Combustion Science and Technology, Vol.188, No.11-12, 2077-2104, 2016
Enhancing the Stability Limits of Biogas Non-Premixed Flame
The effect of fuel nozzle geometry on the stability of a low swirl non-premixed biogas flame has been examined experimentally. Fuel nozzle geometry was varied by changing its diameter or the number of peripheral holes/slots, while keeping constant the total cross-sectional area. In addition, the effect of the nozzle slot discharge angle was investigated. A low-swirl strength (25 degrees-angle vanes) was used in the co-airflow, and the biogas fuel composition was kept constant (60% CH4 and 40% CO2 by volume). The results revealed that the swirl is essential for stabilizing a turbulent non-premixed biogas lifted flame. More importantly, fuel nozzle was found to influence drastically both the attached and lifted biogas flame stability limits. Finally, semi-empirical correlations have been proposed to describe the lifted biogas flame blowout limits.