淇县地区地下水化学特征及其影响因素分析

为了解淇县地区地下水化学特征,选取57个水样数据,运用统计分析、相关性分析以及Gibbs方法分析了淇县地区地下水水化学特征。结果表明,淇县地区从山区到平原地下水更新速度逐渐变慢,EC逐渐升高;TDS与Na~+、Cl~-、SO_4~(2-)、HCO_3-相关性很高;深层地下水整体呈HCO_3-Ca·Mg型水,浅层地下水化学整体呈水平分带性,从淇河上游HCO_3-Ca型水到淇河中游的HCO_3-Ca·Mg型水再过渡到淇河下游的HCO_3·Cl-Ca·Mg和HCO_3·SO4-Ca·Mg·Na型水;局部地区出现地下水点状污染。淇县地区水化学主要受岩性控制,局部地区受水动力条件及人为因素影响。研究成果可为淇县地区地下水污染防治提供参考。     

桐梓隧道岩溶地下水化学特征及水质评价

为分析桐梓隧道岩溶地下水水化学特征和水质情况,运用Piper三线图、Gibbs模型、离子比例系数及Pearson相关系数矩阵等方法探究其类型及成因,并结合模糊综合评价法对地下水水质进行分类评价。结果表明,研究区地下水中Mg~(2+)、Ca~(2+)、HCO_3~-占主要优势,Mn、As、Se的含量极低;地下水化学类型以HCO_3-Ca、HCO_3·SO_4-Ca·Mg型水为主;水化学形成主要来源于岩石风化碳酸盐岩(如方解石、白云石),少部分来源于硅酸盐岩、石膏、钠长石等矿物溶滤,大气降水和人为因素也有一定影响,表现为隧道施工加速了岩石溶蚀风化;模糊综合评价表明研究区地下水水质良好,以Ⅰ、Ⅲ类为主。研究结果可为隧道区地下水水资源保护及利用提供参考。     

阳泉市娘子关岩溶地下水水化学特征及其成因

针对娘子关泉域水化学分析不能即时评价且偏主观性的问题,加入离子空间分布图,对娘子关泉域岩溶地下水的13个水化学特征指标运用描述性统计、水化学类型、TDS和总硬度分布图等进行分析,并辅助以Pearson相关分析探究其成因。结果表明,个别水样超过地下水环境质量标准,Fe~(3+)、Na~+具有较大空间变化,其他元素相对稳定;除少部分为微咸水和软水、微硬水、硬水,大部分地区为淡水和极硬水;地下水水化学类型以HCO_3-Ca·Mg、SO_4·HCO_3-Ca、SO_4·HCO_3-Ca·Mg型为主,部分补给区和径流区已转变为硫酸盐类型为主的水。该水化学特征成因主要受工矿产业影响,其次受水岩作用和农业、生活污染的影响。     

泰莱盆地地下水水化学特征及水质评价

为分析泰莱盆地地下水水化学特征及水质现状,选取2017年丰水期140件水样,其中,孔隙水样47件、岩溶水样61件和裂隙水样32件,运用数理统计、Piper三线图、箱型图等方法,分析了研究区主要离子及水化学特征,并运用模糊综合评价法、Wilcox图解法评价了水质现状及灌溉水质。结果表明,泰莱盆地主要阳离子为Ca~(2+)、Na~+,占阳离子总数的80%以上,主要阴离子为HCO_3~-、SO_4~(2-),占阴离子总数的67%以上,其中NO3-含量也相对较高;水化学类型以HCO3·SO4-Ca型水为主;pH值整体呈弱碱性,TDS存在孔隙水岩溶水裂隙水的关系,这与地下水径流条件有关;Ⅳ、Ⅴ类水样占总水样的29.3%,影响因子为SO_4~(2-)、NO3-、TDS、总硬度,其主要影响因素为人为活动;绝大部分区域均属于好—可用及以上级别,合理利用地下水灌溉可有效预防土壤盐碱化问题。     

豫北平原地下水水化学和水质分布特征

豫北平原为河南省重要的农业生产基地,其居民生活用水和农业生产用水主要依赖于地下水。为了保证工农业生产和生活用水安全,根据2018年的105个地下水化学取样分析数据,利用Piper三线图和Gibbs图研究了水化学的主要离子的空间分布特征及水化学形成机制,从而揭示了研究区水化学分布特征和主要形成作用,采用综合指标法和单因子法评价了水质问题,并分析了主要影响因素的超标情况。结果表明,豫北平原地下水类型以HCO₃-Ca·Mg、HCO₃·SO₄-Mg·Na、HCO₃·Cl-Na型水为主,地下水水化学成因以蒸发浓缩和水岩相互作用为主,浅层、中深层地下水水质Ⅳ～Ⅴ类水分布面积约占90%,深层地下水水质较好,Ⅱ～Ⅲ类水分布面积约占40%。     

双城盆地矿泉水地球化学特征与成因探讨

总结了双城盆地地下水化学特征,得出本区地下水为锶质偏硅酸矿泉水,并从水岩作用角度对矿泉水的形成机制进行了分析,结果表明:本区矿泉水主要的成因为含水层上部及含水层岩层经过长期降水渗入、溶滤作用形成可溶解性的锶岩和偏硅酸岩.     

临汾盆地地下水位动态变化数值模拟研究

采用GMS软件构建临汾盆地地下水数值模型，预测了不同驱动因素情景下地下水位的变化规律，并量化不同驱动因素对地下水位变化的影响程度，发现仅降水情景(枯、平、丰)时，浅层地下水位变幅大于承压地下水水位，降水量由458.8 mm至568.0 mm时，浅层地下水年平均水位变化速率差绝对值为0.11 m;仅压采情景(以2018年开采量为基准)下，浅层地下水位与承压地下水位有较大变化，压采由0%升至50%时，浅层地下水和中深层承压水年平均水位变化速率差绝对值分别为0.16、0.25 m;在汾河水位抬升情境下，仅对河流两侧的浅层地下水产生一定影响。研究结果可为临汾盆地地下水的合理利用提供参考依据。     

白城市浅层高氟地下水分布特征及富集机理

为分析白城市浅层地下水氟含量的分布特征和富集机理,采用Piper三线图、Kringing插值、Pearson分析、氯碱指数、Gibbs图等方法讨论了研究区F-分布规律和富集机理。结果表明,长石类矿物的溶解为F-富集提供了碱性环境。研究区F-浓度由外部向内部增大,其对应的主要水化学类型由HCO3-Ca·Na型过渡至HCO3-Na型。地下水化学成分的形成作用成为制约地下水氟富集的重要因素。方解石的沉淀和石膏的溶解影响着萤石的溶解与沉淀,蒸发浓缩作用和离子交换作用为最终高氟地下水中阳离子是Na+提供了依据。     

青居电站基础廊道渗漏水中SO_4~(2-)、Ca~(2+)浓度显著偏高成因分析

青居电站泄洪闸基础廊道渗漏水中SO_4~(2-)、Ca~(2+)的浓度异常偏高,但在闸坝变形、渗流监测中未发现大规模石膏带出量。通过分析、计算不同环境水样的水化学特征,获得了电站运行至今通过排水廊道渗漏水排出的石膏溶蚀量,结合电站库区地质条件,得出异常偏高离子浓度产生的原因并非完全是闸基地层中石膏质溶蚀,而是在更广大的区域范围内,地下水通过在地层中交错发育的陡立结构面渗流过程中溶蚀沿途石膏质后在闸基帷幕上游侧局部富集而成。     

低温烟气预浓缩脱硫废水过程中SO2溶解行为实验研究

为减少烟气浓缩过程中SO_2转移至液相而产生的SO_3~(2-)/SO_4~(2-)污泥量,通过实验研究了脱硫废水烟道内低温烟气浓缩过程中SO_2的迁移转化规律,探究了控制SO_2溶解的技术措施。结果表明:当Cl~-质量浓度高于120 000 mg/L,SO_4~(2-)质量浓度高于20 000 mg/L时对SO_2溶解有明显抑制作用;高入口SO_2质量浓度、高温和低pH可有效抑制SO_2溶解,其中pH对SO_2溶解性能的影响最明显;当pH为1.5左右时,SO_2几乎难以转移进入液相;调酸后浓缩3倍的脱硫废水仅有7.4%质量分数的SO_2溶解,脱硫废水浓缩倍数与脱硫效率成反比。     

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%.     

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.     

Contents in Volume 23,2014

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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。     

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.     

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.