An Exponential Integrator in Krylov Subspace to Solve Stiff Combustion Chemical Reaction System

In order to improve the efficiency in solving stiff combustion chemical reaction equations with large time steps, an exponential integrator in Krylov subspace (EIKS) was developed. The method is based on the Multi-timescale (MTS) method. It employs exponential scheme to solve linearized stiff chemical reaction equations, and to reduce matrix dimension with Krylov subspace method. The MTS-EIKS was used to simulate the ignition delays of mixtures of H ₂ /CO/air and CH ₄ /air. Additionally, the Correlated dynamic adaptive chemistry (CoDAC) method was introduced. The results show that the combined reduction method CoDAC-MTS-EIKS method can predict the ignition delays accurately and efficiently with a time steps of 10 ^-6 s, which demonstrates that the method has a good application prospect in solving stiff chemistry problems with large time steps.