Session: 03-01 Hydrogen

Paper Number: 81131

81131 - Analysis of the NOx Emissions Deriving From Hydrogen/Air Combustion in a Swirling Non-Premixed Annular Micro-Combustor 

The integration of hydrogen in the design of combustion chambers for gas turbines is considered as one of the most challenging. In fact, its high calorific value causes high wall temperatures and higher NO_x production. The objective of this paper is to analyze the thermal performances and emission levels of a swirling non-premixed annular micro-combustor. A three-dimensional simulation of the internal flow in an annular combustion chamber fueled by hydrogen/air in non-premixed conditions was carried out through Ansys Fluent 2020 R2. A detailed mechanism involving many species and reactions was required to represent the complexity of the combustion process. A 19 reactions and 9 species mechanism was deemed to be appropriate to predict the combustion characteristics with great accuracy and limited processing resources. The reaction mechanism was implemented in Fluent through Chemkin. This model was then compared with the built-in model of the chemical kinetics, which involves just one reaction. The results showed that the 19 reactions model is more accurate to reproduce the centerline temperature distribution than the default simpler model. The comparison between the velocity of the mixture inside the combustor with and without combustion was also carried out, providing an estimate of the influence of temperature on the flow field. Finally, in order to meet emission limits established by the European Council in 2015, the thermal and prompt NO_x emissions were examined on both the outlet and the centerline of the combustor.  The study reveals great potential for emission reduction by hydrogen combustion and provides insights on the cooling power required to guarantee wall materials reliability.  

Presenting Author: Luca Mazzotta La Sapienza Università di Roma

Presenting Author Biography: N/A

Authors:

Luca Mazzotta La Sapienza Università di Roma
Orlando Palone La Sapienza Università di Roma
Francesca Di Gruttola La Sapienza Università di Roma
Gabriele Guglielmo Gagliardi La Sapienza Università di Roma
Domenico Borello La Sapienza Università di Roma