戽斗式反推力装置气动特性数值仿真研究

在发动机短舱系统上设计反推力装置是民用飞机减小着陆滑跑距离、减轻起落架刹车系统负担的重要手段,对于主体不易更改的发动机而言,戽斗式反推力装置具有原理简单、实施方便等优点,是较好的设计选择形式。 戽斗包角是此类反推力装置设计中的重要参数,对反推性能有较大影响。 为了全面研究不同戽斗包角对反推性能的影响规律,基于某型涡轮风扇发动机设计了戽斗式反推力装置初步方案,并对反推力装置工作时的流场分布进行了数值仿真研究,着重分析了反推力及反推效率的变化情况。 研究结果表明:在所研究的角度范围内,随着戽斗包角逐渐增大,反推力及反推效率先增大后减小,包角为 110°时,反推效率最高;但是,在接近于停机状态的小速度条件下,戽斗包角相对较小时,反向排气流会被大量吸入进气道内,从而影响发动机的正常工作;通过对比不同方案的计算结果,给出了戽斗包角的设计建议值,可为反推力装置的详细设计及后续工程应用提供参考。

Numerical simulation study on aerodynamic characteristics of bucket type reverse thrust device

The design of thrust reverser on the engine nacelle system is an important means for civil aircraft to reduce the landing distance and lighten the load on the landing gear braking system. For the engine whose main body is not easy to change, the bucket type thrust reverser has the advantages of simple principle, convenient implementation, etc. , and is a better design option. The bucket angle is an important parameter in the design of this kind of thrust reverser, which has greater impact on the thrust reverser performance. In order to comprehensively study the influence of different bucket angle on thrust reverser performance, a preliminary scheme of bucket type thrust reverser was designed based on a certain turbofan engine, and the flow field distribution of the thrust reverser during its operation was numerically simulated. The change of thrust reverser and thrust reverser efficiency was emphatically analyzed. The results show that, within the angle range studied, with the bucket angle increasing gradually, the reverse thrust and reverse thrust effect increase first and then decrease. When the bucket angle is 110°, the reverse thrust efficiency is the highest. However, at a low speed close to the shutdown state, when the bucket angle is small, a large amount of reverse exhaust flow will be drawn into the inlet, thus affecting the normal operation of the engine. By comparing the calculation results of different schemes, the recommended design value of bucket angle is given, which can provide reference for the detailed design of reverse thrust device and subsequent engineering application.