热科学学报

Select

《热科学学报》2021年第6期目录，Vol30，No.6

热科学学报. 2021, 30(6): 1-1.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

Select

Thermo-Economic Modeling and Evaluation of Physical Energy Storage in Power System；电力储能系统热经济性建模与分析

热科学学报. 2021, 30(6): 1861-1874.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

中文导读：本文在传统热经济学概念的基础上，对容量型和功率型储能进行了热经济性建模和评估，同时考虑了政策、环境、社会等综合因素的影响，首次提出了㶲经济收益率综合评估指标。利用该模型和指标，本文对抽水蓄能、压缩空气储能、飞轮储能三个典型物理储能进行了热经济性评估，结果表明：抽水蓄能调峰、压缩空气储能调峰和飞轮储能调频三种应用情景中，㶲经济收益率均大于零，说明热经济均可行；当考虑政策、环境、社会等效益后，㶲成本降低25%，㶲经济收益率约增加一倍。同时，通过对容量型和功率型储能的敏感性分析表明，储能系统效率均是容量型和功率型储能热经济性影响的首要因素，但对于采用价差套利的容量型储能，峰谷电价差为第二大影响因素，对于采用调节里程收益模式的功率型储能，里程比率为第二大影响因素。总体来看，在三个典型案例中，抽水蓄能的热经济性最好，压缩空气储能次之，飞轮储能最差，主要原因是抽水蓄能的非能量成本最低，而飞轮储能的非能量成本最高。本文研究为储能技术的评估提供了新方法，研究结果为储能技术路线和商业模式的选择提供了参考。

Select

A Comprehensive Review on Multi-Dimensional Heat Conduction of Multi-Layer and Composite Structures: Analytical Solutions

热科学学报. 2021, 30(6): 1875-1907.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

Heat conduction in multi-layer and composite materials is one of the fundamental heat transfer problems in many industrial applications. Due to different materials types, interface conditions, and various geometries of these laminates, the heat conduction mechanism is more complicated than that of one-layer isotropic media. Analytical solutions are the best ways to study and understand such problems in depth. In this study, different existing analytical solutions for heat conduction in multi-layer and composite materials are reviewed and classified in rectangular, cylindrical, spherical, and conical coordinates. Applied boundary conditions, internal heat source, and thermal contact resistance as the most critical parameters in the solution complexity investigated in the literature, are discussed and summarized in different tables. Various types of multi-layer structures such as isotropic, anisotropic, orthotropic, and reinforced laminates are included in this study. It is found that although more than half a century has passed since the beginning of the research on heat transfer in multi-layer composites, new researches that can help with a better understanding in this area are still being offered. The challenges and shortcomings in this area are also discussed to guide future researches.

Select

A Neural Regression Model for Predicting Thermal Conductivity of CNT Nanofluids with Multiple Base Fluids；基于神经回归模型预测多种基液的碳纳米管纳米流体热导率

热科学学报. 2021, 30(6): 1908-1916.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

碳纳米管纳米流体的高导热特性受到了极大的关注，然而由于目前实验的研究条件有限，对其热导率变化规律缺乏全面的认识。鉴于近年来数据驱动方法的提出，利用实验数据驱动预测各种相关条件的热导率值，是阐明热导率的变化规律的有效途径，能够大大节省实验成本和时间成本。本工作提出了一种用于预测碳纳米管纳米流体的神经回归模型，考虑了碳纳米管直径、体积分数、温度和基液热导率四种影响因素。其中，基础液体为R113、水、乙二醇和乙二醇-水混合液四种常规流体。通过训练该模型，预测了四种因素影响的多组热导率，讨论了热导率增强所考虑的四个影响因素的变化规律，并给出了不同影响因素与碳纳米管纳米流体增强之间的相关性。最后，将该模型与九种常见的机器学习方法比较，本文提出的神经回归模型在这些方法中具有最高的准确度。

Select

Effects of Monovacancy on Thermal Properties of Bilayer Graphene Nanoribbons by Molecular Dynamics Simulations；空位对双层石墨烯热物性影响的分子动力学研究

热科学学报. 2021, 30(6): 1917-1924.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

本文采用非平衡分子动力学方法研究了单空位缺陷对双层石墨烯纳米带(BGN)热导率的影响。我们的结果表明，双层石墨烯纳米带中单空位缺陷的存在显著降低了其热导率。计算表明，导热系数随单空位浓度的增加近似线性降低。与理想BGN中的温度相关热导率相比，缺陷BGN的热导率随温度的升高先升高后降低。此外，当两层之间的单空位密度差异较大时，BGN的热导率较高。我们还计算了声子态密度、声子弛豫时间以及声子参与率，以加深对微观机理的理解。我们的研究证实，基于双层石墨烯纳米带的纳米器件可以通过缺陷工程应用于热管理系统。

Select

Thermal-Hydraulic Characteristics of Twisted Elliptical Tube Bundle in Staggered Arrangement；错列扭曲椭圆管束传热及流动阻力性能研究

热科学学报. 2021, 30(6): 1925-1937.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

扭曲椭圆管是一种性能优异的被动强化传热元件，凸显出了其管内外双侧强化传热且明显降低壳侧流动阻力的优势，在纵流型换热器中得到了推广应用，然而扭曲椭圆管在横向冲刷流动中的换热性能还鲜有报道，本文基于实验数据，在管壁温度恒定的情况下，采用数值模拟研究了管束结构参数和雷诺数（2300~38000）对错列扭曲椭圆管束传热及流动阻力特性的影响规律。扭曲椭圆管外的螺旋形变通道对气流具有组织分流作用，使得近壁区域中的空气具有三维流动特性，该三维流动可以分解为垂直于扭曲椭圆管长方向的绕流和沿螺旋曲面的螺旋流。扭曲椭圆管束综合传热性能优于普通圆管管束，扭曲椭圆管束的平均努塞尔数均随椭圆形横截面的长短轴比的增大和雷诺数的增大而增大，随螺距的增加而减小；平均欧拉数均随雷诺数的增大和螺距的增加而减小，随长短轴比的增大而增大。所得到的关于平均努塞尔数和平均欧拉数计算关联式可为扭曲椭圆管换热器设计提供理论参考。

Select

Experimental Investigation on the Vapor Chambers with Sintered Copper Powder Wick；基于烧结铜粉吸液芯的均热板的实验研究

热科学学报. 2021, 30(6): 1938-1950.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

高功率电子元器件产生的高热流密度对这些设备的可靠性造成了极大的威胁。由于均热板（VC）的传热速率较高，故其在电子产品的散热方面具有较广泛的应用。本文对具有粒径分别为50μm（I-50μm），I-75μm，I-110μm，I-150μm的不规则状烧结铜粉吸液芯的均热板进行了实验研究。并探究了液体充液率对均热板传热性能的影响。实验结果表明，所有均热板的热阻均随着加热功率的增加而减小。吸液芯的毛细性能是影响具有不同种类吸液芯的均热板的传热性能的主导因素。提出采用毛细性能因子来评价均热板的毛细性能。在本研究中，具有I-75μm吸液芯的均热板的毛细性能因子远高于其他类型的均热板。均热板的热源表面温度可能受液体充液率和吸液芯结构的影响。但是，当吸液芯具有较好的毛细性能因子时，热源表面温度对充液率不敏感。在相同加热面积和相似吸液芯结构的情况下，均热板的最大热流密度将随着蒸气腔高度的降低而减小。

Select

An Improved Treatment on the Apparent Contact Angle of a Single-Bubble in Consideration of Microlayer for Simulations of Nucleate Pool Boiling；核态池沸腾模拟中考虑微液膜的单气泡视觉接触角改良处理法

热科学学报. 2021, 30(6): 1951-1959.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

本论文作者在前期研究中提出了基于VOF法，在气泡底部导入虚拟微液膜（仅作为质量源项导入微液膜蒸发量），针对单个沸腾气泡生长过程的数值模拟方法。该方法的正确计算需依赖然基于视觉接触角（连接微液膜和主流流体的部分）实验数据的经验公式，使用范围具有局限性。为了摆脱上述限制，本论文提出了方法改良。通过分析微液膜及主流流体间的受力，通过施加外力源项替代使用视觉接触角，从而摆脱了使用视觉接触角经验公式的限制，使数值模拟方法具有更高的适用性。通过采用本论文所改良后的方法进行计算，得到了与原有计算结果一致的结果。模拟结果与实验结果也具有良好的一致性。因此，本文所改良的计算方法，可用于核态池沸腾领域单个气泡生长及传热特性的模拟研究。

Select

Thermal Conductivity of Room Temperature Deep Eutectic Solvents

热科学学报. 2021, 30(6): 1960-1972.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

As deep eutectic solvents (DESs) became a prevalent category of materials, reporting their physical and chemical properties turned to be urgent. In this work, a database of the thermal conductivity of 39 DESs was experimentally investigated in a temperature range of 25 degrees C to 60 degrees C, since this property was not broadly reported yet. Knowing the thermal conductivity is a significant approach to obtain the fluids' heat transfer coefficients, which are essential for fluid heat transfer applications and equipment design. The selection of the reported DESs was based on their liquid phase status at room temperature and commonness. Herein, the thermal conductivity was studied as a function of temperature and compositions. Also, the data were fit with the conventional equations to predict the thermal conductivity value at a certain temperature. The highest R-2 was selected to identify the best behavior with the common types of equations. It was found that the thermal conductivity reduced by raising the temperature, which was attributed to the enhancement that occurred in electrons' randomness and reduction in electrons' free motion. Furthermore, as the temperature rises up, the density decreases, and molecular distance increases. DESs contained choline chloride showed higher thermal conductivity stability than other DESs. While an opposite scenario was noticed for glycerol and ethylene glycol DESs due to the possibility of generating water.

Select

A Multi-Scale Thermal Analysis Method for Data Centers with Application in a Ship Data Center；一种应用于船舶数据中心的数据中心多尺度热分析方法

热科学学报. 2021, 30(6): 1973-1985.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

为确保计算机芯片能够保持在临界温度以下工作，同时降低冷却能耗，迫切需要进行数据中心的热分析工作。在容纳几百个甚至更多机架的大型数据中心中，很难通过直接测量的方式获得热点位置和芯片温度的详细信息。本文提出了一种多尺度热分析方法，用于预测数据中心内部芯片和焊点的温度分布。多尺度模型共分为六个尺度：房间、机架、服务器、绝缘栅双极晶体管(IGBT)、芯片和焊点。文中提出了子模型的概念并将上面六个尺度划分成四个子模型进行模拟。子模型1包含房间、机架和服务器(RRS)；子模型2包含服务器和IGBT(SI)；子模型3包含IGBT和芯片(IC)，子模型4包含芯片和焊点(CS)。这四个子模型通过传递相邻级间的结果作为边界条件实现单向耦合。在单个机柜的数据中心模型中，采用全场模拟方法对多尺度模拟方法的有效性和准确性进行了验证。两种模拟方法的结果表明：最高温度均出现在同一位置，但单机架全场模型(SRFFM)的计算时间是单机架多尺度模型(SRMSM)的2.5倍。两种模型下的芯片和焊点的最高温度偏差分别为1.57℃和0.2℃，表明多尺度模拟方法在数据中心热模拟中具有良好的应用前景。最后，将该多尺度热分析方法应用于容纳15个机架的舰船数据中心。

Select

Numerical Investigation on Convective Heat Transfer of Supercritical Carbon Dioxide in a Mini Tube Considering Entrance Effect；考虑入口效应的超临界二氧化碳在微管道内对流换热数值研究

热科学学报. 2021, 30(6): 1986-2001.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

研究超临界CO2流动和传热特性时，为避免入口效应对流动换热的影响，常在加热段前后设置绝热段，但研究没有讨论超临界CO2微管道内流动换热时绝热段长度及入口效应影响。本文利用FLUENT 19.0对超临界CO2在不同工况（入口雷诺数、入口压力、壁面加热热流和流动方向）和绝热段长度下微管道内传热进行数值研究。通过对比不同工况和绝热段长度下的浮升力效应、流动加速效应以及加热段入口处无量纲速度分布，研究发现当入口雷诺数处于过渡状态且壁面热流相对较高时，入口效应对传热的影响更加明显，其导致的传热恶化使得壁面局部温度和对流换热系数急剧上升。随着绝热段的增加，传热恶化的位置向加热段入口移动并最终消失。研究表明超临界CO2在微管道流动换热时，绝热段长度超过25后传热恶化影响不大，但当工况为低入口雷诺数、高壁面密度时传热恶化仍然存在。入口边界层发展和物性参数剧烈变化导致壁面剪应力，而壁面剪应力降低是导致换热恶化的主要因素。本文采用非平衡分子动力学方法研究了单空位缺陷对双层石墨烯纳米带(BGN)热导率的影响。我们的结果表明，双层石墨烯纳米带中单空位缺陷的存在显著降低了其热导率。计算表明，导热系数随单空位浓度的增加近似线性降低。与理想BGN中的温度相关热导率相比，缺陷BGN的热导率随温度的升高先升高后降低。此外，当两层之间的单空位密度差异较大时，BGN的热导率较高。我们还计算了声子态密度、声子弛豫时间以及声子参与率，以加深对微观机理的理解。我们的研究证实，基于双层石墨烯纳米带的纳米器件可以通过缺陷工程应用于热管理系统。

Select

Temperature-Dependent Rheological Behaviors of Binary Eutectic Mixtures of Sugar Alcohols for Latent Heat Storage: A Comparative Study with Pure Sugar Alcohols；面向储热的二元共晶糖醇不同温度下的流变特性：与单组份糖醇的比较性研究

热科学学报. 2021, 30(6): 2002-2014.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

流变特性是相变材料的重要输运性质之一，对其熔化及结晶性能有重要影响。基于已有对单组份糖醇在熔融及过冷液态的研究，本研究对筛选出的5种二元共晶糖醇的流变特性也分别在熔融及过冷液态下进行了测试。结果表明木糖醇 (75mol%)+赤藓糖醇和赤藓糖醇 (84mol%)+甘露糖醇为拟塑性流体，d-甘露糖醇(70mol%)+d-半乳糖醇为宾汉流体,含有环状分子结构肌糖醇的d-甘露糖醇 (82mol%)+肌糖醇和d-半乳糖醇(69mol%)+肌糖醇两种混合物表现出Herschel-Bulkley流体的性质，其粘度曲线存在第一牛顿区、非牛顿区及第二牛顿区。除肌糖醇之外，其余二元共晶糖醇的动力粘度均高于其单组份糖醇。例如：木糖醇(75mol%)+赤藓糖醇在其熔点下的动力粘度约为0.546 Pas, 均高于木糖醇(0.396 Pas) 和赤藓糖醇(0.035 Pas)在各自熔点下的动力粘度。此外，使用Arrhenius模型拟合共晶糖醇的动力粘度-温度曲线发现，共晶糖醇的黏流活化能也高于单组份糖醇。虽然通过制备共晶糖醇的方法可有效降低糖醇的熔点，但共晶后粘度和黏流活化能的增大在一定程度上导致了共晶糖醇结晶缓慢或结晶困难，从而对实际应用中相变材料的储热和释热性能产生不利影响。

Select

Performance Analysis of an Ejector Enhanced Two-Stage Auto-Cascade Refrigeration Cycle for Low Temperature Freezer；喷射器增效的两级自复叠低温冷柜制冷循环性能分析

热科学学报. 2021, 30(6): 2015-2026.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

本文提出了一种适用于-80℃低温制冷的喷射器增效两级自复叠制冷循环，并选用三元非共沸混合物R600a/R32/R1150为工质进行了热力学分析。该新型循环利用喷射器回收节流过程的膨胀功用以提高压缩机吸气压力。通过热力学方法对比分析了新型循环与传统两级自复叠制冷循环的性能，研究了重要的运行参数包括工质配比，第二级气液分离器进口干度，冷凝温度、蒸发温度以及节流膨胀比对系统性能的影响规律。结果表明三元工质R600a/R32/R1150存在最佳配比（0.45/0.2/0.35）获得最大COP。新型循环在系统COP，㶲效率和容积制冷量方面均优于传统循环，且COP和用效率分别提高了4.9-36.5%和6.9-34.3%。该研究表明新型的喷射器增效两级自复叠制冷循环在低温制冷领域具有良好的应用潜力。

Select

A Theoretical Criterion for Evaluating the Thermodynamic Effectiveness of Regenerators in Organic Rankine Cycle Systems；有机朗肯循环回热有效性理论判据

热科学学报. 2021, 30(6): 2027-2036.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

有机朗肯循环是一种很有前景的中低品位能源热功转化技术。为了提高有机朗肯循环系统的能量转化效率，常在系统中加装回热器。加装回热器需要额外的管道和设备，必将产生额外的压力损失和功率损失。同时考虑回热器的贡献和附加压力损失引起的功率损失，利用数学和热力学方程，导出了评价安装回热器效果的理论判据。该判据的核心是回热临界压力损失。如果该值为负，表明安装回热器不能提升有机朗肯循环的热效率。如果要使回热器有效工作，必须保证回热临界压力损失为正，同时要求引入回热器产生的附加压降值小于回热临界压力损失。本文同时研究了有机朗肯循环的蒸发温度、冷凝温度、膨胀机效率、回热完善度和工质类型对回热临界压力损失的影响。研究发现，较低的蒸发温度或使用具有较高临界温度的工质可降低回热临界压力损失。

Select

Performance Analysis of Thermoacoustic Refrigerator of 10 W Cooling Power made up of Poly-Vinyl-Chloride for Different Parallel Plate Stacks by using Helium as a Working Fluid；以氦气为工质的不同平行板堆用聚氯乙烯10W制冷功率热声制冷机性能分析研究

热科学学报. 2021, 30(6): 2037-2055.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

Refrigerants are usually provided in the conventional refrigeration system although the refrigerants produce Chlorofluorocarbons (CFCs) and Hydro-chlorofluorocarbons (HCFCs), which are hazardous to the environment. However, these disadvantages can be overcome by using air or inert gas in the thermoacoustic refrigeration system. In the present experimental work, helium is used as a working gas with an operating pressure range of 0.2 MPa to 1.0 MPa in order to study the performance of thermoacoustic refrigerator (TAR) which is fabricated using Poly-Vinyl-Chloride (PVC). The parallel plate stacks with different porosity ratios have been considered to study the performance of TAR. The temperature difference between the hot and cold heat exchanger and acoustic dynamic pressure were recorded by using Bruel and Kjaer data acquisition system under different operating conditions. The effect of different operating parameters such as operating frequency (200 Hz to 600 Hz), cooling load (2 W to 10 W) and drive ratio (0.6% to 1.6%) have also been considered to study the performance of TAR. The TAR also modeled in DeltaEC software and the results are compared with the experimental outcomes and found to be in good agreement. The experimental results show that -2.1 degrees C is the lowest temperature measured at cold heat exchanger by achieving the highest temperature difference of about 32.9 degrees C. An improvement is around 36% as compared to that of previous experiments that used aluminium TAR. The highest Coefficient of Performance (COP) and the Relative Coefficient of Performance (COPR) are found to be 2.024 and 0.217 respectively.

Select

Characterization of Particle Emissions of Turbocharged Direct Injection Gasoline Engine in Transients and Hot Start Conditions；涡轮增压直喷汽油机瞬态和热起动工况微粒排放特性

热科学学报. 2021, 30(6): 2056-2070.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

Reducing pollutant emissions, particularly soot particles emitted by internal combustion engines, is a major challenge for car manufacturers. In this paper, the experimental setup is a turbocharged three-cylinders gasoline direct injection engine installed on a HORIBA dynamic test driven by a HORIBA STARS computer. The particle-measuring device is a Pegasor Particles Sensor that measures the current carried by previously electrically charged particles. The hot engine stabilized tests, with lambda parameter lower or equal to one, have very low emission levels, unlike dynamic tests. As a consequence, the present paper deals with experiments in transient conditions. Unlike diesel engine, cycle tests show that particulate emissions vary widely. To understand the phenomenon, a simple transient was created and reproduced a hundred times in order to obtain enough data to analyze and compare these different tests. This transient starts from idle to reach the speed of 2000 r/min and 60 N.m in 5 s. To reach this point, it is necessary to stay in full load for about 3 s.

Select

A Phased Aerodynamic Optimization Method for Compressors Based on Multi-Degrees-of-Freedom Surface Parameterization；基于多自由度曲面参数化的压气机分阶段气动优化方法

热科学学报. 2021, 30(6): 2071-2086.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

压气机高保真气动优化面临“维数灾难”问题，难以在工程有限时间内得到优化解。本文提出一种在兼顾曲面参数化低维特性的同时，具备良好的设计灵活性的多自由度曲面参数化方法，并采用“先模态搜索、后精细开发”的分阶段优化策略，进一步实现降维。将该优化方法应用于跨音转子Rotor37高保真气动优化，在111h左右得到优化解。为了探索该参数化方法对叶身控制变量的更优给定方式，采用吸、压力面控制点“独立变化”和“同步变化”两种方式进行对比，发现“同步变化”方式具有更好的灵活性。在满足约束的条件下，以“同步变化”方式改变叶身控制点，设计点效率提升了2.2%，喘振裕度提升了0.5%，证明了该优化方法在压气机高保真度气动优化中的有用性。

Select

Application of New Empirical Models based on Mathematical Statistics in the Through-Flow Analysis；基于数理统计方法的新经验模型在通流特性分析中的应用

热科学学报. 2021, 30(6): 2087-2098.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

通流特性分析是压气机设计过程中重要一环，其中包含着大量用于预测压气机气动性能的经验模型。由于各经验模型均基于早期低速低负荷压气机试验结果建立的，其对现代压气机性能的预测能力明显不足。本次研究首先回顾了各预测模型的发展历程，之后基于大量压气机平面叶栅数值结果，采用数理统计方法建立了预测压气机叶栅最小损失系数和最小损失落后角的经验模型。接着，在通流特性分析程序中，将新建立的经验模型与对应的原始模型进行替换。最后采用三台压气机对新模型的预测能力进行校验。结果表明新模型对三台压气机的预测精度均明显高于原始模型，说明采用数理统计方法建立的预测模型应用在通流特性分析过程中是合适的，这种建模方式同时也为其他经验模型的改进提供了思路。

Select

Performance Improvement of a Centrifugal Compressor for the Fuel Cell Vehicle by Tip Leakage Vortex Control；基于叶尖泄漏涡控制的燃料电池离心压气机性能优化研究

热科学学报. 2021, 30(6): 2099-2111.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

空压机是车用燃料电池动力系统功耗最大的部件，功耗可达电堆输出功率的25%。提高空压机效率是降低功耗的主要途径。受驱动电机转速限制，离心式燃料电池空压机的叶轮流道狭长，叶尖泄漏损失大，导致气动效率低。本文揭示了离心压气机前缘叶尖泄漏涡运动轨迹与叶片吸力面之间的夹角是影响叶尖泄漏损失的关键因素。增大该夹角可减小前缘叶尖泄漏涡与叶片下游叶尖泄漏流之间的掺混损失，提高空压机气动效率。据此提出叶尖载荷前加载叶型，应用于80 kW级燃料电池系统空压机设计。仿真结果表明，空压机叶轮气动效率在设计工况下比常规叶轮提高1.3个百分点，在大流量工况下提高约10个百分点。空压机在设计工况下的整机试验效率（含电机）达到72.1%，功耗约为电堆输出功率的16%。

Select

Large Eddy Simulation of the By-pass Transition Process under Different Inlet Turbulence Conditions；不同进口湍流条件下旁路过渡过程的大涡模拟

热科学学报. 2021, 30(6): 2112-2121.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

The transition process of the boundary layer developing over a flat plate with elevated inlet Free Stream Turbulence Intensity (FSTI) has been studied by means of Large Eddy Simulation (LES). To this purpose, four cases with different inflow disturbances have been tested varying the magnitude and the length scale of turbulence. LES has been performed by using the finite-volume ANSYS Fluent code. The computational domain, which was constituted by a rectangular domain with a zero thickness plate, was based on an ERCOFTAC test case in order to provide a validation with a well-known set of data by comparing the boundary layer integral parameters and mean and fluctuating streamwise velocity profiles. The four cases were discussed within the paper by looking at classical statistical properties as well as advanced post-processing tools.

Select

Experimental Investigation of Effects of Reynolds Number and Incidence Angle on Secondary Flow within a Linear Blade Cascade；雷诺数和入射角对线性叶栅二次流影响的实验研究

热科学学报. 2021, 30(6): 2122-2136.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

The kinetic energy loss and the secondary loss downstream of a high turning nozzle cascade were investigated. Influence of the incidence angle (i= -25 degrees, 0 degrees and 25 degrees) and Reynolds number (Re-2,Re-is =0.8x10(5), 1.2x10(5), 2.5x10(5) and 4.5x10(5)) were studied on two cascade configurations defined by different pitch to chord ratio (t/c=0.6 and 0.9), respectively. Measurements at the cascade inlet were performed by means of Preston tube, while at the cascade outlet by means of miniature pyramid five-hole pressure probe. An effect of studied parameters on the flow field at the cascade outlet was shown by the distribution of the kinetic energy loss, secondary loss, mix-out loss and streamwise vorticity.

Select

A Comprehensive Experimental Study on Immiscible Displacements in Porous Media: Effects of Capillary Forces, Viscous Forces, Wettability and Pore Geometries；多孔介质内非混相驱替过程系统性实验研究：毛细力、粘性力、润湿性和孔隙结构的影响

热科学学报. 2021, 30(6): 2137-2149.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

多孔介质内非混相驱替过程对于很多自然过程和工业应用都具有重要的基础研究价值。虽然该领域已有大量研究工作，但由于影响因素众多，一些局限性仍然存在。在本文中，我们开展了关于多孔介质内非混相驱替过程的系统性实验研究，讨论了毛细力、粘性力、润湿性和孔隙结构的综合影响。通过高分辨率微流控实验，残余流体分布和动态侵入过程都可以被清晰捕捉和定量表征。在排驱过程中，随着毛细数Ca增大，侵入流体呈现出一种“空隙填充”行为。然而在不利粘度比吸吮过程中，侵入流体会表现出一种相反的“空隙留出”行为，即中等Ca条件下可以被侵入的带状区域在大Ca条件下不再能被侵入。具有较大孔喉比的孔隙结构可以强化这种空隙留出行为。对于动态侵入实验结果，我们通过侵入流体饱和度增速的波动性表征了侵入过程的间歇性现象。具有不利粘度比的排驱过程呈现出最强烈的间歇性。具有较高孔隙度的孔隙结构可以对侵入间歇性产生抑制作用。本文的实验结果不仅展示了不同条件下多孔介质内非混相驱替行为的“全景”，而且提供了较为完整的数据集，可用于测试目前正在高速发展的多种孔尺度模型。

Select

Experimental Investigation of Flow Patterns in a Pump Intake with Different CWL (Critical Water Level) and Back-Wall Clearance；进水池内不同临界水位与后壁距下流态试验研究

热科学学报. 2021, 30(6): 2150-2163.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

针对不同工况，从实验和理论上研究了后壁间隙、CWL(临界水位)和水中气体含量对进水池内流态的影响。统计数据表明，两相流的CWL比相对低流速的单相流低，随着流量增加，这一趋势则完全相反。在亚临界、临界和超临界流速条件下获得的详细实验数据表明，后壁间隙越大，涡旋越多，自由表面漩涡强度越高。最小后壁间隙下，入口来流占据了喇叭管管口下方的大部分空间，并且入口来流和后壁折射流动相对于除喇叭管轴线之外的某一垂直线不对称。对于较大和最大的后壁间隙，入口来流和后壁折射流动相对于喇叭管轴线几乎对称。不同后壁间隙大小下的两条PIV测速线上的速度分布表明，最小后壁间隙(Lbc=1.2 D)对喇叭管周围的流动具有明显影响效应。

Select

Influences of Lateral Double-Layered Deflectors on Cooling Performance of Air-Cooled Condenser；横向双层导流板对空冷凝汽器冷却性能的影响

热科学学报. 2021, 30(6): 2164-2177.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

空冷凝汽器（ACC）的冷却性能容易受到环境风的不利影响。为减弱这种不利影响，本文提出了三种安装在空冷平台下的横向双层导流板。通过数值模拟的方法，得到了2×660 MW直接空冷系统的流动传热性能的主要参数。结果显示，得益于其引导作用，导流板可以有效降低进气温度,并提高迎风侧风机的质量流量，特别是在高风速时，且在0°风向下空冷凝汽器的冷却能力的提升是最小的。在所研究的导流板中，‘倾斜-垂直’导流板在提升空冷凝汽器性能上的表现优于其他形式的导流板。当风速为12m/s时，它能使背压降低12.15%。因此，在实际工程中可以应用该形式的导流板来提高空冷凝汽器的性能。

Select

Experimental and Numerical Analysis of Cavity/Mean-Flow Interaction in Low Pressure Axial Flow Turbines；低压轴流式水轮机内腔/平均流相互作用的实验与数值分析

热科学学报. 2021, 30(6): 2178-2185.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

The increasing performance of modern aeroengines led the research towards the optimization of machine components not deeply analyzed in the past. In this context, the mechanisms driving the interaction process between the secondary flows evolving at the hub of low-pressure turbines with the rotor-stator cavity systems have been poorly investigated in the literature. In this work, an experimental and numerical analysis of the interaction between the endwall near wall flow and the leakage flow of a real cavity system is presented. The experimental results were carried out in the annular low-pressure axial flow turbine of the University of Genova. Experimental blade loading and pressure distributions into the cavity, as well as the measured total pressure loss coefficient, have been used for a proper validation of CFD results. Both steady and unsteady calculations were carried out through the commercial solver Numeca. Particularly, several numerical approaches have been tested into this work: RANS, Non Linear Harmonic (NLH), and URANS.

Select

Stable Combustion under Carbon Dioxide Enriched Methane Blends For Exhaust Gas Recirculation (EGR)；废气再循环（EGR）用富二氧化碳甲烷混合物下的稳定燃烧

热科学学报. 2021, 30(6): 2186-2195.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

Exhaust gas recirculation (EGR) is one of the main techniques to enable the use of oxyfuel combustion for carbon capture and storage (CCS). However, the use of recirculated streams with elevated carbon dioxide poses different challenges. Thus, more research is required about the cumulative effects on the desirable outcomes of the combustion processes such as thermal efficiency, reduced emissions and system operability, when fuels with high CO2 concentration for CCS exhaust gas recirculation or biogas are used. Therefore, this study evaluates the use of various CO2 enriched methane blends and their response towards the formation of a great variety of structures that appear in swirling flows, which are the main mechanism for combustion control in current gas turbines systems.

Select

Thermochemical Aspects of Activated Ammonium Perchlorates with Superior Thermal Stability, Decomposition Enthalpy, Propagation Index, and Decomposition Kinetic Parameters；具有优异热稳定性、分解焓、传播指数和分解动力学参数的活性高氯酸铵的热化学特性

热科学学报. 2021, 30(6): 2196-2201.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

Ammonium perchlorate (AP) includes oxidizing and reducing elements on the same molecule. AP can act as an efficient oxidizer and mono-propellant as well. In this study, AP experienced crystallographic phase change from orthorhombic centrosymmetric to non-centrosymmetric under controlled isothermal heat treatment. XRD diffractograms confirmed this crystallographic phase change. The thermal behaviour of activated AP had been investigated using DSC. Activated AP demonstrated high chemical stability with an increase in endothermic phase transition enthalpy by 170%. The enthalpy of the subsequent two main exothermic decomposition reactions was increased by 250%. Whereas AP demonstrated total decomposition enthalpy of 733 J/g, activated AP showed 2614 J/g. Activated AP can secure self-sustained response at a high rate.

Select

An Experimental Study on the Phenomena inside the Burning Aviation Kerosene Droplet；航空煤油液滴在燃烧过程中液滴内部现象的实验研究

热科学学报. 2021, 30(6): 2202-2213.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

本文以航空煤油作为研究对象，采用液滴悬挂法，在静止高温环境中进行单液滴燃烧实验，研究液滴内部和液滴表面的行为特性。将液滴内部的碳烟颗粒作为示踪物，观察液滴内的流动方向。利用高速摄像机记录下燃烧过程中液滴的形状变化、液滴内部流动规律以及气-液界面的不稳定性。研究表明，液滴内部流动是由液滴表面的表面张力梯度所产生的Marangoni效应引起的。Marangoni效应对液滴内部流动有显著影响。液滴表面毛细波的振幅不均匀，呈现出大-小-有的特征。毛细波的波长范围为110-120 μm。

Select

The Impact of Key Factors on Flow Characteristics of 14 MW Reverse-Swirl Pulverized Coal Burner；14 MW逆喷旋流煤粉燃烧器的关键因素对其空气动力场的影响

热科学学报. 2021, 30(6): 2214-2222.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

逆喷旋流燃烧器将逆向射流稳燃技术和旋流稳燃技术耦合达到稳定火焰并且已经实现工业化。本文利用Dantec多通道恒温热线风速仪在1:2的燃烧器模型上进行了不同逆向一次风率和旋流内二次风率对其流动特性的影响试验。实验结果表明：环形耦合回流区的形状一直保持对称结构，逆向一次风率是影响耦合回流区内的轴向速度、RMS速度和径向速度方向的主要影响因素，逆向一次风率和旋流内二次风率都对耦合回流区面积、相对回流率、旋流内二次风和外二次风的混合程度以及旋流强度都有较大影响。当逆向一次风率为11.92%或旋流内二次风率为17.03%时，耦合回流区面积达到最大，然而当逆向一次风率和旋流内二次风率分别达到14.86%和28.41%时，逆向一次风和旋流内二次风的耦合效果较好，耦合回流区面积、相对回流率以及旋流强度适宜，逆向一次风和旋流内二次风的混合相对滞后。该研究结果对逆向射流燃烧器的后续设计和运行具有重要的理论和实践意义。

Select

Characteristics of Axial and Radial Development of Solids Holdup in a Countercurrent Fluidized Bed Particle Solar Receiver；新型逆流流化床颗粒太阳能接收器中固含率的轴向和径向发展特性

热科学学报. 2021, 30(6): 2223-2240.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

A novel particle solar receiver (PSR) with gas-solids countercurrent fluidized bed (CCFB) was proposed. The cold-mold prototype was set up to investigate the gas-solids flow structure by using optical fiber probes. The local solids holdup distribution, its evolution with various operating conditions and the fluctuations of the local flow structures were investigated experimentally. The results show that the novel CCFB can achieve much higher solids holdup (similar to 9%) compared to the traditional downer ones (similar to 1%). The solid particles are mainly distributed in the near-wall region and the particles are more difficult to get a fully developed state in the near-wall region. The excellent gas-solids mixing and contacting demonstrated by the standard deviation and intermittency index means a better wall-to-bed heat transfer process. The distribution of the solid particles in the CCFB transport tube is revealed, which can provide a significant reference for the structure design of the hot-mold PSR. Moreover, the research can fill in the research gap in the gas-solids counterflow field.

Select

Experimental Investigation on the Hydrodynamic Characteristics of Fluidized Bed Particle Solar Receiver with Gas-Solid Countercurrent Flow Pattern；逆流气固两相流流化床颗粒太阳电池水动力特性的实验研究

热科学学报. 2021, 30(6): 2241-2253.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

To design a particle solar receiver (PSR), a vital energy conversion system, is still a bottleneck for researchers. This study presents a novel PSR based on countercurrent fluidized bed (CCFB) technology, named CCFB receiver. In this design, downward-moving particles are subjected to the action of an up-flow gas to reduce the falling speed and enhance the radial disturbance, and hence increase the residence time of particles and improve the heat transfer. A cold-mold visual experimental setup is established. The influence factors are investigated experimentally, including the superficial gas velocity, solid flux, aeration gas, particle size and transport tube diameter. The results indicate that the maximum solid holdup can exceed 9% or so with fine particles of diameter d(p) = 113.5 mu m and a tube diameter of 40 mm. It is proved that the CCFB can operate stably and adjust the solid flux rapidly. The results of this study provide a new structure for PSRs in the concentrated solar power field and could fill the research insufficiency in the gas-solid counterflow field.

Select

A Novel Combined Trombe Wall System for Village Houses in Cold Regions of China；一种适用于中国寒冷地区村镇农房的新型组合式特朗伯墙体系统

热科学学报. 2021, 30(6): 2254-2266.

摘要 ([an error occurred while processing this directive]) PDF全文 ([an error occurred while processing this directive])

可视化

本文提出了一种结合百叶窗和地下室的新型特朗伯墙系统，并对四种类型房间的集热性能进行了现场测试。实验组分别为：(ⅰ)无特朗伯墙(对照组)房间，(ⅱ)传统特朗伯墙(TW) 房间，(ⅲ)带百叶窗的特朗伯墙(TW+VB)房间，和(ⅳ)带有百叶窗和地下室的新型特朗伯墙系统（TW+VB+B）房间。本研究的目的是：(ⅰ)评估TW+VB+B系统在不同工况下的集热性能。 (ⅱ)确认采暖期内该系统百叶窗的最佳角度。试验结果表明，TW+VB+B系统有效地减少了日落后室内温度的波动。在白天，该系统的测试房间的平均空气温度比对照组高13.6℃，出风口平均温度比TW+VB系统高4.9℃，预测平均投票数（PMV）比对照组高1.02。当百叶窗角度设置为45°时，热效率保持在40-65%。不仅减少了室内温度波动，还提高了冬季集热效率。因此，该被动式节能技术的应用，能够减少建筑供暖能耗和污染物排放量，为提高严寒村镇地区带有特朗伯墙农房的集热性能提供了有价值的建议。

2021年, 第30卷, 第6期 刊出日期：2021-06-25

2021年, 第30卷, 第6期　刊出日期：2021-06-25