Numerical analysis of fuel injection configuration on nitrogen oxides formation in a jet engine combustion chamber

Abstract

Emissions of nitrogen oxides from the aviation sector, contrary to the land-based sources, have doubled compared to 1990. Aircraft unique location in the upper atmosphere and daily growth of air-based traffic require particular attention to the effects of these emissions. One way to cope with this problem is to develop and design more efficient combustion systems. In this research, the numerical modelling of combustion process inside a jet engine combustion chamber is presented. The investigated chamber is a theoretical can type chamber mounted with a double stage radial swirler. The advanced k-zeta-f turbulence model was utilised to model the turbulent behaviour, while the spray process was described by the Euler Lagrangian spray modelling approach. Two different modelling approaches for describing the combustion process were employed: reduced chemical mechanism and the 3-zone extended coherent flame (ECFM-3Z) combustion model. Considering the analysis of relevant physical quantities and taking into account the reduction of computational costs while using the ECFM-3Z combustion model, it was employed for analysis of the influence of spray and emission processes by varying number and positioning of fuel introduction nozzle holes. Increase in the number of nozzle holes and their correct positioning can result in emission reduction up to 60%. Such behaviour could be addressed to the specific spray cloud formation and smaller high-temperature regions. Results showed that the presented model can be used as a modern design tool in the early stage of the combustion chamber development.