宏压电纤维致动的水下推进器性能及机理

提出了一种宏压电纤维复合材料(macro fiber composite, 简称MFC)致动的仿鲹科身体/尾鳍(body or caudal fin,简称ＢＣＦ)水下推进器。利用搭建的实验平台测试了不同驱动电压条件下推进器的摆动性能，推进器在峰峰值为1 000 V，频率为17.7和3 Hz的激励电压下分别取得空气中最大摆幅峰峰值为45 mm，水下最大摆幅峰峰值13 mm。借助计算流体力学(computational fluid dynamics,简称ＣＦＤ)研究了仿生推进器在稳定摆动过程中流场特性和尾迹旋涡的分布情况，从推进器端部观察到的“反卡门涡街”结构揭示了仿生推进器的流体动力学机制和摆动式推进机理。推进器端部在x方向上的平均推进力可达1.5mN。研究成果对压电纤维致动器在仿生推进器的优化设计和提高其推进效率提供技术支持

Oscillation Performance and Propulsion Mechanisms of Biomimetic Underwater Propeller Actuated by Macro Fiber Composites (MFC)

Fiber-based piezoelectric composites offer the advantages of excellent flexibility and geometric scalability in the applications of bio-inspired locomotion and flexible actuation. A biomimetic underwater propeller mimicking the body or caudal fin (BCF) oscillating behavior of carangidae fish is proposed, and macro fiber composites (MFC) are used as actuators. Oscillation performance of the propeller is presented at different actuation voltage levels. Experimental results show that the maximum oscillating displacement of the proposed propeller in air is 45 mm (peak-to-peak value), with the actuation of 1 000 V (peak-to-peak value) at 17.7 Hz. The distributions of flow field and vortexes around the propeller tip in a steady oscillating cycle are obtained by the use of computational fluid dynamics (CFD) technologies. The anti-Karman vortex street phenomenon is revealed during the time sequence of vortices generation, expand, shed and breakdown processes. Meanwhile, a jet flow ejecting downstream the tip between the two counter-rotating vortices is observed. Accordingly, the propulsion locomotion of the propeller is achieved with the reactive force of the jet flow. Thus, the propulsion mechanism of the proposed biomimetic underwater propeller is demonstrated. The average propulsion force at the end of the propeller in the x direction is up to 1.5 mN.