Inertial effects of the semi-passive flapping foil on its energy extraction efficiency

2015 ◽  
Vol 27 (5) ◽  
pp. 053103 ◽  
Author(s):  
Jian Deng ◽  
Lubao Teng ◽  
Dingyi Pan ◽  
Xueming Shao
Keyword(s):  
Extraction Efficiency ◽  
Energy Extraction ◽  
Inertial Effects ◽  
Flapping Foil

Study on Performance Enhancement of a Flapping Foil Energy Harvester Using Circulation Control

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
Fangrui Shi ◽  
Xiaojing Sun
Keyword(s):  
Extraction Efficiency ◽  
Performance Enhancement ◽  
Net Energy ◽  
Circulation Control ◽  
Energy Extraction ◽  
Injection Port ◽  
Flapping Foil ◽  
Momentum Coefficient ◽  
Reduced Frequency ◽  
Wide Range

Abstract Oscillating motion, an effective way to harvest energy, has gradually become a hotspot in bionic motion research in recent years. Means of improving the energy-extraction efficiency of a flapping foil harvester have long been a focus of researchers. This paper proposes a new flapping foil harvester with circulation control and explores the effects of different parameters on its energy-extraction capacity to improve efficiency and achieve lowest cost. Setting the injection ports on the upper and lower surfaces near the trailing edge of the foil and implementing injection control during motion, the effects of the location of the injection port, pitching amplitude, momentum coefficient, reduced frequency, and jet mode on the circulation control flapping foil are systematically investigated under the condition of a Reynolds number of 13,800. The results show that circulation control can enhance the energy-extraction efficiency of a flapping foil across a wide range of parameters, in which the location of the injection port and momentum coefficient have the most obvious influence on efficiency, followed by pitching amplitude and reduced frequency. In addition, the jet mode is a crucial factor affecting net efficiency. Relative to the constant mode, the triangular mode of circulation control has the lowest energy consumption, and the net energy-extraction efficiency reaches up to 38.77% under a reduced frequency of 0.12, which is 22.24% higher than that of the plain flapping foil.

ASE effect and energy extraction efficiency in high-power DF laser systems with MOPA configuration

2011 ◽  
Vol 23 (4) ◽  
pp. 885-889
Author(s):  
陈星 Chen Xing ◽  
刘文广 Liu Wenguang ◽  
姜宗福 Jiang Zongfu ◽  
靳冬欢 Jin Donghuan
Keyword(s):  
High Power ◽  
Extraction Efficiency ◽  
Energy Extraction ◽  
Laser Systems

scholarly journals A Two-stage Energy Extraction Circuit for Energy Harvesting in Non-Sinusoidal Excited Environments

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 700 ◽  
Author(s):  
Philipp Dorsch ◽  
Toni Bartsch ◽  
Florian Hubert ◽  
Heinrich Milosiu ◽  
Stefan J. Rupitsch
Keyword(s):  
Energy Harvester ◽  
Extraction Efficiency ◽  
Tracking System ◽  
Electrical Energy ◽  
Use Case ◽  
Energy Extraction ◽  
Two Stage ◽  
Asset Tracking ◽  
Piezoelectric Energy ◽  
Radio Signals

We present a two-stage energy extraction circuit for a piezoelectric energy harvester, powering an asset-tracking system. Exploiting non-sinusoidal accelerations generated by many logistic transport devices, e.g., pushcarts, forklifts, assembly belts or cars, we are able to harvest sufficient electrical energy to transmit radio signals, which will allow to track the object when it is moving. By using the proposed energy extraction circuit, the energy extraction efficiency could be improved by at least 30% compared to a single-stage solution for sinusoidal excitations. In the practical use-case, the two-stage energy extraction network performs more than four times better compared to the single staged on.

scholarly journals The revived Penrose process can power the central engine in active galactic nuclei

1986 ◽  
Vol 119 ◽  
pp. 395-398
Author(s):  
Sanjay M. Wagh ◽  
N. Dadhich
Keyword(s):  
Magnetic Field ◽  
Active Galactic Nuclei ◽  
Extraction Efficiency ◽  
Galactic Nuclei ◽  
High Energy ◽  
Energy Extraction ◽  
Central Engine ◽  
Penrose Process ◽  
The Magnetic Field ◽  
Very High

Using the fact that the efficiency of the revived (Wagh et al 1985) Penrose process of energy extraction from black holes immersed in electromagnetic fields can be very high (Parthasarathy et al, 1986) we show that this process can comfortably power the ‘central engine’ in Active Galactic Nuclei. The microphysical Penrose process energized particles will be ultrarelativistic in the asymptotic frame. Hence the kinematical analysis of escaping photons by Piran and Shaham (1977) will be a good approximation to the kinematics of these particles. From this analysis one expects the energized particles to emerge within an angle∼ 40° above and below the equatorial plane. These energetic particles, which are collimated in the funnel of an accretion disk and further on by the magnetic field, then, form supersonic, relativistic, bilateral jets. The relativistic Y factor for such jets can be expected to be ∼ 2 since these ultrarelativistic particles will effectively mimick radiation in ‘dragging’ the matter already injected inside the funnel. Various implications of high energy extraction efficiency are illustrated.

Use of synthetic jet to a fully-active flapping foil for power extraction enhancement

2020 ◽  
pp. 095440622091522
Author(s):  
Yadong Li ◽  
Guoqing Zhou ◽  
Jie Wu
Keyword(s):  
Vortex Shedding ◽  
Extraction Efficiency ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Foil Surface ◽  
Power Extraction ◽  
Flapping Foil ◽  
Extraction Performance ◽  
Rotational Motions ◽  
Inclined Angle

The power extraction performance of a fully-active flapping foil with synthetic jet is numerically investigated in this work. An elliptic airfoil with ratio of 8, which is placed in a two-dimensional laminar flow, is adopted to extract power from the flow. The foil implements the imposed translational and rotational motions synchronously. A pair of synthetic jets with the same frequency and strength is integrated into the upper and lower surfaces of flapping foil. As a result, the flow field around the foil could be affected by the synthetic jets greatly. At the Reynolds number of 1000 and the pitching axis location of half chord, the effects of the jet strength, the inclined angle between the jet direction and the chord line, as well as the phase angle between the synthetic jets and the flapping motion on the power extraction performance are systematically investigated. Compared with the traditional flapping foil, it is demonstrated that the enhancement of power extraction efficiency can be achieved with the help of synthetic jets. Based on the numerical analysis, it is indicated that the jet flow on the foil surfaces alters the vortex-shedding process and modifies the pressure distribution on the foil surface. As a result, the overall power extraction of the flapping foil can be benefitted.

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