Short-hot-wire method for the measurement of total hemispherical emissivity of a fine fibre
Short-hot-wire method for the measurement of total hemispherical emissivity of a fine fibre
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DOI：
10.1068/htwu375
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发表时间：
2001-12
影响因子：
1.1
通讯作者：
S. Fujiwara;Xing Zhang;M. Fujii
中科院分区：
文献类型：
--
作者：
S. Fujiwara;Xing Zhang;M. Fujii
本文提出了一种测量细纤维半球总发射率的新方法--短热线法。该方法使用两个短热线，并基于一维稳态热传导的解析解沿着热线和纤维。两个热线彼此平行布置。两个热线都被提供恒定的直流电以产生热量并保持相同的平均温度。测试纤维桥接电线，其末端连接到每条热线的中心位置，形成H型探头。通过使用这种双热线技术，从热线传递到纤维的总热量在真空条件下完全从纤维辐射到周围环境。因此，热线的平均温升取决于纤维的发射率。对H型探头的稳态热传导进行了解析求解，得到了热线温升与光纤发射率之间的精确关系。根据这种关系，当测量具有已知热特性的热线的平均温度和加热速率时，可以估计纤维的发射率。理论分析表明，对于直径为10 μm左右的光纤，本方法可获得发射率在0.1 ~ 1.0范围内，误差在± 1%以内。
A new short-hot-wire method for the measurement of total hemispherical emissivity of a fine fibre is proposed. This method uses two short hot wires and is based on the analytical solution of one-dimensional steady-state heat conduction along the hot wires and fibre. Two hot wires are arranged parallel to each other. Both the hot wires are supplied with a constant direct current to generate heat and maintain the same average temperature. A test fibre bridges the wires and its ends are attached to the centre position of each hot wire to form an H-type probe. By the use of this two hot wires technique, the total heat transmitted from the hot wires to the fibre is completely radiated from the fibre to the surroundings under vacuum conditions. Therefore, the average temperature rise of the hot wire depends on the emissivity of a fibre. The steady-state heat conduction for the H-type probe is analytically solved to obtain the accurate relationship between the temperature rise of the hot wires and the fibre emissivity. Based on this relationship, the emissivity of the fibre can be estimated when the average temperature and the heat rate of the hot wires with known thermal properties are measured. The theoretical analysis has confirmed that the present method can obtain emissivity in the range of 0.1 - 1.0 within an error of ± 1% for the fibre with its diameter around 10 μm.