Numerical study of fuel temperature influence on single gas jet combustion in highly preheated and oxygen deficient air

Combustion of a single jet of propane in a cross-flowing stream of preheated and oxygen deficient air is numerically analyzed with emphasis on influences of fuel temperature. Both Eddy-Break-Up and PDF/mixture fraction combustion models coupled with RNG k–var epsilon turbulent model were applied and the predicted results were compared. Thermal and prompt NO models were employed to calculate NO emissions. Results show that the Eddy-Break-Up model is more suitable for predicting temperature field and flame shape. It was showed that flame during high temperature air combustion condition is spread over a much larger volume. Flame volume increases with a reduction of oxygen concentration, and this trend is clearer if oxygen concentration in the preheated air is below 10%. Additionally, it is almost constant at fixed oxygen concentration and fuel inlet temperature for the temperature of the preheated and oxygen deficient air equal to 1041–1273 K. Increase of the fuel inlet temperature results in smaller flame, shorter mean residence time, smaller temperature peaks, and lower emission of NO.