Numerical Study Of Afterburner Performance Of Aero Engine

With the continuous updating and iteration of aero-engine technology,the technical indicators of afterburner are increasing day by day.Especially the fourth and fifth generation afterburner,its intake conditions are more demanding,and a series of problems such as high gas temperature at the outlet of the main combustion chamber,large turbulence,and a certain Angle between gas direction and central axis need to be solved urgently.Therefore,it is of great significance to carry out comprehensive research on new-generation afterburner technology,improve the performance of afterburner under complex incoming flow conditions,and ensure the stealth performance of military aircraft in cruise state and the reliability in combat state.In this paper,the numerical simulation method is used to study the cold and hot flow field structure,mixing characteristics,combustion performance and dynamic characteristics of flame stabilizer in the integrated afterburner under the condition of strong residual rotation and nonuniform incoming flow.(1)Firstly,based on the integrated afterburner structure,the mixing characteristics of internal and external culvert air flow under cold conditions were analyzed.By setting different opening area ratios on the struts and stabilizers,the changes of component structural parameters on the velocity and temperature distribution uniformity and component cooling efficiency after mixing were obtained.The effects of non-uniform inlet residual rotation Angle and velocity on flow field structure,component cooling,velocity and temperature distribution and total pressure recovery coefficient are further studied.(2)The research on combustion performance under different inlet conditions was carried out,including strong residual spin,uneven velocity and turbulivity.The results showed that:with the increase of residual spin Angle,the uniformity of velocity and temperature distribution in the combustion chamber decreased,especially when the residual spin Angle increased to more than 10～20°,the combustion efficiency was significantly reduced.The uneven increase of the intake speed reduces the uniformity of the velocity distribution in the combustion chamber,and the influence of the uniformity of the temperature distribution is small.At the same time,the increase of the velocity uniformity will greatly reduce the combustion efficiency.The increase of intake turbulence increases the uniformity of velocity and temperature distribution in the combustion chamber,and also improves the combustion efficiency.(3)At last,the dynamic characteristics of flame stabilizer were studied,and the process of vortex shedding after uniform inlet was analyzed,and the pressure and velocity pulsation changes at different axial positions were summarized.Further,the change law of inlet residual rotation Angle,velocity heterogeneity and pressure and velocity pulsation at different positions with different turbulivity were compared,and the characteristics and change law of shedding frequency under different inlet parameters were mastered.