Numerical Techniques For Future Applications In Termo-Fluid-Dinamic Projects Of VHTGR Reactors: Viscous Case

Abstract

The present work consisted in solving the Navier-Stokes equations, in conservative and structured forms, in the two-dimensional space, employing a finite difference formulation for spatial discretization. It was implemented the Jameson and Mavriplis algorithm to perform the numerical experiments, as well the isotropic scalar linear and nonlinear models of Pulliam, aiming to provide numerical stability to the algorithm. The Backward Euler method for explicit marching in time was also implemented to accelerate the convergence process. The physical problem of subsonic internal flow to a rectangular channel with obstacle configuration was studied. A spatially variable time step is employed aiming to accelerate the convergence to the steady state solution. The main objective was to implement computational tools to the future application in the nuclear sector of numerical techniques widely applied in aeronautical problems, due to the common employed governing equations of the fluid motion, for preliminary studies of density, velocity, pressure, Mach number and energy contours to the flow of gas helium coolant present in the core of the Very High Temperature Gas-cooled Reactor, the VHTGR. A study involving the algorithm's characteristics in relation to the overall quality of the solution is also accomplished. After the simulations, it was found good behavior of Jameson and Mavriplis algorithm, as well as satisfactory performance of the nonlinear Pulliam operator in scheme convergence, showing the nonlinear model as providing better treatment to the numerical solutions obtained.