Image-based microstructural simulation of thermal conductivity for highly porous wood fiber insulation boards

The thermal conductivity of wood fiber insulation boards is significantly influenced by the microstructure of the fiber network and in general, the efficiency of wood fiber insulation boards increases with porosity. For higher raw densities, the raw density is a good predictor for the thermal conductivity. For lower raw densities however, this simple relation does not hold anymore. Here, structural information gained from 3D computed tomography images at several scales, modeling of the microstructure, and numerical simulation of the thermal conductivity are combined to get deeper insight into which and how microstructural features influence the thermal conductivity. The model-based simulation as described here shows that the presence and orientation of wood fiber clusters impact the thermal conductivity significantly.