In this paper CFD analysis of the steady two-phase turbulent combusting flow in a single annular low-NOx combustor is presented. For this purpose the commercial code CFD-ACE (1998) was used, where Eulerian equations are solved for the gas phase and the liquid spray fuel droplets are treated in a Lagrangian frame of reference allowing for evaporation of droplets and providing source terms for the gas phase. The standard k-ε model was used for turbulence and an assumed shape probability density function was used for the instantaneous chemistry in the conserved scalar combustion model. Thermal NOx is assumed to be the only source of NOx production and is decoupled from the gas phase reacting flow and calculated in a postprocessing step. The calculation is done on a block structured multi-domain computational grid. Particular attention has be paid to the detailed modeling of the fuel injector having multiple air swirler passages starting from the trailing edge of the air swirler vanes and utilizing up to 400000 computational grid cells for the entire model.
The model represents the single annular low-NOx combustor for the BR700 aircraft engine family, which is based on a Rich Burn - Quick Quench - Lean Burn (RQL) concept. CFD analysis is done for high power reduced take off conditions and is compared with full annular rig test results for the temperature traverse and the integral EINOx. The results imply satisfactory prediction capability for the EINOx and the average radial temperature distribution. The prediction of the details of the temperature traverse is not satisfactory and will remain a challenge for the future.