基于流机电多物理场耦合下涡激振动能量收集模型及特性

发布时间：2018-01-23 09:50

本文关键词： 涡激振动流机电耦合能量收集模型计算方法能量收集特性　出处：《重庆大学》2014年博士论文　论文类型：学位论文

【摘要】：随着微能源、MEMS、无线传感器网络等技术的飞速发展，使用压电转换振动能量收集原理(PEH)收集流体机械能成为近年的研究热点。压电振动能量收集作为一种有效的环境能源收集技术，受到了国内外广泛关注，主要应用于健康监控、无线传感器系统、微小型电机耦合器件等领域。因此，研究压电振动能量收集技术具有广阔的应用前景和实用价值。涡激振动(VIV)现象可将流动能转化为振动能。涡激振动中的锁定效应可有效增加振动强度，从而提高能量收集的效率，具有重要研究价值。然而目前针对涡激振动能量收集技术(VIVPEH)的研究极少，特别是针对流场流动-机械振动-带电回路(流机电)多物理场耦合模型建立和求解方法的研究鲜有报道。因此，本文针对流机电多物理场耦合涡激振动能量模型及特性的研究具有非常重要的学术意义和价值。本文首先针对涡激振动中存在的流固耦合问题，进行了流固耦合涡激振动的数学模型建立和求解方法的研究。其次，进行了如何将涡激振动现象与压电能量收集系统进行流机电多物理场耦合的研究，重点进行了如何建立流机电多物理场耦合数学模型以及如何对该模型进行求解的研究。然后，本文基于以上流机电多物理场耦合模型与方法，对光滑圆柱、PTC圆柱、带攻角方柱、不同顶角三角柱等几种不同形状柱体VIVPEH在不同外接负载条下，不同来流速度时的振动响应、流场特性和能量收集特性进行了深入研究。得出了以下主要成果： ①首次建立了一种计算流固耦合VIV动态响应的数值计算方法，该方法可以将流体连续性方程和N-S方程与柱体振动方程同时求解，，并且可以克服传统动网格技术的畸变和扭曲等问题。为验证流固耦合涡激振动求解方法，首先使用静态柱体绕流的方法，验证了本文外流场求解数值方法在求解大范围雷诺数时的准确性。然后，在风洞实验中，通过测试不同来流速度下的光滑圆柱VIV振幅，与利用本文数值求解方法所得结果进行对比，验证了本文VIV流固耦合数值求解方法的准确性。 ②基于压电悬臂梁能量收集的集总参数模型，同时考虑钝体的振动、外部流场的流动和压电回路三者的相互作用，首次建立了将钝体绕流涡激振动作为动态载荷，带动压电悬臂装置进行振动并且收集涡激振动能量的数学模型，并提出了该模型的数值求解方法。首先，使用系数矩阵法，求解由机电耦合钝体振动方程的线性形式和高斯定律组成的方程组，求得了外接负载对钝体振动系统的负反馈作用，从而消除了振动方程中的电压项，使得振动方程降维，从而可以使用本文的流固耦合VIV数值计算方法中进行求解，并得出振动响应和流场特性；然后使用基于正弦波的准稳态理论，求解高斯定律，得到能量收集电压和功率输出的一般形式。最后，将振动振幅的计算结果代入电压输出和功率输出的表达式中，即可获得流机电多物理场耦合的涡激振动能量收集特性。 ③基于流机电多物理场耦合涡激振动能量收集数学模型和求解方法，首次获得了流机电多物理场耦合下，光滑圆柱、PTC圆柱VIVPEH在不同外接电阻对振动系统的负反馈下的涡激振动响应及能量收集特性。机电耦合阻尼会随电阻增大而先增大后减小，而机电耦合频率在经历一个阶跃性上升后重新达到平稳。振幅曲线中观察到了振幅曲线中的三个分支，光滑圆柱与PTC圆柱的振幅最大值较为接近，且PTC圆柱的锁振区域得到了延后。光滑圆柱与PTC圆柱VIVPEH的输出电压和功率最大值较为接近。 ④获得了不同攻角方柱和不同顶角三角柱VIVPEH的能量收集特性，结果表明方柱VIVPEH能量收集特性要优于圆柱，而三角柱VIVPEH要优于方柱。攻角对方柱振动振幅最大值和锁振区域有着较大影响，最大振幅、电压、功率输出出现在攻角为45°时。三角柱VIVPEH的能量收集能力要明显强于圆柱和方柱，锁振区域和电压、功率输出最大值均得到了提高。 ⑤在对比多种柱体VIVPEH的能量收集特性的基础上，发现60°顶角三角柱VIVPEH的能量收集能力最强，最有利于涡激振动能量收集。60°顶角三角柱较之PTC圆柱的最大电压提升了176.23%，最大功率提升了661.8%。
[Abstract]:With the rapid development of micro energy, MEMS, wireless sensor network technology, using the piezoelectric conversion principle of vibration energy collection (PEH) collection of fluid machinery can become a research hotspot in recent years. The piezoelectric vibration energy harvesting as an effective environmental energy harvesting technology, has attracted wide attention at home and abroad, mainly used in health monitoring. Wireless sensor system, the field of micro motor coupler. Therefore, the research of piezoelectric vibration energy harvesting technology has a wide application prospect and practical value. The vortex induced vibration (VIV) phenomenon can be transformed into vibrational energy flow. The locking effect of vortex induced vibration in vibration can effectively increase the strength, so as to improve the efficiency of energy collection and it has important research value. However, the vortex induced vibration energy harvesting technologies (VIVPEH) few studies, especially for electric circuit with flow - mechanical vibration (electromechanical flow) There are few reports on the establishment and solution methods of multi physical field coupling models. Therefore, it is of great academic significance and value to study the energy model and characteristics of multi physics field coupled vortex induced vibration.
Aiming at the existence of vortex induced vibration of the fluid solid coupling problem, studied the mathematical model of fluid solid coupling of vortex induced vibration is established and the solving method. Secondly, for how the vortex induced vibration phenomenon and the piezoelectric energy harvesting system flow research of electromechanical coupled multi physics field, focusing on how to establish flow and multi field coupling mathematical model and study how to solve the model. Then, the above flow of electromechanical coupled multi physics model and method based on smooth cylindrical, PTC cylindrical, square columns with angle of attack, different angle three prism shapes column VIVPEH in different load. The vibration response of the different flow speed, flow characteristics and energy collection characteristics were studied. The following main results:
For the first time established a calculation method for the calculation of fluid solid coupling dynamic response of VIV value, the method can make the fluid continuity equation and N-S equation and the cylinder vibration equations are solved simultaneously, and it can overcome the traditional technique of dynamic mesh distortion and distortion problems. The fluid solid coupling method for vortex induced vibration test method the first use of static column flow, verify the accuracy of the flow field numerical method in solving a wide range of Reynolds numbers. Then, during the wind tunnel experiments, through the test of different flow velocity under the smooth cylindrical VIV amplitude, the results were compared with the use of numerical methods in this paper, to verify the accuracy of the VIV a numerical method for solving the flow solid coupling.
The lumped parameter model of piezoelectric cantilever beam energy collection based on considering the vibration blunt body, interaction between external flow field and piezoelectric loop three, first established the vortex induced vibration action as dynamic load, driven by the mathematical model of piezoelectric cantilever device for vibration and vortex collection the vibration energy, and puts forward the numerical solution of the model. First, using the coefficient matrix method, equations composed of electromechanical coupling vibration equation of the linear form of the bluff body and Gauss's law, the external load feedback effect of vibration system of the bluff body is obtained, which eliminates the voltage vibration equation. So, the vibration equation of dimensionality reduction, which can be used in the numerical calculation method of fluid solid coupling in VIV is solved, and the response and flow characteristics of vibration; and then use the quasi steady state theory based on sine wave, the solution of Gauss The general form of energy collection voltage and power output is obtained. Finally, the calculation results of vibration amplitudes are substituted into the expressions of voltage output and power output, and the energy harvesting characteristics of vortex induced vibration of multi electromechanical coupling of flow and electromechanical can be obtained.
The multi field coupling vortex vibration energy collection mathematical model and solving method of electromechanical flow based on the obtained flow electrical multi physics coupling, cylindrical, cylindrical PTC VIVPEH resistor under different external vibration system of the negative feedback of the vortex induced vibration and energy harvesting characteristics of electromechanical coupling damping will begin. Increases and then decreases with the increase of resistance, and the electromechanical coupling frequency after a step up again after reaching steady. The amplitude curves were observed in the three branches of the amplitude curves, maximum amplitude and smooth cylindrical PTC cylinder is closer, and the vibration of PTC cylindrical lock region has been delayed. The output voltage and the maximum power of PTC and VIVPEH of the cylindrical cylinder is close to.
The obtained energy collection characteristics at different angles of square column and different angle triangular VIVPEH, results show that VIVPEH is superior to the characteristics of energy collection column column, and the triangular column of VIVPEH is better than that of the square column. Had a great influence on other column vibration amplitude maximum angle of attack and lock vibration area, the large amplitude, voltage, power output the attack angle is 45 degree. The energy harvesting capability of triangular VIVPEH is better than the circular and square column, lock vibration region and voltage, the maximum power output are improved.
Based on the characteristics of energy collection and comparison of a variety of column VIVPEH, found that 60 degree angle triangular VIVPEH energy harvesting ability is the strongest, most conducive to the vortex induced vibration energy collection maximum voltage.60 DEG angle triangular column than PTC columns increased by 176.23%, the maximum power increased by 661.8%.

【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TB535

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