Numerical Investigation On The Comprehensive Influence Of Crosswind And Reverser Flow To Engine Inlet Flow Field

In recent years,with the development of civil aviation and large transport aircrafts,higher request of the high bypass ratio turbofan engine has been put forward.The thrust reverser is a special type of mechanism in the large bypass ratio turbofan engine.After the thrust reverser is opened,the reverse thrust flow will have a significant impact on the aerodynamic stability of the large bypass ratio turbofan engine,especially in the case of crosswinds,the gas flow environment faced by the engine is more complicated.In order to investigate the influence of crosswind and reverser flow on the inlet flow field of high bypass ratio turbofan engine,computational fluid dynamics(CFD)technology was used to simulate the three-dimensional flow field of a single engine and the whole aircraft under the open state of the thrust reverser.The influence of inlet flow field under the condition of no crosswind,different speed crosswind and crosswind at different angles is analyzed.In the condition of no crosswind,the calculation results of a single engine indicate that the reverse thrust airflow is not inhaled by the engine.The integrated calculation results of the aircraft and the engine show that the reverse thrust airflow is re-ingestion by the engine when the rolling Mach number was reduced to 0.1.The total pressure loss of the inlet airflow increases with the decrease of the Mach number,and the circumferential steady-state total pressure distortion index of the inlet section also increases.Under different speeds of 90 degrees crosswind,the calculation results of a single engine show that the reverse thrust airflow is re-ingestion by the engine when the rolling Mach number decreased to 0.05.When the rolling Mach number is greater than 0.1,the total pressure loss of the engine inlet airflow increases with the increase of the crosswind wind speed,and the circumferential steady-state total pressure distortion index also increases.Under different rolling Mach numbers,different crosswind speeds have different effects on the engine inlet flow field,and the most influential crosswind speed becomes smaller with the decrease of Mach number.When the rolling Mach number is small,the smaller speed of 90 degrees crosswind has a great influence on the engine inlet flow field.The integrated calculation results of the aircraft and the engine show that the reverse thrust airflow is re-ingestion by the engine when the rolling Mach number was reduced to 0.1.The smaller the rolling Mach number,the more easily the reverse airflow is re-inhaled by the engine.The increase of crosswind speed further increases the possibility of re-ingestion by the engine.Under different angles of crosswind with 15m/s,the single engine calculation results show that when the rolling Mach number is reduced to 0.1,the reverse thrust airflow is re-inhaled by the engine.When the rolling Mach number is not less than 0.1,the circumferential steady-state total pressure distortion index of the engine inlet section does not change much as the crosswind angle increases.When the rolling Mach number is 0.05,the circumferential steady-state total pressure distortion index increases as the crosswind angle increases.When the rolling Mach number is small,the larger crosswind angle has greater influence on the inlet flow field of the engine.The integrated calculation results of the aircraft and the engine show that when the Mach number is reduced to 0.1,the reverse thrust airflow is re-inhaled by the engine.Generally speaking,under the same rolling Mach number,the total pressure loss of the inlet airflow increases with the increase of the angle of crosswind;under the same crosswind angle,total pressure loss increases with the decrease of Mach number.When the Mach number is small,the larger crosswind angle has a greater influence on the engine inlet flow field,and the total pressure distortion is more serious.