2DT, 3DT and 2DS - Two- and Three-Dimensional Transient and Two-Dimensional Steady State Heat-Transfer Finite-Difference Computer Programs

摘要

Technical assessment of accident conditions in nuclear reactors, and many problems in other fields, require the solution of the transient temperature distribution in solid regions in contact with flowing fluids. In this situation the fluid temperatures are dependent on heat transfer between the fluids and the solids, and so these temperatures cannot be supplied as preset boundary conditions. The transient programs deal with this problem by a method used in the three-dimensional program RAT-3D. This method uses a two-step iteration procedure in which solution of the set of time-dependent heat-conduction finite-difference equations alternates with solution of the heat-balance equations for Newtonian cooling so that a new set of boundary conditions are obtained for the next solution of the heat-conduction equations. The set of heat-conduction equations are solved by the alternating-direction method. The two-dimensional steady-state program, 2DS, cannot accept internal coolants, and must be supplied with temperatures and heat-transfer coefficients for all external boundaries. It is simpler to use than the transient program in that no time history is required, and its use is therefore preferred for the solution of steady-state problems which do not contain internal coolants. Radiation between solid regions and to the outside environment is allowed for in all the programs. Thermal expansion is taken into account for heat transfer across radial gaps between solid materials. The programs are written to keep input data simple and computing costs low. (Atomindex citation 10:433399)