Impact of aromatic structures and content in formulated fuel for jet engine applications on particulate matter emissions

Fuel formulation with the particular selection of fuel components is a promising approach that offers the reduction of harmful emissions without altering the combustion system performance. Each fuel component has its own combustion characteristics and hence contribution to emissions. Aromatic is one of the main components of fossil-based fuels and has a strong correlation with the formation of particulate matter (PM) emissions. Besides, aromatics presence in fuel is essential for the compatibility of fuel with the combustion system and maintaining the energy density of the fuel. In this regard, a Rolls-Royce combustor rig was used to test 16 aromatics blended with jet fuels in three different proportions. Moreover, a novel approach of flame luminosity imaging is employed to measure the PM emissions through the soot propensity profile. The results show that PM emissions increase with the proportional increase of aromatics. The di- and cyclo-aromatics produced significantly higher PM emissions compared to alkyl-benzenes. 3-Isopropylcumene tends to lowest PM formation and thus is a consideration as a selection of aromatic type in future fuels for lower PM emissions. Furthermore, it was also observed that PM number concentration measured by the extractive method with DMS 500 instrument correlates well with imaging methods for all the tested fuels. The present study provides information on particular selection of aromatic for future fuel development.