Abstract
Modern aircraft turbines, which inject liquid hydrocarbon fuels into compressed air at high temperatures, aim for a limited residence time of the fuel in the combustion chamber before autoignition. The residence time however is important in terms of vaporizing and turbulent mixing of the fuel with air. A well stirred mixture with a lean overall equivalence ratio (near the adiabatic flammability limit) will reduce the combustion temperature and in turn reduce the production of nitric oxides (NO, N2O and NO2) through the Zel'dovich mechanism. This report details some of the results obtained under the ESA MAP project CPS (Combustion Properties of Partially Premixed Spray Systems), where (amongst other topics) n-heptane sprays are observed under machine conditions and these experimental results are compared to numerical results obtained with the ZARM closed vessel code for single droplet ignition.
