Predicting the effective thermal conductivity of Perforated Hollow Sphere Structures (PHSS)

Abstract

This chapter investigates the thermal properties of a new type of hollow sphere structures. For this new type, the sphere shell is perforated by several holes in order to open the inner sphere volume and surface. The effective thermal conductivity of perforated sphere structures in several kinds of arrangements is numerically evaluated for different geometrical parameters such as: hole diameter of the perforated hollow spheres, hollow spheres' wall thickness and joining element dimension. The results are compared to classical configurations without perforation. In addition the influence of different joining techniques, i.e. sintering and adhesively bonding, on the thermal conductivity has been compared. Three dimensional finite element analysis was used in order to investigate the heat conductivity of simple cubic, body-centered cubic, face-centered cubic and hexagonal unit cell models. A linear dependency behavior was found for the heat conductivity of different hole diameters for several kinds of arrangements when the results were plotted over the average density for homogeneous models.