Nodal Integral Method Research

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Chapter 1 Introduction Nodal methods were first introduced and developed to solve neutron diffusion equations in 1970’s [2]. The success of Nodal methods in the field of neutronics was stimulated into the heat flow and fluid flow problems in 1980 [3]. The Nodal Integral Method scheme is developed by approximately satisfying the governing differential equations on finite size brick-like elements. These differential equations are obtained by discretizing the space of independent variables [4]. In the early development of nodal schemes these brick-like elements were referred to as nodes and hence the scheme was called nodal. Nodes in Nodal Integral Method is however similar to the elements of the finite element approach, but the nodes have finite volumes and not only the points in the space of independent variables [5]. An error analysis on NIM methodology is performed to establish the convergence of the solution of two-dimensional heat diffusion equation to the exact solution [1]. Motivation Some of the fluid flow, heat flow and particle flow problems are the most complex problems. It is difficult to find the analytic solution of these problems due to their extra-ordinary complexity. Scientists and engineers are facing this problem from decades and then they turned to the numerical methods. By developing increasingly better numerical schemes, researchers have been able to solve increasingly more complex flow problems [11]. The heat diffusion equations are used to describe the flow of heat. In chapter 2 we use Nodal Integral Method to solve the heat diffusi... ... middle of paper ... ... (2.11) T ̿_(i,j)=(〖T ̅^y〗_(i,j)+〖T ̅^y〗_(i-1,j))/2-a^2/3 〖S ̅^y〗_(0 i,j) (2.12) Substituting the value of 〖S ̅^x〗_(0 i,j) and 〖S ̅^y〗_(0 i,j) from the equations (2.11) and (2.12) in the equations (2.6), (2.7) and (2.8) , finally we will get the following three equations. 〖T ̅^x〗_(i,j-1)+4 〖T ̅^x〗_(i,j)+〖T ̅^x〗_(i,j+1)=3 (T ̿_(i,j)+T ̿_(i,j+1) ) (2.13) 〖T ̅^y〗_(i-1,j)+4 〖T ̅^y〗_(i,j)+〖T ̅^y〗_(i+1,j)=3 (T ̿_(i,j)+T ̿_(i,j)) (2.14) 3((〖T ̅^y〗_(i-1,j)+ 〖T ̅^y〗_(i,j))/(2 a^2 ))+3 ((〖T ̅^x〗_(i,j-1)+ 〖T ̅^x〗_(i,j))/(2 b^2 )) - (3/(a^2+b^2 )) T ̿_(i,j)=-S ̿_(i,j)/k (2.15) Equations (2.13), (2.14) and (2.15) represent the averaged temperature variable, averaged in x-direction, y-direction and cell averaged respectively.

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