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本文首先使用Callaway热导率模型对SiO_2纳米颗粒的热导率进行了近似计算,然后耦合堆积纳米孔隙内的导热和辐射、颗粒接触热阻,基于颗粒堆积单元结构模型的一维传热分析,最终推导得到了颗粒堆积有效热导率关于颗粒直径和温度、堆积孔隙率、颗粒热导率、气相热导率、辐射传热和接触热阻的关系式,并用该式进行了相关讨论。研究结果表明,对于纳米颗粒堆积,界面接触热阻不容忽略;在低孔隙率和颗粒不参与辐射的条件下,由于受到接触热阻的影响,存在最佳孔隙率(或密度)使得堆积热导率存在最大值。
In this paper, Callaway thermal conductivity model was used to approximate the thermal conductivity of SiO 2 nanoparticles. Then, the thermal conductivity and radiation in the nanopores were coupled and the thermal contact resistance of the particles was obtained. Based on the one-dimensional heat transfer analysis of the particle stacking unit structure model, Finally, the relationship between the effective thermal conductivity of the particles and the particle diameter and temperature, the porosity of the particles, the thermal conductivity of the particles, the thermal conductivity of the gas phase, the radiative heat transfer and the thermal contact resistance is derived. The related discussions are made with this formula. The results show that the interface thermal contact resistance can not be neglected for the deposition of nano-particles. Under the conditions of low porosity and particles not participating in radiation, due to the contact thermal resistance, the optimal porosity (or density) There is a maximum rate.