Dynamic modeling of the interaction of gas and solid phases in multistep reactive micropyretic synthesis

Abstract

A mathematical model of micropyretic synthesis, including the consideration of pressure rise (due to gas evolution) in a porous compact, is developed for a multistep reaction. D'Arcy's law of gas flow, continuity equation, and gas law are combined to obtain a relationship between the pressure and temperature of gas. This equation for the gas pressure is solved along with the energy equations of gas and solid phase. The numerical analysis shows that the magnitude of pressure increase depends on the initial gas pressure, temperature, and permeability. When gas evolution is considered, the pressure increase depends on the variables that determine the kinetics of the gas evolution reaction, such as the activation energy and the pre-exponential factor. The pressure increase is maximum when the gas evolution takes place in the combustion reaction zone. The gas evolution is noted not to influence the combustion wave propagation.