Ionisation in premixed fuel-lean flames of H2, O2 and N2. Part 1.—Naturally occurring positive ions

摘要: Mass spectrometric measurements have been made of the axial concentration profiles positive ions in six fuel-lean flames H2, O2 and N2, incorporating no additives. The principal positively charged species is hydronium ion, H3O+, whilst sole negative free electron, e–. reaction H + OH ⇌ H3O++ e–(1) found to be responsible for establishing H3O+ e– concentrations close their values equilibrium well downstream burnt gases. constant, K1, measured (2.16 ± 0.80)× 10–11× exp(–11 591/T) atm–1. forward step (1) determines initial rate formation has a coefficient, k1, (3.3 1.6)× 10–36 exp(–13 800/T) cm6 molecule–2 s–1. activation energy equal endothermicity (1), namely 97 10 kJ mol–1. These expressions k1 yield constant reverse (–1), 1.9 2.3 × 10–7 cm3 molecule–1 s–1, approximately independent temperature. proton affinity water gas phase H2O H+→ also derived 674 14 mol–1, at 0 K.