A model for gas permeation in three-dimensional braided seal

High temperature three-dimensional (3D) braided seals are required for advanced hypersonic airframe applications to avoid a lot of hot air leaking into the internal structure. The gas permeation of 3D braided seals at room temperature was studied. According to Darcy’s Law, we present a computational model based on K-C equation and Kozeny theory for prediction. The model is combined with microstructure of the 3D four-directional braided seal and 3D five-directional braided seal, to predict the gas permeation as a function of fiber volume fraction, compression ratio, and pressure drop across the seal. The comparison showed that the predictions are in good agreement well with the experimental data. The 3D four-directional braided seal and 3D five-directional braided seal were fabricated and their gas permeation was measured in order to verify the prediction model.