Numerical Study On The Cold Flow Characteristic Of The Integrated Afterburner

Afterburner is the best way to increase engine thrust in a short period of time.Especially for military fighters,afterburner is an indispensable part.With the development of aero-engines,the total temperature of the inlet airflow of the afterburner is getting higher and higher,and the working environment is getting worse.In the traditional afterburner,the flame stabilizer and the fuel supply facility are installed in the flow path,which inevitably causes a large flow resistance loss.Therefore,in order to obtain superior performance under severe conditions,it is necessary to carry out research on new concepts and new ideas for the afterburner.The integrated design of the rectifying struts of the afterburner and the flame stabilizer not only greatly reduces the flow resistance loss under the non-energized state,but also shortens the length of the afterburning combustion chamber,thereby improving the thrust-to-weight ratio of the engine.The integrated afterburner uses the cavity as an ignition zone,and the cavity recirculation zone is connected to the low-speed recirculation zone behind the struts,thereby igniting the high-speed mixed fuel to achieve flame propagation and stable combustion of the combustion chamber.In addition,struts has a rectifying action,which can rectify the incoming flow with a certain angle after passing through the turbine to be parallel with the axial direction,which is beneficial to reduce energy loss.Therefore,the study of the flow field after the cavity and the struts and the rectification effect of the struts are of great significance to the integrated afterburner.In this paper,the basic problems of the cold flow field of the integrated afterburner are studied by numerical simulation method,and the flow resistance,total pressure recovery of the integrated afterburner and the total pressure recovery of the diffuser structure,inlet working condi:tions and struts are discussed.The variation of the flow characteristics of the internal flow field.The research results show that the integrated afterburner with large expansion ratio has small flow resistance loss,strong total pressure recovery capability and the good cold flow characteristics.Compared with the straight struts,the torsion strut has better flow resistance characteristics and the cold flow characteristics of the integrated afterburner.With the increase of the inlet Mach number,the flow resistance loss of the integrated afterburner is slightly reduced,but the mainstream residence time is shortened,resulting in insufficient mixing of fuel and air.The effect of the struts rectification is related to the inlet deflection angle and the diffuser structure.For the integrated afterburner with the center cone as the step type,the rectification effect of the straight struts is better when the inlet deflection angle is larger;the rectification effect of the torsion struts is better when the inlet deflection angle is smaller.The integrated cone-shaped combustion chamber with a cone-shaped central cone exhibits an opposite change.The V-shaped groove struts not only can greatly reduce the flow resistance loss of the afterburner,but also better improve the cold flow characteristics,accelerate the flame propagation,and improve the combustion efficiency.