Investigation On The Mixing And Combustion Performances Of Chevron Mixer For The Afterburner

The mixer of turbofan engine afterburner plays a significant role in its characteristics. Among the afterburner design schemes, adopting chevron mixers to enhance the mixing of core flow and bypass flow represents a key direction. The computation of three-dimensional flow fields, and the combustion features of afterburner which used reasonable chemical reaction model were used together to investigate the aerodynamics and combustion characteristics with chevron mixers. For comparison, confluent mixer was also investigated.A research on the analytical prediction of aerodynamics characteristics for the chevron mixer is performed firstly basing on FLUENT. Compared with the opened experimental data, it is indicated that the computational results conformed the experimental results very well. Also, the simulation results confirm with the experimental data reasonably. The fact validated the reliability of the numerical method.Three-dimensional flow fields of mixers were numerically investigated and some related flow features were obtained. Key aerodynamics characteristics of chevron mixers (including chevrons tilted core flow, chevrons tilted bypass flow and chevrons tilted core flow and bypass flow alternately ) were analyzed, such as stream-wise vortices structures, thermal mixing efficiency, the inlet temperature of outer circle flame stabilizer and the total pressure recovery coefficient. The results revealed that the effects of the stream-wise vortices induced by chevrons can get higher thermal mixing efficiency at the cost of less total pressure loss in a shorter downstream distance. The chevrons tilted core flow could bring negative factor for the inlet flow temperature of the outer circle stabilizer, but the chevrons inclined bypass flow or alternately arranged could enhance the temperature dramatically. Considering all the factors, the mixer with chevrons alternately arranged (in short MA) showed the better capability.The combustion characteristics of afterburner with MA were analyzed under four different fuel supplying schemes. Final results showed that: the combustion efficiency by MA was higher than the confluent mixer as much as 14.9%; the initial temperature of fuel can affect the combustion efficiency significantly, during reasonable range, we can get higher combustion efficiency at the higher initial temperature.