热辐射对碳纳米管纱名义热导率的影响

碳纳米管纱是完全由碳纳米管构成的宏观材料,因其类似“气凝胶”的结构,具有较大的比表面积,相对于普通宏观材料,会有更多的热量通过表面热辐射耗散出去。本文详细地推导了电加热时,准一维热传播材料表面温度分布和热导率计算公式,并引入热辐射项对上述传热过程进行修正,获得表面真实温度分布,进而结合碳纳米管纱的物理性质,分析了测试样品长度对碳纳米管纱名义热导率(指测试获得的热导率)的影响。对于长度为5 mm的碳纳米管纱测试样品,名义热导率约为真实热导率的4倍。

Effect of Thermal Radiation on the Nominal Thermal Conductivity of Carbon Nanotube Sheet

Carbon nanotube sheet is a macro material made of carbon nanotubes. Because of its "aerogel" structure, it has a larger specific surface area. Compared with ordinary macro materials, more heat could be dissipated through surface by thermal radiation. In this paper, we derived the quasi one-dimensional heat propagating formular of temperature distribution and thermal conductivity, then the thermal radiation was introduced to correct the heat transfer model, and the true temperature distribution was obtained. Finally, the physical properties of the carbon nanotube sheet was used to analyze the effect of the length on the nominal thermal conductivity (nominal thermal conductivity referred to the thermal conductivity of the test). The nominal thermal conductivity of the carbon nanotube sheet with a length of 5 mm was about 4 times that of the true thermal conductivity.