In order to achieve a rapid design of intermediate compressor/turbine duct (ICD/ITD) geometries for turbofan engines, a novel preliminary design method is proposed in this paper. An arc-line-arc configuration is adopted to design diffused contour, which is the shroud for an ITD and the hub for an ICD. Then undiffused contour is built under a specified width along the duct mean line. It is also corrected by considering strut blockage effects. A parametric study is conducted for an ITD using two-dimensional (2D) axisymmetric CFD simulations to reasonably select arc radii of the diffused contour. Furthermore, an empirical formulation between the arc radii and flow Reynolds number is established. Finally, two cases, including an ICD and an ITD, are redesigned. The performance of designed geometries is compared to their baseline structures via 3D CFD simulations. Results indicate that the total pressure loss coefficient is decreased by 7.9% and 5.5% by the redesigned ICD and ITD, respectively, without sacrificing diffusion performance. Flow filed check reveals that mitigated pressure gradient is obtained for the two cases. This validates the effectiveness and feasibility of the proposed preliminary design method.

为了实现涡轮风扇发动机中间压气机/涡轮管道 (ICD/ITD) 几何形状的快速设计，本文提出了一种新颖的初步设计方法。采用弧线弧配置设计扩散轮廓，它是ITD的护罩和ICD的枢纽。然后沿着管道中线在指定宽度下构建未扩散的轮廓。它也可以通过考虑支柱阻塞效应来纠正。使用二维 (2D) 轴对称 CFD 模拟对 ITD 进行参数研究，以合理选择扩散轮廓的圆弧半径。此外，建立了弧半径和流动雷诺数之间的经验公式。最后，重新设计了两个案例，包括 ICD 和 ITD。通过 3D CFD 模拟将设计几何形状的性能与其基线结构进行比较。结果表明，在不牺牲扩散性能的情况下，重新设计的 ICD 和 ITD 的总压力损失系数分别降低了 7.9% 和 5.5%。流场检查表明，两种情况都获得了减轻的压力梯度。这验证了所提出的初步设计方法的有效性和可行性。