Abstract:

Wool fiber assembly is a porous media whose structure is too complicated to be characterized. To solve this question, the concept of fractal was introduced to fiber assembly. A box-counting method was used to calculate fractal dimension, and a flat fabric heat retention tester was adopted to test thermal properties of wool fiber assemblies. Then quantitative relation between the fractal dimension and basic structural parameters and also thermal properties were acquired. Results indicate that fractal dimension is applicable in characterizing structure of fiber assemblies, and increasing with the increased of the fiber mass and volume fraction, showing more complicated structure. Furthermore, the CLO and warmth retention rate increase with increasing of the fractal dimension, while the heat transfer coefficient tends to decrease, i.e. the warmth retention property of fiber assemblies is enhanced.

Key words: wool fiber, fiber assembly, box-counting method, fractal dimension, warmth retention property