Modeling of the three-dimensional structure of open cell foam and analysis of the model quality using the example of pressure drop calculation

Interdependent partitions located in three-dimensional porous structures pose a problem for understanding the flow field, which differs significantly from the flow in traditional porous media. The structure of open cell foam requires the use of various flow laws (Darcy, Forchmeyer, or the direct solution of the Navier–Stokes equations, because the value of medium permeability is unknown in advance). The purpose of this work is to determine the effect of smoothing in the open cell foam structure on the resistance of the medium. As a characteristic of the resistance, the pressure drop has been considered for the given gas flow rate. The main parameters of porous medium are the cell diameter, the fiber diameter, and the porosity. Thus, we have determined the parameter that makes the greatest contribution to the pressure drop change. The computer model of open cell foam has been presented as an ordered set of intersecting spheres. For hydrodynamic calculation, we have used the ANSYS Fluent software package. We have compared the calculation results of pressure drop with the experimental data of other authors. It has been established that the model of a porous medium using of automatic smoothing of all the faces (performed by AutoCAD package) provides the biggest pressure drop at a fixed value of the porosity of the foam compare to the model with smoothed faces manually and the model without smoothing. Thus, the approximation of an elementary porous cell substantially distorts the flow field. It is not good in the detailed simulation of the open cell foam material. In addition, we have made calculations of the pressure drop with different fixed parameters of the medium – porosity, cell diameter, and fiber diameter of the medium. The calculations have shown that hydrodynamics is determined by the fiber diameter of the porous structure.