储能飞轮风损的理论计算与试验研究

高速旋转的储能飞轮与真空室内的稀薄气体因摩擦而产生的能量损耗即风损,从理论上对飞轮转子外壁和端面与气体的摩擦损耗功率进行推导,得到了飞轮风损的计算公式,依据对计算结果的分析,提出降低飞轮风损的措施。在飞轮储能系统试验系统上进行的风损测试结果与理论计算基本相符。当真空低于0.01Pa时,试验复合材料飞轮的风损可以忽略不计。     

风力发电设备无损检测技术研究

风力发电是一个集计算机技术、空气动力学、结构力学和材料科学等综合性学科的技术。对风力发电设备进行无损检测和健康监控是增加其寿命、降低其发电和维护成本的有效手段。文章介绍了风力发电设备的失效分析,无损检测技术在风力发电设备在线状态监控方面的应用现状及技术难点和发展趋势,特别是目前国内风电设备状态监控的现状与前景。     

大型风洞承压壳体声发射评价的试验研究

在耐压试验期间及在役增压试验状态下,针对某大型风洞承压壳体开展了以结构完整性评价、缺陷监测和返修部位的缺陷活度监测为目的的声发射检测,得出了风洞承压壳体能够有效开展声发射检测,风洞承压壳体的耐压试验及在役状态下增压试验时的声发射检测能够有效评估结构完整性并进行实时监控的结论。     

Sex Pheromone of the Bud Borer <Emphasis Type="Italic">Epinotia aporema</Emphasis>: Chemical Identification and Male Behavioral Response

Epinotia aporema (Walsingham) is a Neotropical pest of legumes in southern South America. Its importance has increased during the last decade owing to the significant growth of soybean production in the region. Monitoring of E. aporema is difficult due to the cryptic behavior of the larvae, and hence, chemical control is carried out preventively. We analyzed the female-produced sex pheromone so as to develop monitoring traps and explore pheromone-based control methods. We analyzed pheromone gland extracts by combined chromatographic, spectrometric, and electrophysiological methods. Based on the comparison of retention indices, mass spectra, and electroantennogram (EAD) activity of the insect-produced compounds with those of synthetic standards, we identified two EAD-active compounds, (Z,Z)-7,9-dodecadienol and (Z,Z)-7,9-dodecadienyl acetate (15:1 ratio), as sex pheromone components of E. aporema. We also studied the behavior of males in wind tunnel tests using virgin females and different combinations of synthetic standards (15:1, 1:1, and 1:0 alcohol/acetate) as stimuli. A significantly greater percentage of males reached the chemical source with the 15:1 synthetic mixture than with any of the other treatments, indicating that these two compounds are pheromone components. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

离网式液压发电系统研究

介绍了离网式液压发电仿真系统及工作原理,对该系统进行了数学建模及Simulink仿真,并建立了系统的实验模型,通过改变液压马达的输入压力和流量的方式模拟了自然界的风能。结果表明：永磁发电机的效率在正常工况下是较高的,但整个系统的发电效率较低。     

风洞流场特性分析

根据不可压缩流体理论,加载修正后的入口风速表达式,并利用流体仿真软件建立风洞模型,对流场进行仿真分析;通过对比实验数据与仿真结果来验证模型的合理性,并对改进收缩段风洞进行仿真,比较两组风洞的流场品质;通过对流体域入口及出口处气流速度的积分运算,计算出风能利用率的差值。结果表明:改进模型能够进一步提高风洞内空气的流速,增强风能的利用效率。     

基于Visual C++与OpenGL的风电机组仿真系统研究

以风力发电机为研究对象,详细阐述了利用Visual C++与OpenGL实现风力发电机各部件的建模过程,利用显示列表与双缓存技术实现三维模型的动画显示,再通过网络通信实时传递仿真数据,实现风电机组模型与实际风电机组的联动,以达到系统的动态仿真.系统具有良好的实时性、交互性及动态仿真能力,为进一步研究风力发电机在线实时动态监测奠定基础.     

Monoliths in catalytic oxidation

Catalytic combustion is useful to avoid emission of nitrogen oxides, to combust fuel gas of different calorific levels, and to combust low contents of badly smelling or hazardous gaseous compounds. After dealing with some characteristics of catalytic combustion it is argued that catalytic combustion to a final temperature lower than about 800°C calls for a rapid transport of thermal energy out of the reactor. A fluidized bed in which combustion has been successfully performed is dealt with as well as a reactor filled with metal bodies sintered to each other and to the wall of the reactor. To achieve a sufficiently high catalytically active surface area a thin layer of silicone rubber is applied to the surface of the metal bodies and subsequently pyrolyzed to a highly porous layer of silica. To raise the thermostability alumina can be added to the silica layer.

To establish a final temperature above 900°C the homogeneous gas-phase combustion can be ignited by a solid catalyst or the reaction can be performed completely catalytically. Since the combustion reaction proceeds very rapidly at elevated temperatures, a large gas flow can be utilized, which calls for a reactor exhibiting a low-pressure drop. For catalytic combustion monoliths and gauzes are appropriate. The chemical composition of ceramic and metallic monoliths is dealt with as well as the cell densities and wall thicknesses of commercial monoliths. The application of active components to the surface of the walls of monoliths is subsequently discussed. Since monoliths do not allow radial mixing, a homogeneous gas mixture has to be fed to the monolith to prevent very high temperature levels moving randomly over the channels of the monolith and deactivating the catalyst.

With monoliths in gas turbines often catalytic ignition is used. To limit the temperature a fraction of the fuel feed is injected into the homogeneous combustion chamber. A number of alternatives of transporting the fresh fuel to the homogeneous combustion zone is mentioned. The cause of the catalyst temperature being higher than that of the gas flow is dealt with as well as the low volatility at elevated temperatures required for the catalytic components. Selection of the catalytically active materials is discussed and the procedure to bring the gas flow at the light-off temperature of the catalyst.

Monolithic combustors used in radiant heaters display often an oscillatory behavior. After dealing with the cause of the oscillations, prevention by means of a flame arrestor is mentioned.     

具有间隙的风力机变桨距系统模糊自整定PID控制

因加工、安装和磨损的原因,大型风力机的变桨距电液控制机构铰链处不可避免的存在间隙,过大的间隙会使得变桨过程超调量增大,调节过程震荡次数过多,甚至引起叶片与塔架共振,最终导致风力机停机事故。分析了变桨距机构铰链处间隙的形成机制,提出了用模糊自整定PID控制算法对间隙进行补偿的方法,依据间隙的振-冲模型制定模糊推理规则,对PID控制器参数进行自适应整定。在间隙分别为0.2、0.4、0.6和0.8 mm时对常规PID控制器与模糊自整定PID控制性能进行对比研究。结果表明:相比常规PID控制器,模糊自整定PID控制方法使得变桨距控制系统超调量和震荡次数显著减小,有效地避免了系统变桨冲击。     

Dual-loop self-optimizing robust control of wind power generation with Doubly-Fed Induction Generator

This paper presents a self-optimizing robust control scheme that can maximize the power generation for a variable speed wind turbine with Doubly-Fed Induction Generator (DFIG) operated in Region 2. A dual-loop control structure is proposed to synergize the conversion from aerodynamic power to rotor power and the conversion from rotor power to the electrical power. The outer loop is an Extremum Seeking Control (ESC) based generator torque regulation via the electric power feedback. The ESC can search for the optimal generator torque constant to maximize the rotor power without wind measurement or accurate knowledge of power map. The inner loop is a vector-control based scheme that can both regulate the generator torque requested by the ESC and also maximize the conversion from the rotor power to grid power. An ℋ_∞ controller is synthesized for maximizing, with performance specifications defined based upon the spectrum of the rotor power obtained by the ESC. Also, the controller is designed to be robust against the variations of some generator parameters. The proposed control strategy is validated via simulation study based on the synergy of several software packages including the TurbSim and FAST developed by NREL, Simulink and SimPowerSystems.