Geometrical modelling and thermal analysis of nonwoven fabrics

Nonwoven fabric can be produced for insulation. It has low fibre volume because insulation property of fibrous materials depends on not only the thermal conductivity of fibre but also the entrapped static air. If fibre volume fraction is low in fibrous assembly it means that more air in the volume therefore the insulation property of the fabric increases, or vice versa. In this research thermal bonded nonwoven fabrics were used to analyse the heat transfer phenomena and predict the effective thermal conductivity and thermal resistance by using finite element (FE) method. FE models of nonwoven fabrics were created by two techniques: 3D reconstruction and solid modelling. For validation purpose the effective thermal conductivity results obtained from an in-house developed instrument were compared with predicted results from the developed FE models. Furthermore, this research work also contains an investigation of the effect of fibre volume fraction and thermal conductivity of fibre on the overall heat transfer of nonwoven structures.