Application of Automatic Target Species Selection and Global Sensitivity Analysis Methods in Chemical Mechanism Reduction

The reduced mechanisms driven from detailed mechanisms for fuel are essential to combustion simulation. The directed relation graph with error propagation (DRGEP) method for mechanism reduction determines the active species based on the static target species. Inspired by the better performance of automatic target species selection method (ATSS) in dynamic adaptive chemistry simulation and the effectiveness of global sensitivity analysis (GSA) in assessing the importance of elementary reaction, the present work proposes a new reduction procedure. This procedure utilizes the ATSS method, which has not been applied to obtaining the overall reduced mechanism. Total 5610 status points are sampled densely during the ignition process to obtain resulting local reduced mechanisms in present work. The overall active species are selected according to the total occurrence probability. The primary active reactions determined by the active species are further eliminated using the GSA method. By comparing the auto-ignition delay times (AIDT) of reduced methane mechanisms obtained by DRGEP and new reduction procedures under typical initial conditions. The simulation results prove the superiority of the combination of ATSS and GSA methods. The ATSS method can avoid improper selection of active species compared with traditional DRGEP method.