Study on Fractal Model for Predicting Permeability and Effective Thermal Conductivity to Fibres of Cut-Tobacco

The permeability and the effective thermal conductivity of cut-tobacco were studied using two-dimensional fractal theory. The porous structure of cut-tobacco samples on their cross sections was analysed and their box-counting dimensions were calculated. The permeability process of gas through cut-tobacco has been analysed and fractal model of the process has been established. The heat conduction process of a single hole was studied and the thermal conductivity of cut-tobacco was obtained by the thermal resistance method. The results show that the fractal dimension of porous structure of cut-tobacco approximately is equal to 1.3. With the increasing of the fractal dimension, high porosity cut-tobacco is in favor of permeability process. Oppositely, with the decreasing of the fractal dimension, the porosity of cut-tobacco decreases corresponding to the component of cut-tobacco increasing which lead to the strength of the thermal conductivity coefficient. Comparison between theoretical and experimental results, the results show that the fractal model can effectively predict the permeability and effective thermal conductivity to fibres of cut-tobacco.