Title : Numerical analysis of NG + H2 fuel mixtures in swirl stabilized burner
Abstract:
Improving the combustion of hydrogen gas and hydrogen-enriched hydrocarbons in gas turbines is an area of great current interest. The flame stability characteristics of a premixed burner supplied with pure methane and hydrogen-enriched methane have been investigated. Numerical simulation of combustion is carried out on a combustion chamber with a swirl burner equipped with a radial injector with 8 fuel inlet holes located in a transversal direction to the swirled air. These holes are located 3 mm below the burner head. Hydrogen is injected radially into the burner through small-diameter holes located on opposite sides of each air channel. In this manner, the area in which hydrogen or CH4 and air are premixed is minimized to avoid the problem of flame flashback. Flame stability was also studied under a range of fuel-less operating conditions, as lean-burn is currently recognized as an effective approach to reducing NOx emissions. In addition to pure hydrogen and air, mixtures of hydrogen, methane and air were examined to evaluate improvements in flame stability when hydrogen replaces methane as the main fuel component. Hydrogen added to methane significantly improves flame stability during lean-burn combustion, and enables stable combustion at the low temperatures required to minimize NOx emissions. The results obtained show a good agreement between numerical and experimental results, and demonstrated that the RNG k-? turbulence model presents a good prediction. In general, the velocity profile is well represented by our model. The RNG k-? model consistently demonstrated superiority, and the recirculation zones are well identified by negative axial velocities. In the combustion regime, the Re-Normalisation Group (RNG) k-? model results demonstrate strong agreement with experimental measurements.
Audience Takeaway Notes:
Our work focuses on advancing combustion processes by implementing innovative techniques like lean combustion mode and swirled flows. These techniques enhance combustion efficiency, resulting in reduced pollution and negative impacts on the environment, nature, and human health. By addressing these issues, we offer practical solutions to rectify these anomalies.
