The wing-mounted ducted fan configuration is regarded as one of the most promising power-wing integration layouts for Distributed Electric Propulsion (DEP) aircraft. Understanding and characterizing the lift-thrust coupling between the ducted fan and the wing is crucial for the design of such aircraft. To address the lack of a unified quantitative method for describing ducted fan-wing coupling effects, low-speed wind tunnel experiments are combined with numerical simulations to investigate the aerodynamic characteristics of three configurations: an isolated wing, an isolated ducted fan, and a wing-mounted ducted fan combination. The aerodynamic performance under coupled and uncoupled conditions is compared, and the improvement in lift-thrust characteristics per unit energy consumption is analyzed relative to the simple superposition of the individual components. Furthermore, coupling factors are proposed to quantitatively represent the interaction mechanism between the ducted fan and the wing, providing new key parameters for the overall design and aerodynamic layout optimization of DEP aircraft. The results show that the wing-mounted ducted fan generates significant lift augmentation at low speeds and demonstrates a distinct overall efficiency advantage in the medium-speed regime, while at higher speeds the coupling effect gradually transitions to thrust dominance, with diminishing gain. These findings establish a theoretical and methodological foundation for the integrated aerodynamic-propulsive design of distributed electric propulsion aircraft.

To reconcile the high-lift demands of short takeoff and landing (STOL) with the requirement for efficient cruise in unmanned aerial vehicles (UAVs), this paper presents a novel distributed propulsion wing lift enhancement configuration (DPWLEC) that capitalizes on aerodynamic-propulsive coupling. Based on the technical background of a specific distributed electric propulsion (DEP) STOL UAV, numerical simulations for multiple flight conditions, including STOL and cruise, are conducted. The study analyzes the aerodynamic-propulsion coupling characteristics and the evolution of the flow field structure for this configuration, revealing the influence of the propulsor number on the lift and drag characteristics. The research results indicate that during the STOL phase, the aerodynamic-propulsion coupling effect can be utilized to achieve optimal lift enhancement and drag reduction. A high lift coefficient of 2.68 is obtained simultaneously with a lift-to-drag ratio of 14.11. As the propulsor number increases from 6 to 18, the total lift increases by more than 60%. The total drag reaches its minimum value with a configuration of 12 propulsors, which represents the optimal DEP distribution for achieving the best combined lift-enhancement and drag-reduction effect. On the other hand, during the cruise phase, increasing the propulsor number effectively improves the overall lift-to-drag characteristics. After the propulsor number is increased to 18, the lift-to-drag ratio reaches up to a maximum value. These findings can provide theoretical support for the design of a new-generation of high-efficiency, high-maneuverability STOL aircraft.

The Distributed Propulsion Wing (DPW) presents prominent advantages in terms of energy conservation during flight, but the intense integration of propulsive internal flow with aerodynamic external flow brings significant design challenges. To tackle this issue, this paper undertakes a comprehensive investigation of the aero-propulsive coupling performance of the DPW under both hovering and cruising conditions, and subsequently proposes a multi-level collaboration optimization design method based on the decomposition principle. Specifically, the complex 3D surfaces of DPW are systematically dissociated into simple 2D curves with inherent relationships for design. The decomposition is achieved based on the analysis results of the aero-propulsive coupling characteristics. And a DPW design case is conducted and subsequently analyzed in order to further validate the effectiveness and feasibility of the proposed design method. It is shown that a 115.75% drag reduction of DPW can be achieved at cruise under a specified thrust level. Furthermore, the DPW exhibits inherent characteristics of consistent lift-to-drag ratio with the thrust-drag balance constraint, regardless of variations in incoming flow velocity or total thrust.

Based on the research background of advanced aerodynamic design technology of distributed hybrid electric propulsion aircraft, a loose coupling design method of rectangle ducted fan unit under engineering constraints is proposed for the propulsive/aerodynamic coupling problem of distributed propulsion wing. Through the coupling iteration of the rotor blade design optimization module influenced by the duct wall and the duct wall design optimization module based on a given rotor blade momentum source model, the complexity of the design problem is effectively reduced, and the multi-objective design optimization considering both hovering and forward flight characteristics of the rectangle ducted fan unit is achieved for this complex, multi-parameter object. Finally, the effectiveness and feasibility of the present loose coupling design method are verified through wind tunnel tests including force and pressure measurements.

Based on the distributed hybrid electric propulsion aircraft technology, we conducted numerical simulation and analysis on propulsive/aerodynamic coupled characteristics of the Distributed-Propulsion-Wing (DPW) during forward flight. Firstly, the parametric model of the DPW was constructed in the component dismantling way by using the super-elliptic equation, the fourth-order Bezier curve, and the Class Function/Shape Function Transformation (CST) arameterization method. Secondly, the numerical analysis on propulsive/aerodynamic coupled characteristics of the DPW sectional airfoil, the unit DPW section, and the whole DPW was carried out in sequence, and comparison with the conventional airfoil-wing performance parameterization. Finally, the internal relationships between the internal and external flow coupling effect and the section-wing performance similar to airfoil-wing were discussed, and suggestions on the propulsion/ aerodynamic integrated design of DPW were presented.