基于目标压力分布优化的翼型反设计方法研究

【作者】 李焦赞；

【导师】 高正红；

【作者基本信息】 西北工业大学 ， 飞行器设计， 2007， 硕士

【摘要】 先进跨音速翼型的设计研究成为当前设计空气动力学的重要研究方向，而翼型设计方法本身的发展也希望能够跟上CFD技术总的发展步调。飞行器气动设计方法可简略分成两类：直接优化方法和反设计方法。直接优化方法直接以飞机气动性能为目标进行外形设计，可以按工程上的要求对型面提出各种约束，但其缺点是计算工作量大，尤其是针对本身计算量就很大的气动分析问题。反设计方法求解经典的空气动力反问题，即由给定的目标压力分布求解满足这一压力分布的气动外形，通常比直接优化设计方法省时高效，但也存在难以给定合理的目标压力分布的问题。通过对这两类设计方法中比较典型的两种方法的对比研究，即基于余量修正原理的翼型反设计方法和遗传优化设计方法，了解到了两种方法的优缺点。 本文在分析两种气动设计方法优缺点的基础上，以Takanashi提出的基于正反迭代、余量修正原理的翼型反设计方法为基础，针对翼型反设计方法中目标压力分布难以给定的问题，进行了反设计方法与优化方法相结合的研究，建立了翼型反设计方法中定义目标压力分布的遗传优化模型。首先提出翼型表面压力分布参数化方法，选择遗传算法作为压力分布的优化算法并对其做有约束优化，将优化结果作为反设计的目标压力分布，减小设计中的经验性影响；然后应用华俊等开发发展的基于Takanashi余量修正原理的反设计方法，通过反设计得出翼型气动外形，发挥反设计高效省时的优点。翼型设计结果表明，这种方法是可行的。更多还原

【Abstract】 The design techniques of modern transonic airfoils have been the important goals of design aerodynamics, and the airfoil design methods themselves are also hoped to match the overall progress of CFD. The aerodynamic design methods are categorized into two classes simply: direct optimization methods and inverse design methods. The direct optimization methods minimize (or maximize) a given aerodynamic object function directly with the constraints gotten from the project. Such procedures, however, become extremely expensive at computation quantity. The inverse design methods solve the classical inverse problem of determining the aerodynamic shape that will produce given pressure distribution. However, they leave the users with the problem of translating the design goals into properly defined pressure distribution exhibiting the required aerodynamic characteristics. Here we have studied two classical design methods with compare, the iterative residual correction inverse design method and the genetic algorithm optimization method.Since the problem of hard to specify the target pressure distribution for the airfoils inverse design method, we try to carry out the research on combining the inverse methods and the optimization methods. A genetic algorithm has been applied to optimize target pressure distribution for inverse design methods. Pressure distributions around airfoils are parameterized and the airfoil drag is minimized under constraints on lift, airfoil thickness, and other design principles. Once target pressure distributions are obtained, corresponding airfoil geometries can be computed by an inverse design code coupled with a Navier-Stokes solver. The presented results of designed airfoil show that the method developed is feasible.更多还原