Examinando por Autor "Osorno, María"

Mostrando 1 - 2 de 2
  • No hay miniatura disponible
    Ítem
    Determining the limits of geometrical tortuosity from seepage flow calculations in porous media
    (WILEY-VCH Verlag, 2014) Uribe, David; Osorno, María; Sivanesapillai, Rakulan; Steeb, Holger; Ruíz, Óscar; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    Recent investigations have found a distinct correlation of effective properties of porous media to sigmoidal functions, where one axis is the Reynolds number Re and the other is the effective property dependent of Re, Θ = S (Re) -- One of these properties is tortuosity -- At very low Re (seepage flow), there is a characteristic value of tortuosity, and it is the upper horizontal asymptote of the sigmoidal function -- With higher values of Re (transient flow) the tortuosity value decreases, until a lower asymptote is reached (turbulent flow) -- Estimations of this parameter have been limited to the low Reynolds regime in the study of porous media -- The current state of the art presents different numerical measurements of tortuosity, such as skeletization, centroid binding, and arc length of streamlines -- These are solutions for the low Re regime. So far, for high Re, only the arc length of stream lines has been used to calculate tortuosity -- The present approach involves the simulation of fluid flow in large domains and high Re, which requires numerous resources, and often presents convergence problems -- In response to this, we propose a geometrical method to estimate the limit of tortuosity of porous media at Re → ∞, from the streamlines calculated at low Re limit -- We test our method by calculating the tortuosity limits in a fibrous porous media, and comparing the estimated values with numerical benchmark results -- Ongoing work includes the geometric estimation of different intrinsic properties of porous media
  • No hay miniatura disponible
    Ítem
    Estimation of large domain Al foam permeability by Finite Difference methods
    (WILEY-VCH Verlag, 2013) Osorno, María; Steeb, Holger; Uribe, David; Ruíz, Óscar; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    Classical methods to calculate permeability of porous media have been proposed mainly for high density (e.g. granular) materials -- These methods present shortcomings in high porosity, i.e. high permeability media (e.g. metallic foams) -- While for dense materials permeability seems to be a function of bulk properties and occupancy averaged over the volume, for highly porous materials these parameters fail to predict it -- Several authors have attacked the problem by solving the Navier-Stokes equations for the pressure and velocity of a liquid flowing through a small domain (Ωs) of aluminium foam and by comparing the numerical results with experimental values (prediction error approx. 9%) -- In this article, we present calculations for much larger domains (ΩL) using the Finite Difference (FD) method, solving also for the pressure and velocity of a viscous liquid flowing through the Packed Spheres scenario -- The ratio Vol(ΩL)/Vol(Ωs) is around 103 -- The comparison of our results with the Packed Spheres example yields a prediction error of 5% for the intrinsic permeability -- Additionally, numerical permeability calculations have been performed for Al foam samples -- Our geometric modelling of the porous domain stems from 3D X-ray tomography, yielding voxel information, which is particularly appropriate for FD -- Ongoing work concerns the reduction in computing times of the FD method, consideration of other materials and fluids, and comparison with experimental data