Exergy Based Design Methodology For Multi-Objective Airfoil Shape Optimization

Airfoils have a vital impact on aerodynamic performance of aircrafts as its lifting systems. Traditional airfoil shape optimization methods mostly maximize lift-drag ratio as optimization objectives and do not take energy efficiency into account. It usually results in optimized airfoils satisfied the lift-drag ratio requirement, but with greater energy losses.In this thesis, we combine an exergy-based method with airfoil shape optimization to demonstrate the impact of exergy on aerodynamics design. We analyze an open system energy transformation process, describe the exergy balance equation and derive entropy generation rate formula of an open system theoretically. And then we have developed a UDF function for Fluent to compute the entropy generation rate.We use the CST parametric method to model the airfoil configuration and combine the Fluent package code and NSGA2 code respectively, to compute aerodynamics quantities such as lift, drag and entropy generation rate in varying working conditions. We have obtained the optimized airfoils, that maximize lift-drag ratios and minimize entropy generation rates as optimization objectives. The optimized results show that the aerodynamic performance is improved in the increase of lift-drag ratio and the decrease of entropy generation rate, compared with a standard airfoil.