Aerodynamic Property Analysis Of Aircraft-Model Propeller

In order to improve the design technique and the aerodynamic performance of UAV propellers, modern computational Fuild Dynamics(CFD) is introduced into the propeller design process and flow analysis in this thesis. Main research work carried out includes the following:Based on the lift surface method with undistorted wake model, a lift surface method with a free wake model established and the computer code to predict the performance of propellers is developed in which the velocity induced by vortex core is taken into account and an iterate relaxation algorithm of the free wake calculation is constructed. Examples show that the numerical results are in good agreement with experimental data available and the capacity is successfully extended to heavy loaded propeller.A more accurate method based on the vortex theory, taking account of the effects of compressibility and the number of blades is established and a computer code is developed.Based on the condition for Betz's minimum energy loss, a optimal design code of propeller is developed. Example is found to be much satisfactory.By means of the above CFD codes, the aerodynamic performance of a UAV propeller is examined and the technogical approach of improving the efficiency of this propeller is raised. The results of analysis show that compressible effect can make 9.5% to 12% reduction of the propeller efficiency at design point, the wake contraction reaches 10% at advanced ratio of 0.2, and the loss of strong shock and viscous effect due to the only airfoil contour blade seams to be the main season responsible to the lowefficiency of this propeller.Results and examples suggest that the CFD methods developed in the thesis...