Reduction of a detailed reaction mechanism for hydrogen combustion under gas turbine conditions
- SINTEF Energy Research, 7465 Trondheim (Norway)
The aim of this study is to find a reduced mechanism that accurately represents chemical kinetics for lean hydrogen combustion at elevated pressures, as present in a typical gas turbine combustor. Calculations of autoignition, extinction, and laminar premixed flames are used to identify the most relevant species and reactions and to compare the results of several reduced mechanisms with those of a detailed reaction mechanism. The investigations show that the species OH and H are generally the radicals with the highest concentrations, followed by the O radical. However, the accumulation of the radical pool in autoignition is dominated by HO{sub 2} for temperatures above, and by H{sub 2}O{sub 2} below the crossover temperature. The influence of H{sub 2}O{sub 2} reactions is negligible for laminar flames and extinction, but becomes significant for autoignition. At least 11 elementary reactions are necessary for a satisfactory prediction of the processes of ignition, extinction, and laminar flame propagation under gas turbine conditions. A 4-step reduced mechanism using steady-state approximations for HO{sub 2} and H{sub 2}O{sub 2} yields good results for laminar flame speed and extinction limits, but fails to predict ignition delay at low temperatures. A further reduction to three steps using a steady-state approximation for O leads to significant errors in the prediction of the laminar flame speed and extinction limit. (author)
- OSTI ID:
- 20700735
- Journal Information:
- Combustion and Flame, Vol. 144, Issue 3; Other Information: Elsevier Ltd. All rights reserved; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
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