Image Import: Homogenized Pore Scale Flow and Thermal Conduction

Model ID: 12211


You can now use image data to represent 2D material distributions or to identify regions with different materials by their color or gray scale. Images used in this way can have many origins such as scanning electron microscope (SEM), computed tomography (CT), or magnetic resonance imaging (MRI).

An important application of image import is for easy computation of equivalent volume-averaged material properties for highly inhomogeneous or porous materials. This includes properties such as conductivity, permittivity, elasticity, or porosity and allows for converting spatially distributed values to a single representative averaged value. Such equivalent material properties can then be used for simulations of larger structures avoiding detailed microscopic information. This modeling approach has several advantages such as avoiding the often difficult operations of image segmenting and image-to-geometry conversion. It also brings greatly simplified meshing, less memory usage, and shorter computation times--this can be particularly important when the same type of analysis needs to be repeated many times for different images.

An imported image is made available as a general COMSOL interpolation function that can be used for any modeling purposes.

Supported image formats are:

JPG, JPEG, BMP, PNG, GIF

These two examples show applications of the new image import functionality in version 4.2a.

The first example shows how image import can be used to replicate the Pore Scale Flow example of the Subsurface Flow Module. A penalty friction force is applied as a distributed volume force to avoid flow in the solid part of the continuously represented material domain.

The second example shows how an equivalent thermal conductivity can be computed for the same porous structure but this time reinterpreted as an aluminum foam.

The original non-homogenized example from the Subsurface Flow Module is also made available in a version that can be used with the base package.

This model was built using the following:

COMSOL Multiphysics