Systematically derived one-step kinetics for hydrogen-air gas-turbine combustion

Abstract

A previously derived one-step reduced chemical-kinetic mechanism, describing hydrogen flames under near-limit conditions involving peak temperature not far from the crossover temperature, is used in computations of hydrogen-air flamelets at elevated pressures typical of gas-turbine combustion. Besides freely propagating laminar deflagrations with compositions spanning the whole range of flammability conditions, the calculations address strained premixed and nonpremixed flames as well as partially premixed propagating fronts. The comparisons with results of detailed-chemistry computations reveal that, for most purposes, the one-step mechanism provides sufficiently accurate predictions of burning rates under all conditions of interest for gas-turbine combustion. The reduced-chemistry model, featuring an explicit analytic expression for the hydrogen oxidation rate in terms of the local temperature and the O2, H2, and H2O concentrations, can be easily implemented in numerical codes, thereby facilitating future numerical analyses based on direct-numerical and large-eddy simulations.