A numerical method is presented for chemically reactive fluid flow in which equilibrium and nonequilibrium reactions occur simultaneously. The equilibrium constraints on the species concentrations are established by a quadratic iterative procedure. If the equilibrium reactions are uncoupled and of second or lower order, the procedure converges in a single step. In general, convergence is most rapid when the reactions are weakly coupled. This can frequently be achieved by a judicious choice of the independent equilibrium reactions. In typical transient calculations, satisfactory accuracy has been achieved with about five iterations per time step.

At the time of writing, John Ramshaw was affiliated with Los Alamos National Laboratory.