Investigation On The Design And Flow Characteristics Of Ultra-compact Inlets

In the thesis the design and the combined computational and experimental studiesare conducted on the flow characteristics and performance for an ultra-compact UCAVinlet. Results indicate:Firstly, a cross-sectional shape generating method for subsonic inlet design isproposed according to curvature regulation. This unique method can realize thetransformation of an arbitrary entrance shape to the exit circular shape easily andsmoothly. Utilizing this method, an inlet design procedure, which can accomplish thesurface composition of subsonic inlet with complex cross-sectional shape and complexbending style quickly and graphically, is programmed.Secondly, using the three-dimensional numerical simulation, the effects of thedifferent geometrical parameters on the flow characteristics and performance of theUltra-compact inlet have been obtained. The flow distortion index at the exit issubstantially sensitive to the duct curvature while the total pressure recovery varieswithin1%. Furthermore, the good contraction in the width can be beneficial to theinternal flow structure of the inlet and reduce the flow distortion index to3.272%.Different middle section shapes have litter influence on the inlet performance.Thirdly, an ultra-compact inlet is designed basing on the parametric analysis results.The combined computational and experimental results show that the inlet has a goodperformance level. At M0=0.8,α=0°,β=0°, the total pressure coefficient can reach0.96and the circular flow distortion index is less than2.0, which meets with the operatingrequirements of the engine.Finally, experimental results indicate that the numerical method adopted with theproper turbulence model and the near-wall method can give the good prediction for thecomplex flow structure and performance of the ultra-compact inlet.