Journal of Zhejiang University

Journal of Zhejiang University SCIENCE A

Accepted manuscript available online (unedited version)

Aerodynamic optimization of an externally tilted hex-rotor hovering unmanned aerial vehicle

Author(s): Hengxing YANG, Yao LEI, Jifu HU, Guobin SHI
Affiliation(s): School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350116, China; more
Corresponding email(s): yaolei@fzu.edu.cn
Key Words: Unmanned aerial vehicle (UAV); Aerodynamic performance; Hover efficiency; Inter-rotor interference; Computational fluid dynamics (CFD)

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Hengxing YANG, Yao LEI, Jifu HU, Guobin SHI. Aerodynamic optimization of an externally tilted hex-rotor hovering unmanned aerial vehicle[J]. Journal of Zhejiang University Science A,in press.Frontiers of Information Technology & Electronic Engineering,in press.https://doi.org/10.1631/jzus.A2500352

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author="Hengxing YANG, Yao LEI, Jifu HU, Guobin SHI",
journal="Journal of Zhejiang University Science A",
year="in press",
publisher="Zhejiang University Press & Springer",
doi="https://doi.org/10.1631/jzus.A2500352"
}

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%T Aerodynamic optimization of an externally tilted hex-rotor hovering unmanned aerial vehicle
%A Hengxing YANG
%A Yao LEI
%A Jifu HU
%A Guobin SHI
%J Journal of Zhejiang University SCIENCE A
%P 610-624
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doi="https://doi.org/10.1631/jzus.A2500352"

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T1 - Aerodynamic optimization of an externally tilted hex-rotor hovering unmanned aerial vehicle
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A1 - Yao LEI
A1 - Jifu HU
A1 - Guobin SHI
J0 - Journal of Zhejiang University Science A
SP - 610
EP - 624
%@ 1673-565X
Y1 - in press
PB - Zhejiang University Press & Springer
ER -
doi="https://doi.org/10.1631/jzus.A2500352"

Abstract
Chinese Summary
Academic Network
Reviewer Comment

Abstract: We investigate the aerodynamic performance and flow field synergy of an externally tilted hex-rotor unmanned aerial vehicle (UAV) in hovering mode, aiming to enhance its hovering efficiency through tailored flow interactions. Experimental measurements and computational fluid dynamics (CFD) simulations are combined to examine the effects of rotor spacing ratio (i=0.50–0.83) and tilt angle (θ=0°–40°) on thrust, power consumption, figure of merit (FM), and power loading (PL), with particular emphasis on the underlying aerodynamic coupling mechanisms. The results demonstrate that the optimal configuration (i=0.56, θ=24°) achieves a 5.43% thrust increase, a 2.73% power reduction, an 11.15% improvement in FM, and a 3.77% enhancement in PL compared to a conventional planar configuration. Flow field analyses reveal that moderate tilting (θ=24°) promotes downwash convergence and strengthens vortex coupling, thereby increasing the effective flow velocity while minimizing the inter-rotor turbulent interference. Furthermore, the spacing ratio of i=0.56 effectively balances the reduction of detrimental flow interference with the promotion of beneficial flow interactions, as evidenced by stabilized primary vortex structures and constrained recirculation zones in the CFD simulations. This work highlights how the aerodynamic optimization of non-planar rotor configurations is critically dependent on the synergistic control of tilt-induced flow deflection and spacing-dependent interference, and establishes a theoretical framework for understanding multi-rotor flow dynamics; as such, the findings may aid the design of efficient rotor systems for UAVs.

具有外偏转构型的六旋翼飞行器悬停气动优化

作者：杨恒星¹，雷瑶^1,2，胡继府¹，时国宾³
机构：¹福州大学，机械工程及自动化学院，中国福州，350116；²福州大学，流体动力与电液智能控制福建省高校重点实验室，中国福州，350116；³中山大学，智能工程学院，中国深圳，518000
目的：本文旨在通过实验测量与计算流体动力学（CFD）模拟相结合的方法，系统研究旋翼间距比（i=0.50~0.83）与倾斜角（θ=0°~40°）对具有外偏转构型的六旋翼无人机在悬停状态下气动性能的影响，特别是推力、功率消耗、品质因数（FM）与功率负载（PL）的变化规律，并深入揭示倾斜构型下旋翼间流动相互作用的协同机制。研究致力于优化旋翼配置，通过提升下洗流汇聚与涡流耦合效应，抑制不利的流动干扰，从而提高悬停效率与有效载荷能力，为非平面多旋翼系统的气动设计与流动控制提供理论与实验依据。
创新点：1.揭示了外倾斜六旋翼相对于传统平面构型提升悬停效率的流体动力学机制；2.阐明了旋翼间距比与倾斜角在调控推力生成中的协同作用机制；3.确定了外倾斜六旋翼在悬停状态下的气动最优构型参数组合。
方法：本研究采用实验测量与CFD模拟相结合的集成方法。首先，通过参数化实验，在定制测试台上系统测量不同旋翼间距比和倾斜角下的推力、扭矩和功率，并计算品质因数和功率负载等性能指标。同时，利用高保真瞬态CFD模拟对相同工况进行数值计算，并通过网格无关性分析和实验数据验证确保模型的可靠性。该方法通过实验获取宏观性能数据，并借助CFD深入揭示下洗流汇聚、涡结构演化等内部流场协同机制。
结论：1.适度的外倾斜（θ=24°）能通过流场协同有效提升悬停效率；该角度促进了旋翼下洗流的汇聚，增强了轴向流速与推力；同时强化了旋翼间的涡流耦合，稳定了主涡结构，从而抑制了湍流损失。2.旋翼间距比与倾斜角存在关键协同效应；最优间距比（i=0.56）在减少有害流动重叠的同时，为有益的流场耦合创造了条件；与θ=24°结合，可实现稳定的压力梯度和涡结构，而过大倾角会破坏此平衡。3.确定了气动最优构型（i=0.56,θ=24°）；相比传统平面构型，该配置实现了推力提升5.43%、功耗降低2.73%、品质因数提高11.15%、功率负载增强3.77%的综合优化，其流场表现为稳定的涡动力学和受约束的回流区。

关键词组：无人机；空气动力学性能；悬停效率；转子间干扰；计算流体动力学

Darkslateblue:Affiliate; Royal Blue:Author; Turquoise:Article

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