3D computer-aided simulation of SHS macrokinetics in the Ni-Al porous medium with the closest packing of “mesocells”

Abstract

Abstract The paper discusses the methodological features of the procedure for simulation the SHS process in the “etalon” model structure of the closest packing of the so-called mesocells in the form of balls of the same radius. In the center of the mesocell there is a spherical Ni particle (radius R Ni = 30 μm), around which aluminum particles of radius R Al = 10 μm are contained in a spherical interlayer with a thickness of 20 μm. The etalon structure is formed by a program that takes into account the distribution of mesocells in the structure of the closest packing (alternating flat layers with square symmetry). The software has implemented the procedure for preparing the “calculation area” in the form of a three-dimensional grid of nodal points (3D Cartesian calculation grid with the same step h= 1 μm along the x, y, z coordinates), for which a 3D data structure Points[i][k][l] with several record fields was created. The record fields of the structure Points[i][k][l] are the following: T- temperature, η - depth of chemical conversion, type - type of material and etc. A technique for numerical solution of the heat conduction equation using an implicit scheme of bicyclic splitting based on the symmetric Krank-Nicholson scheme is implemented. Together with the bicyclic splitting scheme, a procedure is implemented for numerically solving the diffusion kinetics equation in mesocells. For computational speedup, the parallelization schemes of cycles are used, which determine the main time costs for performing “runs (sweep)” in the computing schemes. As a result of 3D simulation of SHS macrokinetics, sets of temperature profiles and time-varying relative radii (external boundaries) of intermetallic phase layers in mesocells are given.