Research On Aerodynamic Design Of Civil High Bypass Ratio Fan Blades

The fan is the important part of turbofan engine. The focus of this paper is researching theaerodynamic performance of civil high bypass ratio fan blade which uses the optimization designplatform of the laboratory to design a type of high bypass ratio fan blade on the basis of the researchgroup’ work. Then further make a self-design of high bypass ratio fan blade and optimized designaccording to summary optimization results.This paper is mainly divided into the following three parts:The first part is studying aerodynamic performance of a certain type of high bypass ratio fan thatexists and making an optimized design. First is to carry on numerical simulation using commercialsoftware Numeca and understand its flow characteristics through the analysis of flow field. Second isto use numerical optimization method combined with the direct problem calculation basing on theoptimization design platform of the laboratory to realize the combination optimization includingstacking line, meridian plane, profiles and chord length along radial direction. Numerical optimizationuses parallel genetic algorithm based on LAN. Flow field calculation uses the method of Dentonviscous body force. After optimized design, blade flow range that can steady work significantlyincreases and the pressure ratio is approximately constant, which efficiency is improved by more than0.5percentage in most rang of the work flow and the highest efficiency has increased nearly1percentage. The optimization examples verified the feasibility and efficiency of the optimizationmethod as well.The second part is about the initial design of high bypass ratio fan. Quasi three dimensional bladedesign software of the laboratory is adopted which is based on S1/S2two stream surfaces as the basicidea, realizes the high bypass ratio fan blade of the initial design. And Numeca software is used toinitially check calculation and analyze performance of the initial blade, which also verifies thefeasibility and effectiveness of the design software. The initial design of high bypass ratio fan blade isbased on the fan blades in order to ensure the same overall performance under the circumstance ofreducing the rotating speed of the blade.The third part is optimization design on the initial design fan. First is to make an arbitrary surfaceof revolution optimization design on the initial design blade to get a good blade. Second is to make a3D optimization design on the stacking blade of arbitrary surface of revolution optimization design toimprove its aerodynamic performance.