Convergence study of DGFEM SN based 2D/1D coupling method for solving neutron transport k-eigenvalue problems with Fourier analysis

2D/1D coupling method is widely used for solving 3D transport equation due to its high-fidelity and affordable computational burden. The convergence analysis is a key issue for 2D/1D coupling transport method. In this work, the convergence of an outstanding DGFEM SN based 2D/1D coupling method with CMFD acceleration is performed for neutron transport k-eigenvalue problem by Fourier analysis. In detail, the DGFEM based SN as 1D axial solver is coupled with the 2D MOC solver, accelerated by the 3D adCMFD. The Fourier analysis results show that adCMFD acceleration can significantly reduce the spectral radius and achieve excellent convergence. Moreover, the effects of the number of inner iterations on the convergence are analyzed. A combination of 4 times inner iteration for 1D axial solver and 4 times inner iteration for 2D planar solver is recommended. Additionally, the spectral radius of 2D/1D coupling method is insensitive to the order of DGFEM SN, the order of SN quadrature sets and the number of fine meshes per coarse mesh.(c) 2022 Elsevier Ltd. All rights reserved.