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Improving the performance of ducted fans for VTOL applications: A review

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Abstract

Ducted fans have been widely used in VTOL aircraft due to the high propulsion efficiency and safety. The efficiency and stability of ducted fans deteriorate in some flight conditions such as hovering in crosswinds or ground effect. It is necessary to optimize the ducted fan’s structures or apply flow control methods for better adaptions to the typical conditions. This paper presents a detailed review on the ducted fan technology for VTOL applications, especially the methods for improving its efficiency and stability. We first simplified the classification categories based on boundary conditions instead of flight conditions, since the new classification method covers more situations and is easier to distinguish flow field characteristics. The flow characteristics, thrust properties and the optimal structures under different boundary conditions were summarized and discussed. Finally, new configurations and flow control methods for increasing the efficiency and stability were introduced. The newly proposed integration design between the ducted fan and the motor was emphasized for increasing the power density of the ducted fans. This review would be helpful to improve our understanding of the relationship between the structures, flow characteristics and thrust properties of ducted fans under different flight conditions, and inspires scientists to design high-efficiency and high-stability propulsion systems with ducted fans.

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  1. These authors contributed equally to this work.

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  1. State Key Laboratory of Automotive Safety and Energy, School of Vehicle and Mobility, Tsinghua University, Beijing, 100084, China

    YuPing Qian, YiWei Luo, XuanYang Hu, ZeZhi Zeng & YangJun Zhang

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  1. YuPing Qian
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Correspondence to YangJun Zhang.

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This work was supported by the National Key Research and Development Program of China (Grant No. 2020YFC1512500), the Advanced Aviation Power Innovation Institution, the Aero Engine Academy of China, and Tsinghua University Initiative Scientific Research Program.

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Qian, Y., Luo, Y., Hu, X. et al. Improving the performance of ducted fans for VTOL applications: A review. Sci. China Technol. Sci. 65, 2521–2541 (2022). https://doi.org/10.1007/s11431-021-2110-x

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