Investigations of Soot Nucleation and Oxidation in a Micro-Flow Reactor

The emission of particulate matter or soot from gas-turbine engines is a major environmental and health concern globally. The production and oxidation of soot depend on the operating conditions and fuels used in gas-turbine engines. The aim of this study was to investigate the nucleation and growth of soot particles during the oxidation of Jet fuels (traditional and alternate bio-derived) using a micro-flow tube reactor in the laboratory. To achieve this goal, Scanning Mobility Particle Sizer (SMPS) with a nano-differential mobility analyzer and condensation particle counter was used to obtain real-time measurements of nascent soot particles. The particle size distributions (from 3nm to 150 nm) were obtained for a range of reactor temperatures, flow residence times, and species compositions. Specifically, for a pressure of 1 atm, the nominal reactor temperature varied between 1173 to 1323 K while the residence time was varied between 80 to 160ms. The results showed that the particle size distributions during the oxidation of Jet fuels were normally distributed. Additionally, the number density of soot particles increased with increasing flow residence times and with increasing temperature. More importantly, alternate jet fuels containing C10 iso-paraffins and trimethyl benzene showed a much stronger propensity for soot nucleation when compared to C12 and C16 highly branched paraffins. Data obtained from this type of experiment can be used in developing and validating soot nucleation/oxidation models used in CFD simulations of next generation gas-turbine engines with alternate bio-derived Jet fuels.