Optimization Design Of The Inlet And Unmanned Aerial Vehicles Inside And Outside The Flow Field Coupling Calculation

Modern aircrafts such as fighter, cruise missile etc., require the high performance of their engines, moreover the engine is highly influenced by its inlet. Therefore it is highly significant to design the inlet reasonably in order to improve the engine performance.In this dissertation, Numerical Aerodynamic Optimization method is attempted to apply in the inlet design. Firstly, the algebraic mapping method is introduced to quickly generate the calculation grid. In order to simulate the flow, the finite volume method is adopted to solve Reynolds-averaged compressible N-S equations, and Baldwin-Lomax algebraic eddy-viscosity turbulence model (B-L model) is introduced to enclose the equations. A direct searching nonlinear optimization algorithm—complex box searching method is introduced to optimize the inlet. In order to change the model easily during the optimization, control lines of the model are parameterized, and then, a numerical aerodynamic optimization system for inlet is programmed. As a computing example, a S-shaped inlet with rectangular-to-circular sections is optimized, by using this system. The results show that the inlet performance is improved after optimization.As another portion of the dissertation, the external flow field and the inlet-coupled inner-outer flow field around a high altitude long endurance unmanned aircraft vehicle (UAV) are studied. This UAV is a flying wing aircraft. UG is adopted as a CAD tool to build the aircraft model and Fluent is introduced as a CFD analysis tool. By using these commercial soft, the flow fields of a wing, a wing-body blended configuration and corresponding modified ones are computed. The change of characteristic curves, such as lift coefficient, drag coefficient and moment coefficient, are analyzed. And the results show that the modified wing and the wing-body configuration have better performance. The flow field of a wing-body-inlet configuration is also computed. The influence between the wing and the inlet is analyzed. We find that the pressure distributing on the top and under surfaces of thewing is more homogeneous and the lift characteristic of the wing-body-inlet configuration is better than that of the wing-body configuration. The moment characteristic of the wing is changed due to the inlet influence.