Asymmetric structural aramid nanofiber aerogel membranes (ASAAMs) have been considered ideal thermal insulators due to their unique characteristics, such as dense surface layers and nanoscale 3D fibrous body components. Fractal theory has been used in studying the pore size distribution of fibrous aerogels with symmetrical structures but is rarely used in studying the thermal conductivity of asymmetric structural aerogels. In this work, two basic fractal units are used to simulate the pore size distribution of ASAAMs. The models are transformed into series and parallel fractal resistance networks using the equivalent resistance method. Additionally, a marginal weighting function is proposed to modify the heat transfer model, which is applied to calculate the total effective thermal conductivity of ASAAMs. Results showed that: (1) The correlation between the porosity and the effective thermal conductivity of ASAAMs is negative. (2) The basic fractal units of 7 × 7 size selected in this paper could be described the pore size distribution of ASAAMs well. (3) The modified model demonstrates only 2.58% error, which is closer to the experimental data.

不对称结构芳纶纳米纤维气凝胶膜 (ASAAM) 因其独特的特性（例如致密表面层和纳米级 3D 纤维体成分）而被认为是理想的热绝缘体。分形理论已被用于研究具有对称结构的纤维气凝胶的孔径分布，但很少用于研究非对称结构气凝胶的导热系数。在这项工作中，使用两个基本分形单元来模拟 ASAAM 的孔径分布。使用等效电阻法将模型转化为串联和并联分形电阻网络。此外，提出了一个边际加权函数来修改传热模型，该模型用于计算 ASAAM 的总有效导热系数。结果表明：(1) ASAAMs的孔隙率与有效导热系数呈负相关。(2)本文选取的7×7尺寸的基本分形单元可以很好地描述ASAAMs的孔径分布。(3) 修改后的模型误差仅为2.58%，更接近实验数据。