Characterization of Microstructure in Glass Wool Insulation Using Micro X-ray CT

We investigate microstructures of three insulation samples made of glass wool fiber with low to high density through X-ray Computed Tomography. Analysis results indicate that the volume fraction of fibers increases linearly with increasing bulk density, and thermal conductivity decreases nonlinearly with increasing volume fraction of fibers. In addition, the insulation samples have nonuniform structures, particularly for the low-density sample, showing that the average local volume fraction of fibers in one layer varies up to two times. The sample with the highest density exhibits a more distinct layered structure than the other two relatively low-density samples.