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a b s t r a c tThe temporal variation of OH * (A 2 R + ) chemiluminescence in hydrogen oxidation chemistry has been studied in a shock tube behind reflected shock waves at temperatures of 1400-3300 K and at a pressure of 1 bar. The aim of the present work is to obtain a validated reaction scheme to describe OH * formation in the H 2 /O 2 system. Temporal OH * emission profiles and ignition delay times for lean and stoichiometric H 2 /O 2 mixtures diluted in 97-98% argon were obtained from the shock-tube experiments. Based on a literature review for the hydrogen combustion system, the key reaction considered was H + O + M = OH * + M (R1). The temperature dependence of the measured peak OH * emission from the shock tube and the peak OH * concentration from a homogeneous closed reactor model are compared. Based on these results a reaction rate coefficient of k 1 = (1.5 ± 0.4) Â 10 13 exp(À25 kJ mol À1 /RT) cm 6 mol À2 s À1 was found for the forward reaction (R1) which is slightly higher than the rate coefficient suggested by Hidaka et al. (1982). The comparison of measured and simulated absolute concentrations shows good agreement. Additionally, a one-dimensional laminar premixed low-pressure flame calculation was performed for where absolute OH * concentration measurements have been reported by Smith et al. (2005). The absolute peak OH * concentration is fairly well reproduced if the above mentioned rate coefficient is used in the simulation.

A detailed kinetics model for the thermal oxidation of ethanol-air mixtures at intermediate temperatures and high pressures is proposed and validated against ignition delay times measured in a shock tube under stoichiometric conditions at 10, 30, and 50 bar and for lean mixtures (φ = 0.3) at 30 bar in the 650-1220 K temperature range. The measurements showed a typical decrease of the ignition delay at low temperatures and a reduced sensitivity to pressure for higher pressures. All data were scaled to 30 bar by a multiple linear regression, yielding τ = τ 30 (p/30) -0.88 . A temperature dependence of τ/(p/bar) -0.88 = 10 -3.21 exp(139 kJ/mol/RT) μs was derived for the stoichiometric mixture. The chemical kinetics model was built upon sub-mechanisms for ethanol (