摘要
瞬态条件下的热整流有广阔的实际应用背景,本文建立了一维板状复合结构热整流器的瞬态热整流模型,并利用有限元方法研究了不同恒定热阻、不同界面间隙、周期性温度边界条件以及材料和几何参数对瞬态热整流效果的影响规律.研究结果表明,界面热阻的存在可以提高系统的瞬态热整流系数,而初始界面间隙的引入让瞬态热整流系数实现了量级的飞跃.通过几何以及材料参数的合理设置有利于优化结构的热整流效果,针对周期性高温边界条件,温差和频率的变化可进一步提升复合结构的热整流系数.本文所提出热整流机制可以指导瞬态下热整流器的优化设计.
Like an electric diode,thermal diode transmits heat in a specific direction,and thermal rectification is also a fundamental phenomenon for active heat flow control.However,in practical applications,thermal rectification needs to be operated under transient conditions.In this study,transient thermal rectification ratio of a onedimensional heterostructure is numerically investigated by using the finite element method.The effects of interface thermal resistance,interface initial gap,periodic boundary condition and geometric and material parameters on the transient thermal resistance ratio are obtained.Research indicates that the interface thermal resistance can enhance the thermal rectification effect of the system,and the introduction of the initial interface gap improves the transient thermal rectification ratio by an order of magnitude.The ability to engineer the thermal diffusivity of materials allows us to control the heat flux and improve transient thermal rectification ratio.Since interface thermal resistance can enlarge the difference in heat transfer capability between forward case and reverse case,it is reasonable to suggest that adjusting the interface thermal resistance may also enhance the thermal rectification effect,but excessive interface thermal resistance will reduce it.Under the periodic temperature boundary conditions,the larger the temperature difference in boundary fluctuation,the larger the fluctuation amplitude of the transient thermal rectification ratio is.The fluctuation frequency of thermal rectification changes with the periodic boundary frequency,which also affects the amplitude of the fluctuation.Furthermore,by adjusting the initial interface gap,the gap is closed during heat transfer and the interface thermal resistance is reduced in the forward case,while the interface gap is kept open in the reverse case,thereby improving the overall thermal rectification ratio by an order of magnitude.For different transient stages,the equivalent thermal conductivity can be changed by adjusting the material and geometrical properties to improve the thermal rectification ratio.Therefore,the proposed numerical approach and results can guide the optimal design of the transient thermal rectifier.
作者
赵建宁
魏东
吕国正
王子成
刘冬欢
Zhao Jian-Ning;Wei Dong;LüGuo-Zheng;Wang Zi-Cheng;Liu Dong-Huan(Beijing Key Laboratory for Magneto-Photoelectrical Composite and Interface Science,School of Mathematics and Physics,University of Science and Technology Beijing,Beijing 100083,China;Computational Aerodynamics Institute,China Aerodynamics Research and Development Center,Mianyang 621000,China;School of Advanced Engineering,University of Science and Technology Beijing,Beijing 100083,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第4期127-137,共11页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11772045)
国家数值风洞工程(批准号:NNW2019ZT2-B04)资助的课题。
关键词
瞬态热整流
复合结构
界面热阻
周期性边界条件
transient thermal rectification ratio
composite structure
interface thermal resistance
periodic boundary condition
作者简介
通信作者:刘冬欢.E-mail:liudh@ustb.edu.cn。
