This paper addresses the design of swirl recovery vanes for propeller propulsion in tractor configuration at cruise conditions using numerical tools.Amultifidelity optimization framework is formulated for the design purpose, which exploits low-fidelity potential flow-based analysis results as input for high-fidelity Euler equation-based simulations. Furthermore, a model alignment procedure between low- and high-fidelity models is established based on a shapepreserving response prediction algorithm. Two cases of swirl recovery are examined. The first is the swirl recovery by the trailing wing, which leads to a reduction of the lift-induced drag. This is achieved by the optimization of the wing twist distribution. The second case is swirl recovery by a set of stationary vanes, which leads to production of additional thrust. In the latter case, four configurations are evaluated by locating the vanes at different azimuthal and axial positions relative to the wing. An optimum configuration is identified where the vanes are positioned on the blade-downgoing side downstream of the wing. For the configuration and conditions examined, the wing twist optimization reduces the induced drag by 3.9 counts (5.9% of wing-induced drag), whereas the optimized 4-bladed SRVs lead to an induced-drag reduction of 6.1 counts (9.2% of wing-induced drag). @en

This paper addresses the design of swirl recovery vanes for propeller propulsion in tractor configuration at cruise conditions using numerical tools. A multi-fidelity optimization framework is formulated for the design purpose, which exploits low-fidelity potential flow-based analysis results as input for high-fidelity Euler equation-based simulations. Furthermore, a model alignment procedure between low-and high-fidelity models is established based on the shape-preserving response prediction algorithm. Two cases of swirl recovery are examined, i.e. swirl recovery by the trailing wing which leads to a reduction of the lift-induced drag, and swirl recovery by a set of stationary vanes (SRVs) located inside the propeller slipstream which leads to production of additional thrust. In the first case, the optimization of the wing circulation distribution is achieved by twist optimization. The resulting reduction in induced drag is 5.9% out of 66.1 counts at the design cruise condition of C_L= 0.5. In the case of the SRV design, four configurations are evaluated by locating the vanes at different azimuthal and axial positions relative to the wing. The interactions between SRVs and wing are discussed and an optimum configuration is identified, where the vanes are positioned on the blade-downgoing side downstream of the wing. In this configuration, the wake and tip vortices of the vanes have negligible effect on the wing circulation distribution and consequently introduce no extra drag. With a blade count of 4, the total system drag has decreased by 6.1 counts, which is equivalent to 2.4% of propeller thrust.

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