Investigation of a Novel Wave Energy Generator Using Dielectric Elastomer

2020 ◽  
Author(s):  
Changqing Jiang ◽  
Seiki Chiba ◽  
Mikio Waki ◽  
Koji Fujita ◽  
Ould el Moctar
Keyword(s):  
Wave Energy ◽  
Ocean Waves ◽  
High Energy ◽  
Absorption Efficiency ◽  
High Energy Density ◽  
Floating Body ◽  
Dielectric Elastomers ◽  
Direct Drive ◽  
Floating Bodies ◽  
Optimal Arrangement

Abstract The type of electroactive polymer, known as dielectric elastomers, has shown considerable promise for harvesting energy from environmental sources such as ocean waves, wind, and human motions, etc. The high energy density and conversion efficiency of dielectric elastomers (DEs) can allow for very simple and robust “direct drive” generators. In such generators, a DE transducer is directly driven by the up and down motions of waves. These generators can be simple, low-cost and robust. The efficiency of a wave energy convertor using DEs was confirmed by our previous experimental work. In this study, a wave energy convertor using DEs was numerically investigated as a moored floating body. First, the numerical model is validated against existing benchmark experiments. Then the moored floating body is numerically modelled, and the simulated results are compared to physical wave tank tests. The analyzed conditions vary from single body, two bodies with different intervals, and three bodies. The fluctuation, energy absorption efficiency, as well as the influence of multiple moored floating bodies on each other are discussed. The purpose of present work is to clarify the influence of floating body intervals and number of floating bodies on the motions, the mooring tensions, as well as the power generation efficiencies for a plurality of floating bodies arranged in a series in head seas. This kind of optimal arrangement is expected to be popularized in the future, which may contribute to the increasing demand of renewable energy solutions.

scholarly journals A Wave Energy Extraction System in Experimental Flume

2016 ◽  
Vol 2016 ◽  
pp. 1-4
Author(s):  
Qin Guodong ◽  
Pang Quanru ◽  
Chen Zhongxian
Keyword(s):  
Wave Energy ◽  
Ocean Waves ◽  
High Energy ◽  
Ocean Wave ◽  
High Energy Density ◽  
Extraction System ◽  
Energy Extraction ◽  
Linear Generator ◽  
Ocean Wave Energy ◽  
Experimental Flume

Ocean wave energy is a high energy density and renewable resource. High power conversion rate is an advantage of linear generators to be the competitive candidates for ocean wave energy extraction system. In this paper, the feasibility of a wave energy extraction system by linear generator has been verified in an experimental flume. Besides, the analytical equations of heaving buoy oscillating in vertical direction are proposed, and the analytical equations are proved conveniently. What is more, the active power output of linear generator of wave energy extraction system in experimental flume is presented. The theoretical analysis and experimental results play a significant role for future wave energy extraction system progress in real ocean waves.

scholarly journals Assessment of Model Confidence of a Laser Source Model in xRAGE Using Omega Direct-Drive Implosion Experiments

2018 ◽  
Vol 3 (4) ◽  
Author(s):  
Brandon M. Wilson ◽  
Aaron Koskelo
Keyword(s):  
Energy Density ◽  
National Laboratory ◽  
High Energy ◽  
Source Model ◽  
High Energy Density ◽  
Laser Source ◽  
Direct Drive ◽  
High Energy Density Physics ◽  
Model Confidence ◽  
Omega Laser

Los Alamos National Laboratory is interested in developing high-energy-density physics validation capabilities for its multiphysics code xRAGE. xRAGE was recently updated with the laser package Mazinisin to improve predictability. We assess the current implementation and coupling of the laser package via validation of laser-driven, direct-drive spherical capsule experiments from the Omega laser facility. The ASME V&V 20-2009 standard is used to determine the model confidence of xRAGE, and considerations for high-energy-density physics are identified. With current modeling capabilities in xRAGE, the model confidence is overwhelmed by significant systematic errors from the experiment or model. Validation evidence suggests cross-beam energy transfer as a dominant source of the systematic error.

3D SPH Simulation of Wave Interaction Between Wave Energy Converters: Towards Optimum Wave Power Absorption in Wave Farms

2020 ◽  
Author(s):  
N. Sasikala ◽  
S. A. Sannasiraj ◽  
Richard Manasseh
Keyword(s):  
Wave Energy ◽  
Oscillation Amplitude ◽  
Excitation Frequency ◽  
Ocean Waves ◽  
Dynamic Responses ◽  
Q Factor ◽  
Floating Bodies ◽  
Sustainable Resources ◽  
Wave Energy Converters ◽  
Energy Converters

Abstract Ocean waves are one of the sustainable resources of renewable energy for carbon-free electricity. For cost-effective commercial-scale projects, Wave Energy Converters (WECs) are deployed in arrays with optimum spacing as an alternative for a large (oscillatory) device in isolation. It has been found that when the wave excitation frequency is close to the resonant frequency of the WEC, the efficiency factor of energy farms, called q-factor, increases with the oscillation amplitude of the device. It has been found that the maximum absorbed energy of WECs depends directly on array configuration as that the radiated and incident wave fields interfere to direct the energy flux in the ocean towards the floating bodies. In this paper, the fully nonlinear interaction between two 3D floating bodies in close proximity and excited near its’ resonance is studied using Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH). Apart from the calculations of q factor, hydrodynamic forces acting on the floating bodies and their dynamic responses are also calculated. An optimum array of WECs is proposed.

scholarly journals Performance analysis of a point-absorber wave energy converter with a single buoy composed of three rigidly coupled structures

2021 ◽  
Vol 4 (2) ◽  
pp. 37-45
Author(s):  
Aldo Ruezga ◽  
José M. Cañedo C. ◽  
Manuel G. Verduzco-Zapata ◽  
Francisco J. Ocampo-Torres
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Floating Body ◽  
Analysis Tool ◽  
Direct Drive ◽  
Energy Converter ◽  
Drive Power ◽  
Point Absorber ◽  
Single Body ◽  
Coupled Structures

A single-body point absorber system is analysed to improve its power absorption at a finite water depth.  The proposed wave energy converter consists of a single floating body coupled to a direct-drive power take-off system placed on the seabed. The structure of a cylindrical buoy with large draft is changed by a single body composed of three structures rigidly coupled, reducing its volume and improving its frequency-dependent hydrostatic parameters that are obtained through a numerical analysis tool called NEMOH. The undamped natural frequency of the oscillating system is tuned to a specified wave period and the performance of the WEC system is obtained assuming a linear Power Take-Off system. In time domain, the performance of the WEC device is carried-out under a regular (sinusoidal) and irregular incident wave profile. Comparing the performance of the WEC system using the cylindrical and the proposed buoy outcomes that the system with the proposed buoy is able to absorb more energy from incident waves with a wider frequency range, whereas the oscillating system is kept as simple as possible.

Nonlinear impulse of ocean waves on floating bodies

2012 ◽  
Vol 697 ◽  
pp. 316-335 ◽  
Author(s):  
Paul D. Sclavounos
Keyword(s):  
Time Derivative ◽  
Ocean Waves ◽  
The Body ◽  
Offshore Wind ◽  
Floating Body ◽  
Offshore Platforms ◽  
Wave Loads ◽  
Floating Bodies ◽  
Bernoulli’S Equation ◽  
Hydrostatic Force

AbstractA new formulation is presented of the nonlinear loads exerted on floating bodies by steep irregular surface waves. The forces and moments are expressed in terms of the time derivative of the fluid impulse which circumvents the time-consuming computation of the temporal and spatial derivatives in Bernoulli’s equation. The nonlinear hydrostatic force on a floating body is shown to point vertically upwards and the nonlinear Froude–Krylov force and moment are derived as the time derivative of an impulse that involves the time derivative of a simple integral of the ambient velocity potential over the time-dependent body wetted surface. The nonlinear radiation and diffraction forces and moments are expressed as time derivatives of two impulses, a body impulse and a free surface impulse that represents higher-order wave loads acting along the body waterline. Numerical results are presented illustrating the accuracy of the new force expressions. Applications discussed include the nonlinear seakeeping of ships and offshore platforms and the extreme wave loads and responses of offshore wind turbines.

scholarly journals Electromagnetic Analysis and Experimental Study to Optimize Force Characteristics of Permanent Magnet Synchronous Generator for Wave Energy Converter Using Subdomain Method

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1825
Author(s):  
Kyung-Hun Shin ◽  
Tae-Kyoung Bang ◽  
Kyong-Hwan Kim ◽  
Keyyong Hong ◽  
Jang-Young Choi
Keyword(s):  
Experimental Study ◽  
Permanent Magnet ◽  
Wave Energy ◽  
Synchronous Generator ◽  
High Energy ◽  
High Energy Density ◽  
Electromagnetic Analysis ◽  
Electromagnetic Excitation ◽  
Permanent Magnet Synchronous Generator ◽  
Electromagnetic Forces

This paper presents an electromagnetic analysis and experimental verification to optimize the noise, vibration, and harshness (NVH) characteristics of a permanent magnet synchronous generator (PMSG) for wave energy converters (WECs). WECs applicable to breakwater installed in island areas require a wider operating range and a robust design for maintenance compared with wind-turbine systems. Owing to the use of a permanent magnet with a high energy density, the PMSG has a higher power density than other types of generators; however, strong electromagnetic excitation forces that affect the NVH characteristics are generated. Therefore, in this study, the electromagnetic forces are analyzed through an electromagnetic-field analysis using a subdomain analytical method. Based on the analytical solution, electromagnetic forces were determined. Four electromagnetic excitation forces were classified, and the methods for reducing electromagnetic excitation forces are presented here. Finally, a method for evaluating the system resonance through electromechanical analysis is presented. The proposed analysis, optimization, and experimental study are validated through comparison with finite-element analysis and experimental results.

Recent progress in quantifying hydrodynamics instabilities and turbulence in inertial confinement fusion and high-energy-density experiments

2020 ◽  
Vol 379 (2189) ◽  
pp. 20200021 ◽  
Author(s):  
A. Casner
Keyword(s):  
Energy Density ◽  
Inertial Confinement Fusion ◽  
Fusion Energy ◽  
High Gain ◽  
High Energy ◽  
High Energy Density ◽  
Inertial Confinement ◽  
Direct Drive ◽  
Energy Part ◽  
Confinement Fusion

Since the seminal paper of Nuckolls triggering the quest of inertial confinement fusion (ICF) with lasers, hydrodynamic instabilities have been recognized as one of the principal hurdles towards ignition. This remains true nowadays for both main approaches (indirect drive and direct drive), despite the advent of MJ scale lasers with tremendous technological capabilities. From a fundamental science perspective, these gigantic laser facilities enable also the possibility to create dense plasma flows evolving towards turbulence, being magnetized or not. We review the state of the art of nonlinear hydrodynamics and turbulent experiments, simulations and theory in ICF and high-energy-density plasmas and draw perspectives towards in-depth understanding and control of these fascinating phenomena. This article is part of a discussion meeting issue ‘Prospects for high gain inertial fusion energy (part 2)’.

A novel fully floating three-body system for direct-drive wave energy converter

2020 ◽  
pp. 1-16
Author(s):  
Chuan Liu ◽  
Renwen Chen ◽  
Yuxiang Zhang ◽  
Liping Wang ◽  
Jinchang Qin
Keyword(s):  
Wave Energy ◽  
Parametric Design ◽  
Wave Energy Converter ◽  
Direct Drive ◽  
Floating Bodies ◽  
Energy Converter ◽  
Halbach Array ◽  
Electromagnetic Power ◽  
Three Body ◽  
Multi Body

Converting persistent and renewable wave energy into electricity has been studied in recent years. This research develops a novel fully floating three-body direct-drive wave energy converter (DD-WEC) prepared for the research of the multi-body DD-WEC. Its prototype consists of three floating bodies, but both three bodies act as buoys to extract the wave energy, not just a body. And the relative motion of the buoys induces the voltage in Halbach array permanent magnet linear generators coils. Its feasibility is investigated theoretically by analyzing the dynamics of motion of the floating buoys. As a result, parametric design of the WEC is achieved. The load performance of the DD-WEC is investigated by using the Simulink, and it can be found that the relative displacements between buoys are different. Then, the electromagnetic power of the proposed WEC is much higher compared to a two-body DD-WEC by using numerical simulation Finally, the DD-WEC prototype is manufactured and tested in the wave tank. The results show that the WEC can produce the most electricity for the case with the wave period of 1.6 s, and the maximum voltage reaches 14.2 V, which is consistent with the simulation results. The results show that the proposed DD-WEC is well suited for wave energy conversion.

ISWEC: Design of a Prototype Model for Wave Tank Test

2010 ◽  
Author(s):  
Giovanni Bracco ◽  
Ermanno Giorcelli ◽  
Giuliana Mattiazzo
Keyword(s):  
Wave Energy ◽  
Ocean Waves ◽  
Research Process ◽  
Full Scale ◽  
Wave Energy Converter ◽  
Floating Body ◽  
Prototype Model ◽  
Mathematical Tool ◽  
Energy Converter ◽  
Wave Tank

The extraction of energy from ocean waves has been investigated in Europe since the 1970s. During the research process hundreds of devices have been proposed and a few of them have been built full scale and deployed to the ocean. Unlike other renewable energies, so far there has not been a device standing out to be the most suitable to exploit wave power. One of the practical problems to be solved in a Wave Energy Converter (WEC) is durability in the harsh marine environment. This could be critical if parts of the converter such as turbine rotors or auxiliary floats are needed to move or to react while exposed to seawater and spray. One method to solve the problem is to use a WEC composed just by one sealed floating body carrying a gyroscope. The inertial effects of the gyroscope are activated by the float motion and are used to drive a generator. The whole system operates in the clean environment inside the float. In this work a procedure to design the ISWEC device (Inertial Sea Wave Energy Converter) is outlined. The mechanical equations describing the system are linearized, studied in the frequency domain and used as a mathematical tool in the design process. The method is then applied iteratively to design a scaled prototype model to be tested in the wave tank at the University of Naples. The final version of the prototype model is then scaled up to evaluate the performances of a full scale device.

scholarly journals Soft, tough, and fast polyacrylate dielectric elastomer for non-magnetic motor

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Li-Juan Yin ◽  
Yu Zhao ◽  
Jing Zhu ◽  
Minhao Yang ◽  
Huichan Zhao ◽  
...  
Keyword(s):  
High Performance ◽  
Crosslinking Agent ◽  
High Energy ◽  
Dielectric Elastomer ◽  
High Energy Density ◽  
Dielectric Elastomers ◽  
Dielectric Elastomer Actuators ◽  
Response Bandwidth ◽  
Electrically Actuated ◽  
Soft Actuators

AbstractDielectric elastomer actuators (DEAs) with large electrically-actuated strain can build light-weight and flexible non-magnetic motors. However, dielectric elastomers commonly used in the field of soft actuation suffer from high stiffness, low strength, and high driving field, severely limiting the DEA’s actuating performance. Here we design a new polyacrylate dielectric elastomer with optimized crosslinking network by rationally employing the difunctional macromolecular crosslinking agent. The proposed elastomer simultaneously possesses desirable modulus (~0.073 MPa), high toughness (elongation ~2400%), low mechanical loss (tan δm = 0.21@1 Hz, 20 °C), and satisfactory dielectric properties ($${\varepsilon }_{{{{{{\rm{r}}}}}}}$$ ε r  = 5.75, tan δe = 0.0019 @1 kHz), and accordingly, large actuation strain (118% @ 70 MV m−1), high energy density (0.24 MJ m−3 @ 70 MV m−1), and rapid response (bandwidth above 100 Hz). Compared with VHBTM 4910, the non-magnetic motor made of our elastomer presents 15 times higher rotation speed. These findings offer a strategy to fabricate high-performance dielectric elastomers for soft actuators.

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