Experimental and Numerical Investigation of Flow, Combustion and Emission Characteristics of Novel Multi-Swirl LDI burners.

Abstract

Academic investigations and development have been directed towards exploring alternatives that can enhance aircraft engines' efficiency while minimizing emissions. We have developed two novel multi-swirl LDI burners, named LDI-3AB and LDI-4C, for low-emission aero propulsion systems, which consists of numerous lean direct injection modules with distributed fuel injection surrounded by airflow through hexagonal swirlers with a 45° vane angle. This study presents an experimental and numerical analysis of these burners' flow, combustion and emission characteristics under various operating conditions. Numerical analysis is carried out using the URANS with the realizable \(\kappa\)-\(\varepsilon\) turbulence model in combination with the FGM combustion model, and it is compared against the results of stereo PIV data. The numerical results correlated well with the experimental data, and all simulations accurately captured the flow patterns. The comparative study showed that LDI-4C exhibits vigorous mixing activity, which gives low mixture fraction values throughout the combustor length compared to the LDI-3AB burner. This is because the cross-fuel injection effectively distributes the fuel to the shear layer of the swirling air stream and helps in quick mixing. The LDI-4C always has a lower \(NO_{x}\) value at the exit of the combustion chamber than LDI-3AB due to low temperature and residence time and it has high \(CO_{2}\) production, and more \(O_{2}\) consumption indicates better combustion efficiency than the LDI-3AB burner.