Trans-atmospheric Vehicle Force Heat Analysis And Flight Planning Research

A basic aerodynamic shape for trans-atmospheric vehicle was optimized based on waverider configuration, the three-dimensional flight dynamics model was constructed for trajectory simulation, maximum-range trajectory was optimized with the new put forwarded subsection optimization method and the improved maximum principle in this dissertation, the force and heat environment of trans-atmospheric vehicle was analyzed, flight planning was researched. The main work and achievements are summarized as follows:Trans-atmospheric vehicle configuration was studied from many aspects and waverider was proved to be the idealist one. The design model of waverider configuration was founded, which was optimized with the improved multi-object optimum genetic algorithm based on NSGA-II, and relatively better basic shape for trans-atmospheric vehicle with high volumetric efficiency and lift to drag ratio was obtained. Flow Fields of the aircraft was analyzed with CFD method, the aerodynamic coefficient was calculated and curve fitted. A wind tunnel experiment was designed and the lift to drag ratio agreed well with CFD results in small region angle of attack.The aerodynamic heat model was established, which was verified by CFD result. Combined with the trajectory, the force and heat environment during the trans-atmospheric flight was studied and the conclusions had instructed significance for aerodynamic heat-resist and trajectory synthesized optimization.The three-dimensional flight dynamics model was set up and the simulation that based on the maximum lift to drag ratio was chosed as the basic trajectory. The change law of trajectory parameters with the parameters of the shut-down point and aerodynamic coefficient were analyzed; the characteristic of several types of skipping and gliding trans-atmospheric trajectory was investigated, which showed that the trans-atmospheric trajectory has the advantage in penetration and flight performance comparing with the inertia trajectory. The feasibility of trans-atmospheric flight was confirmed by the following three aspects: the theory of flight dynamic, energy analytic and engineering realization. It shows that the trans-atmospheric flight could be another maneuver penetration means and can be referenced in future new type of weapon equipment.The subsection optimization method was put forward for trans-atmospheric flight trajectory optimization. The method did not have the sensitivity problem of initial value, and its optimum result approaches to the real maximum range trajectory infinitely as long as the subsection step is small enough and the iterative number is big enough. It is an availability method for long-range trajectory optimization both in theory and in practicality effect. The maximum principle model applied to three-dimensional trans-atmospheric trajectory optimization was established, the partial derivative of the right function was deducted considering earth circumrotate and flat ratio. The key point applying the maximum principle is the solution of two-point boundary value problem. Because of the long integral time corresponding to the long distance hypersonic skipping-gliding flight, the maximum principle is sensitive to initial values of state variables. Moreover, the traditional maximum principle needs to satisfy six rigorous terminal constraints simultaneously to simulate three-dimensional trajectory. The way combining the genetic algorithm and the downhill simplex method can solve the above two questions. The improved method gives more practicality of the maximum principle in optimum control field.Comparing and researching many kinds of flight scheme of maximum range in skipping-gliding trajectory, it is found that gliding at maximum lift to drag ratio is the best one, and it is certified by sensitivity analysis methods. Then the boundary condition of gliding at maximum lift to drag ratio was proposed, proved with trajectory simulation and theory analytical methods. The conclusion has consequence in optimum design of skipping-gliding flight or other maneuver trajectory.The trajectory was optimized with multi-object including force, heat and range. Based on the trajectory environment analysis and multi-object optimization, the restriction boundary of flight corridor was studied and determined. The shut-down parameters'effect to the flight corridor was analyzed and its numerical region in flight corridor was obtained. Considering all the restriction of flight corridor boundary, the flight planning of trans-atmospheric vehicle was researched.The achievements obtained in this dissertation provide an important guidance to integrated design of trans-atmospheric vehicle and flight planning research. The methods and conclusions can provide analysis and demonstrating methods for aerodynamic heat-resist and trajectory synthesized optimization。...