以所研制的涡激振动能量收集器(VIVPEHS)为研究对象,联合开源软件OpenFOAM和Matlab对大涡模拟(LES)方程、二阶范德波尔(Van der Pol's)方程和高斯定律(Gauss'law)进行涡街振动俘能耦合计算,建立流机电耦合VIVPEHS数值模型,同时搭建并列双圆柱VIVPEHS俘能测试平台对数值模型开展实验验证.结果表明:升/阻力、压电梁位移、机电转换效率和尾流形态的预测值与实验数据符合良好.实验和计算结果表明,当圆柱直径(D)不变时,随着俘能距离(Sn)的增加,输出电压先增大后减小,在Sn=8D时输出电压最大;随着负载阻抗的增大,输出功率先增大后减小,存在最优负载阻抗(25000 Ω),此时并列双圆柱VIVPEHS的输出功率可达72 mW,且直接点亮21只商用LED.
RESEARCH ON VORTEX-INDUCED VIBRATION AIRFLOW ENERGY HARVESTING PROPERTIES BASED ON LES METHOD
In this paper,the energy capture characteristics of the vortex-induced vibration piezoelectric energy harvesters(VIVPEHS)with two side-by-side circular cylinders are deeply studied,Based on the open-source platform of OpenFOAM&Matlab software,coupling calculation for vortex-induced vibration is taken on LES equation,second-order Van der pol equation and Gauss law.Meanwhile,the two side-by-side circular cylinders of VIVPEHS is prepared,and a energy collection platform is established for above model verification.The numerical results show that the lift and drag force,piezoelectric cantilever displacement,electromechanical conversion efficiency and wake morphology are in good agreement with the experimental data,and this results show the accuracy and rationality of VIVPEHS numerical calculation.Moreover,the results of experiment and calculation show that the output voltage(U)first increases and then decreases with the energy capture distance(Sn)increases when the cylinder diameter(D)is certain,the U is the largest at Sn=8D.In addition,the results of experiment and calculation show that the output power(P)first increases and then decreases with the increase of load impedance(R).It is noteworthy that the P reaches 72 mW when the optimal R is 25000 Ω,and 21 commercial LEDs are lit by our device when D=0.1 m,v=2.0 m/s,Sn=8D.
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