环量控制扑翼式获能器气动特性的数值研究

Numerical study on the aerodynamic performance of a circulation controlled flapping wing energy harvester

提出了一种采用环量控制的新型扑翼获能技术,首先对这种扑翼在不同折合频率下的获能效率进行了数值模拟,并与传统扑翼和表面施加协同射流控制扑翼的获能效率进行了对比,发现不同工况下对翼型尾缘部施加持续射流均能有效改善翼型的气动性能,使扑翼的能量转换效率显著提高,且提升幅度优于协同射流控制方法,表明该方法具有一定的开发应用潜力。此外,针对连续射流能耗较高的缺点进一步改进了射流施加策略,建立了四种不同射流喷射控制模式,对比研究了连续式、方波式、正弦式和三角波式射流模式下扣除射流能耗后采用环量控制扑翼的获能净效率,旨在以获取最高能量转换效率为目标的前提下尽可能降低射流所需能耗。不同射流模式下的能耗分析表明,连续式环量控制模式下所需能耗最高,方波式、正弦式和三角波式的能耗依次次之,因此扣除主动控制射流的能耗后,三角波式射流喷射模式下扑翼的获能净效率最高,比传统扑翼获能效率相比提升幅度最高可达22.2%,更具实际应用价值。

A new circulation controlled flapping wing for energy harvesting was proposed in this paper.Its energy harvesting efficiency was numerically examined under different reduced frequency.The comparison of the energy harvesting efficiency among the proposed flapping wing,traditional plain flapping wing,and co-jet flow controlled flapping wing was performed.Results suggest that the application of continuous jet flow to the airfoil tail can improve the aerodynamic performance,which enhances the energy conversion efficiency of flapping wing.Greater improvement can be achieved compared with the co-jet flow controlling method,indicating the high potential of future development.Modification of jet flow patterns was adopted to reduce the energy consumption.Four jet patterns including continuous,square wave,sine,and triangular wave were developed.And their net energy harvesting efficiency was compared aiming at high energy conversion efficiency while low energy consumption by jet.Energy analysis of four jet patterns show that the highest energy consumption is observed by continuous circulation controlling pattern,and the others followed the descending order of square wave,sine,and triangular wave.Therefore,the highest energy harvesting efficiency is achieved by the triangular wave jet,which increases by 22.2%when comparing with traditional flapping wing.Great practical value can be realized.