Parametric CFD Analysis of Low NOx Combustor Designs for Commercial Supersonic Aircraft

An overview is provided of the impact on NOx emissions of design variations in the six axial airflow Main swirlers of a seven-element lean-direct injection (LDI) module. The CFD study was motivated by the goal of reducing EINOx emissions of a combustor operating at supersonic cruise condition to a nominal value of 10 or below. The Open version of the National Combustion Code (OpenNCC) was used to perform two-phase reacting flow computations with various axial airflow swirler LDI flametube designs with an ‘average’ Jet-A (A2) fuel. The predicted EINOx emissions for four different air swirler designs were computed with the OpenNCC code were within 25% of each other. The best design in the parametric study showed 20% lower NOx than previous generation LDI injector designs using axial airflow swirlers. Two of the four designs analyzed with the OpenNCC code were down-selected for 3-D manufacturing and testing in NASA Glenn Research Center’s CE-13C combustion facility.