Analytical method of radiation by a wave energy device with dual rectangular floating bodies

The system with one floating rectangular body on the free surface and one submerged rectangular body has been applied to a wave energy conversion device in water of finite depth. The radiation problem by this device on a plane incident wave is solved by the use of an eigenfunction expansion method, and a new analytical expression for the radiation velocity potential is obtained. The wave excitation force is calculated via the known incident wave potential and the radiation potential with a theorem of Haskind employed. To verify the correctness of this method, an example is computed respectively through the bound element method and analytical method. Results show that two numerical methods. are in good agreement, which shows that the present method is applicable. In addition, the trends of hydrodynamic coefficients and wave force are analyzed under different conditions by use of the present analytical method.

Exciting Forces for a Wave Energy Device Consisting of a Pair of Coaxial Cylinders in Water of Finite Depth

Two coaxial vertical cylinders-one is a riding hollow cylinder and the other a solid cylinder of greater radius at some distance above an impermeable horizontal bottom,were considered.This problem of diffraction by these two cylinders,which were considered as idealization of a buoy and a circular plate,can be considered as a wave energy device.The wave energy that is created and transferred by this device can be appropriately used in many applications in lieu of conventional energy.Method of separation of variables was used to obtain the analytical expressions for the diffracted potentials in four clearly identified regions.By applying the appropriate matching conditions along the three virtual boundaries between the regions,a system of linear equations was obtained,which was solved for the unknown coefficients.The potentials allowed us to obtain the exciting forces acting on both cylinders.Sets of exciting forces were obtained for different radii of the cylinders and for different gaps between the cylinders.It was observed that changes in radius and the gap had significant effect on the forces.It was found that mostly the exciting forces were significant only at lower frequencies.The exciting forces almost vanished at higher frequencies.The problem was also investigated for the base case of no plate arrangement,i.e.,the case having only the floating cylinder tethered to the sea-bed.Comparison of forces for both arrangements was carried out.In order to take care of the radiation of the cylinders due to surge motion,the corresponding added mass and the damping coefficients for both cylinders were also computed.All the results were depicted graphically and compared with available results.

Bibliometric Study Applied to the Overtopping Wave Energy Converter Device

The present study aims to analyze the state of the art of scientific studies about the Overtopping device used to convert sea wave energy into electrical energy,by means the Bibliometric methodology.The development of this study took place through the selection of articles from conference proceedings,as well as national and international journals.The Bibliometric methodology consists of a statistical tool that allows quantifying the measurement of production indexes.Using selected keywords,it was conducted a survey of studies in the online databases of Science Direct,SciELO and Google Scholar.The works found then went through a filtering process,in order to limit the Bibliometric study only to studies about Overtopping devices as sea Wave Energy Converter(WEC).Finally,the investigation of these selected articles was carried out under the optics of production and authorship study,content study and study of bibliographic references.Where it was identified growth in publications related to the topic,methodologies used and,among other indicators,the authors most cited in the analyzed articles.The predominant keywords used were“Wave Energy Converter”and“Overtopping”.It was noted that Brazilian universities are leaders in the productivity,presenting more than 36%of the scientific production regarding Overtopping WECs.

Experimental Study on Hydrodynamic Characteristics of Vertical-Axis Floating Tidal Current Energy Power Generation Device

To study the characteristics of attenuation, hydrostatic towage and wave response of the vertical-axis floating tidal current energy power generation device （VAFTCEPGD）, a prototype is designed and experiment is carried out in the towing tank. Free decay is conducted to obtain attenuation characteristics of the VAFTCEPGD, and characteristics of mooring forces and motion response, floating condition, especially the lateral displacement of the VAFTCEPGD are obtained from the towing in still water. Tension response of the #1 mooring line and vibration characteristics of the VAFTCEPGD in regular waves as well as in level 4 irregular wave sea state with the current velocity of 0.6 m/s. The results can be reference for theoretical study and engineering applications related to VAFTCEPGD.

Wave Energy Study in China: Advancements and Perspectives

The history and current status of research and development of wave energy in the world is briefly introduced. The main problems existing in these studies are pointed out. The description is focused on the current status and the advancements achieved in China. After analysis of the wave energy resources and practical situations in China, it is pointed out that the studies on wave energy should be not only concentrated on the conversion efficiency and costs of wave energy devices, but also focused on the technology of independent operation and stable output of electricity. Finally, the perspectives of application of wave energy in China are discussed.

Numerical examination of wave power absorption by the Edinburgh Duck wave energy converter device

A two-dimensional computational fluid dynamics(CFD)numerical model is developed to study the power takeoff(PTO)efficiency of an Edinburgh duck wave energy converter(WEC)device by using the OpenFOAM source package.After the numerical validations and the convergent verifications,the characteristics of the duck WEC device for the power takeoff in various incident wave periods are examined.The present numerical investigation indicates that the maximum absorbed power of the duck WEC device is attained in its resonant period,while the maximum efficiency is achieved in a lower period.The influence of the damping coefficient on the PTO is also investigated.The optimal damping coefficient for acquiring more power and better efficiency is determined from a numerical examination.

基于测量不确定度评定理论的波浪能发电装置实验数据质量评价研究

通过采用测量不确定度评定理论提出波浪能发电装置实验室俘获宽度比测试的数据质量评价模型并进行验证,可为后续建立波浪能发电装置实验数据的量值溯源链,完善波浪能发电数据评估技术提供研究基础。研究表明,在同一工况下实验结果的测量不确定度与样本量有关,在采用测量不确定度评价不同装置的实验数据质量时应在相同或相近的样本量条件下进行,避免由于样本量的不同造成实验结果的评价差异。

波浪能供电观测浮标防腐方案设计及仿真

针对波浪能供电观测浮标的结构组成,分析其工作原理、运动特性、各系统处的海洋腐蚀环境,将浮标划分成多个海洋污损区域。基于目前的防腐方法和浮标复杂的海洋腐蚀环境,综合考虑成本及施工时效性,提出一种防腐油漆涂层加阴极保护双组合的防腐方法,并进行外加电流阴极保护防腐系统及关键参数的设计。通过数值模拟,确定该系统布置在浮标主浮体侧面可实现较好的防腐效果。最后,提出两种防腐系统位置布置方案。

振荡浮子式波能装置的功率计算分析及参数设计

波浪能是重要的可再生资源之一,提高波浪能装置的能量捕获率是波浪能规模化利用的关键。本文对波浪能的能量转换装置进行了研究,针对装置于不同摇荡条件下的最大平均输出功率、最优阻尼系数及相关参数进行演化分析及求解。利用牛顿定律及质心系、转动惯量等建立二自由度、四自由度波浪能转换装置耦合运动模型,基于时间离散化的差分原理求解,同时采用模拟退火算法降低时间复杂度,提出了改良的粒子群算法,得到较为准确的结果,为实际工程中波浪能的高效采集提供思路和途径。

中心管振荡水柱式波浪能装置外形设计性能试验

为了探索中心管振荡水柱式波浪能装置的结构外形对其性能的影响,本文进行了装置外形结构设计,通过入射波要素、浮筒吃水深度、尾管高度、水下结构比例等类型的多种工况的物理模型试验,验证不同参数对装置性能的影响。试验结果表明:设计的模型对入射波周期变化敏感,对特定入射波高响应较优越,且在波高为65 mm,周期为1.1 s时,获得最大俘获宽度比为67.64%;模型浮筒吃水深度越大,则俘获宽度比越小,通频带越窄;锥形尾管高度值对模型的俘获宽度比和通频带宽影响较小;不同水下结构比例的模型之间俘获宽度比数值差距较小,比例为0.3时,模型的俘获宽度比通频带最宽。模型试验结果对装置的进一步优化具有理论指导意义。

留巷切顶聚能爆破空孔效应研究及应用

本文以常村矿2303回风巷道为工程背景,进行留巷切顶聚能爆破空孔效应研究,结合弹性力学理论建立空孔效应力学模型,确定聚能爆破在爆破孔与空孔连线的垂线方向实现最大拉应力,聚能爆破工艺通过增加聚能药包、定位块等装置,较传统切顶爆破,能实现更好的预裂效果,经过多方案数值模拟验证分析,确定空孔能够显著改变空孔附近有效应力状态,且距离空孔越近爆破效果越明显,空孔能够有效增加主裂缝扩展长度,进而增大爆破孔距离,通过综合分析爆破预裂效果,确定空孔作用下爆破孔合理间距为800 mm。

基于GTF星型齿轮传动系统的高效能源转换装置设计与优化

当前能源转换装置正面临着能量传递损耗较大、转换效率较低等问题。基于此,研究提出了一种星型齿轮传动系统优化方法,以提高振荡浮子波能转换装置的能源输出效率。该方法通过使用刚柔耦合模型对传动系统的结构进行优化,同时还将该优化的传动系统应用在振荡浮子波能转换装置的改进中。最后研究通过对优化后的振荡浮子波能转换装置进行数值模拟得出了改进后掌指单位时间内捕获的能量达到了43.291 kW,明显高于改进前转换的能量,同时,经计算传动系统的平均能量损失率也降低了0.67%。研究提出的改进方案具有可行性。

一种2450MHz大功率连续波磁控管输出天线耦合区的分析

文章分析了2450 MHz大功率连续波磁控管输出天线耦合区位置变化对磁控管输出性能的影响。首先,采用了等效电路法对耦合区位置变化对磁控管的参数影响进行了理论分析,发现耦合区位置变化会对磁控管外观品质因数Qe产生影响;其次,运用电磁仿真软件对输出天线的径向位置和引出位置进行了PIC粒子模拟分析,发现了耦合区位置变化会对磁控管输出功率、工作频率及输出效率产生相应的影响,为实际装制管中遇到的问题提供一些参考。

振荡型波浪能转换装置中两种优化方法研究

该文基于线性波理论,从载体在波浪中的运动方程出发,以两种不同的优化角度推导了波能装置输出能量最大时的表现形式,最后以圆柱体作为波浪能转换的载体分析了两者方法的差异。数值计算表明在同一水深下,波能装置浮体的水线面决定了波能装置最优转换效率的趋势,而吃水深度决定了波能装置可达到的最大转换效率;对波能装置参数优化后运动在共振点的波能装置其转换效率并不是最大,而优化后的最大转换效率并不发生在共振点上。

海洋波浪能发电装置的研究现状与发展前景

海洋波浪能作为一种清洁环保并且可再生的新型能源已经吸引了世界各国科学人员的目光,并已取得一定的研究成果。介绍了海洋波浪能发电装置的原理,对海洋波浪能发电装置进行了分类,总结了几种典型海洋波浪能发电装置的优缺点,并针对现阶段国内外研究现状指出目前存在的问题和今后海洋波浪能发电装置的发展前景。

一种矿用消波耗能缓冲装置设计及试验初探

针对采矿支护设备在冲击地压中呈现的损坏问题,利用泡沫金属材料优异的防冲吸能特性,研制一种能够快速消减冲击波、消耗外界冲击能的装置,并通过力学分析和室内试验,对装置的预期功能做了初步的研究和验证,得到较为理想的结果。试验结果表明:装置通过外部弹簧的控制,基本实现100 kN承载力的预期目标;装置可以实现变形让位的功能,即随着压力的增加,卡销最终可以突破最大静摩擦向外扩张,没有发生自锁现象;吸能材料具有良好的抗压强度和较高的吸能效率。此次试验中装置总的吸能量为1 650 J,与理论计算结果 1 550 J相近。该装置的设计与研究,为进一步解决支护设备在冲击地压中呈现的失稳破坏问题、提高支护设备的防冲支护能力打下一定基础。

智能超声波驱鸟装置的设计与实现

根据电力输电线路的鸟害特点,设计了一种智能超声波驱鸟装置。重点分析了基于微波多普勒雷达的飞鸟探测原理,详细介绍了系统的软硬件设计及工作流程。该装置由太阳能电池板供电,通过微波多普勒雷达探测飞鸟,利用超声波和强闪光驱鸟。经试验验证:该装置具有成本低、免维护、可靠性高、驱鸟效果持续时间长等优点,可满足电力输电线路的驱鸟需求,具有较好的市场前景。

国外波浪能开发利用技术进展

对波浪能发电装置进行更系统的分类总结,介绍了国外几种主要的波浪能发电装置(振荡水柱式、摆式、筏式、鸭式、振荡浮子式),阐述其基本工作原理与相应的最新技术应用情况。在优化现有技术的基础上,介绍国外在波浪能发电技术基础上研发的基于新原理的或改进的各种波浪能发电技术。重点揭示了波浪能开发利用技术所面临的三大关键性问题(发电效率与稳定性、生存可靠性、成本),并提出相应的解决方法。最后,总结得出波浪能发电技术的发展趋势是高效率、高可靠性、低造价;研发趋势是基于新原理的或改进的波浪能发电技术,考虑与其他能源发电技术集成与综合利用,由波浪能近岸应用向深海应用发展。

移动式太阳能增氧机的增氧性能评价

为改善池塘养殖环境,设计了一种移动式太阳能增氧机,由光伏供电装置和水面行走装置搭载涌浪机而成,能在水面沿钢丝绳移动并利用涌浪机的波浪增氧和水层交换作用,大范围扰动水体并为池塘增氧。该研究的目的是通过机械增氧效率检测、提水能力测定和池塘增氧能力测定3个试验,评估太阳能增氧机的机械增氧性能、水层交换性能和实际应用效果,以期全面了解移动增氧机增氧能力。结果表明,该移动式太阳能增氧机最大机械增氧能力为1.24 kg/h,动力效率2.59 kg/（k W·h）;最大提水能力1 254.4 m3/h,提水动力效率2 613.3 m3/（k W·h）;并在晴好天气白天（09：00—19：00）,在对照组底层溶氧为3.1~3.8 mg/L时,大幅度提升池塘底层溶氧水平,最高时达7.8 mg/L,维持池塘上下溶氧均匀度72%~84%,极大改善了底层溶氧环境。数据表明移动式太阳能增氧机具有良好的机械增氧和水层交换性能,因而能有效改善池塘底层溶氧环境,提高上下水体溶氧均匀度。该研究结果可为太阳能增氧机的进一步推广应用提供数据支撑。

基于限压型电涌保护器能量配合的分析

B+C型电涌保护器是将B级大通流型SPD和C级箝位限压型SPD设计在一个防雷装置中,以降低输出端电压和减小安装空间。笔者运用行波理论阐述了在B+C限压型防雷器中,用电路学原理分析8μH退耦器代替5 m线缆的观点是错误的,并结合实验验证了行波理论的正确性。结果表明,性能相同的压敏电阻并联能起到分流及延长寿命的作用;当退耦器电感量再增大时(≥8μH),对输出端残压的影响不大。