1990 Fiscal Year Final Research Report Summary
Thermal Radiation Characteristics of Metallic Materials in Actual Industrial Environments
| Project/Area Number |
01550176
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thermal engineering
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| Research Institution | Kyoto University |
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Principal Investigator |
MAKINO Toshiro Kyoto University, Dept. Engineering Science, Associate professor, 工学部, 助教授 (30111941)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Thermal Radiation / Heat Transfer / Thermophysical Property / Measurement / Spectrum / Metallic Material / Real Surface / High Temperature |
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| Research Abstract |
A series of experimental and theoretical works were performed to clarify radiation characteristics of metallic materials in actual industrial environments.
In the experimental works, firstly, visible to infrared reflection characteristics were investigated on several kinds of stainless steels and super-alloys in an air-oxidation process at high temperatures, with using the high-speed spectroscopy. The characteristics were clarified to change transiently with following to a few simple rules of interference and diffraction at the surfaces. Secondly, reflection and emission characteristics of paradium at high temperatures were investigated in the near-infrared region. An interesting phenomenon of temperature hysteresis in the spectra was found at around 1000K. It was attributed to a combined reaction of oxidation and desociation at the surface. Thirdly, an ellipsoidal mirror-type reflectometer system was developed to measure the normal-incident hemispherical reflectance of real surfaces. T
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his system measures the absorptance of a surface with one scanning operation. Fourth, this system was applied to a fundamental study of wavelength and angular characteristics of reflection at mechanically processed rough surfaces.
In the theoretical works, new algorithms were investigated for describing the thermal radiation characteristics of real surfaces, which are strongly affected by the surface films and the surface micro-geometry. Firstly, algorithm for modelling rough surfaces was proposed. The surfaces were modelled as a fractal-like three-dimensional structure which consists of discrete and statistically controlled surface elements. The diffraction/ scattering characteristics were calculated to demonstrated the reality of the model. Secondly, another idea was proposed to deal with the transient behavior in reflection characteristics of real surfaces in actual industrial environments. The above surface model was combined with a three-dimensional non-parallel film element model. The experimentally found behavior of the spectrum transition was readily reproduced on a basis of a computer. Less
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