On projected Newton–Krylov solvers for instationary laminar reacting gas flows

Numerical aspects of computational modeling of chemical vapor deposition are discussed. Large sparse strongly nonlinear algebraic systems are to be solved per time step. For this, inexact Newton methods and preconditioned Krylov subspace methods are suitable. To ensure positivity of concentrations, we propose a novel approach, namely a projected inexact Newton method. Unlike the commonly used method of clipping, this conserves mass. Efficiency of several preconditionings is compared. Our numerical tests culminate in an unusually large computation, namely a three-dimensional case with 17 species and 26 reactions.