Research On Aerodynamic Morphing Scheme Design And Shape Optimization Method Of Hypersonic Vehicle

The increasingly complex world situation puts forward new demands on the performance and mission form of air vehicle,based on the large investment and fierce competition of countries in the field of hypersonic vehicle attack and defense,in order to gain a favorable position in the competition,it is necessary to introduce new ideas and new concepts to promote the research progress in related fields.The concept of morphing vehicle and the concept of hypersonic vehicle have been paid attention to by the world as an important means of asymmetry,this paper mainly focuses on the cross-integration of morphing vehicle technology and hypersonic vehicle technology for a preliminary discussion,and systematically carried out the relevant research of morphing technology applied to hypersonic vehicle.Firstly,the application prospects of the morphing technology in hypersonic environment are analyzed and combed.Combined with the typical trajectory characteristics,the possible shortcomings of the current hypersonic vehicles and the potential applications of the morphing vehicle are introduced.The concept of the windward surface morphable waverider is introduced and the properties of morphing amplitude and morphing area are analyzed to verify the feasibility of the windward surface deformation.Subsequently,the computational fluid dynamics numerical simulation for aerodynamic analysis and optimization is introduced,including the Euler equation for inviscid flow field simulation with engineering viscosity correction for the optimization process and the viscous flow field simulation method based on Navier-Stokes equation for flow field analysis.The simulation method of flow field has been verified through an experimental model of a hypersonic slender wing-body aircraft with precision and efficiency.The grid convergence analysis is carried out on the baseline shape for both combination and fusion configurations.Due to the time comsuming in flow field simulation during aerodynamic shape design,the surrogate model optimization method is introduced to cutdown the computational cost and improve the optimization efficiency.MOEA/D and the sequence iterative optimization method based on Kriging are introduced.On this basis,a MOEA/D-based constrained surrogate model optimization method is developed,which is based on local search and global exploration.The probability of feasible is also used as an optimization objective.MOEA/D is used to optimize three targets.On the obtained three-objective PF,multiple candidate points are selected to do the optimization process by using the probability of feasible as the optimization objective,the optimization process can better find the boundary of the feasible area,combined with the ability of local search and global exploration,making it more efficient to solve the optimization problem with constraints.Based on the above theoretical analysis methods,the design and evaluation of the hypersonic combination morphing aircraft are carried out for the most widely used morphing scheme like telescopic,variable sweep and folding wing,and a comparative analysis of aerodynamic characteristics in different morphing modes are carried out.Taking the range of the gliding phase and the total heat absorption of the leading edge of the wing as the target,MOEA/D method is adopted to optimize the multiobjective trajectory of the two-stage morphing vehicle with three morphing modes.The performance gains of different wing morphing modes in hypersonic environment are studied.The results show that the variable sweep wing morphing mode has better overall performance in hypersonic environment.Finally,the aerodynamic shape optimization design of the fusion vehicle based on the windward surface morphing is carried out,and an aerodynamic shape optimization method considering the payload size constraints is established.The analytical method and the clamped cubic spline is combined in establishment of the patametric model and to realize the judgement and correction of payload size constraints.The multi-point sequence iterative method based on MOEA/D is used to optimize the problem.The results show that the shape obtained by the above method is more suitable for specific payload size constraints than the multi-objective optimization with volumetric ratio as an optimization objective.Based on the optimized reference shape,the design method of the fusion morphing vehicle is studied.The parametric model axially controls the cross-section of the windward surface spline curve to complete the morphing of the windward surface.The morphing control parameters are chosen as the design variables,and the optimal shape with maximum L/D under different flight conditions are optimized.At the same time,focus on the dashing in the end of the trajectory,an optimization aiming at improving the pitching moment under fixed condition is carried out,and the feasibility of pitching maneuver control through windward surface morphing is explored.Based on above research,the aerodynamic shape optimization design framework of the hypersonic morphing vehicle with morphable windward surface is proposed.In short,the thesis focuses on the protential problems of morphing technology applied in hypersonic vehicles.Starting with the application demand analysis,this paper makes some research on aerodynamic performance analysis,multiobjective trajectory optimization and surrogate based optimization with time-consuming constraints,and provides some useful references for the research of the future hypersonic morphing vehicle.