A PRECONDITIONED FLUX-DIFFERENCING SCHEME FOR CHEMICALLY REACTING FLOWS AT ALL MACH NUMBERS

A new computation procedure is developed for solving time-accurate, ch emically reacting flows over a wide range of Mach numbers. The algorit hm is based on scaling the pressure terms in the momentum equations an d preconditioning the conservation equations to circumvent numerical d ifficulties at low Mach numbers. The resulting equations are solved us ing the lower-upper (LU) factorization method in a fully-coupled manne r, with incorporation of a flux-differencing upwind TVD scheme to achi eve high-order spatial accuracy. The transient behavior of the modeled system is preserved through implementation of the dual time-stepping integration technique. The capabilities of the scheme are illustrated by applying it to selected problems, including one-dimensional nozzle flows, two-dimensional channel flows, rocket-motor internal flows, and acoustic waves in a porous chamber with surface transpiration.