Dynamic Analysis Of Emergency Release Of Ram Air Turbine Power Plant

Ram air turbine is an important emergency power unit on the aircraft.To reduce the air resistance during flight,ram air turbines are often designed as retractable.Due to the uncertainty of flight conditions in the event of an emergency,it is necessary to conduct a dynamic analysis of release processes under various operating conditions.In this thesis,the multi-body dynamics method is used to acquire dynamic characteristics of a certain type of ram air turbine,judging whether it can be smoothly released under different conditions and predicting the elapsed time and the stress response during release.As a consequence,the analysis will provide the basis for the design process of ram air turbine,shorten the design cycle and reduce the cost of experiment.Firstly,the aerodynamic loads on ram air turbines at different flight altitudes and flight velocities should be calculated.Considering the difference of flow field between turbine's high-speed rotation and release,the modeling and solution were carried out respectively.By doing this,the aerodynamic load curves during the release were obtained and the aerodynamic load database for dynamic analysis was established.After that,in virtue of VirtualLab.Motion and AMESim,the multi-rigid body model and the cylinder model were established respectively.Loads were applied simulating actuality and coupling method was utilized for the sake of dynamic response of the air turbine.Finally,the main components in the release mechanism were made flexible and the rigid-flexible coupling model was established.As for completing the strength analysis,simulation was carried out and the stress responses in the flexible bodies were calculated.