Research on permeability of 3D full five-directional braided preforms

In order to obtain the permeability of 3D full five-directional braided preforms and study the law of its change with processing parameters, based on the micro-structure of the 3D full five-directional braided composites' inner unit cell and the double scale characteristics of braided preform porosity, a model for calculating the permeability of 3D full five-directional braided preforms is established in this paper. By applying periodic boundary condition, the axial and vertical filling processes of 3D full five-directional braided preforms are simulated using the two-phase model in Fluent, and the axial and vertical unsaturated permeability of the preforms with different braiding angles is obtained.At the same time, the permeability of 3D full five-directional braided preforms is measured by radial flow techniques.The experimental results are compared with the simulation results, both of which have the same trends with the change of braiding angles, and the experimental and calculated values are in good agreement.