PLASIMO's neutral transport module describes mixtures of neutral components. The module describes advection and diffusion of the species of a multi-component system. The transport of species in such system is dictated not only by its own concentration gradient, but also by the concentration gradients of the other species in the system via the Stefan-Maxwell equations. Also pressure and thermal diffusion can be taken into account. This results in a system of strongly coupled non-linear second-order partial differential equations.
Example
As an example of the neutral transport module, we compare the PLASIMO results with a testcase from S. Mazumder [1]. This test case represents the mixing of H2O, H2 and N2 gases entering the system at different inlets as shown in figure 1.
Figure 1: Geometry and boundary conditions for the two-dimensional test problem from Mazumder [1].
Mass fraction distribution of H2
Mass fraction distribution of H2O
Mass fraction distribution of N2
Figure 2: Species mass fraction distributions for the two-domensional test problem: results from Mazumber [1] (left) and from PLASIMO (right).
The screenshot below shows PLASIMO's model results of a three-dimensional variant of the Mazumder test case. This has two additional inlets at the bottom and top planes, where the same boundary conditions are applied as at the south and north inlets, respectively.
References
[1] Mazumber S. (2006) Critical assessment of the stability and convergence of the equations of multi-component diffusion. Journal of Computational Physics, 212, 383-392.