Research On STOVL Aircraft Thrust Nozzle

Short take-off and vertical landing technology refers to the aircraft can take off and landingwithout rollout. Aircraft Equipped with lifting system can balance the dead weight of the plane itselfby changing the exhaust nozzle exit airflow direction, to keep hovering, or vertical take-off andlanding in flight. When the aircraft near the land, the ground changed nozzle exit flow direction,affecting the airplane flow field, produce suckdown, which can cause lift loss. The supersonic impactjet between the ground and aircraft fuselage is the main factors of lifting loss, in relation to the liftloss, foreign researchers have done a lot of work, but are still limited to the static process. STOVLaircraft doing vertical take-off and landing is a dynamic process.This paper aims at STOVL aircraft the lift loss of dynamic process, using adaptive growthdynamic grid, the combination of numerical simulation and experiment research. Discussing the liftloss of vertical take-off and landing aircraft in static and dynamic process. This paper considered theparameters such as the nozzle pressure ratio and landing velocity in the influence of the lift loss.Using the schlieren technology to measure the supersonic impinging jet flow plate shock wave,impinging wall jet, entrainment flow and separation flow. This paper explains the reason for the liftloss.It can be conclude that the impact height is the key influence factors of the lift loss. NPR is alsoan influence factor. As the NPR increase, the lift loss absolute value decrease. At the same time, theinfluence of NPR resides in the near ground condition. According to the dynamic process numericalsimulation of lift loss, the effect of the velocity of STOVL process may appear in the near groundstage. Dynamic test showed that the flow field dynamic response time is in the magnitude of0.1s, alsothe spectrum analysis showed that the dynamic frequency characteristic mainly concentrated in thelow frequencies, the magnitude in10Hz.