Research Projects

Real jet fuels and their biofuel blends are complex mixtures of many organic components, some of which are aromatic compounds. Towards the high-temperature end of the distillation curve, some of these aromatics may contain multiple rings. A trace amount of these high molecular weight species in the fuel would directly allow for soot nucleation in practical engines especially when the fuel is injected as a spray. The primary objectives of this proposal are three-fold. First, the NOx emissions and sooting propensity of jet fuels and their biofuel blends as a function of distillate fractions will be studied systematically to provide experimental data on the sensitivity of NOx and soot formation to distillation fractions. The experimental results from this study will help in the development and validation of a reduced NOx and soot model for gas turbine applications and will also provide a reference database for the nascent soot formation in real distillate fuels. Second, the NOx emissions and sooting propensity of jet fuels and their biofuel blends will be measured and compared to conventional jet fuels to estimate the sooting behavior of such fuels for possible applications in gas turbine engines. The sampled soot particles will also be characterized for their internal nanostructure, morphology, and optoelectronic properties to investigate the physicochemical evolution of soot particles as a function of particle residence time. Numerical computations will be carried out for premixed stagnation flames using a detailed chemical kinetics model. Modeling of soot particle size distribution functions and soot volume fraction will be carried out in the present study for a series of premixed stagnation flames and results will be compared against the experimental data. Lastly, the validity of the surrogate fuel concept in emulating soot and NOx emissions from real fuels will be examined in a well-defined combustion environment. NOx and soot formation from conventional jet fuels and their biofuel blends will be investigated in a series of premixed stretch-stabilized stagnation flames at three different cold gas velocities where NOx, soot volume fraction, number density, and particle size distribution functions (PSDFs) will be measured to provide a reference database for NOx and soot emissions in real distillate fuels and their biofuel blends. The proposed study aims to provide a deeper understanding of the NOx and soot formation mechanisms in real distillate fuels and their biofuel blends for applications in gas turbine engines. The proposed research will augment the experimental research of NOx and soot formation in real distillate fuels and their biofuel blends by carrying out detailed soot measurements in a series of premixed stretch-stabilized stagnation flames that are amenable to numerical simulation using the OPPDIF code.