59392 - A Numerical Sensitivity Study of Modeling Parameters in the Combustion of a Swirler 

Swirl injectors have been broadly implemented for modern gas-turbine engine combustors and other energy-conversion systems. The flame shape and combustion behavior from the swirler are difficult to determine experimentally, while a numerical analysis provides much useful information about the basic mechanisms for turbulent mixing and energy transfer in the swirling flows. However, both the turbulence model and combustion model have numerous options that must be selected for the specific application. In this study, a sensitivity analysis based on Reynolds Averaged Navier–Stokes (RANS) equations has been conducted  to model the reacting turbulent flow in a swirler used in a (Disk-Oriented) gas-turbine  using propane-air mixture.  Several popular turbulence models and combustion models have been compared at different equivalence ratios. The effects of the simulation parameters such as turbulence intensity, TKE Prandtl number, gravity direction, and Schmidt number have been studied. The CFD results have been compared with the available experimental images  from the Air Force Institute of Technology. The contour plots of the species mass fraction (H₂, OH) and temperature distributions are in  good agreement with the experimental visual results. The results showed that the realizable k-ε model and the steady diffusion flamelet model (SDF) are more suitable to model the turbulence combustion in the swirl domain. The computations further  showed that the TKE Prandtl number and gravity are sensitive parameters to model the combustion from the swirler, while the Schmidt number and turbulence intensity showed less sensitivity in the simulation results.