气体燃料发动机增压技术

在气体燃料发动机的开发过程中,增压器匹配的正确与否,是决定发动机最终性能的重要环节之一。本文论述了气体燃料发动机增压技术的特点,提出了气体燃料发动机与涡轮增压器配合运行的基本要求,阐明了气体燃料发动机在增压器选型、匹配试验过程中需要注意的一些问题。     

气体燃料发动机新技术(二)

介绍气体燃料发动机几种新技术的基本原理和特点。气体燃料发动机可用的技术包括：增压中冷技术、废气再循环技术、催化氧化还原技术、天然气缸内直接喷射技术、层状进气稀薄燃烧技术、预燃室技术等。     

点燃式内燃机气体燃料电控喷射技术的研究

气体燃料被认为是很有前途的车用低污染代用燃料。本文对气体燃料进气门电控喷射技术进行了研究，研制了气体燃料喷射系统、电子点火系统和发动机控制系统，对空燃比、压缩比和充气系数等参数对发动机性能的影响进行了试验与分析。     

一种生物质气体燃料发动机控制系统及其仿真研究

针对生物质气化发电技术中气体燃料成分的差异对生物质气体燃料发动机的输出功率造成不稳定影响的问题,文章提出一种控制系统,给出了系统的控制方案,根据生物质气体燃料发动机的原理,建立数学模型,并完成了控制系统的仿真研究。结果表明,该控制系统能够有效改善生物质气体燃料发动机的输出功率,具有较好的动态性能和抗干扰性,满足控制要求。     

6~ГЧ36/45型气体燃料发动机的使用经验

为了确定气体燃料发动机和普通柴油机相比的技术经济效果,苏联中央柴油机研究所在斯塔夫罗波尔一莫斯科天然气输气管的四个发电站对6~ГЧ36/45型气体燃料发动机的使用情况进行了研究.同时对一座柴油发电站也进行了研究,以便比较气体燃料发动机和柴油机的指标. 《革命发     

气体燃料发动机动力性分析及对策

根据不同燃料的理化特性,从理论和试验上研究了天然气体燃料发动机动力不足的原因.研究表明,气体燃料发动机容积效率并未发生明显变化,动力不足的主要原因在于气体燃料理论空燃比大、混合气密度低和分子量较低.其相应的最有效对策是采用缸内喷射技术.     

气体燃料发动机超载保护装置的研制

<正> 一般情况下,气体燃料发动机与柴油机相比,其进气空气过量系数小、排气温度高,因此它的超载保护尤为重要。本文简要介绍一种通过检测发动机转速和进气升压来控制被驱动侧负载的超载保护装置,这种装置适用于气体燃料发动机热泵系统。1 气体燃料发动机进气管系气体燃料发动机进气管系如图1所示。来自供气管道1的气体燃料经调压器2调整后进入膜片式汽化器3,同时空气也经过滤清器4     

28/32气体喷射发动机技术状况

<正> 1 前言气体喷射发动机是以气体燃料为主,以少量柴油作为引燃点火的双燃料发动机,这种发动机采用了一个与柴油机喷油系统相似的气体燃料高压喷射系统,将气体燃料喷入气缸中。气体喷射发动机可用不同品质的气体燃料,对润滑油质量没有特殊要求,热效率与柴油机相同。因而,此类发动机逐步被一些用户接受。国际上一些著名的发动机制造厂     

气体发动机燃料特性参数计算软件开发及应用

不同气体燃料物理、化学性质不同,直接关系到气体发动机的结构设计及各项性能指标;对各种气体燃料特性进行分析及评价是气体发动机设计首先要解决的问题。开发了气体燃料特性参数计算软件,对各种气体燃料的物理、化学特性进行了分析、计算,并就这些参数对气体机性能的影响进行了分析,供气体发动机设计做参考。     

有关国外往复式气体燃料发动机的情况

1.引言气体燃料发动机是内燃机的始祖,最早出现于19世纪后半期.但是,由于当时燃料生产仍以煤炭为主,石油、气体燃料资源开发不足,大大地限制和阻碍了气体燃料发动机的发展.随着石油类液体燃料的开发、国外燃料生产构成发生变化和压燃式发动机的出现,在20世纪前半期,气体燃料发动机便让位给液体燃料发动机了. 随着石油和天然气工业的相继兴起,煤炭在燃料构成中的地位不断下降,石油、天然气     

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.