高孔隙率金属材料微尺度辐射特性研究

发布时间：2018-03-20 06:54

本文选题：多孔材料　切入点：微结构　出处：《哈尔滨工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：微结构因能够激发光子隧道、表面等离子基元、磁极化、微腔谐振等一系列的微尺度辐射效应,在光谱辐射调控、红外探测、能量转化等方面有重要的应用。微尺度辐射现已成为热辐射领域重要的研究课题之一。国内外学者对表面微结构的微尺度辐射特性进行了广泛而深入的研究,而关于空间微结构的研究较少。高孔隙率金属材料涉及光谱选择性、多体散射性,具有复杂的空间微结构,其微尺度辐射特性较为复杂,因此,对其微尺度辐射传输的研究具有重要意义。本文主要采用时域有限差分法,研究了高孔隙率金属材料的微尺度辐射特性,目的是通过空间微结构实现光谱调控。主要内容和结论包括:建立了银立方体元胞结构模型,基于电磁散射理论,研究元胞结构在可见光波段的微尺度辐射特性。分析了元胞结构的空间电场和坡印廷矢量分布,认为当电场、坡印廷矢量与元胞肋筋产生较强的相互作用时,元胞结构表现出较强的吸收特性。考察了结构的变化对立方体元胞辐射特性的影响,发现方腔结构的衰减特性最强。开展了立方体层状结构可见光波段辐射特性研究。为了保证计算的准确性,提出了误差收敛测试方法。分析了立方体单元胞结构、单层立方体多孔结构和无限大平板结构吸收特性的关系,发现单层立方体多孔结构可有效改变光谱辐射特性,其辐射能力不是单元胞结构的线性相加。考虑了孔隙率、倾斜角对单层立方体多孔结构吸收特性的影响,结果表明孔隙率和倾斜角对吸收特性都有较大影响,不同的孔隙率下,单层立方体多孔结构出现明显的强、中、弱三个区域,而倾斜角对吸收的影响没有表现出明显的规律性。分析了多层立方体多孔结构的吸收特性和空间坡印廷矢量分布,发现多层结构在0.457μm产生吸收强化现象,三层结构对0.35~0.55μm波段的可见光具有选择透过性。建立了球形空心铝元胞结构和单层球形空心铝结构模型,研究五种孔隙率下的单元胞结构红外波段的辐射衰减特性,发现该种结构在红外波段具有很强的散射能力,而吸收能力几乎为零。比较了单层球形空心铝结构Drude模型与n,k模型吸收能力的变化,发现两种模型得到的吸收率的变化趋势是一致的,在吸收能力的数值上,大小会有所差别。考察了Si基、SiO2基和表面覆盖单层石墨烯对单层球形空心铝结构吸收能力的影响,发现Si基结构在1~6μm波段有一定的强化吸收作用,当在球形空心铝结构表面覆盖一层石墨烯时,并未发现石墨烯强化吸收的效果。
[Abstract]:Micro structure due to excitation photon tunneling, surface plasmon, magnetic polarization, micro cavity and a series of micro scale infrared radiation effect, radiation control, in the spectrum, has important applications in energy conversion and so on. The micro scale radiation has become one of the important research topics in the field of thermal radiation. The radiation characteristics of micro scale in China foreign scholars on the microstructure of the surface of the extensive and in-depth research, and Research on the micro structure of the space less. High porosity metal materials involving spectral selectivity, multiple scattering, with complex space micro structure, the micro scale radiation characteristics is complex, therefore, the study on microscale radiative transfer is important meaning. This paper mainly uses the finite difference time domain method, the micro scale of high porosity metal materials radiation characteristics, the purpose is through space micro structure to achieve the main content and spectral regulation. The conclusion includes: establish the silver cube cell structure model, based on the theory of electromagnetic scattering and radiation characteristics of cellular structure in micro scale visible light band. Analysis of the cellular structure of the space electric field and Poynting vector distribution, that when the electric field, the Poynting vector and cellular rib produce strong interaction. Cellular structures exhibit strong absorption characteristics. The effects of changes in the structure of the radiation characteristics of cube cell, found the strongest attenuation characteristics of cavity structure. The radiation characteristics of cube layered structure of visible light band. In order to ensure the accuracy of the calculation, put forward the error convergence test method. Analysis of the cubic unit cell structure the relationship between the absorption characteristics of the single cube, porous structure and infinite plate structure, found that the single cube porous structure can effectively alter the spectral characteristics of radiation, the radiation can not force A linear combination of unit cell structure. Considering the porosity, influence of inclined angle on absorption characteristics of single-layer cube porous structure, results show that the porosity and the inclined angle on absorption properties have great influence of different porosity, single cube porous structure appeared strong, weak, three regions, and showed no inclination the obvious regularity of absorption. The effects of absorption Poynting vector and spatial distribution characteristics of multilayer cube porous structure, multilayer structure has found the absorption enhancement phenomenon in 0.457 mu m, permselectivity with three layers of visible light on 0.35~0.55 m wavelength. A spherical hollow aluminum cellular structure and single spherical hollow aluminum structure model, characteristics of infrared radiation unit cell structure of five kinds of porosity under the attenuation, found the structure has a strong ability of scattering and absorbing in the infrared band. The collection ability is almost zero. Compared with single-layer spherical hollow aluminum structure Drude model and N K model, changes of absorptive capacity, discover trends absorption rate of two kinds of models are consistent, in the numerical absorption capacity, the size will be different. The effects of Si based, SiO2 based and effect of surface coverage graphene monolayer of spherical hollow structure of aluminum absorption capacity, found that the structure of Si based enhancement absorption function in 1~6 M band, when covered with a layer of graphene in the hollow spherical structure of aluminum surface, did not find the absorption enhancement effect of graphene.

【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG146.21

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