着陆滑跑状态下的反推力装置重吸入特性数值模拟

对大涵道比涡扇发动机叶栅式反推力装置,利用CFD技术,展示了叶栅式反推力装置开启后的流场流动特征,计算分析了飞机着陆滑跑马赫数和侧风速度对发动机进气道重吸入特性的影响.结果表明:在无侧风影响时,进气道对反推力气流的重吸入现象随着滑跑马赫数的增加而逐渐减弱并消失,重吸入特征参数值随着滑跑马赫数的增加而减小并达到允许值,该临界滑跑马赫数为0.08;在侧风环境中,侧风使得反推力气流在发动机一侧进入发动机进气道,导致风扇进口截面的总温畸变增大,重吸入特征参数值随着侧风速度的增加而增大,侧风的存在使得反推力装置关闭的临界滑跑马赫数从不存在侧风时的0.08提高到0.12. 

Numerical simulation on re-ingestion characteristicsunder landing state for thrust reverser

A numerical study was carried out for a cascade thrust reverser of a turbofan engine with high bypass ratio to investigate the influences of the landing Mach number and crosswind speed on the re-ingestion characteristics of the engine and the flow characteristics with the thrust reverser opened. The results showed that:with the increase of the landing Mach number, the level of re-ingestion of the engine inlet decreased, and then disappeared. The value of the characteristic parameter used to evaluate re-ingestion characteristics reached to an allowable value when the critical landing Mach number was 0.08 without the crosswind. When the thrust reverser encountered the crosswind, crosswind changed the flow direction for the thrust reverser flow. It caused the reverser flow to re-ingest into the engine on the crosswind side with the increase of the total temperature distortion on the air inlet. The value of the re-ingestion parameter increased along with the increases of crosswind speed. Therefore, the critical landing Mach number for the safety increased from 0.08 to 0.12 for the cause of crosswind.