CH4/NOx Reduced Mechanisms Used for Modeling Premixed Combustion

摘要

This study has identify useful reduced mechanisms that can be used in computational fluid dynamics (CFD) simulation of the flow field, combustion and emissions of gas turbine engine combustors. Reduced mechanisms lessen computational cost and possess the ability to accurately predict the overall flame structure, including gas temperature and species as CH4, CO and NOx. The S-STEP algorithm which based on computational singular perturbation method (CSP) is performed for reduced the detailed mechanism GRI-3.0. This algorithm required as input: the detailed mechanism, a numerical solution of the problem and the desired number of steps in the reduced mechanism. In this work, we present a 10-Step reduced mechanism obtained through S-STEP algorithm. The rate of each reaction in the reduced mechanism depends on all species, steady-state and non-steady state. The former are calculated from the solution of a system of steady-state algebraic relations with the point relaxation algorithm. Based on premixed code calculations, The numeric results which were obtained for 1 atm ≤ Pressure ≤ 30 atm and 1.4 ≤ ф ≤ 0.6 on the basis of the ten steps global mechanism, were compared with those computed on the basis of the detailed mechanism GRI-3.0. The 10-step reduced mechanism predicts with accuracy the similar results obtained by the full GRI-3.0 mechanism for both NOx and CH4 chemistry.