上海地区太阳能资源评估与散射辐射推算方法研究

准确评估上海地区的太阳能资源状况对于当地太阳能资源的开发利用有重要意义。根据中国气象局提供的上海地区多年太阳辐射观测数据,评估当地太阳能资源,结果表明上海地区光伏资源丰富、稳定度较高,适合建设光伏电站。为满足缺乏直接辐射和散射辐射数据的地区推算总辐射中直、散分量的需要,结合2001~2010年上海地区经过严格质量控制的总、直、散观测样本序列,针对三种经典"直散分离"模型,通过拟合散射比Hd/H与清晰度指数Kt的函数关系,修正得到适合上海市及周边地区的散射辐射量推算方法,并利用2011年的实测数据对该方法进行独立样本预报验证,其平均百分比误差小于5%,可为光伏发电系统设计、功率预报提供指导和借鉴。     

结合太阳辐射量计算与CNN-LSTM组合的光伏功率预测方法研究

为了提高模型预测性能,提出一种综合太阳辐射模型及深度学习的光伏功率预测模型。首先,利用太阳辐射机理建立太阳辐射模型（SRM）,估算出水平面上总辐射值,再由斜面辐照度转换方法计算出光伏组件所接收的斜面辐射值。其次,通过皮尔逊相关分析法筛选出对光伏功率影响较大的主要因素,将斜面辐射计算值及主要影响因素作为输入,采用卷积神经网络（CNN）和长短期记忆网络（LSTM）建立光伏功率SRM-CNN-LSTM预测模型。分别利用春夏秋冬四季典型日的数据开展对比实验,结果表明：与几种其他方法相比,该文方法具有更好的预测效果。     

低纬度地区水平面太阳辐射的直散分离模型研究

以中国低纬度地区水平面太阳总辐射的直散分离为研究对象,依据福建、广东、广西和海南等低纬度地区4个气象台站1971~2003年的水平面太阳总辐射和散射辐射实测气象数据,采用回归分析方法,建立大气散射透射比与晴空指数之间的回归计算模型。选取LiuJordan模型、Orglill模型和Erbs模型3种代表性分离模型与自建模型比较,结果表明,自建模型准确度最高。得出结论:大气散射透射比与晴空指数之间存在显著的负相关性,建立二者之间的回归模型可实现水平面太阳辐射的直散分离。     

深圳不同气象条件下各朝向太阳辐射分布特征

利用深圳地区搭建的多朝向太阳辐照与光伏发电效率测量系统2013—2017年120个朝向光伏组件实测数据,分析入射太阳辐射最佳朝向及其时间变化规律,不同气象条件下各朝向辐射的表现特征,以及方位角和倾角的差异对辐射影响的程度,得出:1)年均太阳辐射最大值的倾斜面为-15°/10°,即光伏发电最佳方位角南偏东15°,最佳倾角...     

光伏发电功率预测斜面辐射组合模型的评估研究

光伏发电功率预测以准确、可靠的倾斜面太阳辐射量数据为基础。文章通过斜面辐射组合模型的计算,得到倾斜面太阳辐射量。为了分析不同辐射组合模型对光伏发电功率预测结果的影响,建立光伏发电功率预测模型,同时,选取3种典型直散分离模型和4种斜面辐射模型进行理论分析,并将上述模型分别组成12种斜面辐射组合模型,进行光伏发电功率预测。研究结果表明:含Liu-Jordan模型的组合模型的功率预测值与实测值更吻合,其中,Erbs+Liu-Jordan组合模型预测结果的准确度最高;阴雨天,利用King模型进行计算时,会发生地面反射辐射值估计结果偏高的现象,导致预测结果的准确性较低。     

基于地面观测资料的太阳辐射量统计反演法研究

为了在缺乏实测太阳辐射量的情况下精准评估光伏潜力,更好地规划和开发利用太阳辐射气候资源,促进地方经济发展以及助力国家碳中和目标的实现,研究提出一种基于地面观测资料的太阳辐射量计算方法.根据气候学原理,利用与太阳辐射相关的周边地面台站日照百分率和实测日太阳总辐射等观测数据,建立间接估算到达地面的月太阳总辐射量的计算模型;...     

基于GA-BP神经网络的逐时总辐射分组模型研究

通过分析影响太阳辐射的主要因素,提出以太阳高度角、季节和天气（晴空指数）作为数据划分依据的分组模型建立方法。以拉萨和西安地区的逐时气象数据和辐射数据为例,基于遗传算法（genetic algorithm,GA）优化的BP神经网络,建立太阳高度角、季节和天气类型的逐时总辐射分组模型。该研究揭示分组模型误差变化的规律,并将其估算误差与AllData模型比较。结果显示,相较于AllData模型,分组模型的估算误差均有降低。其中,天气分组模型误差最小,且西安的天气分组模型结果优于拉萨。西安天气分组模型平均绝对百分比误差（MAPE）和相对均方根误差（rRMSE）相较AllData模型结果分别下降3.96%和4.18%。研究结果表明分组模型能够降低逐时总辐射估算误差,可为估算逐时总辐射提供方法借鉴。     

基于MLP-Garson模型的分钟尺度太阳辐照直、散射分离建模与验证研究

为模拟分钟尺度的太阳辐射波动,根据江苏省常州市2018—2021年逐分钟辐射数据,采用Garson权重算法优化模型输入特征,并引入前10分钟的清晰度指数k_t时序数据作为附加特征,建立基于时序数据与MLP神经网络的分钟尺度新分离模型。在此基础上,对Engerer2模型、Starke模型和Yang模型3个最新提出的分钟尺度分离模型进行参数本地优化,并设计测试实验验证。验证结果表明：采用时序数据与MLP神经网络的新模型可有效提取短时间内的太阳辐射波动信息,新模型的归一化均方根误差(e_nRMSE)为10.690%,新模型精度较Yang模型提高了17.08%。     

基于传递函数的光伏电池板长期辐射量计算

为获得光伏电池板在不同地区、不同朝向全年所接收的总辐射值,首先应用光照总辐射理论模型和传递函数法,对有辐射记录地区的实际总辐射进行建模,并对所建立模型的可靠性进行验证,然后对所建总辐射模型进行直散分离,最后对电池板不同朝向所接收的全年辐射量进行计算,并获得其分布状况。所得到的电池板最佳朝向与实际应用相符合。该计算方法可为无辐射记录地区估算长期辐射值以及电池板的安装朝向提供参考。     

用于电力系统仿真的水电机组原动机模型适应性研究

鉴于以往研究侧重于水电机组原动机模型开发，较少研究模型的适应性，且缺乏在电力系统仿真中选取模型的指导性建议与方法，提出模型选取原则，通过仿真水轮机模型、水击模型与调压室—分叉管模型的动态行为，分析水击模型的稳定域，从而归纳出模型的适用条件。结果表明，解析非线性模型与理想模型适合于描述水斗式水轮机，混流式水轮机宜使用传递系数模型；可依据Tw/Tr和Tf/Tr的值选取刚性水击模型与降阶弹性水击模型；当仿真时间较长时需要采用调压室—分叉管的模型。     

Ash-forming elements in four Scandinavian wood species. Part 1: Summer harvest

Woody biomass in Finland and Sweden comprises mainly four wood species: spruce, pine, birch and aspen. To study the ash, which may cause problems for the combustion device, one tree of each species were cut down and prepared for comparisons with fuel samples. Well-defined samples of wood, bark and foliage were analyzed on 11 ash-forming elements: Si, Al, Fe, Ca, Mg, Mn, Na, K, P, S and Cl. The ash content in the wood tissues (0.2–0.7%) was low compared to the ash content in the bark tissues (1.9–6.4%) and the foliage (2.4–7.7%). The woods’ content of ash-forming elements was consequently low; the highest contents were of Ca (410–1340 ppm) and K (200–1310), followed by Mg (70–290), Mn (15–240) and P (0–350). Present in the wood was also Si (50–190), S (50–200) and Cl (30–110). The bark tissues showed much higher element contents; Ca (4800–19,100 ppm) and K (1600–6400) were the dominating elements, followed by Mg (210–2400), P (210–1200), Mn (110–1100) and S (310–750), but the Cl contents (40–330) were only moderately higher in the bark than in the wood. The young foliage (shoots and deciduous leaves) had the highest K (7100–25,000 ppm), P (1600–5300) and S (1100–2600) contents of all tissues, while the shoots of spruce had the highest Cl contents (820–1360) and its needles the highest Si content (5000–11,300). This paper presented a new approach in fuel characterization: the method excludes the presence of impurities, and focus on different categories of plant tissues. This made it possible to discuss the contents of ash element in a wide spectrum of fuel-types, which are of large importance for the energy production in Finland and Sweden.     

NEXT GENERATION ENGINEERED MATERIALS FOR ULTRA SUPERCRITICAL STEAM TURBINES

正1 ABSTRACT To reduce the effect of global warming on our climate,the levels of CO2emissions should be reduced.One way to do this is to increase the efficiency of electricity production from fossil fuels.This will in turn reduce the amount of CO2emissions for a given power output.Using US practice for efficiency calculations,then a move from a typical US plant running at 37%efficiency to a 760℃/38.5 MPa(1 400/5 580 psi)plant running at 48%efficiency would reduce CO2emissions by 170kg/MW.hr or 25%.     

Contents in Volume 23,2014

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Aerodynamic performance effects of leading-edge geometry in gas-turbine blades

The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°,   −5°,   +5°,   +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods.     

Hydrogen production by steam-gasification of carbonaceous materials using concentrated solar energy – V. Reactor modeling,optimization, and scale-up

A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified.     

汽轮机数字电液调节系统挂闸异常的技术完善

分析了200MW汽轮机数字电液调节系统在运行中存在的挂闸异常问题,采取了相应的技术处理措施,且运行实践效果良好。     

新型高压共轨ECU升压模块的数字化开发与优化

为了提高喷油器电磁阀的响应速率,提出了一种基于CPLD(复杂可编程逻辑器件)应用于高压共轨ECU的数字升压模块。鉴于该升压电路结构参数多,其升压电压的恢复响应要求高等特征,基于Pspice建立了升压电路的仿真模型,研究了不同电路参数下升压模块的输出特性,全面优化了该升压模块的性能。结果显示,该升压模块的最大转换效率可以达90%以上。在柴油发动机上对ECU的试验表明,升压电压最大波动不超过10%,其恢复时间仅为1.3ms,功率管最大温升仅为41℃,满足整机运行范围内ECU的需求。     

Trace metal chemistry and silicification of microorganisms in geothermal sinter, Taupo Volcanic Zone, New Zealand

As part of a pilot study investigating the role of microorganisms in the immobilisation of As, Sb, B, Tl and Hg, the inorganic geochemistry of seven different active sinter deposits and their contact fluids were characterised. A comprehensive series of sequential extractions for a suite of trace elements was carried out on siliceous sinter and a mixed silica-carbonate sinter. The extractions showed whether metals were loosely exchangeable or bound to carbonate, oxide, organic or crystalline fractions. Hyperthermophilic microbial communities associated with sinters deposited from high temperature (92–94°C) fluids at a variety of geothermal sources were investigated using SEM. The rapidity and style of silicification of the hyperthermophiles can be correlated with the dissolved silica content of the fluid. Although high concentrations of Hg and Tl were found associated with the organic fraction of the sinters, there was no evidence to suggest that any of the heavy metals were associated preferentially with the hyperthermophiles at the high temperature (92–94°C) ends of the terrestrial thermal spring ecosystems studied.     

Assessment methods of material ageing using Sdobyrev''s creep rupture model

The physical aspects of the activation energy, in higher and high temperatures, of the metal creep process were examined. The research results of creep-rupture in a uniaxial stress state and the criterion of creep-rupture in biaxial stress states, at two temperatures, are then presented. For these studies creep-rupture, taking case iron as an example the energy and pseudoenergy activation was determined. For complex stress states the criterion of creep-rupture was taken to be Sdobyrev's, i.e. σ_red = σ₁ β + (1 − β)σ_i, where: σ₁-maximal principal stress, σ_i-stress intensity, β-material constant (at variable temperature β = β(T)). The methods of assessment of the material ageing grade are given in percentages of ageing of new material in the following mechanical properties: 1) creep strength in uniaxial stress state, 2) activation energy in uniaxial stress state, 3) criterion creep strength in complex stress states, 4) activation pseudoenergy in complex stress states. The methods 1) and 3) are the relatively simplest because they result from experimental investigations only at nominal temperature of the structure work, however, for methods 2) and 4) it is necessary to perform the experimental investigations at least at two temperatures.     

Production of hydrogen from sewage biosolids in a continuously fed bioreactor: Effect of hydraulic retention time and sparging

Hydrogen was produced from primary sewage biosolids via mesophilic anaerobic fermentation in a continuously fed bioreactor. Prior to fermentation the sewage biosolids were heated to 70 °C for 1 h to inactivate methanogens and during fermentation a cellulose degrading enzyme was added to improve substrate availability. Hydraulic retention times (HRT) of 18, 24, 36 and 48 h were evaluated for the duration of hydrogen production. Without sparging a hydraulic retention time of 24 h resulted in the longest period of hydrogen production (3 days), during which a hydrogen yield of 21.9 L H₂ kg⁻¹ VS added to the bioreactor was achieved. Methods of preventing the decline of hydrogen production during continuous fermentation were evaluated. Of the techniques evaluated using nitrogen gas to sparge the bioreactor contents proved to be more effective than flushing just the headspace of the bioreactor. Sparging at 0.06 L L min⁻¹ successfully prevented a decline in hydrogen production and resulted in a yield of 27.0  L H₂ kg⁻¹ VS added, over a period of greater than 12 days or 12 HRT. The use of sparging also delayed the build up of acetic acid in the bioreactor, suggesting that it serves to inhibit homoacetogenesis and thus maintain hydrogen production.