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