基于N-S方程的民航机翼双目标优化设计

提出了一种可用于民航机翼的双目标优化设计方法.优化中的设计变量为给定机翼沿展向若干个剖面的厚度与扭角,优化目标为固定升力系数下的升阻比和机翼容积.采取N-S(Navier-Stokes)方程作为流场求解器,Powell方法作为优化求解方法,对Lockheed-AFSOR Wing A 某民航机翼进行了优化设计.在马赫数为0.6217条件下,Wing A 机翼双目标优化结果优于单目标优化结果.对某实际应用的民航机翼在巡航马赫数为0.78、升力系数为0.48的优化结果也表明,该方法能有效提高机翼升阻比和容积.相对初始机翼,双目标优化机翼最大相对厚度在翼根处增大,翼梢处减小,扭角绝对值相对初始机翼沿展向均减小.该双目标优化设计方法优于常规的单目标优化设计方法,可以为民航机翼的工程设计提供有益的参考.

Bi-objective optimization design of civil transport wing using N-S equations

A bi-objective(BO) optimization method was proposed for civil transport wing design.The thickness and twist angle of wing sections along wingspan were chosen as the optimal design factors,the two goals were the lift-to-drag ratio and wing's volume at fixed lift coefficient.Navier-Stokes(N-S) equations were used as flow field solver and Powell method was used as optimization design tool,the Lockheed-AFSOR Wing A and some civil transport's wing were computed as cases.Cases on Wing A at 0.621 7 Mach number condition showed that the BO optimization results were better than the single one.Case on civil transport wing at the cruise Mach number of 0.78 and the lift coefficient of 0.48 also showed that the BO optimization method could lead to higher liftto-drag ratio and bigger wing volume.Comparing with the original wing,the BO optimal wing's maximum thickness-to-chord ratio was bigger at the root and smaller at the tip,and the absolute value of twist angles were all smaller.The BO optimization design method is better than the common single objective optimization design method,and could provide some value for civil transport engineering design.