Accurate Boundary Conditions for Multicomponent Reactive Flows

Abstract

Procedures to define accurate boundary conditions for reactive flows described by Navier-Stokes equations are discussed. A formulation based on one-dimensional characteristic waves relations at the boundaries, previously developed by Poinsot and Lele for perfect gases with constant homogeneous thermodynamic properties, is rewritten and extended in order to be used in the case of gases described with realistic thermodynamic and reactive models. This kind of formulation appears to be particularly accurate and stable, which is a necessity for non-dissipative codes, in particular for direct simulation of turbulent reactive flows. The simple and solid physical basis of the method is also very attractive and makes it an easy technique to implement in any Navier-Stokes solver. Examples of application in several different computations performed with mixtures of gases and using detailed chemistry and thermodynamic modeling are described. In all cases, acoustic waves, entropy waves, and flames are proved to propagate without perturbation through the boundaries.