二甲醚与柴油混合燃料发动机排放性能实验

通过在D6114ZLQB柴油机上进行D30混合燃料与晰柴油的性能对比实验,研究了D30混合燃料对柴油机性能的影响,并通过优化发动机供油系统参数,寻求燃用D30混合燃料的最佳排放。实验结果表明,原机供油系统经优化后燃用D30混合燃料,发动机的动力性与原柴油机相当,燃油经济性有所改善,PM排放大幅度下降,NOx在整个负荷范围内得到有效控制。     

增压柴油机掺烧二甲醚的实验研究

通过在D6114ZLQB柴油机上进行对比实验,研究了D30混合燃料对柴油机性能的影响,并通过优化发动机系统参数,寻求在柴油机上燃用D30混合燃料的最佳排放.实验结果表明:在对原机供油系统进行优化调整后,增大循环供油量,能够保持原机的动力性;优化后与原柴油机水平比较,碳烟排放在中、高负荷时降低明显,在转速为1800r·min(-1)时降幅达到87.8%;在整个负荷范围内Nox排放平均降低20%左右;而HC排放在中、低负荷下较高,但在所有工况下排放均优于柴油.     

可控脉冲增压系统对D6114柴油机性能影响研究

可控脉冲增压系统可以实现气缸相对排气容积的调节,具有兼顾发动机高低转速工况的优势。本文针对D6114ZLQB型柴油机,建立了该发动机可控脉冲增压系统GT-POWER仿真模型,通过不同排气容积条件下发动机性能试验校核了仿真模型。计算研究了不同转速下可控脉冲增压排气系统排气压力波和进气压力变化规律,探讨了脉冲增压系统和准定压增压系统在不同转速下的适应情况。通过仿真计算研究了可控脉冲增压系统对柴油机性能的影响,确定了可变脉冲增压系统的切换边界。     

车用增压二甲醚发动机燃烧和排放特性的试验研究

在一台D6114ZLQB柴油机上进行了燃用二甲醚（DME）的燃烧和排放特性的试验研究。研究结果表明：二甲醚发动机的外特性转矩特别是低速转矩比柴油机高;二甲醚喷油延迟角比柴油大,最高爆发压力、最大压力升高率、燃烧噪声比柴油低;二甲醚扩散燃烧速率比柴油快,燃烧持续期比柴油短。和柴油机相比,二甲醚发动机的NO,排放显著下降,其欧洲稳态测试循环（ESC的NOx排放比原柴油机降低41．6％;二甲醚发动机在全工况范围内碳烟排放为零。     

使D6114车用柴油机排放达到欧洲Ⅰ号标准的试验研究

介绍了国内外车用柴油机的排放法规及限值标准;通过对排气污染物生成机理的分析,对D6114系列柴油机排放进行了大量试验研究,提出了具体的技术措施,如采取增压中冷、推迟喷油、高压喷射及优化燃烧室形状、采用小喷孔油嘴等措施,使其达到了欧洲Ⅰ号标准。     

车用柴油机涡轮增压匹配系统软件开发

根据涡轮增压柴油机的平均参数模型,建立了车用柴油机增压选型与匹配系统,可以完成对增压方案的选取、增压参数的计算以及增压器型号的选取等工作;以Visual C++为开发平台,进行了系统软件的开发;以D6114柴油机为例进行了匹配计算,并与相应的试验结果进行对比,两者吻合良好,进一步验证计算模型、程序的正确性。     

仿真技术在柴油机性能匹配中的应用

采用GT-Power工作过程模拟计算软件建立CA6110/125型增压中冷柴油机计算模型,通过增压系统、进排气系统、配气相位参数等改变预测柴油机性能,确定最终参数,达到柴油机性能优化设计目的.根据计算结果确定的优化方案,在柴油机上进行了配机试验,试验结果表明,实际配机试验结果与计算比较吻合,应用模拟技术手段能对柴油机各系统参数确定起到指导作用.     

用PLC、变频器技术实现数控系统电气改造

ZHS-ZHF1113气缸盖阀座锥面及导管孔精加工专能化机床是加工D6114柴油机气缸盖的关键设备。该机床工作滑台的交流伺服数控系统丝杠存在间蔽误差,为适应上柴公司D6114柴油机批量生产的需要,我们对该机床电气控制系统进行了改造。     

D6114ZL Q8B型柴油机达欧Ⅱ排放性能攻关

以D6114ZLQ8B型220 kW柴油机为例,通过对燃油系统、燃烧系统、增压系统等的改进,优化了发动机的工作过程,使该机型性能良好,且将柴油车尾气污染物一氧化碳(CO)、碳氢化合物(HC)、氮氧化物(NOx)和颗粒污染物(PM)等,特别是控制的重点NOx和PM的排放量得到控制,D6114ZLQ8B型柴油机通过济南汽车检测中心的检验达到了欧Ⅱ排放标准.     

D6114ZL Q8B型柴油机达欧Ⅱ排放性能攻关

以 D6114Z_LQ8B 型220 kW 柴油机为例，通过对燃油系统、燃烧系统、增压系统等的改进，优化了发动机的工作过 程，使该机型性能良好，且将柴油车尾气污染物：一氧化碳(CO)、碳氢化合物(HC)、氮氧化物(NO_x)和颗粒污染物(PM) 等，特别是控制的重点 NO_x 和 PM 的排放量得到控制，D6114Z_LQ8B 型柴油机通过济南汽车检测中心的检验达到了欧Ⅱ 排放标准。     

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.     

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.     

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.