Numerical analysis of swirling non-reacting and reacting flows by the Reynolds stress differential method

So et al.'s isothermal He-air mixing experiment and Wilhelmi's propane-air diffusion-controlled combustion experiment were analyzed with a differential Reynolds stress model. For both experiments, the IPC (isotropization of production and convection) model of Fu et al. for the rapid term improved the normal stress distribution in the large swirl velocity region and the Hanjalic and Launder model for the diffusion term improved the normal stress distribution near the centreline, in comparison with the IP (isotropization of production) model for the rapid term and the Daly and Harlow model for the diffusion term. For Wilhelmi's experiment, the IPC model and the Hanjalic and Launder model yielded improved mixture fraction distributions near the centreline. The intensity of axial and swirl velocities near the centreline was still underestimated, however, and the model requires further improvement.