摘要
实际工程中的翼型设计通常是对某一性能良好的基本翼型进行局部改进以满足特定的工程要求。文中将 N- S方程流场分析程序和序列二次规划结合起来 ,发展了一种实用的翼型优化设计方法 ,用以提高基本翼型在多个设计点、在多种约束条件下的气动性能。由 N- S方程计算得到的升力、阻力等气动参数构成目标函数 ,数值优化程序对其进行最优化。超临界翼型的设计算例表明 ,文中发展的翼型优化方法设计质量高 ,所需机时少 ,易于实施 ,有较大的工程应用价值。
Airfoil design has matured to the point that the designer can select from airfoil database a baseline airfoil that is close to satisfying his design requirements and then optimize it to obtain the practical design of the airfoil that satisfies the design requirements. We propose using Reynolds averaged Navier Stokes equations and SQP (Successive Quadratic Programming) method to do the optimization of a selected baseline airfoil and we are confident that our approach is better than existing approaches to practical design of airfoil. Section 1 describes in detail our practical procedure of multi point airfoil design. Subsection 1.1 illustrates the design variables. Subsection 1.2 discusses the Navier Stokes flow solver; Fig.1 shows the pressure distribution for supercritical airfoil RAE2822, obtained with Reynolds averaged Navier Stokes equations, under the following flow conditions: M =0.730, Re =6.5×10 6 and α =2.78°; the calculated results agree very well with test data. Subsection 1.3 presents the multi point optimization algorithm which performs two tasks: (1) transfer of multiple objective functions into single objective function by Linear Weighted Sum Method; (2) optimization of single objective function by SQP method. In section 2, the design procedure was used for the optimization of RAE2822 airfoil at two design points, subjected to three design constraints. Table 1 indicates that at the primary and the secondary design points the optimization gives drag reductions of 10.26% and 2.00% respectively, with the constraints approximately satisfied. Figs. 2(a) and 2(b) show that the pressure distribution of optimized airfoil has obvious supercritical characteristics. Fig. 2(c) compares the polar curve of baseline airfoil RAE2822 (solid curve) with that of optimized design (dotted curve); the lift/drag characteristics of the optimized airfoil are better than those of the baseline airfoil in a large area near M =0.730, Re =6.5×10 6, and C l =0.70. Fig.2(d) shows that the geometry of optimized airfoil is only slightly different from that of the baseline airfoil. The results were obtained on a Pentium 3 PC in 16 hours and 36 minutes, at only 104 calls for Navier Stokes solver. With higher design quality, easier programming and less expense, this procedure is suitable for the improvement design of an existing baseline airfoil to meet specified engineering requirements.
出处
《西北工业大学学报》
EI
CAS
CSCD
北大核心
2003年第5期523-527,共5页
Journal of Northwestern Polytechnical University
基金
国防科技重点实验室基金 (99JS5 1.2 .1.HK2 30 1)资助
关键词
基本翼型
N—S方程
优化设计
序列二次规划(SQP)
baseline airfoil, Navier Stokes equations, optimization design, SQP (Successive Quadratic Programming)
