Application of continuation techniques to ammonium perchlorate plane flames

We investigate an interface model for ammonium perchlorate (AP) monopropellant flames. The model includes complex chemistry and detailed transport in the gas phase and heat conduction in the solid phase. The interface condition considers sublimation of AP as well as reaction products obtained through a liquid phase. The resulting parameterized two-point boundary value problem is solved by a phase-space, pseudo-arclength, continuation method that employs Euler predictors, Newton-like iterations and global adaptive gridding techniques. We establish that the use of Dirichlet boundary conditions for temperature at the solid phase cold boundary leads to unphysically extinguished flames. We simulate preheated low pressure flames as well as high pressure flames in good agreement with experimental results. We finally obtain qualitative pressure extinction limits of AP flames subjected to heat losses. The work represents a critical step in the ultimate solution of the multidimensional coupled gas and condensed phase propellant problem.