A solution for transverse thermal conductivity of composites with quadratic or hexagonal unidirectional fibres

Abstract

AbstractA solution for the transverse thermal conductivity (Ke) of unidirectional fibre arrays, quadratic and hexagonal, is developed analytically. The solution integrates the thermal conductivity of fibre (Kf) and fluid (Km) based on electricity analogy without thermal contact resistance (Rc) at the fibre/fluid interface. The expression Ke is a function of Kf and Km, as well as of the fibre volume fraction (Vf). In this article, Ke values of four composites were predicted and verified by computational fluid dynamics (CFD) simulations. The results showed good agreement when the ratio of Kf/Km is close to 1. An increase in the ratio or Vf gives poorer agreement owing to the local temperature gradient at the fibre/fluid interface. CFD simulation also showed that Ke is decreasing as the Rc value increases.