Characteristics of premixed, laminar CO/N2O flames

Abstract

Several properties are studied of fuel-rich (CO:N2O = 1.5:1) and stoichiometrie (CO:N2O = 1:1) carbon monoxide/nitrous oxide flames with varying water content up to 10%. Flame temperatures, ranging from 2680 to 2860°K. are measured with the line-reversal method, and compared with calculated adiabatie values. Excess concentrations of H and OH radicals are determined by the LiOH/Li method; the ratios [H]/[H2O] appear to exceed their (calculated) equilibrium values by a factor 1.5 to 3.0. even after 10 msec rise time of the flame gases. Burning velocities of the various mixtures, estimated from the height of the combustion cones, range from 30 to 75 cm/see and are markedly dependent on the water content of the mixture. The absolute spectral intensity of the (quasi) continuous emission of the burnt pases was measured and was found to have the same dependence on CO and O concentrations as in CO/air flames. Electron concentrations of 109 to 1010 cm−3, measured with a HF resonance method, are tentatrvely attributed to (thermal) ionization of NO.