Case Studies in Thermal Engineering最新文献_第8页

Thermal and energy performance of hybrid aluminum nitride–alumina (AlN–Al2O3) suspension: A pathway toward enhanced stability and efficiency 氮化铝-氧化铝（AlN-Al2O3）混合悬浮液的热性能和能量性能：提高稳定性和效率的途径

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-02-25 DOI: 10.1016/j.csite.2026.107860

Hafedh Belmabrouk , A. Belhadj Mohamed , Iskander Tlili

The growing demand of efficient energy systems has driven integration of modern nanofluid suspensions capable of overcoming the traditional thermal limitations. In this contest, the hybridization of aluminum nitride (AIN) and alumina nanoparticles (Al₂O₃) provide a promising pathway to the attain boosted thermal stability and energy efficiency, making it attractive for the modern engineering and energy applications. With such motivation, this continuation aims to presents the optimized thermal impact of Casson hybrid nanofluid (HNF) with suspension of aluminum nitride (AIN) and alumina nanoparticles (Al₂O₃). The base fluid properties of analyzed by using engine oil (SAE10W-30) base liquid which is essentially used energy production and automobile industries. A single-phase nanofluid model is used to model the hybrid nanofluid problem. The modelling associated to single-phase nanofluid provide significance applications in micro and nano-scale cooling systems, microchannel heat applications, heat exchangers etc. The flow is driven by oscillatory elastic surface with permeability of porous media. The investigation of heat transfer is subject to nonlinear thermal radiation. In order to capture the propagation wave features, the energy and concentration equations are updated by using the Cattaneo-Christov model. The analytical simulations of modeled equations are performed by using the homotopy analysis method. The significance of modeled flow parameters is physical entertained. It is observed that velocity profile declined for Casson fluid parameter and permeability of porous medium. The thermal enhancement of engine oil can be enhanced by increasing nanoparticles volume fraction. Moreover, skin friction coefficient periodically varies with increasing amplitude by enhancing Hartmann number. The simulated results comprise significance in advanced heat exchangers, renewable energy systems, automobile engine cooling, turbine blade cooling, and energy storage units.

对高效能源系统日益增长的需求推动了现代纳米流体悬浮液的集成，能够克服传统的热限制。在本次竞赛中，氮化铝（AIN）和氧化铝纳米粒子（Al2O3）的杂化提供了一个有前途的途径，以获得提高热稳定性和能源效率，使其具有吸引力的现代工程和能源应用。基于这样的动机，本续文旨在展示氮化铝（AIN）和氧化铝纳米颗粒（Al2O3）悬浮液卡森混合纳米流体（HNF）的优化热影响。以主要用于能源生产和汽车工业的发动机油（SAE10W-30）基液为研究对象，对基液的性质进行了分析。采用单相纳米流体模型来模拟混合纳米流体问题。与单相纳米流体相关的建模在微纳米级冷却系统、微通道热应用、热交换器等方面提供了重要的应用。流动是由多孔介质具有渗透率的振荡弹性面驱动的。传热问题的研究涉及到非线性热辐射。为了捕捉传播波的特征，利用Cattaneo-Christov模型对能量和浓度方程进行了更新。利用同伦分析法对模型方程进行了解析仿真。模拟的流动参数具有物理意义。观察到卡森流体参数和多孔介质渗透率的速度分布呈下降趋势。提高纳米颗粒的体积分数可以增强机油的热强化性能。此外，通过增强哈特曼数，表面摩擦系数随振幅的增加而周期性变化。模拟结果在先进的热交换器、可再生能源系统、汽车发动机冷却、涡轮叶片冷却和储能装置中具有重要意义。

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引用次数: 0

Thermo-physical properties of marine lubricant/hydraulic fluids and enhancing hot surface ignition characteristics considering coupling influences 船用润滑油/液压油的热物理特性及考虑耦合影响的热表面点火特性增强

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-03-04 DOI: 10.1016/j.csite.2026.107885

Kan Wang , Xinjie Gong , Hanzhe Chen , Yang Ming

Ship fires frequently originate from an accidental ignition of spilling marine fuels on hot surface in engine room, yet detailed characterization of the initial ignition behavior remains limited. This study investigates the hot surface ignition (HSI) characteristics of marine lubricant and hydraulic oil under simulated ship engine room conditions using a dedicated experimental platform. Critical ignition parameters and thermal data were systematically obtained. The results reveal that the vapor-air mixture formed after fuel contact with the hot surface exhibits a highly stratified distribution in the vertical dimension, distinct from conventional marine diesel. As the hot surface temperature T_s increases, the initial HSI position shifts closer to the high-temperature substrate. Following flame kernel formation, the flame propagates downward toward the hot surface, with hydraulic oil exhibiting higher heat flux intensity compared to the marine lubricant. When hot surface temperature T_s exceeds 765 K, the HSI delay time of the marine lubricant stabilizes, whereas the hydraulic oil continues to show significant variability. Based on heat transfer theory and experimental data, an ignition delay prediction model is developed, and a probability-based HSI assessment framework is specifically optimized for these fuels. By integrating multi-parameter measurements and validation data, this study provides a novel methodology for evaluating the initial fire risks associated with specialized marine fuels in ship engine room.

船舶火灾通常是由于船舶燃料在机舱热表面的泄漏而引起的，但对其初始点火行为的详细描述仍然有限。利用专用实验平台，研究了船舶润滑油和液压油在模拟船舶机舱条件下的热表面着火特性。系统地获得了关键点火参数和热数据。结果表明，燃料与热表面接触后形成的蒸汽-空气混合物在垂直维度上呈现高度分层分布，与常规船用柴油不同。随着热表面温度Ts的升高，初始HSI位置向高温衬底靠近。随着火焰核的形成，火焰向下向热表面传播，与船用润滑油相比，液压油表现出更高的热流密度。当热表面温度Ts超过765 K时，船用润滑油的HSI延迟时间趋于稳定，而液压油的HSI延迟时间继续表现出显著的变异性。基于传热学理论和实验数据，建立了点火延迟预测模型，并针对这些燃料优化了基于概率的HSI评估框架。通过综合多参数测量和验证数据，本研究为评估船舶机舱专用船用燃料的初始火灾风险提供了一种新的方法。

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引用次数: 0

Study on the heat transfer enhancement of hydro-turbine thrust bearing with nano-oil 纳米油对水轮机推力轴承强化传热的研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-03-04 DOI: 10.1016/j.csite.2026.107899

Dongbin Ji , Juan Duan , Xiaoxu Zhang , Zeyu Peng , Luyang Chen , Zhumei Luo , Jie Chen

The thrust bearing in a hydro-turbine unit carries the entire axial load, and its cooling performance is crucial for operational safety due to the substantial frictional heat generated. This study numerically investigates the enhancement of heat dissipation in a large-scale 100-MW thrust bearing using lubricating oil doped with copper oxide nanoparticles. Nano-oils with mass concentrations ranging from 0.1 to 0.5 wt% were prepared and experimentally characterized. Their thermal performance was compared with that of pure oil under varying inlet temperatures (297–303 K) and mass flow rates (50–200 kg/s) by means of a validated CFD model. Results demonstrate that the 0.4 wt% nano-oil yields the optimal performance under baseline conditions (300 K, 132 kg/s). It reduces the pad temperature by 0.31 K and raises the outlet oil temperature by 0.14 K, indicating improved heat extraction. The corresponding Performance Evaluation Criterion (PEC) reaches 1.070, reflecting a 7 % overall thermo-hydraulic improvement. Notably, the 0.4 wt% nano-oil achieves comparable cooling without requiring lower inlet temperatures or higher flow rates, thereby lowering the energy consumption of the cooling system. This work provides a quantitative basis for the energy-efficient implementation of nano-oils in hydro-turbine thrust bearing system.

水轮机机组的推力轴承承担全部轴向负荷，由于产生大量的摩擦热，其冷却性能对运行安全至关重要。本文通过数值模拟研究了纳米氧化铜掺杂润滑油对大型100 mw推力轴承散热的增强作用。制备了质量浓度为0.1 ~ 0.5 wt%的纳米油，并对其进行了实验表征。在不同的进口温度（297-303 K）和质量流量（50-200 kg/s）下，通过验证的CFD模型将其与纯油的热性能进行了比较。结果表明，在基准条件下（300 K, 132 kg/s）， 0.4 wt%纳米油的性能最佳。它使垫层温度降低了0.31 K，使出口油温度提高了0.14 K，表明热量的提取得到了改善。相应的性能评价标准（PEC）达到1.070，反映了7%的整体热水力改善。值得注意的是，0.4 wt%的纳米油不需要更低的入口温度或更高的流量就能达到同样的冷却效果，从而降低了冷却系统的能耗。该工作为纳米油在水轮机推力轴承系统中的节能实施提供了定量依据。

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引用次数: 0

A unified standard thermal resistance-impedance-circuit approach for dynamic characteristic analysis of grid-connected solid oxide fuel cell system 并网固体氧化物燃料电池系统动态特性分析的统一标准热阻-阻抗电路方法

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-03-02 DOI: 10.1016/j.csite.2026.107901

Tong Hao , Xingce Wang , Junhong Hao , Guiping Zhou , Chao Xu , Xiaoze Du

The dynamic integration of Solid Oxide Fuel Cell (SOFC) systems with power electronics presents significant challenges due to the disparate time scales of thermo-electrochemical processes and electronic control systems. This manuscript develops a unified standard thermal resistance-impedance-circuit approach for grid-connected SOFC systems. This approach provides a comprehensive cross-scale dynamic model, coupling the standard thermal impedance (STI) method for SOFC modeling with power regulation circuit for converter and inverter, which constructs the overall system topology and characterizes the transmission and coupling characteristics of various physical parameters within different components, integrating the multi-physical processes, cross-timescale dynamics and inter-disciplined areas to facilitate real-time simulation and control. On this basis, we analyze the dynamic response processes of power electronics equipment, and SOFC systems under varying load conditions. The results show that the power electronics respond in sub-second time frames (0.15–0.5 s), Balance of Plant (BOP) components have intermediate response times (7–9 min), and SOFC stack exhibit slow response times (25–39 min) when the load changes. This unified model visualizes the transfer and coupling properties of physical parameters within different components, highlights the interactions between the slow thermal-electrochemical dynamics and the fast-switching power electronics, then emphasizes the topology's capacity to handle transient states and ensure robust performance. The proposed framework provides a pathway for enhancing computational efficiency, improving power quality, and ensuring operational stability in distributed energy systems.

由于热电化学过程和电子控制系统的不同时间尺度，固体氧化物燃料电池（SOFC）系统与电力电子系统的动态集成面临着重大挑战。本文为并网SOFC系统开发了统一的标准热阻-阻抗电路方法。该方法提供了一个全面的跨尺度动态模型，将SOFC建模的标准热阻抗（STI）方法与变换器和逆变器的功率调节电路相结合，构建了整个系统拓扑结构，表征了不同组件内各种物理参数的传输和耦合特性，集成了多物理过程。跨时间尺度动力学和跨学科领域，以促进实时仿真和控制。在此基础上，分析了电力电子设备和SOFC系统在不同负载条件下的动态响应过程。结果表明，当负载发生变化时，电力电子系统的响应时间为亚秒级（0.15-0.5 s），工厂平衡（BOP）组件的响应时间为中等（7-9 min）， SOFC堆栈的响应时间较慢（25-39 min）。这个统一的模型可视化了不同组件内部物理参数的传递和耦合特性，突出了慢热电化学动力学和快速开关电力电子之间的相互作用，然后强调了拓扑处理瞬态和确保鲁棒性能的能力。提出的框架为提高分布式能源系统的计算效率、改善电能质量和确保运行稳定性提供了途径。

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引用次数: 0

A novel global chemical reaction mechanism for large-scale hydrogen detonation simulation 大规模氢爆轰模拟的一种新的全局化学反应机制

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-03-03 DOI: 10.1016/j.csite.2026.107879

Xin Lin , Qing Zhang , Haoyang Liu , Lidong Cheng , Bin Zhang , Wei Zhong

Conventional modeling strategies for large-scale detonation simulations suffer from a critical trade-off: detailed chemical mechanisms involve excessive computational costs, while typical single-step schemes lack sufficient predictive accuracy. To resolve this issue, this study proposes a novel single-step chemical reaction mechanism to simulate hydrogen-fueled detonation wave propagation in large-scale geometric configurations. Due to the substantial discrepancy in equilibrium temperature between the conventional irreversible single-step reaction mechanism and the detailed mechanism, the central concept in developing the new mechanism is to calibrate the equilibrium temperature of the single-step mechanism. The Nelder-Mead simplex optimization algorithm is employed to fine-tune the thermodynamic parameters of the single-step reaction mechanism ensuring agreement with the equilibrium temperature predicted by the detailed mechanism across a broad range of operational conditions. To validate the predictive capability of the new single-step mechanism in detonation wave propagation speed and peak overpressure, three distinct test cases were simulated using an OpenFOAM-type solver. The results demonstrate that the computational accuracy of the new single-step mechanism is comparable to that of the detail model (Keromnes'11-component, 24-reaction mechanism, hereinafter referred to as the KS mechanism in this study) when comparing detonation wave velocities and overpressure peaks. Furthermore, the total simulation time of the new single-step mechanism in this study was only 1.25% of that of the KS mechanism, and the new single-step mechanism exhibits lower sensitivity to grid resolution compared to the detailed mechanism. These findings indicate that the proposed mechanism is particularly well-suited for large-scale simulations of hydrogen fuel detonation.

大规模爆炸模拟的传统建模策略面临着一个关键的权衡：详细的化学机制涉及过多的计算成本，而典型的单步方案缺乏足够的预测精度。为了解决这一问题，本研究提出了一种新的单步化学反应机制来模拟大尺度几何构型下氢燃料爆震波的传播。由于常规的不可逆单步反应机理与详细的不可逆单步反应机理的平衡温度存在较大的差异，因此建立新的不可逆单步反应机理的中心思想是对单步反应机理的平衡温度进行标定。采用Nelder-Mead单纯形优化算法对单步反应机理的热力学参数进行微调，确保在广泛的操作条件下与详细机理预测的平衡温度一致。为了验证新的单步机制对爆震波传播速度和峰值超压的预测能力，使用openfoam型求解器模拟了三个不同的测试用例。结果表明，在比较爆震波速度和超压峰值时，新的单步机制的计算精度与详细模型（Keromnes的11组分，24反应机制，以下简称KS机制）相当。此外，本研究中新的单步机构的总模拟时间仅为KS机构的1.25%，并且与详细机构相比，新的单步机构对网格分辨率的敏感性较低。这些发现表明，所提出的机制特别适合于氢燃料爆轰的大规模模拟。

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引用次数: 0

Thermally thin-intermediate-thick transition on horizontal wood flame spread under external radiation 外辐射作用下水平木材火焰传播的热薄-中-厚转变

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-03-05 DOI: 10.1016/j.csite.2026.107910

Yang Zhou , Chunli Liu , Wenxi Qiu , Chao Ding , Zhengyang Wang , Rongwei Bu

Wood and its engineering products are promising materials for sustainable construction. However, flammable nature limits their further applications. The spread of fire is a disastrous behavior, which may undergo a thermally thin-intermediate-thick transition as external radiation (

{\dot{q}}_{e x t}^{″}

) increases. Yet, this remains insufficient understanding. The current study combines both experimental measurements and theoretical analyses to address this issue. Thermal thickness (the ratio of sample thickness to its thermal penetration depth) regimes of wood and its transition were emphasized. Both flame spread rate (v_f) and flame height increased with enhanced

{\dot{q}}_{e x t}^{″}

but presented an unusual non-monotonic trend (first increase then decrease) with increased thickness. The transitioning thickness coincided at 8 mm. The received total heat flux showed a similar trend to v_f with an identical transition thickness. Wood was sufficiently preheated so increasing the thickness enhanced the total fuel load and thus v_f. Wood underwent a thermally thin-intermediate-thick transition with increased thickness and

{\dot{q}}_{e x t}^{″}

. Analytical equations to calculate horizontal v_f of thermally intermediate materials were proposed. The thermal thickness range for thermally intermediate materials was quantitatively determined to be 0.85-3.75. The calculated v_f optimized with thermally intermediate equations better aligns with the measurements, with a determination coefficient R² of 0.96.

木材及其工程产品是一种很有前途的可持续建筑材料。然而，可燃性限制了它们的进一步应用。火灾的蔓延是一种灾难性的行为，随着外部辐射（q˙ext″）的增加，可能经历热薄-中-厚的转变。然而，这仍然是不够的理解。目前的研究结合了实验测量和理论分析来解决这个问题。强调了木材的热厚度（样品厚度与其热渗透深度的比值）及其转变。火焰蔓延速率（vf）和火焰高度均随q˙ext的增大而增大″，但随厚度的增加呈先增大后减小的非单调趋势。过渡厚度为8 mm。在相同的过渡厚度下，接收到的总热流密度表现出与vf相似的趋势。木材被充分预热，因此增加厚度提高了总燃料负荷，从而提高了vf。随着厚度和q˙ext的增加，木材经历了一个热薄-中-厚的转变″。提出了计算热中间材料水平vf的解析方程。定量确定了热中间材料的热厚度范围为0.85 ~ 3.75。利用热中间方程优化计算得到的vf与实测结果吻合较好，决定系数R2为0.96。

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引用次数: 0

Sensitivity-guided thermo-hydro-mechanical modeling and operation of a multi-well geothermal system: A case study in the Xiong'an new area, China 灵敏度导向多井地热系统热-水-力学建模与运行——以雄安新区为例

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-03-07 DOI: 10.1016/j.csite.2026.107919

Liyuan Liu , Xuchang Yang , Tao Wang , Pengpeng Ma , Yaohui Li , Shengwen Luo , Le Zhang

Hydrothermal geothermal systems are increasingly deployed as low-carbon sources for district heating, making it essential to assess both their thermal efficiency and long-term geomechanical stability. In this study, we develop a field-scale numerical model of a multi-well hydrothermal heating system in the Xiong'an New Area, China. A coupled three-dimensional thermo-hydro-mechanical (THM) model is constructed to simulate 10 years of reservoir operation and to jointly evaluate heat extraction performance and geological stability. Distance-based generalized sensitivity analysis (DGSA) is then applied to systematically identify the parameters that exert the greatest control on thermal behavior and geomechanical response. The simulations indicate that, under the current operating conditions, the reservoir remains geomechanically stable, whereas several production wells face a pronounced risk of thermal breakthrough. Overall, injection rate and injection temperature emerge as the dominant controlling parameters, with rock heat capacity exerting an additional influence on the mechanical response. Guided by these sensitivity results, we design a sensitivity-informed injection–production strategy that mitigates thermal breakthrough and enhances long-term energy extraction. Additional THM simulations confirm the effectiveness of this strategy, underscoring its potential as a practical guideline for the design and operation of multi-well hydrothermal geothermal systems in similar geological settings.

热液地热系统越来越多地被用作区域供热的低碳来源，因此评估其热效率和长期地质力学稳定性至关重要。本文建立了雄安新区多井热液采暖系统的现场尺度数值模型。建立了三维热-水-力耦合模型，模拟了水库10年的运行情况，并对储层的抽热性能和地质稳定性进行了综合评价。然后应用基于距离的广义灵敏度分析（DGSA）系统地识别对热行为和地质力学响应发挥最大控制作用的参数。模拟结果表明，在目前的作业条件下，储层的地质力学性能保持稳定，但有几口生产井面临明显的热突破风险。总的来说，注入速度和注入温度是主要的控制参数，岩石热容对力学响应有额外的影响。在这些敏感性结果的指导下，我们设计了一种基于敏感性的注采策略，以减轻热突破并提高长期能源开采。额外的THM模拟证实了该策略的有效性，强调了其作为类似地质环境中多井热液地热系统设计和操作的实用指南的潜力。

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引用次数: 0

Microfluidic fabrication of phase change materials capsules with polyanine-reinforced shells for enhanced mechanical and thermal properties 微流控制备具有聚胺增强外壳的相变材料胶囊，以增强其机械和热性能

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-02-24 DOI: 10.1016/j.csite.2026.107859

Dingfan Zhang , Tong Shen , Cheng Yu , Dongcheng Cao

Thermal energy storage using phase change materials (PCMs) plays a vital role in enhancing energy efficiency across various applications, with the performance of PCM capsules being a critical determinant in packed bed thermal energy storage (PBTES) systems. This study introduces an innovative strategy to overcome the inherent limitations of low thermal conductivity and mechanical strength in conventional capsule shells by developing microfluidic-fabricated PCM capsules featuring polyaniline (PANI)-reinforced calcium alginate (CA) shells. An optimal PANI concentration of 2% is identified, which synergistically enhances the shell's thermal conductivity by 22% (from 0.6932 to 0.8451 W/(m·K)) and its mechanical strength, evidenced by a 22.69% increase in yield strength (from 658.08 to 807.37 kPa) and a 35% improvement in elastic modulus compared to pure CA shells. System-level experimental evaluation demonstrates that integrating these reinforced capsules into a PBTES system significantly improves thermal performance, reducing charging time by 6.25%, at a flow rate of 0.2 L/min. Comprehensive energy and exergy analyses confirm an increase in charging energy efficiency and exergy efficiency, indicating a reduction in thermodynamic irreversibilities. Although the incorporation of PANI results in a minimal reduction (∼0.1%) in the energy storage capacity due to the altered specific heat of the shell material, this is decisively offset by the enhancement in thermal conductivity and improvement in mechanical strength. The PANI-reinforced capsules presented herein offer a promising and effective solution for advancing the development of efficient, responsive, and durable PBTES systems.

相变材料（PCM）在提高各种应用中的能源效率方面发挥着至关重要的作用，相变材料胶囊的性能是填充床热储能（PBTES）系统的关键决定因素。本研究提出了一种创新策略，通过开发具有聚苯胺（PANI）增强海藻酸钙（CA）外壳的微流体制造PCM胶囊来克服传统胶囊壳的低导热性和机械强度的固有局限性。当聚苯胺浓度为2%时，壳的导热系数提高22%（从0.6932 W/（m·K）提高到0.8451 W/(m·K)），力学强度与纯CA壳相比提高22.69%（从658.08 kPa提高到807.37 kPa），弹性模量提高35%。系统级实验评估表明，将这些增强胶囊集成到PBTES系统中可以显著提高热性能，在0.2 L/min的流量下，充电时间缩短了6.25%。综合能源和火用分析证实了充电能源效率和火用效率的增加，表明热力学不可逆性的减少。虽然聚苯胺的掺入会导致由于壳材料比热的改变而导致储能容量的最小降低（~ 0.1%），但这被导热性的增强和机械强度的提高决定性地抵消了。本文提出的聚苯胺增强胶囊为推进高效、反应灵敏、耐用的PBTES系统的开发提供了一个有前途的有效解决方案。

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引用次数: 0

Heat transfer deterioration in helically coiled tubes with supercritical water: A numerical study on the impact of cross-sectional shapes 超临界水中螺旋盘管传热恶化：截面形状影响的数值研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-02-28 DOI: 10.1016/j.csite.2026.107844

Jiaqi Yang , Xiaoyi Wu , Haode Zheng , Zheng Lu , Shaopeng Si , Fucheng Chang , Huixiong Li

Supercritical water flow in helically coiled tubes (HCTs) offers a promising solution for high-efficiency, compact heat exchangers in advanced power systems. This study conducts a numerical investigation of wall temperature and heat transfer coefficient (h) in circular HCT (C-HCT), horizontally elliptical HCT (HE-HCT), and vertically elliptical HCT (VE-HCT) at 25 MPa. Numerical analysis reveals that local heat transfer coefficient (h_local) distributions exhibit distinct sensitivities to cross-sectional shapes: the order of h_local at the top of the inner wall of the tube is HE-HCT > C-HCT > VE-HCT, whereas at the inner side of the inner wall of the tube, the order is VE-HCT > C-HCT > HE-HCT, with the h_local at the inner side of VE-HCT being 41.1% higher than C-HCT at high heat flux. As bulk fluid temperature or mass flux increases, centrifugal force dominates, and temperature and velocity distributions become increasingly symmetrical, and the location with the lowest h_local moves inward. In terms of the average h on the cross-section, C-HCT outperforms HE-HCT and VE-HCT across the investigated bulk fluid enthalpy range, demonstrating its superior overall heat transfer efficiency. At high mass flux, although VE-HCT exhibit a 63.1% lower circumferential wall temperature inhomogeneity compared to C-HCT, indicating improved temperature uniformity, this comes at the expense of heat transfer performance. The average h on the cross-section for VE-HCT is only 71% of that for C-HCT. These results could provide essential theoretical insights and actionable recommendations for the design of high-performance heat exchangers in the lead-cooled fast reactors.

螺旋盘管（hct）中的超临界水流为先进电力系统中高效、紧凑的热交换器提供了一种很有前途的解决方案。本文对25 MPa下圆形HCT （C-HCT）、水平椭圆形HCT （HE-HCT）和垂直椭圆形HCT （VE-HCT）的壁面温度和换热系数(h)进行了数值研究。数值分析表明，局部传热系数（hlocal）分布对截面形状有明显的敏感性，管内壁面顶部的hlocal顺序为HE-HCT >； C-HCT > VE-HCT，管内壁面内侧的hlocal顺序为VE-HCT >； C-HCT > HE-HCT，其中高热流密度时，VE-HCT内侧的hlocal比C-HCT高41.1%。随着体流体温度或质量通量的增加，离心力起主导作用，温度和速度分布越来越对称，局部最低的位置向内移动。就截面上的平均h而言，C-HCT在所研究的体积流体焓范围内优于HE-HCT和VE-HCT，表明其具有优越的整体传热效率。在高质量通量下，虽然VE-HCT的周向壁温度不均匀性比C-HCT低63.1%，表明温度均匀性得到改善，但这是以牺牲传热性能为代价的。VE-HCT的平均横截面h值仅为C-HCT的71%。这些结果可以为铅冷快堆中高性能热交换器的设计提供重要的理论见解和可行的建议。

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引用次数: 0

Damage evaluation and resistance enhancement technologies for highway tunnels under high-power fire conditions 公路隧道在大功率火灾条件下的损伤评估与抗火性增强技术

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-02-25 DOI: 10.1016/j.csite.2026.107865

Yufeng Sun , Miaohang Kang , Mingxia Zhang , Fei Ye , Xiaolin Weng , Chaodi Zhu , Dengfei Xu

The operation of highway tunnels involves numerous complex challenges, which become particularly pronounced during extreme disasters such as fires. This study takes the Qinling Tiantai Mountain Highway Tunnel as the engineering background and focuses on damage evaluation and resistance enhancement technologies under fire scenarios. First, a coupled thermal-mechanical numerical model of the highway tunnel is established using FDS and ANSYS co-simulation to identify the most hazardous cross-section under a 100 MW fire source. Subsequently, a resilience quantification model is developed based on strain energy, and a resilience evaluation system for highway tunnels under fire conditions is constructed by selecting appropriate recovery functions and recovery times to calculate the resilience index. Finally, the effectiveness of five protective measures, including fire-resistive coatings, fire-resistive panels, concrete sacrificial layers, concrete types, and sprinkler systems, in enhancing the fire resilience of the lining structure is compared and analyzed. This study introduces resilience theory into the field of tunnel fire safety, and the proposed resilience evaluation method can provide a theoretical basis and important references for the disaster prevention design, disaster assessment, and post-disaster recovery of highway tunnels.

高速公路隧道的运营涉及许多复杂的挑战，在火灾等极端灾害中尤为突出。本研究以秦岭天台山公路隧道为工程背景，重点研究了火灾场景下隧道的损伤评估与抗御增强技术。首先，利用FDS和ANSYS联合仿真技术建立了公路隧道的热力耦合数值模型，确定了100mw火源下的最危险断面；在此基础上，建立了基于应变能的回弹量化模型，通过选择合适的恢复函数和恢复次数，构建了火灾条件下公路隧道的回弹评价体系，并计算了回弹指标。最后，对比分析了防火涂料、防火板、混凝土牺牲层、混凝土类型、喷水灭火系统等五种防护措施对提高衬砌结构耐火性能的效果。本研究将弹性理论引入隧道消防安全领域，提出的弹性评价方法可为公路隧道的防灾设计、灾害评估和灾后恢复提供理论依据和重要参考。

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引用次数: 0