Topology optimization and simulation of the supersonic air ejector in the aero-engine thermal protection system

The application of a supersonic ejector in aero-engine thermal protection system can effectively solve the problem of the flow reduction taken into the combustion chamber caused by the excessive high-pressure air extracted from the compressor of the aero-engine. To improve the ejector performance, the topology optimization method was employed to optimize the ejector structure. The optimization results show that a spoiler element is added to the inlet area of the mixing chamber. Further, the airfoil-like air ejector (ASE for short) was proposed learning from the drag reduction mechanism of wind turbine airfoil blades. The flow field shows that the secondary nozzle effect produced by the spoiler element is the main reason the main reason for the improvement in ejector performance. Then, the effects of the structural parameters of airfoil-like spoiler elements are analyzed. As the maximum thickness (D) of the airfoil-like spoiler element increases, the entrainment ratio increases, and the performance improvement coefficient ξ firstly increases and then decreases. As the ratio of front chord length to back chord length (x1/x2) and the distance between the spoiler element and the nozzle throat (S) increases, the entrainment ratio and performance improvement coefficient firstly increased and then decreased. In this study, the entrainment ratio of the ASE increases by 145.8% - 224% in comparison to the traditional ejector. The optimal values of D, x1/x2 and S is 3.3 mm, 1:4, 5.9 mm separately. The maximum entrainment ratio is 2.073.