Detailed Chemical Modelling Predictions of Emissions From a Reheated Gas Turbine Engine With Application to Future Supersonic Aircraft

The exhaust plumes of modern gas turbine engines are of great concern due to the emission of atmospheric pollutants, such as carbon monoxide, unburnt hydrocarbons and oxides of nitrogen (NO_x) and visibility caused by the presence of black carbonaceous smoke and nitrogen dioxide (NO₂) giving rise to a new plume visibility phenomena of “yellow smoke”. A detailed hydrocarbon oxidation and NO_x scheme was used to simulate chemical reactions occurring through the gas turbine engine and near-field plume. In addition limited experimental measurements have been made directly behind a reheated gas turbine engine to measure gaseous emissions and to quantify the rate of conversion of nitric oxide to nitrogen dioxide. Two experimental methods were employed to measure emissions; the first a conventional probe technique, the second a non-intrusive method. Results show a fair agreement between experimental data and predicted emissions, showing the maximum conversion of NO to NO₂ at low reheat fuel flowrates. These detailed results can be used as an input to atmospheric modelling codes.