A Quasi-Steady-State Solver for the Stiff Ordinary Differential Equations of Reaction Kinetics

A quasi-steady-state method is presented that integrates stiff differential equations arising from reaction kinetics. This predictor–corrector method is A-stable for linear equations and second-order accurate. The method is used for all species regardless of the time scales of the individual equations, and it works well for problems typical of hydrocarbon combustion. Start-up costs are low, making the method ideal for use in process-split reacting-flow simulations which require the solution of an initial-value problem in every computational cell for every global time step. The algorithm is described, and error analysis and linear stability analysis are included. The algorithm is also applied to several test problems, and the results are compared to those of the stiff integrator CHEMEQ. The method, which we call α-QSS, is more stable, more accurate, and less costly than CHEMEQ.