The dual-layer staggered multirotor aircraft represents a promising solution for operations in confined spaces. To address the aerodynamic interaction phenomena between rotors on different layers, this study conducts performance experiments and numerical simulations based on a Three-Rotor System Model (TRSM). By analyzing hovering rotor performance and wake structures under various configuration parameters, the aerodynamic characteristics of a single rotor simultaneously influenced by two adjacent rotors on the opposite layer are specifically investigated. The results show that radial spacing (L/R) is the dominant parameter governing the intensity of aerodynamic interaction between rotors, while rotational speed, axial spacing(H/R), rotation direction, and arm angle all exhibit weak correlations. Rotor performance exhibits unsteady periodic fluctuations, with thrust loss at the trough attributed to the deterioration of inflow conditions and reduction in blade pressure differential. The thrust loss and fluctuation amplitude of the lower rotor are significantly greater than those of the upper rotor. Furthermore, due to the combined slipstream and induced effects of the two adjacent rotors, the thrust loss of the TRSM is approximately three times that of the staggered counter-rotating rotor system. Partial rotor disk overlap leads to high distortion of the wake structure and the emergence of numerous irregular secondary vortices. Evaluations based on a non-dimensional configuration factor reveal that quadrotor, hexacopter, and octocopter systems achieve a favorable balance between overall vehicle size and aerodynamic efficiency at L/R = 1.6, 1.4, and 1.8R, respectively. This study provides a reference for the aerodynamic layout design and performance prediction of compact multirotor aircraft.
He Zhu, Zhiyang Xin, Hong Nie et al.· The Physics of Fluids· 0 citations
The staggered rotor system is a potential power system layout for compact multi-rotor aircraft designed for urban air mobility. Deeply revealing the aerodynamic interaction mechanism between rotors under the influence of key configuration parameters is crucial for the refined aerodynamic design of such aircraft. Therefore, this study experimentally measured the effects of parameters such as rotor speed, rotation direction, axial spacing (H/R), and radial spacing (L/R) on hover performance. Furthermore, by integrating smoke flow visualization technology, the transient flow field structures under different rotation directions and radial spacings were captured, with a focus on exploring their correlation mechanisms with hover performance. The results indicate that, within the experimental parameter range, radial spacing is the dominant parameter affecting the degree of aerodynamic interaction between rotors. The influence of rotation direction and axial spacing is secondary and exhibits a coupling effect with radial spacing, while the influence of rotor speed is minimal. A high correlation exists between the transient flow field structure and hover performance. At small radial spacings, the high immersion of the lower rotor in the downwash of the upper rotor causes a thrust loss of ∼50% for co-rotating and 30% for counter-rotating configurations. As L/R increases, the flow field structure stabilizes, and thrust recovers. In addition, by comparing rotation directions, it was found that the wake contraction rate shows a proportional relationship with rotor thrust loss. This study can provide a reference basis for the aerodynamic layout design and optimization of compact multi-rotor aircraft.
He Zhu, Zhiyang Xin, Hong Nie et al.· AIP Advances· 0 citations