节块积分方法求解圆柱几何对流扩散方程

Nodal Integral Method for Convection-Diffusion Equation in Cylindrical Geometry

  • 摘要: 为改进高温气冷堆中热工场方程的计算方法,研究了求解圆柱几何对流扩散方程的节块积分方法。针对圆柱几何下的r向横向积分方程的特殊性,提出了两种可行的近似方法——移项处理和常数近似,并进行相应的误差分析。数值计算结果表明:节块积分方法求解圆柱几何对流扩散方程的数值解具有迎风特性,一维和多维问题的计算结果均与解析解符合得很好;当节块在r向靠近零点时,常数近似带来的误差较移项处理带来的误差小,但当节块远离零点时,二者误差基本相当。

     

    Abstract: 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.

     

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