Four-step and three-step systematically reduced chemistry for wide-range H₂–air combustion problems

The feasibility of developing multipurpose reduced chemistry that is able to describe, with sufficient accuracy, premixed and non-premixed flames, one-dimensional detonations, high-temperature autoignition, and also low-temperature autoignition is explored. A four-step mechanism with O and OH in steady state is thoroughly tested and is shown to give satisfactory results under all conditions. The possibility of reducing this to a three-step mechanism, to decrease computation times without compromising the range of applicability is then investigated. The originality of this work resides in introducing a single species X, representing either HO₂ for high-temperature ignition or H₂O₂ for low-temperature ignition. An algorithm is defined that covers the entire range without significant degradation of accuracy. Integrations show promising results for different laminar test cases, and applicability to turbulent flows is indicated.This work was supported by the UE Marie Curie ITN MYPLANET, by the Spanish MCINN through Project # CSD2010-00010, by the Comunidad de Madrid through Project # S2009/ENE-1597, and by the US AFOSR Grant # FA9550-12-1-0138