Experimental Study on thermal Radiation Characteristics of Metallic Materials in Actual Environments of Industry

本课题以光谱实验为基础，研究了金属材料在工业实际环境中的热辐射特性。首先研制了高速分光计系统，对其瞬态特性进行测量，实现了每0.93秒重复测量近紫外至红外光谱。发现辐射干涉现象不仅出现在氧化镜面的镜面反射光谱中，而且出现在氧化粗糙表面的漫反射光谱中。这一现象较为清晰，重现性较好，为理论研究表征金属材料真实表面的辐射特性提供了可能。其次，提出了电磁辐射表面散射的概念，作为该特性的理论基础。本文讨论了在辐射波长一阶的金属基底上形成具有三维非平行界面的吸收膜的元件的干涉和衍射问题。一般描述了无限宽系统在双介质界面处的边界条件。利用基尔霍夫衍射理论，将所得结果应用于非平行膜元模型。第三，提出了一种三维表面模型来描述工业中粗加工和氧化金属材料真实表面的热辐射特性。该算法基于叠加的多重分散面思想。它与上述膜元模型相结合。研究了辐射的干涉和衍射。通过数值计算对辐射模型进行检验，对实验结果进行定性讨论。

The present project investigates the thermal radiation characteristics of metallic materials in the actual environments of industry, on a basis of spectral experiments. A high-speed spectrometer system is developed firstly, to measure the transient behaviors in the characteristics, so that it can measure the spectra of the near-ultraviolet to the infrared repeatedly at every 0.93 second. Interference phenomenon of radiation is found to appear not only in the specular reflection spectra of oxidizing specular surfaces but also in the diffuse reflection spectra of oxidizing rough surfaces. The phenomenon are fairly clear and reproduced well, which suggests a possibility of the theoretical study characterizing the radiation characteristics of real surfaces of metallic materials. Secondly, an idea relating to the surface scattering of electro-magnetic radiation is presented as a theoretical basis for the characteristics. The interference and diffraction are discussed for a element, in which an absorbing film with three-dimensionally non-parallel interfaces is formed on a metallic substrate of an order of the wavelength of radiation. Boundary conditions at a two-medium interface are described generally for the infinitely wide system. The results are applied to a non-parallel film element model with the Kirchhoff's diffraction theory. Third, a three-dimensional surface model is presented to describe the thermal radiation characteristics of real surfaces of metallic materials roughend and/or oxidized in industry. The algorithm is based on an idea of the supperimposed multiplily-dispersed facets. It is combined with that of the above film element model. The interference and diffraction of radiation are investigated. Numerical computation is performed to examine tha radiation models for the qualitative discussion on the experimental results.