The emissivity of a groove
The emissivity of a groove
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凹槽的发射率
DOI：
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发表时间：
1954
期刊：
影响因子：
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通讯作者：
L. Daws
中科院分区：
文献类型：
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作者：
L. Daws
为了检查任何依赖于辐射的温度测量设备的性能，应提供具有尽可能接近单位的热发射率的标准散热器。提高发射率的一种方法是使用凹槽靶标，在本文中，对使用这种靶标可预期的改善进行了估计。确定了有效发射率随视场角的变化规律。结果表明，当瞄准角在凹槽顶角范围内时，凹槽目标表现为朗伯面，而对于其他瞄准角则不再是这样。对于表面发射率为0.64的石墨靶，用松弛法计算了刻槽前各瞄准角下的平均有效发射率。开槽后，坡口顶角为60°、30°和15°时分别为0.77、0.82和0.82。当瞄准角在凹槽顶角范围内时，相应的发射率分别为0.78、0.88和0.94。
In order to check the performance of any temperature measuring device, which is dependent on radiation, a standard radiator should be available which possesses a thermal emissivity as close to unity as possible. One way the emissivity may be increased is to use a grooved target and in this paper an estimate is made of the improvement to be expected by using such a target. The variation of the effective emissivity with sighting angle is determined. It is shown that a grooved target behaves as a Lambert surface when the angle of sighting is within a groove apex angle, but that this is no longer true for other sighting angles. The mean effective emissivity over all sighting angles is calculated using the relaxation method for a graphite target having a surface emissivity of 0.64 before grooving. After grooving it becomes 0.77, 0.82 and 0.82 for groove apex angles of 60°, 30° and 15° respectively. The corresponding emissivities when the angle of sighting is within the groove apex angle are 0.78, 0.88 and 0.94 respectively.