Nodal integral method for convection-diffusion equation in cylindrical geometry

In order to improve the calculation performance of thermal-hydraulic problems in high-temperature gas-cooled reactor (HTGR), the nodal integral method (NIM) was applied to solve the steady-state convection-diffusion equation in cylindrical geometry. Two kinds of treatments were proposed to solve the challenge of r-directed transverse integrated equation which was brought by cylindrical geometry, and corresponding error analyses were presented. The results show that the inherent upwind characteristic of NIM in solving the cylindrical convection-diffusion equation is proved, and the results of NIM agree very well with the analytical solutions for one-dimensional problem and multi-dimensional problem. When nodes close to the original point in r direction, constant approximation has better accuracy over treatment of moving terms, however, when nodes away from original point, both methods show almost the same accuracy.