As governments realize the negative impact of greenhouse gasses on the planet, a drive to reduce our dependence on fossil fuels and switch to renewable clean energy sources has begun. However, while reducing our dependence on fossil fuels is required, this cannot be accomplished instantaneously without a significant negative impact on the world economy. Thus, to reduce the amount of greenhouse gasses in the near future, more efficient combustion processes are required to reduce both greenhouse gas emissions and pollutants such as nitrogen oxides (NOx). In conjunction with experimental investigations, numerical simulations of turbulent combustion are required to further understand the physical phenomena involved.
The present talk focuses on Moderate and Intense Low Oxygen Dilution (MILD) combustion as it increases efficiency, while reducing emissions. In this talk, I will present two turbulent combustion model formulations based on the principles of Conditional Source-term Estimation (CSE) which have been applied to MILD combustion. First, a non-adiabatic RANS-CSE formulation is applied to a semi-industrial furnace. Detailed predictions for temperature and emissions are obtained and compared to experimental data. Next, a multi-stream CSE formulation is applied to the Delft-jet-in-hot-coflow burners in the RANS and LES framework to determine if CSE can reproduce the physical characteristics seen in these flames. The present simulations demonstrate that these CSE formulations are able to predict the main characteristics seen in these semi-industrial and laboratory scale burners, including the ignition stabilization mechanism and emissions.