Research On The Structure And Aerodynamic Performances Of The Cascade Thrust Reverser

The thrust reverser is the important element of the aero engine for the civil and army plane with high pass ratio engine. It plays an important role on the braking on the purpose of shorting the landing roll distance. This paper aims at the cascade thrust reverser to demonstrate the three dimensional numerical simulations. Some analysis were conducted to reveal the effects of cascade geometry, engine power, landing speed, side wind, single engine/double engine on the performances of the reverser. In addition, the re-ingestion of reverse flow, which induces the distortion of the fan inlet, was discussed. The main achievements are included as follows.Firstly, based on the experimental data, the proper numerical method was chosen to simulate the cascade flow to evaluate the aerodynamic performances. The numerical results show that the reverse thrust efficiency, which reaches to the peak of 0.73, is enhanced by the increase of inlet and outlet angle of cascade. However, the total pressure recovery coefficiency is decreased by the increase of inlet and outlet angle of cascade inversely. With the increase of solidity of the cascade, the reverse thrust efficiency increases firstly, and then flattens out. The performance gains to the maximum on the condition of the 1.08 solidity of the cascade. The total pressure recovery coefficiency whose minimum value is about 0.9 decreases firstly, and then increases. Comprehensively, the solidity of the cascade is supposed to suggest from 1 to 1.25.Secondly, it exhibits the reveres flow field on the condition of varying the engine power, landing speed, side wind, and so on, for the whole engine. The distortion indexes are evaluated for the re-ingestion of reverse flow. The numerical results show that the reverse thrust efficiency, flow coefficiency and velocity coefficiency are all improved by the enhancement of the engine power. Reversely, the loss of the flow increase with the enhancement of the engine power. The landing speed and side wind seemly have no effects on the aerodynamic performances of the reverse thrust efficiency, the total pressure recovery coefficiency and the flow coefficiency, except for the velocity coefficiency. The existence of side wind enhances the critical landing speed from 0.08 Ma to 0.12 Ma.Lastly, it demonstrates the reverse flow field on the condition of double engine deployment with airframe. With the increase of landing speed, the engine incurring severe re-ingestion change from the inner side to out side. When the landing speed exceed to 0.12 Ma, the re-ingestion phenomenon of inner side engine disappear. Comparing to the single engine deployment, the ingestion of reverse flow each other for the double engine happens. It causes the critical landing speed enhances to 0.14 Ma.