Numerical Study on the Mixing Characteristics of Chevron Mixer for the Afterburner

摘要

To improve the performance of the afterburner of the turbofan engine, an innovative type of mixer, the chevron mixer, was arranged to enhance the mixing between the core flow and bypass flow. Based on three-dimension CFD for the chevron mixer, the effects of chevron mixer geometry parameters on the mixing performance are revealed. The velocity vector of the flow field shows that chevron could induce counter-rotating streamwise vortices, which can enhance entrainment of two-flow remarkably. The temperature profile of flow located downstream of mixer was more uniform than that of confluent mixer. It means that the ignition temperature increase for afterburner with chevron mixer. With the increase of penetration angle of tabs, the thermal mixing efficiency is improved, but the pressure loss coefficient is enhanced slightly. For a fixed penetration angle, with the increase of number of tabs, the thermal mixing efficiency is decreased by 5%~15%. The distribution of tabs has significant effect on the mixing characteristics. The structure of tabs with tilted inward and outward alternately is of benefit to form stronger streamwise vortices, and its intensity is more than 2 times than that with tabs tilted inward or outward only. These computational results could be used to optimize the mixer structure in the further research.