An optimized implicit scheme for compressible reactive gas flow

A base state formalism is used to maximize the dominance of adiabatic compression wave propagation terms solved directly (implicitly) at the advanced time level in a filtered trapezoidal time integration scheme designed for subsonic compressible gas flows. This approach is enhanced by using efficient direct SEVP solvers for the resulting variable coefficient elliptic system. To facilitate implicit treatment of the dominant adiabatic compression wave terms, a convenient form of the energy equation is used. Extensions to two-phase flow and general equations of state are described. Applications to jet penetration and to a coal gasification reactor are described.