Aerogels in Aerospace: An Overview

Table 2

Approaches to predict the thermal conductivity of silica aerogels (adapted from Jun-Jie et al. [66]).

Model	Author	Structure representation	Method	Comments
Empirical	Lu et al. [60]; Wang et al. [67]	Ignored	Volume average as a function of density or porosity	Cannot be applied for aerogels with different microstructures
Analytical	Wei et al. [10]; Lu et al. [65]; Wei et al. [10]	Cubic array of nanospherical structure	Standard equivalent circuit method	Cannot represent the randomness and complexity of aerogels
	Jun-Jie et al. [66]	3D random DLCA structure	Standard equivalent circuit with improved analytical parallel-series model	Does not require any empirical parameters as input
Numerical	Spagnol et al. [68]; Zhao et al. [12]	Von Koch snowflake fractal structure and random DLCA structure	Finite volume method based on the mesh division	3D calculations are time consuming