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Journal of Thermal Science 2024年第2期33卷 591-601页

作者： WANG Zhaowen ZHOU Hao LUO Jiawei LI Yawei FANG Hao LIU Tianxiao State Key Laboratory of Clean Energy Utilization Institute for Thermal Power EngineeringZhejiang UniversityHangzhou310027China

This paper studied the thermal physical properties of foundation materials in the molten salt tank of thermal energy storage system after molten salt leakage by Transient plane source experiment and X-ray computed microtomography simulation methods.The microstructure,thermal properties and pressure resistance with different particle diameters were addressed.The measured heat conductivities from Transient plane source experiment for three cases are 0.49 W/(m·K),0.48 W/(m·K),and 0.51 W/(m·K),and the porosity is 30.1%,30.7%,and 31.2% respectively.The heat conductivity simulating results of three cases are 0.471 W/(m·K),0.482W/(m·K),and 0.513 W/(m·K).The ratio of difference between the results of simulation and Transient plane source measurement is as low as 1.2%,verifying the reliability of experimental and simulation results to a certain degree.Compared with the heat conductivity of 0.097-0.129 W/(m·K) and porosity of 71.6%-78.9% without leaking salt,the porosity is reduced by more than 50% while the heat conductivity increased by 4 to 5 times after molten salt leakage.This significant increase in heat conductivity has a great impact on security operation,structure design,and modeling of the tank foundation for solar power plants.

关键词： heat conductivity X-ray computed microtomography foundation materials three-phase threshold algorithm molten salt leakage

Interrelationships between leaf heat conductivity and tissue structures of different varieties of Populus tomentosa Carr

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Forestry Studies in China 2008年第3期10卷 173-178页

作者： WANG Min ZHANG Wen-jie XIAO Jian ZHANG Zhi-yi LIU Jing College of Science Beijing Forestry University Beijing 100083 P. R. China Technical Institute of Physics and Chemistry Chinese Academic of Sciences ByiJing 100080 P. R. China Key Laboratory for Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education Beijing Forestry University Beijing 100083 P. R. China

Plant heat conductivity largely depends on tissue structure. Different structures lead to different heat conductivity. As well, water transfer also plays a very important role in heat transfer in plants. We have studied leaf heat conductivity and tissue structure of 3-and 30-year-old Populus tomentosa Carr. trees using infrared thermal imaging, steady state heat conductivity surveys and paraffin section and investigated the relationship between leaf heat conductivity, tissue structure and water content of leaves. The results show that the temperature on leaf surfaces among the various varieties of trees was almost the same. Leaf heat conductivity, temperature and water content of leaves are positively correlated. The thicker the leaf tissue structures, the larger the heat resistance. That is, the tighter the cells and the smaller the interspaces, the smaller the heat conductivity, which is not conducive for heat transfer.

关键词： Populus tomentosa Carr. leaf infrared thermal imaging heat conductivity paraffin section

Rationally tailoring interface characteristics of ZnO/amorphous carbon/graphene for heat-conduction microwave absorbers

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Nano Research 2022年第10期15卷 8677-8687页

作者： Maofan Zhou Xuefei Xu Gengping Wan Pengpeng Mou Shengjie Teng Guizhen Wang State Key Laboratory of Marine Resource Utilization in South China Sea Hainan UniversityHaikou 570228China

With the increasingly severe electromagnetic interference issue and the huge heat dissipation demand caused by the miniaturized and integrated electronic devices,exploring the heat-conduction microwave absorption(MA)materials is highly desired and remains a great challenge.Herein,we reported the fabrication of ZnO/amorphous carbon(ZnO/AC)hybrid films covered on the surface of graphene(ZnO/AC/Graphene)to simultaneously apply as the MA and thermal management materials.The ZnO/AC coatings synthesized with the auxiliary of an atomic layer deposition(ALD)method are highly uniform and controllable,which can significantly improve the MA performance and thermal conduction properties of graphene.The reflection loss(RL)of−55.4 dB and the effective absorption bandwidth of 5.3 GHz were achieved with thickness of 2.0 mm for ZnO/AC/Graphene at a low loading content(3 wt.%).The minimum RL of−57.9 dB can be obtained in the ZnO/AC/Graphene composites at a low frequency(7.8 GHz).Moreover,the absorption frequency can be regulated by changing the ZnO/AC which can be readily implemented by adjusting the ALD cycles of ZnO.The thermal conductivity of ZnO/AC/Graphene is up to 257.8 mW·m^(−1)·K^(−1),increased by 53.2%compared with natural rubber.The enhancement mechanisms of microwave loss and heat conduction are systematically studied in detail.This work not only develops an excellent candidate,but also provides a novel strategy to design functional materials for heat-conduction MA application.

关键词： atomic layer deposition graphene microwave absorption heat conductivity

A building unit decomposition model for energy leakage by infrared thermography image analysis

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Frontiers in Energy 2020年第4期14卷 901-921页

作者： Yan SU Fangjun HONG Lianjie SHU Department of Electromechanical Engineering University of MacaoTaipaMacaoChina School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Faculty of Business Administration University of MacaoTaipaMacaoChina

A quantitative energy leakage model was developed based on the thermography image data measured for both external and internal building surfaces.The infrared thermography images of both surfaces of doors,windows,and walls of an office building in the Hengqin Campus of University of Macao were taken at various times in a day for four seasons.The transient heat flux for sample units were obtained based on measurements of the seasonal transient local temperature differences and calculations of the effective thermal conductivity from the multiple-layer porous medium conduction model.Effects of construction unit types,orientations,and seasons were quantitatively investigated with unit transient orientation index factors.The corresponding electric energy consumption was calculated based on the air conditioning system coefficient of performance of heat pump and refrigerator cycles for different seasons.The model was validated by comparing to the electric meter records of energy consumption of the air conditioning system.The uncertainties of the predicted total building energy leakage are about 14.7%,12.8%,12.4%,and 15.8%for the four seasons,respectively.The differences between the predicted electric consumption and meter values are less than 13.4%and 5.4%for summer and winter,respectively.The typical daily thermal energy leakage value in winter is the highest among the four seasons.However,the daily electric energy consumption by the air conditioning system in summer and autumn is higher than that in winter.The present decomposition model for energy leakage is expected to provide a practical tool for quantitative analysis of energy leakage of buildings.

关键词： heat conductivity heat coefficient heat flux infrared thermography thermal image

heat Shielding Effects in the Earth＇s Crust

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Journal of Earth Science 2017年第1期28卷 161-167页

作者： Yixian Xu Lupei Zhu Qinyan Wang Yinhe Luo Jianghai Xia School of Earth Sciences Zhejiang University Hangzhou 310027 China State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China Hubei Subsurface Multi-Scale lmaging Key Laboratory Institute of Geophysics and Geomatics China University of Geosciences Wuhan 430074 China Department of Earth and Atmospherie Sciences Saint Louis University St. Louis MO 63103 USA School of Earth Sciences China University of Geosciences Wuhan 430074 China

Knowledge of heat flow and associated variations of temperature with depth is crucial for understanding how the Earth functions. Here, we demonstrate possible heat shielding effects that result from the occurrence of mafic intrusions/layers（granulitic rocks） within a dominantly granitic middle crust and/or ultramafic intrusions/layers（peridotitic rocks） within a dominantly granulitic lower crust; heat shielding is a familiar phenomenon in heat engineering and thermal metamaterials. Simple one-dimensional calculations suggest that heat shielding due to the intercalation of granitic, granulitic and peridotitic rocks will increase Moho temperatures substantially. This study may lead to a rethinking of numerous proposed lower crustal processes.

关键词： geotherm crustal laminated structure heat shielding heat conductivity peridotitic in-trusions North Tibet magnetotelluric data.

Considering temperature dependence of thermo-physical properties of sandy soils in two scenarios of oil pollution

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Research in Cold and Arid Regions 2014年第4期6卷 302-308页

作者： Aleksey V.Malyshev Anatoly M.Timofeev Institute of Physical-Technical Problems of the North. V.P. Larionov Siberian Branch of the Russian Academy of Sciences

We analyzed the heat conductivity and volumetric heat capacity of sandy soil contaminated in two scenarios of oil pollution, and also determined the temperature dependencies of these changed thermophysical properties. In the first pollution scenario, the oil product was introduced into wet river sand, and in the second case, dry sand was contaminated by the oil product and was then moistened with water. By considering these two scenarios as multicomponent dispersion systems with varying degrees of contamination and humidity, and by using a polystructural granular model with pore spaces and closed inclusions, we calculated that the heat conductivity of the sandy soil increased under the first pollution scenario and decreased under the second, but the change in the volumetric heat capacity of the sandy soil was proportional only to the amount of oil pollution, not the manner in which it was introduced. We also determined the temperature dependencies of these two thermophysical properties of sandy soil when polluted by oil, of which information will be useful for future containment and remediation of oil-contaminated soil.

关键词： sandy soil heat conductivity heat capacity heat resistance pollution oil product unfrozen water volumeconcentration coordination number