SWAT模型在大尺度流域的应用探索

为检验SWAT模型在大尺度流域径流模拟的应用效果，构建了巴西巴拉那河上游流域分布式水文模型并分析了模型的敏感性参数，利用17个流量站进行模型参数率定和验证。结果表明，土壤蒸发补偿系数和SCS径流曲线数是影响模拟的最敏感参数；对于实测站点密度较大的子流域，模型可以较好地模拟流域径流变化，17个流量站中有11个站的R²值大于0.5;受降水数据不足和土地利用变化等因素的影响，模型验证期表现不如率定期。可见SWAT模型可以作为大尺度流域的径流模拟工具，但模拟精度很大程度上取决于降水数据质量。     

基于SUFI-2算法的SWAT模型在修水流域径流模拟中的应用

为在江西修水流域高沙水文站以上汇水区域构建SWAT分布式水文模型,采用SUFI-2算法进行模型参数敏感性分析、率定、验证及不确定性分析,对修水流域1984~2003年月径流量过程进行模拟。结果表明,敏感度最强的前三个参数依次为土壤饱和导水率、土壤蒸发补偿系数和径流曲线数;率定期与验证期的纳什系数ENS值和相关系数R2值均高于090,月径流量模拟值与实测流量过程线拟合程度较好;95PPU置信区间的模拟值和实测值较为一致;不确定性区间较小,验证期小于率定期;实证了采用SUFI-2算法的SWAT模型在修水流域月径流模拟中具有一定程度的适宜性。     

基于SWAT模型的呼玛河流域径流对气候变化的水文响应

呼玛河流域降水及冰雪融水的补给对于黑龙江干流径流量变化影响巨大,而气候变化是影响呼玛河降水及冰雪融水的一个重要因子。因此,通过收集呼玛河流域呼玛、新林、塔河、呼中气象站及呼玛桥水文站的数据,结合DEM数据、土地利用数据及土壤数据,构建适用于呼玛河流域的SWAT径流模型并进行月径流模拟,同时通过天气发生器设定温度与降水梯度,研究呼玛河流域径流对气候变化的响应。结果表明,SWAT模型在呼玛河流域具有良好的适应性,率定期及验证期的决定系数R²、纳什系数N_NSE均达到了模型的评价标准;呼玛河流域径流对降水变化的敏感性远高于气温,降水是该流域径流变化的主要控制因子。     

基于SWAT模型的岚河流域径流模拟

为探索SWAT模型在干旱半干旱地区径流模拟中的适用性,以岚河流域为例,应用SWAT模型对该流域年、月径流进行了模拟研究,选取1971~1987年的水文气象数据,结合GIS、RS、DEM技术选择径流曲线法（SCS）、蒸散发Penman-Monteith法、河道演算Variable storage法模拟流域分布式径流过程。结果表明,率定期与验证期的决定系数R2和Nash效率系数Ens分别在0.73~0.93和0.69~0.75之间,较好地反映了岚河流域的年、月径流水文过程,模型适用性较好,可为当地水资源评价、开发利用和优化配置提供技术支持。     

信江流域土地利用变化的径流响应研究

针对信江流域土地利用变化的径流响应,基于分布式水文模型（SWAT）及SUFI 2算法,利用流域DEM、土地利用、土壤、气象等时空数据并结合GIS和RS技术,对流域土地利用变化的径流响应进行定量研究。结果表明,率定期和验证期的模拟值与实测流量过程拟合程度较优,相关系数（R2）和纳西效率系数ENS均高于0.90、相对误差|Re|均小于2%,表明SWAT模型应用于该流域径流模拟的精度较高;在相同气候条件下,径流年内分配规律为2000年土地利用情景较1990年土地利用条件下月径流增加,年际分配规律为两期土地利用情景下的年际径流量变化趋势较为一致,2000年略大于1990年。     

石臼湖流域水环境联合数学模型与污染物削减研究

为了解石臼湖流域污染特征,将分布式水文模型SWAT模型与平面二维数学模型MIKE21模型相结合,定量计算石臼湖流域入湖污染负荷和入湖河流污染物削减量.研究表明,SWAT模型对径流、氮负荷和磷负荷模拟决定系数R2均大于0.6,MIKE21模型对总氮、总磷浓度模拟平均相对误差均小于0.3,SWAT模型和MIKE21模型在石...     

基于SDSM-SWAT模型的汉江上游径流变化模拟

为分析汉江上游流域径流对气候变化的水文响应过程,耦合了SWAT水文模型和SDSM降尺度模型,选用石泉和黄家港水文站1990～2005年历史月径流资料,对水文模型进行率定和验证,并将2011～2100年CanESM2模式下低等排放情景(RCP2.6)和高等排放情景(RCP8.5)两种情景输出因子降尺度到汉江上游流域各站点,生成未来气候情景数据,模拟流域未来气候变化下的径流响应过程。结果表明,SWAT模型在该流域径流模拟中具有很好的适用性;未来流域径流会呈现增加态势,RCP8.5情景较RCP2.6情景变化剧烈,且未来各月径流相对基准期变化更加剧烈,这为流域水资源管理与保护提供了参考与支持。     

基于SWAT模型的洮儿河流域气候变化的水文响应

鉴于未来气候变化趋势对洮儿河流域水资源的影响,将直接关系到下游地区湿地保护、区域社会经济发展、白城市各河流与嫩江的河库连通工程等,以SWAT模型为研究手段,选取1988~1996年的流域实测数据,对SWAT模型进行率定和验证,基于率定好的模型分析气候变化情景下洮儿河的径流变化趋势。结果表明,SWAT模型具有较高的模拟精度,可用于洮儿河流域的径流模拟;在未来气候变化情景下,洮儿河流域的径流量（2020、2030、2040年代）比基准期（1990~1996年）稍有增加,其阶段径流量呈现先增后减的趋势。     

不同分辨率下SWAT模型在大汶河径流模拟中的应用

以大汶河流域为例,借助SWAT模型,采用SUFI2方法进行参数率定,以Nash-Sutcliffe为目标函数,分别对2008~2009年大汶河流域8组不同分辨率组合的数据(DEM数据和土地利用数据)进行了16次迭代,每次迭代300次模拟,并通过添加两组分辨率不匹配的组合模拟,探究了分辨率匹配与否对模拟径流结果的影响。结果表明,各分辨率组合模拟的Nash-Sutcliffe效率系数(NSE系数)和决定系数(R2)均超过了0.85,偏差百分比(P_(BIAS))绝对值均小于10%,说明不同分辨率组合下模型对大汶河流域校准模拟结果均较好;分辨率不匹配的模拟结果比分辨率匹配的模拟结果稍差;30×30(DEM和土地利用分辨率均为30m)组合为大汶河流域模拟的最佳分辨率组合。     

点源影响下的SWAT模型非点源负荷核定方法

在多参数模型应用中,单纯以控制断面资料为标准进行校核易导致模型参数的不确定性,而估算点源和实际点源输入的误差将进一步加大此不确定性。为解决点源影响下流域污染负荷核定问题,提出采用断面水质校核与流域输出系数评价相结合的方法进行SWAT模型的率定和验证,并将其应用于鞍山市南沙河流域污染负荷的模拟中。结果表明,南沙河断面水质模拟结果符合污染物质输出规律,不同土地利用类型的输出系数计算结果合理,可见SWAT模型在以点源污染为主的流域同样具有较好的适用性。     

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.