Modeling the thermal expansion boundary layer during the combustion of energetic materials

An approach is presented for modeling the thermal expansion boundary layer in energetic materials such as solid propellants and explosives during thei r combustion. A thermodynamically consistent system of conservation laws is presented that describes the thermo-elastic. solid with a temperature-depe ndent thermal expansion coefficient in order to study the role of thermal e xpansion in heat transfer and deformation in a thin layer adjacent to the c ombustion zone. It is shown that the thermal expansion can produce an effec t that absorbs energy near the burning surface and can significantly reduce the temperature in a small layer. The analysis given here is also relevant to the technologically important problem of laser ablation of materials, b ut the discussion is focused on application to propellant combustion. (C) 2 001 by The Combustion Institute.