检索结果-南通市图书馆

Thermal smart materials with tunable thermal conductivity:Mechanisms, materials, and applications

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2022年第11期65卷 18-35页

作者： ZiTong Zhang bingyang cao Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Engineering MechanicsTsinghua UniversityBeijing 100084China

The demand for active and effective management of heat transfer is increasing in various modern application scenarios. The thermal conductivity of materials plays a key role in thermal management systems, and reversibly tunable thermal properties are one of the fundamental needs for materials. Thermal smart materials, whose thermal properties can be tuned with an external trigger, have attracted the attention of researchers. In this paper, we provide a brief review of current research advances in thermal smart materials in recent years in terms of fundamental physical mechanisms, thermal switching ratios, and their application value. We focus on typical thermal smart materials such as nanoparticle suspensions, phase change materials, polymers, layered materials tuned by electrochemistry and other materials tuned by a specific external field. After surveying the fundamental mechanisms, we present applications of thermal smart components and devices in temperature control, thermal circuits, phonon computers, thermal metamaterials, and so on. Finally, we discuss the limitations and challenges of thermal smart materials, as well as our predictions for future development.

关键词： thermal smart material thermal conductivity smart tuning thermal control system

Study on thermal wave based on the thermal mass theory

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2009年第6期52卷 1786-1792页

作者： HU RuiFeng cao bingyang Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Engeering MechanicsTsinghua UniversityBeijing 100084China

The conservation equations for heat conduction are established based on the concept of thermal *** obtain a general heat conduction law which takes into account the spatial and temporal inertia of thermal *** general law introduces a damped thermal wave *** reduces to the well-known CV model when the spatial inertia of heat flux and temperature and the temporal inertia of temperature are neglected,which indicates that the CV model only considers the temporal inertia of heat *** simulations on the propagation and superposition of thermal waves show that for small thermal perturbation the CV model agrees with the thermal wave equation based on the thermal mass *** larger thermal perturbation,however,the physically impossible phenomenon pre-dicted by CV model,*** negative temperature induced by the thermal wave superposition,is eliminated by the general heat conduction law,which demonstrates that the present heat conduction law based on the thermal mass theory is more reasonable.

关键词： thermal wave thermal mass theory non-Fourier heat conduction CV mode

EXPERIMENTAL STUDY OF ENHANCED HEAT TRANSFER BY FLOW-INDUCED VIBRATION OF ELASTIC TUBE BUNDLES

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2000年第3期12卷 103-109页

作者： Tian, Maocheng Cheng, Fei Cheng, Lin cao, bingyang Shandong Univ of Technology Jinan China

New concept of heat transfer enhancement by flow-induced vibration was put forward, and a novel heat transfer element called elastic tube bundles was designed. The experimental investigation was performed on its characteristics of flow-induced vibration in out-tube or in-tube flow. Under the conditions of fixed heat flux and steam-water heat transfer, the regularity of heat transfer enhancement by flow-induced vibration was examined.

关键词： Flow of water Fluid structure interaction Heat exchangers Heat transfer Vibrations (mechanical)

Entransy and entropy revisited

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2011年第27期56卷 2974-2977页

作者： HU GuoJie cao bingyang GUO ZengYuan Key Laboratory for Thermal Science and Power Engineering of Ministry of Education School of Aerospace Tsinghua University Beijing 100084 China

Entransy, a recently developed concept, is the central physical quantity characterizing heat transfer processes not related to heat-to-work conversions. The entransy of an object pertains to the nature of the potential energy of heat in a thermal field and describes its heat transfer ability. In the present study, we revisit this concept, and develop its relationship to state and process quantities. This then enables a direct comparison to the more familiar concept, entropy, the central physical quantity in thermody- namics. The comparison helps to identify the role entransy has in heat transfer processes and highlight under what conditions state and process quantities related to entransy can be distinguished in such processes. As to embody the entransy loss due to work expended between the system and its environment for the irreversible heat conduction in gases, new quantities, available entransy flow and available system entransy are introduced. Both the entransy of solids and the available system entransy of gases are state quantities and their changes correspond to the entransy flow and the available entransy flow respectively. Thus there is no need to stress the difference between process quantity and state quantity in heat transfer.

关键词：耗散物理量特征气体系统熵传热过程传热能力转移过程状态

在线全文

学校读者我要写书评

暂无评论

一种模拟热导率的非平衡分子动力学方法

计算物理 2007年第4期24卷 463-466页

作者：曹炳阳清华大学工程力学系热科学与动力工程教育部重点实验室北京100084

提出一种计算热导率的非平衡分子动力学(NEMD)方法,通过构造均匀内热源获得抛物线形温度分布,并基于Fourier导热定律计算热导率,与Müller-Plathe发展的反扰动非平衡分子动力学(RNEMD)方法相比,不仅具有能量动量守恒和收敛性好的优点,... 详细信息

提出一种计算热导率的非平衡分子动力学(NEMD)方法,通过构造均匀内热源获得抛物线形温度分布,并基于Fourier导热定律计算热导率,与Müller-Plathe发展的反扰动非平衡分子动力学(RNEMD)方法相比,不仅具有能量动量守恒和收敛性好的优点,还克服了常规NEMD方法中热冷源区域存在局域热力学非平衡的问题,并有模拟系统温差影响小的特点.对液态氩的热导率进行模拟并与RNEMD方法的模拟结果进行对比.

关键词：分子动力学模拟热导率均匀内热源

Million-scale data integrated deep neural network for phonon properties of heuslers spanning the periodic table

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2023年第1期9卷 2155-2166页

作者： Alejandro Rodriguez Changpeng Lin Hongao Yang Mohammed Al-Fahdi Chen Shen Kamal Choudhary Yong Zhao Jianjun Hu bingyang cao Hongbin Zhang Ming Hu Department of Mechanical Engineering University of South CarolinaColumbiaSC 29208USA Theory and Simulation of Materials(THEOS) École Polytechnique Fédérale de LausanneCH-1015 LausanneSwitzerland Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Engineering MechanicsTsinghua UniversityBeijing 100084China Institute of Materials Science Technical University of DarmstadtDarmstadt 64287Germany Materials Science and Engineering Division National Institute of Standards and TechnologyGaithersburgMD 20899USA Department of Computer Science and Engineering University of South CarolinaColumbiaSC 29208USA

Existing machine learning potentials for predicting phonon properties of crystals are typically limited on a material-to-materialbasis, primarily due to the exponential scaling of model complexity with the number of atomic species. We address this bottleneckwith the developed Elemental Spatial Density Neural Network Force Field, namely Elemental-SDNNFF. The effectiveness andprecision of our Elemental-SDNNFF approach are demonstrated on 11,866 full, half, and quaternary Heusler structures spanning 55elements in the periodic table by prediction of complete phonon properties. Self-improvement schemes including active learningand data augmentation techniques provide an abundant 9.4 million atomic data for training. Deep insight into predicted ultralowlattice thermal conductivity (<1 Wm^(−1) K^(−1)) of 774 Heusler structures is gained by p–d orbital hybridization analysis. Additionally, aclass of two-band charge-2 Weyl points, referred to as “double Weyl points”, are found in 68% and 87% of 1662 half and 1550quaternary Heuslers, respectively.

关键词： properties phonon spanning

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

氩晶体导热性质的低维效应

清华大学学报（自然科学版） 2007年第2期47卷 297-300页

作者：曹炳阳过增元清华大学工程力学系北京100084

为研究维数降低对材料导热性质的影响规律，采用非平衡分子动力学方法研究了60～120K氩晶体体材料和理想一维及二维低维结构材料的导热性质。计算得到氩晶体低维材料的热导率明显高于体材料的值，这不同于常规意义上由于界面等因素对载... 详细信息

为研究维数降低对材料导热性质的影响规律，采用非平衡分子动力学方法研究了60～120K氩晶体体材料和理想一维及二维低维结构材料的导热性质。计算得到氩晶体低维材料的热导率明显高于体材料的值，这不同于常规意义上由于界面等因素对载热粒子的散射作用而导致材料热导率减小的尺寸效应。氩晶体理想二维材料较之体材料的热导率有成倍的提高，而理想一维材料较之体材料热导率的增加可达到数十至数百倍。研究还表明低维材料导热性质的低维效应在较高的温度条件下更为显著。

关键词：热导率低维效应尺寸效应分子动力学

在线全文

学校读者我要写书评

暂无评论

热子动力学模拟方法

计算物理 2013年第1期30卷 82-88页

作者：胡帼杰曹炳阳清华大学工程力学系热科学与动力工程教育部重点实验室北京100084

提出热子动力学模拟方法,以理想气体中的热质粒子即热子为模拟对象,建立热子间的碰撞模型,统计可获得热子气系统的热力学性质,实现对热质的直接模拟.基于该方法,对氩热子气的平衡态系统和非平衡态系统进行模拟计算,模拟计算的热子气的... 详细信息

提出热子动力学模拟方法,以理想气体中的热质粒子即热子为模拟对象,建立热子间的碰撞模型,统计可获得热子气系统的热力学性质,实现对热质的直接模拟.基于该方法,对氩热子气的平衡态系统和非平衡态系统进行模拟计算,模拟计算的热子气的状态方程同理论表达式一致,准确得到了氩气热导率在微纳尺度下的变化规律,验证了热子动力学模拟方法的可行性.

关键词：热子动力学模拟热质理论热子气非傅里叶导热

在线全文

学校读者我要写书评

暂无评论

反问题方法在3ω法测量薄膜热导率中的应用

科学通报 2019年第33期64卷 3510-3514页

作者：华钰超曹炳阳清华大学工程力学系热科学与动力工程教育部重点实验室

数值计算证明, 3ω方法结合有限元方法与反问题方法,能够同时确定基底材料与薄膜的相关热物性.基底上薄膜的热导率可以获得很高的测量精度,而且几乎不受测量截止频率的影响;热扩散率的测量精度则相对较低,但随着测量截止频率增加,其测... 详细信息

数值计算证明, 3ω方法结合有限元方法与反问题方法,能够同时确定基底材料与薄膜的相关热物性.基底上薄膜的热导率可以获得很高的测量精度,而且几乎不受测量截止频率的影响;热扩散率的测量精度则相对较低,但随着测量截止频率增加,其测量精度会得到改善.使用上述方法得到了硅基底上二氧化硅薄膜的热导率.得到硅基底的热导率为142.1 W/(m K),相对误差约为2%,二氧化硅薄膜的热导率为1.01 W/(m K),相对误差约为2%,与公认的测量值相符.

关键词： 3ω方法反问题方法热导率薄膜