ABSTRACT

Achieving a unique solution for the 3D inverse design of a curved duct is a challenging problem in aerodynamic design. The centre-line curvature, and cross-sections’ area and shape of a 3D curved duct influence the wall pressure distribution. All the previous developments on the ball-spine method were limited to 2D and quasi-3D ducts, in which only the upper and lower lines of the symmetry plane were modified based on the target pressure distribution. In the present work, the ball-spine method was three-dimensionally developed for the design of curved ducts while considering the effects of cross-sectional shape and area. To validate the method, all the nodes of a 3D duct wall were iteratively corrected under the modified ball-spine method to reach the target geometry. The effects of the ball movement directions (spines) and the grid generation scheme in achieving the unique solution in inverse design were evaluated. The results showed that the new method converges to a unique solution only if the streamline-based grids are applied for the flow numerical solution, and the horizontal spines are considered as the directions for the displacement of the nodes. Finally, the wall pressure distribution of a high-deflected 3D S-shaped diffuser was three-dimensionally modified to reduce the separation, secondary flow, and flow distortion.

摘要

为弯曲管道的 3D 逆向设计实现独特的解决方案是空气动力学设计中的一个具有挑战性的问题。3D 弯曲管道的中心线曲率、横截面面积和形状会影响壁面压力分布。球脊方法的所有先前发展仅限于 2D 和准 3D 管道，其中仅对称平面的上下线根据目标压力分布进行修改。在目前的工作中，球脊法是三维开发的弯曲管道设计，同时考虑了横截面形状和面积的影响。为了验证该方法，3D 管道壁的所有节点都在修改后的球脊方法下进行了迭代校正，以达到目标几何形状。评估了球运动方向（刺）和网格生成方案在实现逆向设计中的唯一解决方案方面的影响。结果表明，新方法只有在流动数值求解中应用基于流线的网格，并且将水平脊线作为节点位移的方向时，才能收敛到唯一解。最后，对高偏转 3D S 形扩压器的壁压分布进行了三维修改，以减少分离、二次流和流动畸变。将水平脊柱视为节点位移的方向。最后，对高偏转 3D S 形扩压器的壁压分布进行了三维修改，以减少分离、二次流和流动畸变。将水平脊柱视为节点位移的方向。最后，对高偏转 3D S 形扩压器的壁压分布进行了三维修改，以减少分离、二次流和流动畸变。