Comparison of multimesh hp-FEM to interpolation and projection methods for spatial coupling of thermal and neutron diffusion calculations

  • Authors:

  • Lenka Dubcova;Pavel Solin;Glen Hansen;HyeongKae Park

  • Affiliations:

  • Institute of Thermomechanics, Dolejskova 5, Prague, CZ 18200, Czech Republic;Institute of Thermomechanics, Dolejskova 5, Prague, CZ 18200, Czech Republic and Department of Mathematics and Statistics, University of Nevada - Reno, 1664 N. Virginia St., Reno, NV 89557-0208, U ...;Multiphysics Methods Group, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840, United States;Multiphysics Methods Group, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840, United States

  • Venue:
  • Journal of Computational Physics
  • Year:
  • 2011

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Abstract

Multiphysics solution challenges are legion within the field of nuclear reactor design and analysis. One major issue concerns the coupling between heat and neutron flow (neutronics) within the reactor assembly. These phenomena are usually very tightly interdependent, as large amounts of heat are quickly produced with an increase in fission events within the fuel, which raises the temperature that affects the neutron cross section of the fuel. Furthermore, there typically is a large diversity of time and spatial scales between mathematical models of heat and neutronics. Indeed, the different spatial resolution requirements often lead to the use of very different meshes for the two phenomena. As the equations are coupled, one must take care in exchanging solution data between them, or significant error can be introduced into the coupled problem. We propose a novel approach to the discretization of the coupled problem on different meshes based on an adaptive multimesh higher-order finite element method (hp-FEM), and compare it to popular interpolation and projection methods. We show that the multimesh hp-FEM method is significantly more accurate than the interpolation and projection approaches considered in this study.