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1.
This paper investigates a flow-induced vibration energy harvester comprising a piezoelectric beam (piezo-beam) installed within a hollow circular cylinder. Under the flow excitation, the energy-harvesting system including the cylinder and the piezo-beam vibrates and generates electricity. A lumped parametric model incorporating the fluid-structure interaction (FSI) is developed to evaluate the performance of the proposed energy harvester. Based on the theoretical analysis, several guidelines on the design and optimization of the proposed energy harvester are provided. Subsequently, a numerical model is used to simulate the FSI between the proposed system and the external flow field. Finally, a physical prototype is fabricated and an experiment is conducted to test the actual performance for validation. The theoretical analysis results are verified by the numerical and experimental results. 相似文献
2.
Small-scale wind energy harvesting from vortex-induced vibrations (VIV) has been introduced in recent years as a renewable power source for microelectronics and wireless sensors. Previous studies have focused on modeling and optimizing the VIV-based piezoelectric energy harvester (VIVPEH) structures and simplified the complicated interface circuits as pure resistors with an alternating current (AC) output. In practice, an AC output is required to be transformed into a direct current (DC) followed by further regulations before being used for real applications. Incorporating the rectification and regulation, traditional theoretical and numerical models will become extremely cumbersome and even impossible. To address this issue, this work proposes an equivalent circuit model (ECM) for a typical VIVPEH. The Scanlan-Ehsan aerodynamic force model is employed to describe the fluid-structure interaction. Wind tunnel experiments are carried out to validate the derived model. The performances of the VIVPEH with AC and DC interface circuits are subsequently analyzed and compared to understand the influences of these circuits on the operational wind speed bandwidth, power output, vibration amplitude, and electrical damping. 相似文献
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Muhammad Iqbal Malik Muhammad Nauman Farid Ullah Khan Pg Emeroylariffion Abas Quentin Cheok Asif Iqbal Brahim Aissa 《国际能源研究杂志》2021,45(1):65-102
Wireless sensor nodes (WSNs) and embedded microsystems have recently gained tremendous traction from researchers due to their vast sensing and monitoring applications in various fields including healthcare, academic, finance, environment, military, agriculture, retail, and consumer electronics. An essential requirement for the sustainable operation of WSN is the presence of an uninterrupted power supply; which is currently obtained from electrochemical batteries that suffer from limited life cycles and are associated with serious environmental hazards. An alternative to replacing batteries of WSNs; either the direct replacement or to facilitate battery regular recharging, is by looking into energy harvesting for its sustainable drive. Energy harvesting is a technique by which ambient energy can be converted into useful electricity, particularly for low‐power WSNs and consumer electronics. In particular, vibration‐based energy harvesting has been a key focus area, due to the abundant availability of vibration‐based energy sources that can be easily harvested. In vibration‐based energy harvesters (VEHs), different optimization techniques and design considerations are taken in order to broaden the operation frequency range through multi‐resonant states, increase multi‐degree‐of‐freedom, provide nonlinear characteristics, and implement the hybrid conversion. This comprehensive review summarizes recent developments in VEHs with a focus on piezoelectric, electromagnetic, and hybrid piezoelectric‐electromagnetic energy harvesters. Various vibration and motion‐induced energy harvesting prototypes have been reviewed and discussed in detail with respect to device architecture, conversion mechanism, performance parameters, and implementation. Overall sizes of most of the reported piezoelectric energy harvesters are in the millimeter to centimeter scales, with resonant frequencies in the range of 2‐13 900 Hz. Maximum energy conversion for electromagnetic energy harvesters can potentially reach up to 778.01 μW/cm3. The power produced by the reported hybrid energy harvesters (HEHs) is in the range of 35.43‐4900 μW. Due to the combined piezoelectric‐electromagnetic energy conversion in HEHs, these systems are capable of producing the highest power densities. 相似文献
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In this study, vibration straight‐line displacements occurring during electric vehicle operations are changed into reversely rotating displacements and divided into small segments by a gear unit. Piezoelectric bending elements are used to form a cantilever beam–based energy feedback mechanism for converting vibration energy into electrical power within an allowable displacement range. A virtual vibration displacement filtering algorithm is proposed to effectively filter virtual displacements that cannot excite the energy harvester and generate electrical power. The average speed of the gear exciting the bender has an accuracy 30%, which is increased using this algorithm compared with 2 other algorithms and directly affects the accuracy of calculating the average power generated by the calculation of piezoelectric bending elements. Theoretical and experimental analyses are conducted for the impact of gear pitch on the regeneration power value by changing the gear pitch at a fixed driving speed. Experiments show that when a vehicle is operated at a fixed speed, the proposed method can be used to obtain the maximum average power of a single piezoelectric bending element through determination of a rational gear pitch. Specifically, when the test vehicle operated at 20 and 60 km/h, the gear pitch should have been 7 and 10 mm. 相似文献
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庞杰;何易卓;方志刚 《节能》2022,41(7):43-48
为解决小型用电设备供电问题,通过分析现有对发电地砖的相关研究,设计了一种基于双向机械式整流装置的机械电磁式发电地砖,以回收地砖顶板上下移动产生的动能。根据机电相似原理建立了发电地砖的仿真模型,在Matlab/Simulink中进行了仿真分析,分析了回位弹簧刚度和负载电阻对系统输出功率以及能量回收率的影响,并对刚度和电阻值进行了优化。结果表明：在所得最优条件下,系统的平均输出功率为4.4 W,能量回收效率为68.25%,证明了该发电地砖具有较高的使用价值。 相似文献
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Energy harvesting technologies are growing rapidly in recent years because of limitation by energy storage and wired power supply. Vibration energy is abundant in the atmosphere and has the potential to be harvested by different mechanisms, mainly through piezoelectric and electromagnetic means. Various architectural structures were also designed for several operating conditions, namely, resonance frequency and range thereof, acceleration, and energy extraction from several motions. The advantages and disadvantages were elaborated on, and improvements on ideas from current research were discussed in this review. 相似文献
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S. Chiriţă 《热应力杂志》2013,36(9):858-878
In the present paper we consider a prismatic cylinder occupied by an anisotropic homogeneous compressible linear thermoelastic material that is subject to zero body force and heat supply and zero displacement and thermal displacement on the lateral boundary. The motion is induced by a harmonic time–dependent displacement and thermal displacement specified pointwise over the base. We establish some spatial estimates for an appropriate cross–sectional measure associated with the amplitude of the corresponding harmonic vibration in the high frequency range that describe how the amplitude evolves with respect to the axial distance to the excited base. In fact, in the high frequency range we establish certain algebraical estimates that predict decay or growth slower than that for the low frequency range. 相似文献
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In this work, consideration is given for a novel technology based on the use of compliant surfaces (membranes) for hydrokinetic energy conversion (HEC) from residual waters where the use of traditional turbines is either not possible or strongly limited. Here, residual waters are understood as waters with a small total pressure difference relative to the surrounding environment that are not suitable to be turbined. Such waters encompass not only domestic or industrial waste water before being discharged into the sewer but also typical flows found in river waterways of small depth or even postturbined water. In summary, the proposed technology is based on the deliberated bifurcation of residual water into two streams separated by a compliant surface or membrane that equalizes the static pressure in both streams and also generates a relative velocity between them. As a result, Taylor instabilities translate into the oscillatory motion of the membrane, which can be transformed into output power. Utilizing linearized flow theory, an analytical expression for the extractable density power is derived. Experiments are carried out for a rectangular membrane, and the data obtained are quantitatively and qualitatively in good agreement with the theoretical model, where it is found that for typical residual water with a velocity of approximately 1.7 m/s, the output power density is on the order of 30 mW/cm2 based on the area of the membrane. Additional research and development is required to arrive at a reliable practical and commercial design. 相似文献
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The existence of various ring sizes of peripheral light harvesting complex (LH2) in photosynthetic bacteria was reported recently. To investigate the dependence of LH2’s functions as an excitation energy transfer (EET) carrier on its structure, the relation of EET in the systems consisting of ring-shaped aggregates and their ring size is evaluated. Setting the square simulation area (70 nm × 70 nm), we defined the EET efficiency as the rate of population transferred from the area irradiated by the incident light to another area, which is separated by ∼20 nm from the former area, by the time corresponding to the dephasing time of pigments (∼4 ps) after the irradiation of the incident light pulse. As the result, the system composed of large ring with 28 pigments realizes the EET efficiency of 5.3%, 7.0%, and 8.8% in the randomly distributed system of rings when the ring number is 15, 20, and 25, respectively. These values are ∼1.5 and ∼3 times higher than the EET efficiency in the systems composed of rings with 18 pigments and 10 pigments, respectively, when the total numbers of pigments in the simulation area are the same. In the lattice structures, on the other hand, the EET efficiency of the three types of systems shows the similar value of ∼20%. The results suggest that forming a large ring as the unit of EET carrier could be effective to realize efficient EET in the systems containing randomness in distribution of units, whereas in the lattice structure, the EET efficiency may be not critically affected by the ring size of ring-shaped unit carrier. 相似文献
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With growing interest in multi source energy harvesting including integrated microchips we propose a comparison of radio frequency (RF) and solar energy sources in a typical city. Harvesting devices for RF and solar energy will be competing for space of a compact micro or nano device as well as for orientation with respect to the energy source. This is why it is essential to investigate importance of every source of energy and make a decision whether it will be worthwhile to include such harvesters. We considered theoretically possible irradiance by RF signal in different situations, typical for the modern urban environment and compared it with ambient solar energy sources available through the night, including moonlight.Our estimations show that solar light energy dominates by far margin practically all the time, even during the night, if there is a full moon in the absence of clouds. At the same time, in the closed compartments or at the new moon RF harvesting can be beneficial as a source of “free” energy. 相似文献
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Wireless sensor networks (WSNs) have aroused the conspectus attention of scholars due to their extensive deployment in the emerging fields of the Internet of Things (IoT's) and self‐driven devices. But WSNs technologies having a major bottleneck has been associated with limited energy. Mostly research in WSNs has been focused on minimizing energy usage to extend the survival time of limited power source in a network. Energy harvesting can be addressing its energy‐scarcity problem of WSNs, so it is giving popularity to Energy Harvesting in Wireless Sensor Networks (EH‐WSNs). The paper presents a comprehensive taxonomic survey on recently energy harvesting techniques and algorithms that proposed by various authors and also examined the work done by the various researchers in the field of EH‐WSNs. For the ready reference of the researchers, a concise summary and comparative analysis of various promising techniques for energy harvesting have also been included in the systematic survey. However, many equipment developed using the hybridization method in a singular package to get full advantages of available free energy, are explored in this review. The review on hybrid energy harvesting (HEH) systems can be considered as the originality of this article. However, the outdoor photovoltaics have been provided maximum power density about ≈100 mW/cm3, and the piezoelectric harvesters have been given maximum voltage about 325 V but the current in very minute amount. The thermoelectric, rectenna and hybrid energy harvesters (EHs) have been given high efficiency more than 80%. Additionally, hybrid EHs have location/time‐independent characteristics which harnessed power from more than one source that can be became more popular for upcoming leading technologies of self‐driven or autonomous devices shifting from battery operated devices. Finally, the survey also identifies often challenges and various significant issues that still essential to be addressed to develop a cost effective, efficient, long‐lasting, and almost maintenance‐free energy harvesting systems for WSNs along with trail to their possible solutions for future perspectives. 相似文献
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Hans Knutell 《Biomass & bioenergy》1992,2(1-6):193-209
Summaries of papers presented at a conference on Bioenergy Supply Systems are presented 相似文献
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This paper proposes a new concept to enhance the efficiency of the vibration energy harvesting via an intermediate booster. The boosters have auxetic structures and exert extra stretching strain in two perpendicular directions. The concept is tested on a conventional cantilever beam under the base excitation. The problem consists of a cantilever beam subjected to a body load at low frequencies. An auxetic substrate is bonded to the beam with a thin epoxy layer, and the piezoelectric (PZT) element is attached on top of it. Two different auxetic structures are investigated in this study. It is shown that employing these kinds of boosters can remarkably enhance the performance of the energy harvesting system. The harvesting efficiency is numerically evaluated in different load amplitudes and frequencies. A parametric study is then carried out, and effects of different geometrical design parameters of the auxetic boosters on the performance of the energy harvesting system are investigated. Comparing with the case in which the PZT is straightly attached to the cantilever, it is shown that adding such intermediate boosters at low-frequency range can increase the extracted power by factors of 3.9 and 7.0 for the two proposed geometries. 相似文献
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机车经过一定时间的运行,各部件都会发生磨耗、变形或损坏,为了使机车稳定可靠地运行或延长其使用期限,必须进行阶段性检修和测试。目前把水阻作为负载的测试手段已被广泛应用于机车柴油机测试,这种静态连续测试消耗的能量占发动机自身寿命周期内产生能量的15%~30%。这不仅造成了极大的能源浪费,也会引起金属极板的严重腐蚀。本工作以对柴油机测试过程产生的电能进行回收的项目为例,介绍了一种新型嵌入式储能系统的整体设计及储能系统中关键设备的功能,并对系统进行了仿真实验,仿真实验结果证明该系统可以稳定可靠地回收柴油机测试过程中产生的能量。 相似文献
17.
Junlei Wang Guifeng Zhao 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2018,40(15):1788-1797
In the present study, an energy harvester with coarse passive turbulence control (PTC) structure is represented to harvest piezoelectric wind energy. Wind tunnel experiments are conducted to investigate the influence of the PTC on the vibrational amplitude of the vortex-induced vibration and piezoelectric power output. Parametric studies of the PTC numbers and sizes are presented to determine the optimized PTC structure to enhance the efficiency of piezoelectric energy harvesting. The experimental results show that the specific parameters of θ= 60° and W = 8 mm are the most efficient PTC group for designing a vortex-induced vibration-based energy harvester with the coarse surface device. 相似文献
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Bekir Sami Yilbas 《国际能源研究杂志》2019,43(1):4-8
In order to minimize dust effects on optical surfaces related to the solar energy harvesting, adhesion between the active surface of energy harvesting device and the dust particles needs to be lowered. Consequently, the pinning force for the dust particles reduces, and the dust particles can be removed via creating the self‐cleaning effect. The wetting state of the active surface becomes critical towards reducing the pinning force. In this case, hydrophobic surfaces remain favorable reducing the dust adhesion on the surfaces. In the present perspective, characteristics of the environmental dust particles and their effects in humid air ambient are presented. The methods for dust removal from the surfaces and the optical transmittance reduction by the dust particles are discussed. The challenges and future perspectives of surface texturing towards achieving hydrophobicity and optical transmittance are also introduced. 相似文献
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发展海洋能源转化技术是优化能源结构、拓展“蓝色经济”空间的战略要求。为此,设计了一种基于筏式波浪能转换和点头鸭型摩擦纳米发电机能量输出的耦合系统,并对影响系统中筏体装置部分捕能特性的压载吃水、筏体尺寸参数以及影响系统输出电势分布的尼龙球径、滚动距离参数进行了仿真分析。结果表明：增大筏体装置的吃水(增加压载)和优化筏体装置的尺寸都可以降低装置的固有频率,使其与波浪频率达到共振,从而可以提高装置捕获波浪能的能力;摩擦纳米发电机两电极之间的电势差随着尼龙球球径的增大呈现出先增大后减小的趋势,在球径为30 mm时电势差达到最大值,该电势差还随着尼龙球滚动距离的增大而增大,并在外部负载电阻为770 M?时实现了瞬时最大功率密度3.7W/m3。由此可见,当在筏式波浪能转换装置中布置多个摩擦纳米发电机阵列时,完全可以将海洋中原本无法利用的大量低频波浪能转化为电能,从而满足深海传感器网络供电需求,这大大扩展了波浪能的发电潜力,使得蓝色能源在未来有望得到更有效地开发。 相似文献