation and reduced tongue-induced excitation, providing a practical geometric strategy to improve the stability and vibration–noise characteristics of fire-fighting centrifugal pumps.

为了抑制消防离心泵的压力脉动和流激振动，根据摆线原理设计了摆线尾缘叶片，并结合时频分析和基于q准则的相干结构识别，利用瞬态CFD对三种变型进行了评估。结果表明，摆线修整通过减弱剪切层卷起和尾迹间歇性来重组叶轮-出口尾迹，从而减轻了舌部相邻的叶轮-蜗壳相互作用，降低了宽带扰动水平。因此，叶轮通道和蜗壳中的压力波动都减少了，低频分量在50 Hz以下的衰减明显。在三种设计中，B2结构的整体抑制效果最好，叶轮压力系数波动降低了42 - 55%，径向和轴向载荷的振荡得到了衰减，同时产生了更平滑的力波形。这些发现将摆线尾缘的有效性与尾迹重组和减少舌形激励联系起来，为提高消防离心泵的稳定性和振动噪声特性提供了实用的几何策略。

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引用次数: 0

A review of the immersion liquid cooling technology for high-performance data centers 高性能数据中心浸没式液体冷却技术综述

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-02-01 DOI: 10.1016/j.ijheatfluidflow.2026.110282

Chunjie Yang, Xianfeng Zhu, Guangyi Zhang, Gui Pan, Xingchuan Wang

In the context of global digital transformation, the rapid expansion of data centers has intensified the challenge of high-power cooling. Traditional air cooling, with its limited efficiency, is increasingly inadequate to meet current demands. Immersion liquid cooling (ILC) has thus emerged as a critical research focus in data center thermal management, owing to its superior heat dissipation capabilities, excellent temperature uniformity, and energy-saving advantages. This paper provides a comprehensive analysis of ILC technology, examining coolant classification and selection criteria, the operating principles and performance of various liquid-cooling structures, and their practical applications. Two primary coolant types—oil-based and fluorocarbon-based—are evaluated, along with three main ILC system configurations: buoyancy-driven single-phase, pump-driven single-phase, and two-phase systems, each suited to different heat load scenarios. Performance improvement strategies, including passive and active enhancement techniques, are also explored. The research concludes that ILC has entered the stage of large-scale demonstration, significantly improving energy efficiency and exhibiting clear trends toward higher density and modularization. However, challenges such as high costs, operational complexity, and the lack of unified standards persist. Future efforts should prioritize technological innovation, cost reduction, and standardization to facilitate wider adoption and support the development of green, efficient data centers.

在全球数字化转型的背景下，数据中心的快速扩张加剧了大功率冷却的挑战。传统的风冷由于效率有限，越来越不能满足当前的需求。浸入式液体冷却（ILC）以其优越的散热能力、优异的温度均匀性和节能优势，成为数据中心热管理领域的重要研究热点。本文全面分析了ILC技术，考察了冷却剂的分类和选择标准，各种液体冷却结构的工作原理和性能，以及它们的实际应用。评估了两种主要的冷却剂类型——油基和氟碳基，以及三种主要的ILC系统配置：浮力驱动单相、泵驱动单相和两相系统，每种系统都适用于不同的热负荷场景。性能改进策略，包括被动和主动增强技术，也进行了探讨。研究认为，ILC已进入大规模示范阶段，显著提高了能源效率，并呈现出高密度和模块化的明显趋势。然而，诸如高成本、操作复杂性和缺乏统一标准等挑战仍然存在。未来的工作应优先考虑技术创新、降低成本和标准化，以促进更广泛的采用，并支持绿色高效数据中心的发展。

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引用次数: 0

Numerical study of flow and heat transfer performance in a novel microchannel under pulsating flow conditions 脉动流动条件下新型微通道内流动与换热性能的数值研究

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-01-08 DOI: 10.1016/j.ijheatfluidflow.2025.110228

Chunquan Li, Jirong Huang, Yilong Hu, Cailin Li, Hongyan Huang

This paper presents a numerical study of the flow and heat transfer performance of a trapezoidal cavity rib-double rectangular circular fin microchannel heat sink (TR-DRRF) combined with a pulsating fluid. The SIMPLEC algorithm is adopted for the pressure–velocity coupling using second order upwind discretization equations. The TR-DRRF microchannel is analyzed in comparison with straight rectangular microchannel (SR), trapezoidal cavity fin microchannel (TR) and trapezoidal cavity fin-single rectangular circular fin microchannel (TR-SRRF). Results indicate that the dual rectangular circular fins of the TR-DRRF significantly increase the fluid–solid interface area, disrupt thermal boundary layer development, and alter flow field distribution. At Reynolds number (Re) = 400, its maximum temperature (

T_{_{m a x}}

) is reduced by 48 K, 15.8 K, and 5.96 K compared to SR, TR, and TR-SRRF, respectively. while the Nusselt number (Nu) increased by 88.72%, 41.76%, and 13.03%, respectively. The performance evaluation criterion (PEC) improved by over 7% compared to the other three designs. The introduction of pulsating flow significantly enhances the overall thermal performance of TR-DRRF compared to steady flow at the same Re number. The core mechanism involves the sustained development of the flow boundary layer and the generation of secondary flow/counterflow. Among these, square-wave pulsed flow exhibits the most effective heat transfer enhancement. Pulsation parameters exert distinct effects: frequencies in the range of 0.2–5 Hz impair heat transfer, whereas those in the range of 5–70 Hz enhance it. Increasing frequency enhances overall heat dissipation performance (PEC outperforms steady flow at f

>

10 Hz). Increasing amplitude (0.2–1.2 m/s) enhances heat transfer (reducing

T_{_{m a x}}

by up to 2.1 K) but increases pressure loss. Only when amplitude

<

0.7 m/s does the overall performance surpass steady flow.

本文对梯形腔肋-双矩形圆鳍微通道散热器（TR-DRRF）与脉动流体结合的流动和换热性能进行了数值研究。采用SIMPLEC算法对二阶迎风离散方程进行压力-速度耦合。将TR- drrf微通道与直矩形微通道（SR）、梯形腔鳍微通道（TR）和梯形腔鳍-单矩形圆鳍微通道（TR- srrf）进行对比分析。结果表明，TR-DRRF的双矩形圆翅片显著增加了流固界面面积，破坏了热边界层的发育，改变了流场分布。在雷诺数(Re) = 400时，其最高温度（Tmax）比SR、TR和TR- srrf分别降低了48 K、15.8 K和5.96 K。努塞尔数（Nu）分别提高了88.72%、41.76%和13.03%。性能评价标准（PEC）比其他三种设计提高了7%以上。与相同雷诺数下的稳态流动相比，脉动流动的引入显著提高了TR-DRRF的整体热性能。其核心机制涉及流动边界层的持续发展和二次流/逆流的产生。其中，方波脉冲流表现出最有效的强化传热。脉动参数对传热的影响明显：0.2-5 Hz范围内的脉动参数对传热不利，而5-70 Hz范围内的脉动参数对传热有促进作用。增加频率提高整体散热性能（PEC优于稳定流在f >； 10赫兹）。增加振幅（0.2-1.2 m/s）可以增强传热（最大热值降低2.1 K），但会增加压力损失。只有当振幅<； 0.7 m/s时，整体性能才会超过稳流。

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引用次数: 0

Multi-scale analysis of solute dispersion in free and forced convection flow between two parallel plates filled with a porous medium 充满多孔介质的平行板间自由和强制对流流动中溶质弥散的多尺度分析

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-01-06 DOI: 10.1016/j.ijheatfluidflow.2025.110234

Aruna A, Swarup Barik

This study investigates the transverse concentration distribution of contaminant transport in free and forced convective flow within a parallel plate filled with a porous medium. The solute undergoes irreversible boundary reactions at the plates. Most previous studies explored similar configurations in free and forced convective flows by incorporating magnetic effects. However, our study introduces a porous medium, which more accurately reflects real-world scenarios, such as pores in particles within flowing rivers or other environments. We develop an analytical solution of the dispersion coefficient, mean and transverse concentration using a multi-scale technique. The present study examines the effects of Grashof number (

G

), porous parameter and relative viscosity in the presence of boundary absorptions on the solute dispersion. Higher porous parameter values reduce permeability, limit solute spreading, and maintain a peak in the mean concentration distribution. In porous media, a negative

G

enhances solute dispersion near the upper boundary, whereas a positive

G

influences dispersion when the lower boundary absorbs. The buoyancy forces dominate for

G > 0

or

G < 0

, driving the flow toward the heating or cooling plates and intensifying non-uniformity in the transverse concentration distribution. This effect becomes more significant with higher porosity and viscosity, as the porous medium reduces permeability and increases resistance to fluid motion. When boundary reactions are considered in the presence of a porous medium under free and forced convection, they cause uneven solute distribution as the walls absorb solute. A higher porous parameter increases resistance to fluid flow, which amplifies concentration gradients and enhances non-uniformity.

本文研究了在一个充满多孔介质的平行板中，污染物在自由和强制对流中的横向浓度分布。溶质在板上发生不可逆的边界反应。大多数先前的研究通过结合磁效应探索了自由对流和强制对流中的类似结构。然而，我们的研究引入了一种多孔介质，它更准确地反映了现实世界的情况，例如流动的河流或其他环境中颗粒的孔隙。我们利用多尺度技术建立了色散系数、平均浓度和横向浓度的解析解。本研究考察了边界吸收存在时，格拉什夫数(G)、多孔参数和相对粘度对溶质弥散的影响。较高的孔隙参数值会降低渗透率，限制溶质扩散，并在平均浓度分布中保持峰值。在多孔介质中，负G增强靠近上界的溶质色散，而正G影响靠近下界吸收时的色散。在G>；0或G<；0时，浮力占主导地位，促使气流向加热板或冷却板流动，加剧了横向浓度分布的不均匀性。随着孔隙度和粘度的增加，这种影响变得更加明显，因为多孔介质降低了渗透率，增加了流体运动的阻力。当考虑在自由和强制对流下存在多孔介质时的边界反应时，由于壁面吸收溶质，它们会导致溶质分布不均匀。较高的孔隙参数增加了流体流动阻力，从而放大了浓度梯度，增强了非均匀性。

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引用次数: 0

Hybrid photovoltaic–thermal and solar thermal collectors with integrated phase change materials: toward sustainable greenhouse energy systems 集成相变材料的混合光电热和太阳能集热器：朝向可持续温室能源系统

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-01-31 DOI: 10.1016/j.ijheatfluidflow.2026.110268

Soroush Entezari , Meysam Khatibi , Mikhail Sorin

Greenhouses require substantial energy for heating, cooling, and electricity, yet current renewable solutions rarely provide all three simultaneously. Most existing systems supply either thermal or electrical output and lack integrated storage, creating mismatches between solar availability and greenhouse demand and reinforcing dependence on fossil fuels. This study addresses this problem by developing and analyzing a hybrid photovoltaic–thermal (PVT) and solar thermal (ST) collector system integrated with phase change materials (PCMs) for combined power generation and heat storage in greenhouse applications. A three-dimensional numerical model examines the effects of PCM type (RT21, RT31, RT35) and heat transfer fluid flow rate under typical summer conditions in Sherbrooke, Québec, Canada. Results indicate that low-melting PCMs (RT21) achieve rapid phase change before solar noon, offering early-day cooling but limited afternoon buffering. Conversely, higher-melting PCMs (RT31, RT35) extend heat absorption throughout peak irradiance, optimizing PV thermal regulation. Parametric analysis reveals that reduced HTF flow rates maximize PCM utilization and outlet temperatures, whereas higher flow rates prioritize electrical stability. Exergy results indicate a fundamental trade-off: RT21 maximizes daily-average thermal exergy through superior temperature gradients, while RT35 optimizes electrical exergy by maintaining lower cell temperatures. Increasing HTF flow rate enhances electrical exergy but reduces thermal exergy by lowering the temperature level of the delivered heat. A 100 m² installation yields approximately 455 kWh/day of thermal energy and 35.5 kWh/day of electricity (July/August), satisfying nearly all thermal loads and 30–34% of electrical demand. This configuration achieves a significant mitigation of 77–78 kg CO₂e/day, primarily through the displacement of carbon-intensive natural gas heating.

温室需要大量的能源来加热、冷却和发电，但目前的可再生能源解决方案很少能同时提供这三种能源。大多数现有系统要么提供热能输出，要么提供电能输出，缺乏综合存储，造成太阳能供应与温室气体需求之间的不匹配，并加强了对化石燃料的依赖。本研究通过开发和分析一种结合相变材料（PCMs）的混合光伏热（PVT）和太阳能热（ST）集热器系统，解决了这一问题，该系统可用于温室联合发电和蓄热应用。三维数值模型研究了在加拿大quemenbec Sherbrooke典型夏季条件下PCM类型（RT21, RT31, RT35）和传热流体流速的影响。结果表明，低熔点PCMs （RT21）在太阳正午之前实现了快速相变，提供了早期的冷却，但有限的下午缓冲。相反，高熔点pcm （RT31, RT35）在整个峰值辐照度中扩展热吸收，优化PV热调节。参数分析表明，降低HTF流量可使PCM利用率和出口温度最大化，而高流量则优先考虑电气稳定性。火用结果表明了一个基本的权衡：RT21通过优越的温度梯度最大化日平均热用，而RT35通过保持较低的电池温度来优化电能。增加HTF流量增加了电能，但通过降低传递热量的温度水平来减少热耗。一个100平方米的装置产生大约455千瓦时/天的热能和35.5千瓦时/天的电力（7月/ 8月），满足几乎所有的热负荷和30-34%的电力需求。这种配置主要通过取代碳密集型天然气供暖，实现了每天77-78千克二氧化碳当量的显著减排。

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引用次数: 0

The effect of composite cement-based materials on the heat loss of geothermal wellbores 复合水泥基材料对地热井热损失的影响

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-02-04 DOI: 10.1016/j.ijheatfluidflow.2026.110257

Kai Wei , Ao Wang , Desheng Wu , Hao Chen , Yulong Liu

Geothermal energy is a widely distributed, high-potential, stable, and reliable non-carbon clean renewable energy source, playing a critical role in energy transition and low-carbon development. Geothermal wells are the primary technical means for geothermal energy extraction. As the core component of geothermal exploitation, a geothermal well consists of a multilayer composite system comprising the casing, cement sheath, and surrounding formation, within which heat transfer processes are highly complex. In this study, a heat transfer model for the casing–cement sheath–formation coupled system is established, together with a thermal conductivity evaluation model for cement-based composites. Numerical simulations are performed to investigate the effects of key influencing factors—including fluid flow conditions, thermophysical properties of the casing and cement sheath, and thermal properties of cementitious composites—on the heat extraction performance of geothermal wells. The results demonstrate that the thermal conductivity of the cement sheath has a significant impact on heat extraction capacity. Reducing the cement sheath thermal conductivity effectively increases the wellhead production temperature, decreases wellbore heat loss, and mitigates the influence of formation parameter uncertainty under different formation conditions. Furthermore, incorporating thermal insulation materials such as glass beads, slag microspheres, and aerogel particles into the cement sheath markedly lowers its thermal conductivity, with aerogel particles exhibiting the most pronounced effect, achieving a reduction of approximately 30%. The proposed models and findings provide theoretical support and technical guidance for optimizing geothermal well design and enhancing the efficiency of geothermal energy exploitation.

地热能是一种分布广泛、潜力大、稳定可靠的无碳清洁可再生能源，在能源转型和低碳发展中发挥着至关重要的作用。地热井是地热能开采的主要技术手段。地热井是地热开发的核心组成部分，是由套管、水泥环和周围地层组成的多层复合系统，其中的传热过程非常复杂。本文建立了套管-水泥环-地层耦合系统的传热模型，建立了水泥基复合材料导热系数评价模型。通过数值模拟研究了流体流动条件、套管和水泥环热物性以及胶凝材料热物性等关键影响因素对地热井采热性能的影响。结果表明，水泥护套的导热系数对抽热能力有显著影响。降低水泥环导热系数可有效提高井口生产温度，减少井筒热损失，减轻不同地层条件下地层参数不确定性的影响。此外，在水泥环中加入玻璃微珠、矿渣微球和气凝胶颗粒等隔热材料可显著降低其导热系数，其中气凝胶颗粒的效果最为显著，可降低约30%的导热系数。所建立的模型和研究结果为优化地热井设计，提高地热能开发效率提供了理论支持和技术指导。

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引用次数: 0

Geometric confinement and fluid properties effects on stability and heat transfer of thermal convection in lateral heated cavities 几何约束和流体性质对侧向加热腔内热对流稳定性和传热的影响

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-02-12 DOI: 10.1016/j.ijheatfluidflow.2026.110312

Hua Hu , Juan-Juan Qin , Lai-Yun Zheng , Xu-Long Li , Bing-Xin Zhao

<div><div>A numerical study is performed to investigate two-dimensional natural convection in a laterally heated cavity, with particular emphasis on the coupled effects of the aspect ratio (<span><math><mi>A</mi></math></span>), Rayleigh number (<span><math><mrow><mi>R</mi><mi>a</mi></mrow></math></span>), and Prandtl number (<span><math><mrow><mi>P</mi><mi>r</mi></mrow></math></span>). The simulations cover mainly the ranges <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>4</mn></mrow></msup><mo>≤</mo><mi>R</mi><mi>a</mi><mo>≤</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>6</mn></mrow></msup></mrow></math></span>, <span><math><mrow><mn>0</mn><mo>.</mo><mn>01</mn><mo>≤</mo><mi>A</mi><mo>≤</mo><mn>10</mn></mrow></math></span>, and <span><math><mrow><mn>0</mn><mo>.</mo><mn>01</mn><mo>≤</mo><mi>P</mi><mi>r</mi><mo>≤</mo><mn>10</mn></mrow></math></span>. A fourth-order compact finite-difference scheme combined with a third-order TVD Runge–Kutta time integration is employed to ensure numerical stability and adequate resolution of unsteady flow features. The results reveal that heat transfer is strongly influenced by the Prandtl number. As <span><math><mrow><mi>P</mi><mi>r</mi></mrow></math></span> increases, the flow transitions from unsteady to steady behavior and the overall heat transfer is enhanced. For low-Prandtl-number fluids (<span><math><mrow><mi>P</mi><mi>r</mi><mo><</mo><mn>1</mn></mrow></math></span>), such as gases and liquid metals, nonlinear solution bifurcations emerge, becoming increasingly pronounced at larger aspect ratios and higher Rayleigh numbers. The onset of unsteadiness is associated with a critical Rayleigh number <span><math><mrow><mi>R</mi><msub><mrow><mi>a</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>, marking the transition from steady to unsteady convection. Scaling analyses show that <span><math><mrow><mi>R</mi><msub><mrow><mi>a</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>∼</mo><msup><mrow><mi>A</mi></mrow><mrow><mo>−</mo><mn>10</mn><mo>/</mo><mn>3</mn></mrow></msup></mrow></math></span> for air and <span><math><mrow><mi>R</mi><msub><mrow><mi>a</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>∼</mo><msup><mrow><mi>A</mi></mrow><mrow><mo>−</mo><mn>7</mn><mo>/</mo><mn>3</mn></mrow></msup></mrow></math></span> for water, indicating a reduced sensitivity to geometric confinement for high-<span><math><mrow><mi>P</mi><mi>r</mi></mrow></math></span> fluids. The aspect ratio is found to exert a non-monotonic influence on heat transfer. The average Nusselt number (<span><math><mrow><mi>N</mi><msub><mrow><mi>u</mi></mrow><mrow><mi>av</mi></mrow></msub></mrow></math></span>) attains its maximum at an optimal aspect ratio <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>m</mi></mrow></msub></math></span> that shifts toward smaller values as <span><math><mrow><mi>R</mi><mi>a</mi></mrow></math></span> increases. Additionally, the heat transfer follows a power-law dependence on the Rayleig

本文对横向加热腔内的二维自然对流进行了数值研究，特别强调了展弦比(A)、瑞利数（Ra）和普朗特数（Pr）的耦合效应。模拟范围主要为104≤Ra≤106、0.01≤A≤10、0.01≤Pr≤10。采用四阶紧凑有限差分格式结合三阶TVD龙格-库塔时间积分保证了数值稳定性和非定常流场特征的充分分辨。结果表明，传热受到普朗特数的强烈影响。随着Pr的增大，流动由非定常向定常转变，整体换热增强。对于低普朗特数流体（Pr<1），如气体和液态金属，会出现非线性解分岔，在较大的纵横比和较高的瑞利数下变得越来越明显。非定常的开始与临界瑞利数Rac有关，标志着对流从定常到非定常的过渡。标度分析表明，空气中的Rac ~ A−10/3和水中的Rac ~ A−7/3，表明高pr流体对几何约束的敏感性降低。长径比对传热有非单调性影响。平均努塞尔数（Nuav）在最佳宽高比Am时达到最大值，随着Ra的增加，该值逐渐变小。此外，传热遵循瑞利数的幂律关系，Nuav=cRaβ，其中0.14≤c≤0.20,0.25≤β≤0.30，系数取决于普朗特数。

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