Measurements of radiative properties of cellular ceramics at high temperatures
Measurements of radiative properties of cellular ceramics at high temperatures
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DOI：
10.2514/3.749
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发表时间：
1996
影响因子：
2.1
通讯作者：
R. Mital;J. Gore;R. Viskanta
中科院分区：
文献类型：
--
作者：
R. Mital;J. Gore;R. Viskanta
选定的适用于辐射燃烧器的蜂窝（网状）陶瓷的消光系数和单次散射反照率在 1200-1400 K 温度范围内测定。测量了在具有两种不同边界条件的管式炉中加热至稳定状态的网状材料层的总辐射强度。逆辐射方法涉及使用灰色各向同性散射模型的双通量近似，用于从测量的强度获得辐射特性。高于统一的光学厚度时，该过程不够灵敏，无法得出消光系数。对于这种情况，消光系数是根据几何光学极限估计的。单次散射反照率从 0.68 到 0.88 变化，不确定度为 ±7%，而消光系数从 81 到 270 m"1 变化，不确定度为 ±11%，具体取决于每厘米孔隙数和样品材料。在温度研究范围内，辐射特性的变化并不显着。命名法 b = 后向散射分数 d = 孔径，m / = 前向散射分数 fv = 固体体积分数/ = 强度，W/m2-sr
The extinction coefficient and the single scattering albedo of selected cellular (reticulated) ceramics that are candidates for use in radiant burners were determined in the 1200-1400 K temperature range. Total radiation intensities leaving layers of the reticulated material heated to steady state in a tube furnace with two different boundary conditions were measured. An inverse radiation approach involving the two-flux approximation using a gray, isotropically scattering model was used to obtain the radiative properties from the measured intensities. Above an optical thickness of unity, this procedure was not sufficiently sensitive to yield the extinction coefficient. For such cases, the extinction coefficient was estimated from the geometric optics limit. The single scattering albedos varied from 0.68 to 0.88 with an uncertainty of ±7%, whereas the extinction coefficients varied from 81 to 270 m"1 with an uncertainty of ±11%, depending on the number of pores per centimeter and the sample material. In the range of temperature investigation the variations in the radiation properties were not significant. Nomenclature b = backscattering fraction d = pore diameter, m / = forward scattering fraction fv = solid volume fraction / = intensity, W/m2-sr