Preliminary results are presented for the solution of non-equilibrium
radiation diffusion problems on dynamic, adaptively refined
grids. Implicit time integration is used to step over the smallest
time-scales in the problem and instead follow the dynamic time scales
of interest. BDF2 and Backward Euler time integration schemes are
considered. At each time step it is necessary to solve a nonlinear
coupled system of equations for radiation energy and material
temperature. A preconditioned inexact Newton-Krylov method is used for
the nonlinear solves. The physics based preconditioner for the Krylov
solver internally uses multilevel solvers based on the Fast Adaptive
Composite(FAC) grid method and its variants.
This work was performed under the auspices of the
U.S. Department of Energy by Los Alamos National Laboratory under
contract W-7405-ENG-36. Los Alamos National Laboratory does not
endorse the viewpoint of a publication or guarantee its technical
correctness. LAUR 07-0584