反推气流对发动机进口流场影响的数值研究

通过求解三维雷诺平均的Navier-Stokes(N-S)方程,获得了某大型运输机降落滑跑过程中,在不同滑跑速度下的反推气流扰流流场细节.单台发动机反推气流扰流流场的计算结果表明,在任何状态下,反推气流都不会被发动机重新吸入.飞机/发动机一体化计算结果表明:随着相对来流马赫数的减小,反推气流被发动机重新吸入的可能性不断增大.当相对来流马赫数减小到0.1时,反推气流会被外侧发动机重新吸入,此时,发动机进口截面出现了明显的流场畸变,周向稳态总压畸变指数增加明显.当相对来流马赫数减小到0.05时,两台发动机都会吸入反推气流.当相对来流马赫数减小到0时,反推气流没有被重新吸入发动机,但是反推气流会干扰吸入发动机的自由流,降低自由流的总压,从而也会造成发动机进口的流场畸变. 

Numerical investigation on influence of reverser flow to engine inlet flow field

By solving the three-dimensional Reynolds averaged Navier-Stokes (N-S) equations, the detailed flow field information of the reverser flow was obtained under different taxiing-velocity conditions during the landing process of a large transport aircraft. The single engine calculation shows that in no case the reverser flow will be re-ingested by the engine. The aircraft/engine integrated calculation indicates that with the decrease of relative wind Mach number, the possibility of the reverser flow being re-ingested by engine keeps increasing. When the relative wind Mach number decreases to 0.1, the reverser flow is re-ingested by the outboard engine. Meanwhile, the inlet flow field of the engine is distored, and the circumferential steady total pressure distortion coefficient increases obviously. When the relative wind Mach number decreases to 0.05, the reverser flow is re-ingested by both the outboard and inboard engines. When the relative wind Mach number decreases to 0, the reverser flow is not re-ingested. But the reverser flow hinders the free flow and reduces the total pressure of the free flow ingested by the engines, finally causing the inlet flow field distortion of the engine.