基于涡致振动的内置压电悬臂梁柔性圆管能量收集结构的数值模拟

为了分析基于涡致振动的内置双晶压电悬臂梁柔性圆管压电能量收集结构的运动机理和性能,对其进行了流固耦合和压电耦合数值模拟。对一端固定一端自由的柔性圆管进行了流固耦合数值模拟,在流速为1.1 m/s,柔性圆管直径D为0.03 m,高度为0.11 m时,该结构的涡致振动能够处于稳定的锁频状态。对折合速度为1.3～4.0,中心距为3D～6D的前置等径刚性圆柱阻流体的柔性圆管进行了流固耦合和压电耦合的数值模拟。研究结果表明,柔性圆管的振幅响应和压电悬臂梁的开路输出电压均随折合速度的增大而增大,在仿真参数范围内,结构的振幅响应和输出电压时程曲线均为稳定的周期函数。当折合流速为4.0,中心距为5D时,结构产生的振幅最大,为2.38×10~(-3) m,电压为6.75 V。证明了根据不同流速,可以通过调节圆管的结构参数以使涡致振动产生锁频现象,从而得到最大振幅和输出电压,进而可将其用于电能收集,为下一步能量收集结构的实验制备提供了理论参考。

Numerical Simulation of Energy-Collecting Structure of Flexible Circular Tube with Built-in Piezoelectric Cantilever Beam Based on Vortex Induced Vibration

In this paper, the motion mechanism and performance of a flexible circular tube piezoelectric energy harvesting structure with built-in bimorph piezoelectric cantilever beam based on vortex-induced vibration are analyzed. The fluid-structure coupling and piezoelectric coupling numerical simulation were carried out. Firstly, the fluid-structure coupling numerical simulation of the flexible circular tube with one fixed end and the other free end was carried out. When the velocity was 1.1 m/s, the diameter of the flexible circular tube was 0.03 m and the height was 0.11 m, the vortex-induced vibration of the structure could be in a stable resonance state. Then the fluid-structure coupling and piezoelectric coupling of the flexible circular tube with the reduced velocity of 1.3 ~4.0 and the center distance of 3 D ~6 D were simulated. The results show that the response amplitude of flexible circular tube and the open circuit output voltage of piezoelectric cantilever beam increase with the reduction velocity, and the time-history curve of response amplitude and output voltage are stable periodic functions within the range of simulation parameters. When the reduced velocity is 4.0 and the center distance is 5 D, the amplitude generated by the structure is the largest, 2.38×10-3 m, and the voltage is 6.75 V. Therefore, it is proved that according to flow rates, the structure parameters of the circular tube can be adjusted so as to produce the phenomenon of resonance in vortex-induced vibration, and then the maximum amplitude and output voltage are obtained, which can provide a theoretical reference for the experimental preparation of energy harvesting structure in the next step.