NUMERICAL-ANALYSIS OF COMBUSTION SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS DYNAMICS

A systematic numerical investigation of the influences of the enthalpy of combustion reaction (Q), activation energy (E), diluent, pre-exponential factor (K0), and initial temperature (T0) on temperature/distance profiles in self-propagating combustion synthesis of NiAl intermetallic compound is presented. The average propagation velocity of the combustion front is increased when the enthalpy, initial temperature, or pre-exponential factor is increased, or the activation energy or diluent is decreased. The effect of porosity, which is related to the initial compaction pressure, is also considered in this study. It is shown that the change of the porosity significantly affects the thermal conductivity, the length of the reaction/pre-heat zones, the temperature patterns, and the propagation velocities. The density and reacted fraction plotted through the reaction and pre-heat zones show the influence of the melting of the various phases, which also affect the combustion parameters. It has been shown that the propagation velocity initially increases and then decreases as the porosity increases. The comparison between the numerical data and experimental results is also made.