The aviation market has seen a drastic rise in past decades, and is projected to follow a similar trend in the coming years. Stricter regulations and ambitious targets have been framed to effectively curtail the rise in emissions due to this surge in aviation. A multi-fuel blended wing body aircraft is being developed in TUDelft, with the goal of drastically reducing aircraft emissions. To this end, a dual-combustor configuration, which operates with a main combustion chamber and an inter-turbine burner has been proposed. The exhaust gas from the main combustion chamber passes through the high pressure turbine and then proceeds to the inter-turbine burner. It is important to accurately model the evolution of exhaust gas species, from the main combustion chamber through the high-pressure turbine, since this constitutes the species concentration at the inlet of the inter-turbine burner. This, in turn, can have impacts on its performance too. Therefore, this thesis aims to do a detailed parametric analysis to study the individual impact of the operating conditions on the chemical kinetics after the main combustor. The operating temperature has been identified as the most significant parameter that would have drastic impacts on the way emissions evolve after the combustor. The predictions of Turbine Inlet Temperatures for future aircraft have shown only a steady increase. Although the assumption of frozen chemistry after the combustor may have been valid for older engines, the same does not hold as good for futuristic configurations. Newer and different engine architectures like the hybrid engine, which are designed to operate on high cycle temperatures and pressures, cannot ignore the consequence of change in emissions after the combustor in order to retain accuracy in estimations.

NOx emissions cause harm to the human body, the world around us and our atmosphere, both directly and indirectly. Flameless combustion is a combustion regime that has the potential to reduce these emissions by more than 95%. Operation in this regime is possible when lowering the availability of oxygen and lowering the combustion temperature in the combustion zone. Key for this operation is the recirculation of flue gases using internal recirculation zones and mixing of these gases with the incoming combustion air and fuel. These aerodynamic characteristics have been researched experimentally and numerically for the DUT flameless combustor. Results show recirculation and mixing can be increased with decreasing the jet size, however with an increase pressure loss. Numerical investigation shows that simulation of this setup is challenging using RANS and that LES might be the only way to go forward.

Gas turbines are the power house of most modern day aircrafts. Combustion of fossil fuels provides the energy required, but this produces harmful emissions. With ever increasing strictness on emissions regulation, it is becoming even more necessary to design gas turbine combustion chambers with the intent of low pollutant output. Gas turbine engines on the other hand also have the property of dense power output, while at the same time being capable of producing lower emissions than internal combustion engines. This has served as an impetus for Mitsubishi Turbocharger and Engine Europe B.V.(MTEE), to develop a gas turbine, designed around its turbocharger unit, to be used as a range extender on Battery Electric Vehicles(BEV) in the future. The common interest of the Propulsion group at TU Delft, LR and MTEE has resulted in this thesis on researching a computational method to obtain accurate predictions of combustion emissions from a gas turbine combustor.

The method explored is the Automatic CFD-CRN method which decouples calculations of fluid mechanics and detailed chemistry by performing them in a CFD simulation and a Chemical Reactor Network respectively. Accurate prediction of emissions requires a detailed chemical kinetic mechanism to be implemented but doing so, directly in CFD, is prohibitively expensive. Hence CFD is used to obtain the combustion flow field, which is influenced mainly by the evolution of major species, whereas the minor species are obtained from the implementation of detailed chemistry in a CRN derived automatically from the CFD mesh. Such a calculation is feasible because ideal reactors, which are the building blocks of a CRN, have a simplified fluid dynamic model and can hence process the detailed chemistry at an affordable time cost.

A software package implementing the Automatic CFD-CRN process is developed and factors affecting the results from this computational tool are studied in this research work.