基于模块化分区转速调控策略的多风扇风洞流场性能分析

Flow field performance analysis of the multi-fan wind tunnel based on a modular partitioned rotational speed control strategy

  • 摘要: 针对小型无人机城市低空作业风场模拟对高稳定性流场的需求,解决多风扇风洞流场均匀性不足、抗横向风干扰能力弱的问题,以3 × 3与4 × 4阵列构型的多风扇风洞为研究对象,发展了双模块、三模块分区的两种转速调控策略,通过数值仿真与3 × 3阵列构型实物实验,分析验证与优化流场流向速度均匀性和抗横向风干扰性能。结果表明,相较于整体调控策略,双模块调控策略中,外侧模块转速适度高于内侧模块可有效补偿外侧流场的扩散衰减,3 × 3与4 × 4阵列构型达到变异系数(流场速度标准差与平均速度之比)控制标准的有效距离分别延长200%和150%;相较于双模块调控策略,三模块调控策略能进一步提升中远距离流场均匀性,3 × 3与4 × 4阵列构型在中远距离流场的变异系数分别平均降低1.13%和3.11%。两种构型的外侧模块转速提升均能显著增强抗横向风干扰性能,相较于整体调控策略,3 m/s横向风干扰下双模块转速调控策略使3 × 3与4 × 4阵列构型的中心区域风速偏差率分别平均降低2.08%和3.62%。

     

    Abstract: To address the critical demand for highly stable flow fields required in the wind field simulation for urban low-altitude operations of small unmanned aerial vehicles, and to systematically solve the inherent problems of insufficient flow field uniformity and weak resistance to environmental crosswind interference typically observed in multi-fan wind tunnel flow fields, multi-fan wind tunnels with 3 × 3 and 4 × 4 array configurations are selected as the primary research objects. Specifically, two novel rotational speed control strategies based on dual-module and three-module partitioning are developed to actively manipulate the flow characteristics. Comprehensive computational fluid dynamics numerical simulations, alongside scaled physical experiments conducted specifically on the 3 × 3 array configuration prototype, were systematically carried out. These methods aim to deeply analyze, thoroughly verify and ultimately optimize the streamwise velocity uniformity as well as the dynamic resistance to crosswind interference within the generated flow fields. The quantitative results demonstrate that in the dual-module rotational speed control strategy, configuring the rotational speed of the outer module to be moderately higher than that of the inner module can effectively compensate for the natural diffusion attenuation occurring in the outer flow field. Consequently, compared with the conventional integral control strategy, under the dual-module rotational speed control strategy, the effective distances required for the flow fields of the 3 × 3 and 4 × 4 array configurations to successfully meet the rigorous coefficient of variation (the ratio of the standard deviation of velocity to the mean velocity) control standard are significantly extended by 200% and 150%, respectively. Furthermore, the three-module rotational speed control strategy can further improve the flow field uniformity specifically at medium and long distances; compared with the dual-module strategy, under the three-module rotational speed control strategy, the average coefficients of variation of the flow field at medium and long distances for the 3 × 3 and 4 × 4 array configurations are reduced by an average of 1.13% and 3.11%, respectively. Finally, increasing the rotational speed of the outer module in both configurations can significantly enhance the resistance to crosswind interference. Compared with the integral control strategy, under 3 m/s crosswind interference, the dual-module rotational speed control strategy reduces the wind velocity deviation ratios in the central regions of the 3 × 3 and 4 × 4 array configurations by an average of 2.08% and 3.62%, respectively.

     

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