Case Studies in Thermal Engineering最新文献_第7页

Research on medium-temperature thermal management method of combustion powered thermoelectric generation with naphthalene heat pipe 萘热管燃烧热电机组中温热管理方法研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-07 DOI: 10.1016/j.csite.2026.107677

Rong Shen , Jiawei Gong , Guoneng Li , Yiyuan Zhu , Yuanjun Tang , Youqu Zheng , Kenan Huang

At present, combustion powered thermoelectric generation (CP-TEG) technology has demonstrated decent energy density, making it suitable for off-grid energy replenishment, emergency power supply, camping and similar applications. However, thermal management remains a critical challenge for CP-TEG systems, particularly in the medium-temperature range (200–650 °C), where issues such as overheating and temperature non-uniformity limit performance and reliability. While heat pipe (HP) offer superior thermal conductivity, their application in this specific medium-temperature range has not been explored comprehensively. This study addresses this gap by proposing a naphthalene-based organic medium-temperature HP (Nap-HP) for thermal management in CP-TEG systems. The integration of Nap-HP enhances temperature uniformity and suppresses local overheating significantly, enabling stable operation under higher input power. Experimental results show a 16.7 % increase in maximum tolerable input power and a 25.2 % improvement in peak power generation (from 94.33 W to 118.12 W). Moreover, the equivalent thermal conductivity of the Nap-HP reaches ∼1619.56 W/m·K, approximately 7.9 times that of the aluminum alloy collector. This work not only provides an effective thermal management strategy to advance CP-TEG performance but also demonstrates the viability and potential of Nap-HPs in medium-temperature applications.

目前，燃烧动力热电发电（CP-TEG）技术已经显示出良好的能量密度，使其适用于离网能源补充、应急电源、露营和类似应用。然而，对于CP-TEG系统来说，热管理仍然是一个关键的挑战，特别是在中温范围（200-650°C），过热和温度不均匀等问题限制了性能和可靠性。虽然热管（HP）具有优异的导热性，但其在特定介质温度范围内的应用尚未得到全面探索。本研究通过提出一种用于CP-TEG系统热管理的萘基有机中温HP （Nap-HP）来解决这一空白。Nap-HP的集成提高了温度均匀性，显著抑制了局部过热，在更高的输入功率下也能稳定运行。实验结果表明，最大可容忍输入功率提高16.7%，峰值发电量提高25.2%（从94.33 W提高到118.12 W）。此外，Nap-HP的等效导热系数达到~ 1619.56 W/m·K，约为铝合金集热器的7.9倍。这项工作不仅为提高CP-TEG性能提供了有效的热管理策略，而且还证明了nap - hp在中温应用中的可行性和潜力。

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引用次数: 0

Solar Distiller Efficiency Enhancement via Optical Concentration and Thermal Storage: Challenges, Materials, and Future Directions 通过光浓缩和热储存提高太阳能蒸馏器效率：挑战、材料和未来方向

IF 6.8 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-06 DOI: 10.1016/j.csite.2026.107659

A.E. Kabeel, M.A. Elazab, Ehab M. Almetwally, A.S. Al-Moisheer, Manar Ayman, Ahmed elgebaly, Mohamed Kamel Elshaarawy

引用次数: 0

Experimental and numerical assessment of a hybrid EAHE–HVAC system under sliding mode control for indoor temperature and CO2 regulation 滑模控制下EAHE-HVAC混合系统室内温度和CO2调节的实验与数值评估

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-06 DOI: 10.1016/j.csite.2025.107637

Yasmine Tiouti, Soukayna Berrabah, Zineb Bouhssine, Kenza Oufaska, Radouane Ouladsine, Mohamed Bakhouya

This study investigates the performance of an Earth-to-Air Heat Exchanger (EAHE) coupled with an Heating-Ventilation-Air-Conditioning (HVAC) unit in a small experimental building. A thermal and CO₂ model was developed and validated with three days of winter measurements from Sal'e, Morocco. A Sliding Mode Control (SMC) strategy was implemented to regulate indoor temperature and CO₂ simultaneously.

The model reproduces the measured temperature within about ±0.9 °C and the CO₂ levels within roughly 10 ppm, which is inside the sensor accuracy. Three operating modes were analysed: EAHE alone, HVAC alone under SMC, and a hybrid EAHE + HVAC configuration. Compared to the HVAC-only baseline, the hybrid mode reduces heating demand by about 17 % and peak power by around 22 %, while maintaining temperature and CO₂ within comfort limits.

These results show that combining a passive EAHE with a robust nonlinear controller can improve indoor comfort and reduce heating energy use in small laboratory buildings.

本研究在一个小型实验建筑中研究了地空热交换器（EAHE）与采暖通风空调（HVAC）机组的性能。开发了一个热和二氧化碳模型，并通过在摩洛哥Sal'e进行的为期三天的冬季测量进行了验证。采用滑模控制策略对室内温度和CO2进行同步调节。该模型再现了大约±0.9°C的测量温度和大约10ppm的二氧化碳水平，这是在传感器精度范围内。分析了三种运行模式：单独的EAHE， SMC下单独的HVAC，以及EAHE + HVAC混合配置。与纯暖通空调相比，混合模式将供暖需求降低约17%，峰值功率降低约22%，同时将温度和二氧化碳保持在舒适范围内。结果表明，在小型实验室建筑中，将被动式EAHE与鲁棒非线性控制器相结合可以提高室内舒适度，降低采暖能耗。

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引用次数: 0

Numerical assessment of hydrodynamic and thermal performance in innovative pyramidal internally corrugated tubes 新型锥形内波纹管流体动力和热性能的数值评价

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-06 DOI: 10.1016/j.csite.2026.107651

Zhi-Min Lin , Zhao-Xia Wang , Hui Zheng , Liang-Bi Wang

This study numerically evaluates the thermo-hydraulic performance of circular tubes equipped with raised pyramidal protrusions on the inner wall, using a steady-state simulation with the standard k–ε turbulence model. These surface modifications serve a dual purpose: they expand the heat transfer area and induce near-wall flow disturbances, thereby enhancing convective heat transfer. Geometric parameterization was conducted through a systematic evaluation of protrusion dimensional ratios, enabling quantification of their effects on both thermal enhancement and hydraulic resistance. Results indicate that optimal thermal performance is achieved with larger relative pyramid lengths, smaller widths, and lower heights. The Nusselt number displays periodic variations, with peak values at the tops and bottoms of the pyramidal structures and minimum values at the “waist"—the midpoint between these extremes. Specifically, at a relative length of 0.53, width of 0.77, and height of 0.089, the pyramidal corrugated tube achieves a mean Nusselt number 2.15 times greater than that of a smooth tube. Moreover, with a relative length of 0.26, width of 0.32, and height of 0.089, the pitch-wise peak of the circumferentially averaged Nusselt number is 3.5 times higher than its smooth counterpart. The proposed correlations relate mean Nusselt number and friction factor to Reynold number and key geometric parameters, with deviations within 7–10 % over the stated ranges. These findings provide actionable guidance for the design and retrofit of tubular heat exchangers—including shell-and-tube and double-pipe configurations—used across industrial services.

本文采用标准k -ε湍流模型，对内壁装有凸起锥体的圆管的热水力性能进行了数值模拟。这些表面修饰有双重目的：扩大传热面积，诱导近壁流动扰动，从而增强对流换热。通过系统评估突出尺寸比，进行几何参数化，从而量化其对热增强和水力阻力的影响。结果表明，较大的相对金字塔长度、较小的相对金字塔宽度和较低的相对金字塔高度可以获得最佳的热性能。努塞尔数表现出周期性的变化，金字塔结构的顶部和底部出现峰值，而“腰部”——这两个极端之间的中点出现最小值。在相对长度为0.53，宽度为0.77，高度为0.089时，锥形波纹管的平均努塞尔数是光滑管的2.15倍。此外，在相对长0.26、宽0.32、高0.089的情况下，周向平均努塞尔数的节向峰比光滑努塞尔数高3.5倍。所提出的相关性将平均努塞尔数和摩擦系数与雷诺数和关键几何参数联系起来，偏差在规定范围内的7 - 10%。这些发现为管式热交换器的设计和改造提供了可行的指导，包括壳管和双管配置，用于工业服务。

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引用次数: 0

Numerical analysis of thermal-hydraulic characteristics of grid positioned triangular fuel assemblies in lead-cooled fast reactor under ocean conditions 海洋条件下铅冷快堆网格定位三角形燃料组件热水力特性数值分析

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-06 DOI: 10.1016/j.csite.2026.107661

Yang Liu , Qianwan Shi , Lu Zhang

The lead-based fast reactor is a promising fourth generation reactor type, which has good natural circulation capability, great fuel proliferation potential, high safety, and easy miniaturization. The design of miniaturized lead-based reactors is expected to become a potential choice for ocean energy supply or ship propulsion. This study is based on CFD(FLUENT) method to investigate the influence of ocean conditions (i.e. rolling motion) on the thermal-hydraulic characteristics of liquid lead cooled grid positioned triangle fuel assemblies. The modeling of liquid lead in triangular channels based on FLUENT has been clarified, the SST k-ω turbulence model and the Cheng et al. turbulent heat transfer models (Prt) indicate that has the highest accuracy in simulating the flow & heat transfer of liquid lead coolant. Based on this, the impact characteristics of rolling on a single channel were analyzed. Research has shown that an increase in rolling amplitude and a decrease in rolling period have an increased impact on the Nusselt number and friction resistance coefficient. And rolling can enhance heat transfer capability, where the heat transfer capacity is more sensitive to rolling amplitude changes and less sensitive to rolling periods. The influence of rolling on the friction resistance coefficient is not significant, with a change amplitude of less than 2 %. Finally, research on typical 7-rod bundles shows that the rolling motion has the greatest impact on the longitudinal pressure of the liquid lead, with an average increase of about 10 %. The impact of rolling on velocity is smaller than the pressure, and the effect varies upstream and downstream of the grid, and the impact on fluid temperature is not significant. The rolling motion increased the Nusselt number value within the rod bundles, with an average increase of about 5 %,and reduced the friction resistance coefficient, with an average decrease of about 10 %. This study demonstrates the influence of rolling motion on the thermal-hydraulic characteristics of the core under a typical fast reactor triangular component arrangement, which has important reference significance for the miniaturization design of marine lead-based fast reactors.

铅基快堆具有自然循环能力好、燃料扩散潜力大、安全性高、易于小型化等优点，是极具发展前景的第四代快堆类型。小型铅基反应堆的设计有望成为海洋能源供应或船舶推进的潜在选择。本研究基于CFD（FLUENT）方法，研究海洋条件（即滚动运动）对液铅冷却网格定位三角形燃料组件热工特性的影响。基于FLUENT的三角通道液态铅的建模已经得到澄清，SST k-ω湍流模型和Cheng等紊流传热模型（Prt）表明，在模拟液态铅冷却剂的流动传热方面精度最高。在此基础上，分析了单通道滚动的冲击特性。研究表明，滚动幅值的增大和滚动周期的减小对努塞尔数和摩擦阻力系数的影响增大。轧制可以增强换热能力，其中换热能力对轧制振幅变化更敏感，对轧制周期变化不太敏感。滚动对摩擦阻力系数的影响不显著，变化幅度小于2%。最后，对典型7杆束的研究表明，滚动运动对液铅纵向压力的影响最大，平均增加约10%。滚动对速度的影响小于压力，且影响在网格的上游和下游有所不同，对流体温度的影响不显著。滚动运动使棒束内的努塞尔数增加，平均增加约5%，摩擦阻力系数降低，平均降低约10%。研究了典型快堆三角形构件布置下滚动运动对堆芯热水力特性的影响，对船用铅基快堆小型化设计具有重要的参考意义。

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引用次数: 0

Effects of variable Miller cycle on combustion performance and fuel economy of highly intensified diesel engines 可变米勒循环对高强化柴油机燃烧性能和燃油经济性的影响

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-05 DOI: 10.1016/j.csite.2026.107656

Jinqun Zhang , Zixing Gan , Shijie Wang , Niancheng Guo , Zongfa Xie

The Miller cycle has received increasing attention and application in the field of diesel engines. However, studies that have addressed the practical application of the variable Miller cycle in multi-cylinder diesel engines remain limited. Here, a six-cylinder highly intensified heavy-duty diesel engine equipped with a high geometric compression ratio and two-stage turbocharger was employed to evaluate a self-designed fully hydraulic variable valve system (FHVVS). This novel system enables early intake valve closure, allowing diesel engine operation in both Diesel and Miller cycle modes. Comparative experiments on a performance test bench were conducted to assess the effects of the variable Miller cycle on combustion and intake characteristics. Combustion matching was achieved by optimizing the injection advance angle. A fuel economy comparison between operating modes suggested that the Miller cycle effectively reduced pumping losses compared with the Diesel cycle, lowering pumping mean effective pressure (PMEP) by an average of 71.5 kPa (60.2%) at 1400 rpm. The Miller cycle also decreased maximum combustion pressures, reducing the mechanical load as well as creating highly favorable conditions for optimal matching of the crank angle at 50% heat release, thus improving combustion performance in highly intensified diesel engines. By improving pumping losses and reasonably matching combustion parameters, the Miller cycle substantially extended the low fuel consumption range at medium speed and medium-to-high load. Compared with the Diesel cycle, the Miller cycle reduced the average fuel consumption rate by 8.5 g/(kW·h), a 4.0% decrease. By ensuring rapid and smooth conversion between operating modes (conversion time <0.075 s), the proposed FHVVS plays an important role in improving the instantaneous acceleration performance of heavy-duty vehicles powered by highly intensified diesel engines under low speed and low load.

米勒循环在柴油机领域得到了越来越多的关注和应用。然而，针对可变米勒循环在多缸柴油机中的实际应用的研究仍然有限。研究人员利用一台配备高几何压缩比和两级涡轮增压器的六缸高强度重型柴油发动机，对自行设计的全液压可变气门系统（FHVVS）进行了评估。这种新颖的系统可以提前关闭进气阀，使柴油机在柴油和米勒循环模式下都能运行。在性能测试台上进行了对比实验，以评估可变米勒循环对燃烧和进气特性的影响。通过优化喷射提前角实现燃烧匹配。两种运行模式的燃油经济性比较表明，与柴油循环相比，Miller循环有效地减少了泵送损失，在1400转/分时，泵送平均有效压力（PMEP）平均降低了71.5 kPa（60.2%）。Miller循环还降低了最大燃烧压力，减少了机械负荷，并为50%放热时曲柄角的最佳匹配创造了非常有利的条件，从而改善了高度强化的柴油发动机的燃烧性能。通过改善泵送损失和合理匹配燃烧参数，Miller循环大大延长了中速中高负荷下的低油耗范围。与柴油循环相比，米勒循环平均油耗降低8.5 g/(kW·h)，降低4.0%。FHVVS保证了工作模式间的快速平稳转换（转换时间<；0.075 s），对于提高高强化柴油机驱动的重型车辆在低速低负荷下的瞬时加速性能具有重要作用。

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引用次数: 0

Experimental study on thermal decomposition and kinetic characteristics of coal in O2/CO2/N2 atmospheres with various CO2/N2 blend ratios 不同CO2/N2混合比下煤在O2/CO2/N2气氛中的热分解及动力学特性实验研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-05 DOI: 10.1016/j.csite.2026.107653

Chunlei Wu , Jing Li , Bobo Shi , Yong Xue

This study explores the inhibitory mechanisms of CO₂/N₂ ratios and O₂ concentrations on coal oxidative pyrolysis to provide theoretical insights into the use of CO₂-N₂ mixed inert gas in goaf fire prevention. Thermogravimetric analysis (TGA) was employed to investigate coal pyrolysis under varying coal metamorphism, heating rates, O₂ concentrations, and CO₂/N₂ ratios. Results show that increasing the heating rate raises characteristic temperatures and enhances the oxidative pyrolysis in DX coal. The apparent activation energies of DX, TX, and YCW coals exhibit an initial increase followed by a decrease as conversion rates rise, peaking at 0.15 conversion. At a constant O₂ concentration, the apparent activation energy is highest when the CO₂/N₂ ratio is 4:6, suggesting more energy is required and oxidation is more effectively inhibited. Conversely, increasing O₂ concentration leads to a linear decrease in the apparent activation energies, indicating enhanced coal oxidative pyrolysis.

本研究探讨CO2/N2比和O2浓度对煤氧化热解的抑制机制，为CO2-N2混合惰性气体在采空区防火中的应用提供理论依据。采用热重分析（TGA）研究了煤在不同变质作用、升温速率、O2浓度和CO2/N2比下的热解过程。结果表明，升温速率的提高提高了特征温度，促进了DX煤的氧化热解。随着转化率的升高，DX、TX和YCW煤的表观活化能先升高后降低，在转化率为0.15时达到峰值。在一定的O2浓度下，当CO2/N2比为4:6时，表观活化能最高，说明需要更多的能量，更有效地抑制氧化。相反，随着O2浓度的增加，表观活化能呈线性降低，表明煤的氧化热解能力增强。

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引用次数: 0

Numerical and SPIV experimental investigation of a novel arc bifurcation insert for synergistic heat transfer enhancement in tubes 一种新型管内协同强化换热电弧分叉插片的数值与SPIV实验研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-05 DOI: 10.1016/j.csite.2026.107660

Qinglin Du, Gen Ou, Zhichun Liu, Wei Liu

The application of longitudinal swirl generators (LSGs) has received considerable attention in recent years as an effective approach for heat transfer enhancement with low consumption. This study proposes a novel insert—bifurcated arc semi-pipes (BASPs)—by introducing a curved bifurcation structure into conventional LSGs, designed to achieve synergistic heat transfer enhancement. The primary semi-pipes generate multiple longitudinal swirling flows to improve temperature uniformity of core flow region, while the curved bifurcations generate local disturbances near wall hotspots, thus improving wall temperature uniformity, with minimal mutual interference between these two mechanisms. The heat transfer enhancement mechanisms of BASPs under laminar conditions are explored via computational fluid dynamics (CFD) simulations and stereoscopic particle image velocimetry (SPIV) experiments. The complex effects of five geometric parameters (slant angle α, branching distance h, branching angle β, curvature coefficient ε, and pitch P) on the thermo-hydraulic performance and irreversibility are systematically examined. The Nusselt number increases to 3.34–9.47 times that of the smooth tube, while the friction factor rises to 2.59–10.23 times. The maximum performance evaluation criteria (PEC) reaches 4.63. Furthermore, geometric parameters of BASPs are optimized based on the dissipation minimization principle. A design on the obtained Pareto front achieves a Nusselt number enhancement of 8.71 times, surpassing all training cases under the same Reynolds number, and the compromise solution also attains a PEC value of 4.12, confirming the theoretical guidance provided by the dissipation minimization principle.

纵向旋流发生器作为一种低能耗强化传热的有效方法，近年来得到了广泛的应用。本研究提出了一种新的插入分叉弧半管(BASPs) -通过在传统的LSGs中引入弯曲的分叉结构，旨在实现协同传热增强。主半管产生多个纵向旋流，提高了岩心流区温度均匀性，弯曲分岔在壁面热点附近产生局部扰动，提高了壁面温度均匀性，两种机制相互干扰最小。通过计算流体力学（CFD）模拟和立体粒子图像测速（SPIV）实验，探讨了层流条件下BASPs的强化传热机理。系统地考察了5个几何参数（倾斜角α、分支距离h、分支角β、曲率系数ε和节距P）对热液性能和不可逆性的复杂影响。努塞尔数增加到光滑管的3.34 ~ 9.47倍，摩擦系数增加到2.59 ~ 10.23倍。PEC （performance evaluation criteria）最高可达4.63。在此基础上，基于耗散最小化原理对其几何参数进行了优化。在得到的Pareto front上设计的Nusselt数增强了8.71倍，超过了相同雷诺数下的所有训练案例，折衷解的PEC值也达到了4.12，证实了耗散最小化原理的理论指导。

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引用次数: 0

Performance evaluation of two-phase direct-to-chip liquid cooling combined with air cooling for data centers 数据中心两相直接对片液冷与空冷相结合的性能评估

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-05 DOI: 10.1016/j.csite.2026.107650

Vahid Ebrahimpour Ahmadi, Henrik A. Barestrand, Jon Summers, Cagatay Yilmaz

The increasing power density of modern data centers presents significant cooling challenges, as traditional air cooling methods approach their physical and economic limits for artificial intelligence and high-performance computing applications. Integrating direct liquid cooling with existing air-cooled infrastructures offers a promising solution to enhance thermal management and energy efficiency. This study investigates the performance of a hybrid cooling system employing two-phase direct-to-chip liquid cooling, retrofitted to nine air-cooled Open Compute Project servers equipped with Intel Xeon E5 v3 microprocessors. Experiments were conducted in a controlled server wind tunnel environment to evaluate thermal and power characteristics under inlet air temperatures ranging from 25 to 45 °C and varying IT workloads. Results demonstrate substantial CPU temperature reductions, from 93 °C with air cooling to 56 °C with hybrid cooling at 25 °C inlet under full load. As inlet temperature increases on the air side, the two-phase system captures a greater proportion of the heat load, reaching up to 90% at 45 °C. These findings demonstrate the potential of hybrid cooling to extend the thermal envelope of existing air-cooled data centers beyond conventional ASHRAE A1 class limits, reduce operational costs, and facilitate waste heat recovery for secondary applications.

现代数据中心不断增加的功率密度带来了巨大的冷却挑战，因为传统的空气冷却方法已经接近人工智能和高性能计算应用的物理和经济极限。将直接液体冷却与现有的风冷基础设施相结合，为加强热管理和能源效率提供了一个有前途的解决方案。本研究研究了一种采用两相直接对芯片液冷的混合冷却系统的性能，该系统被改造为9台配备英特尔至强E5 v3微处理器的风冷开放计算项目服务器。实验在受控的服务器风洞环境中进行，以评估进气温度为25至45°C以及不同IT工作负载下的热和功率特性。结果表明，CPU温度大幅降低，从空气冷却时的93°C降至全负荷进口25°C时的56°C混合冷却。随着空气侧入口温度的升高，两相系统捕获了更大比例的热负荷，在45°C时达到90%。这些发现证明了混合冷却的潜力，可以将现有风冷数据中心的热包线扩展到传统的ASHRAE A1级限制之外，降低运营成本，并促进废热回收用于二次应用。

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引用次数: 0

A centralized smoke exhaust method using branch tunnel in bifurcated tunnel fires: Impact on maximum ceiling temperature in main tunnel 分叉隧道火灾中分支隧道集中排烟方法对主隧道最高顶温的影响

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-05 DOI: 10.1016/j.csite.2026.107652

Wei Cong , Yujie Ma , Kun He , Shaojie Zhang , Wei Peng

Bifurcated tunnels are widely used in urban road and metro systems, yet their branching geometry complicates smoke control compared with single-line tunnels. This study numerically investigates the maximum ceiling temperature (MCT) in the main tunnel when a centralized exhaust vent is arranged in the branch tunnel, considering different fire locations, exhaust velocities (

V_{e}

), and heat release rates. Results show that as

V_{e}

increases from 0 to 8 m/s, the MCT decreases by approximately 50 %. The influence of fire location depends on the exhaust intensity: under weak exhaust (

V_{e} = 2 m / s

), the MCT decreases as the fire moves farther from the junction due to reduced smoke accumulation and recirculation near the bifurcation, whereas under strong exhaust (

V_{e} \geq 4 m / s

, satisfying

V_{e} A_{e} / A_{m} \geq 1.6 m / s

) the MCT becomes weakly dependent on fire location when the smoke layer has developed into the one-dimensional flow before reaching the junction. The flame exhibits a longitudinal tilt toward the junction for non-junction fires and lateral guidance into the branch for junction fires. Based on the flame tilting characteristics, an empirical correlation incorporating exhaust volume, tunnel geometry and fire parameters is developed to predict the MCT under strong exhaust. A comparison indicates that centralized smoke exhaust better protects the downstream region, while longitudinal ventilation is more effective in reducing smoke accumulation near the fire source.

分岔隧道广泛应用于城市道路和地铁系统中，但与单线隧道相比，分岔隧道的几何结构使其烟雾控制复杂化。考虑不同的火灾位置、排风速度和放热速率，对在支洞设置集中排风口时，主洞的最大顶温（MCT）进行数值研究。结果表明，当Ve从0增加到8 m/s时，MCT降低约50%。火灾位置的影响受排气强度的影响，弱排气（Ve=2m/s）下，由于分叉附近的烟雾积累和再循环减少，随着火灾离接点越远，MCT越低，而强排气（Ve≥4m/s，满足VeAe/Am≥1.6m/s）下，当烟雾层在到达接点之前发展成一维流时，MCT对火灾位置的依赖性减弱。火焰表现出纵向倾斜向结的非结火和横向引导到分支的结火。基于火焰倾斜特性，建立了结合排气量、隧道几何形状和火灾参数的经验关联模型，预测了强排气量下的MCT。对比表明，集中排烟能更好地保护下游区域，而纵向通风能更有效地减少火源附近的烟雾积聚。

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引用次数: 0