Research On The Influence Of Engine Jet On The Parachute Opening

The cross parachutes are widely used in the landing process of fighter aircraft as aerodynamic decelerators.But in actual use,the drag parachute may be released accidently due to sudden conditions.At this time,the engine discharging jet will greatly affect the working performance of the drag parachute.In this thesis,the CFD and fluid-structure-interaction numerical calculation methods are used to study the drag parachute under the influence of engine jet flow.The results and conclusions are briefly described as follows:(1)The fluid-structure interaction solver based on the Arbitrary Lagrange-Euler method is used to simulate the inflation process of parachutes,the changes on shape,trajectory and attitude of the parachute during the airdrop are obtained by the finite mass method,and the shape of the full cross parachute is obtained by the infinite mass method.(2)The flow field of the drag parachute under the full state is studied,and the flow field characteristics of the drag parachute under different air conditions are compared and analyzed.The results show that the ground has a large influence on the flow field of the drag parachute,which makes it obvious asymmetric characteristics,and the narrow channel formed between the umbrella clothing and the ground will cause the airflow flowing there to accelerate and expand,which will affect the backflow area of the parachute.The engine discharging jet flow mainly hits the underside of the drag parachute clothing,which increases the pressure value there and causes a backflow area at the upper side of the parachute clothing.With the increase of the jet flow’s speed,the refluex area on the upper side of the parachute clothing,the high pressure area on the lower side of the parachute clothing,and the high pressure area on the windward surface of the parachute clothing also increase,and the change in the flow field after the parachute is not obvious.(3)The fluid-structure interaction solver based on CE / SE is used to simulate the inflation process of the drag parachute at different engine jet speeds.The inflation law of the darg parachute and the influence of engine jet speed are studied.The research results show that when the high-speed airflow generated by the engine jet blows on the canopy,the deformation of the canopy becomes more severe,especially on the side near the ground.When the velocity of engine jet increases,the peak of the umbrella opening dynamic load will appear earlier and its value will increase accordingly.