Investigation of Jets Emerging From Flow Through Thin Open-Porous Materials

This paper investigates randomly distributed streamwise jets generated due to flow through thin open-porous materials and the jet coalescence phenomenon. The pattern and coalescence of jets at the exit of thin porous materials impact their use as membranes, papers and cartons, filters, filtration cakes, porous coatings, fuel cells, textiles, and hygiene products such as wipes and diapers. Computational fluid dynamics (CFD) simulations are performed on the geometry reconstructed using X-ray micro-computed tomography to predict the pressure drop, permeability, and inertial coefficient and validated by measurements. Furthermore, a novel methodology is developed to estimate the jet dimensions by performing a fast Fourier transform of the voxelized streamwise velocity component at the exit of the porous material. Statistical analysis of the resulting spectra reveals the jet length distribution in the flow field and quantitatively confirms jet coalescence. The present work illustrates the jet formation, emergence, and jet coalescence at the exit of a thin porous foam. The proposed methodology allows jet flow characterization and avoids extensive experimentation. Also, the results offer guidelines for jet impingement heat and mass transport augmentation and flow uniformity, and study the impact of flow on sound propagation and mixing.