Airfoil Optimization Design Based On Genetic Algorithm

With the rapid development of aerospace technology and the fierce competition in the market,people have become increasingly demanding on the transport efficiency,flight quality and aerodynamic performance of the aircraft.All make the design process of aircraft face greater challenges.And the optimal design of airfoil plays an important role in the transport efficiency,flight quality and aerodynamic performance.Therefore,it is important and necessary to study the aerodynamic shape of airfoils,explore the optimal design method and develop high performance airfoil.The optimization design of airfoil includes parameterized airfoil,numerical calculation,optimization model and determination of search method.In this paper,we mainly pay close attention to Hicks-Henne function method and CST parameter method,and analyze the fitting accuracy and applicability of these methods.The aerodynamic analysis of airfoil must be carried out before starting the airfoil optimization work.This paper focuses on the airfoil NACA0012 and obtaines the charecteristics of the airfoil under the given flow condition,analyzes the influence on the results of the selection of the turbulence model and the boundary layer meshing,and the simulation results are compared with the experimental results.The optimal design platform is constructed by using computer aided optimization platform Isight to integrate with MATLAB,preprocessing tool ICEM and numerical simulation software ANSYS Fluent,and combining the genetic algorithm to explore the optimal scheme automatically.In the first example,we can use this platform combined with the Hicks-Henne function method or CST method to optimize the shape of reference airfoil and significantly improve the aerodynamic characterisitcs of the airfoil under the given flight speed and air condition.Results show these two kinds of paremeteric method have good optimization ability.In the second example,considering that the aircraft may encounter unknown factors during the flight which will greatly reduce the aerodynamic performance,we need to calculate the aerodynamic charecteristic of airfoil in multiple flight state and flow condition,and apply the multi point optimization method to design airfoil.It is found that the aerodynamic performance of the optimized airfoil is improved significantly at high speed,while good characteristics are maintained at low speed.In the third example,we take transonic airfoil RAE2822 as the optimization object,and improve significantly the aerodynamic efficiency after the optimization of the airfoil.