脉动热管与纳米流体技术在换热器上应用的研究现状及展望

在阐述脉动热管与纳米流体技术在提高换热器效率的基础上,进一步分析了现有研究的特点与存在的问题,提出了在未来的强化换热技术中,脉动热管技术、纳米流体技术以及这2种技术的结合使用,将是强化换热技术的一个重要发展方向。     

抽油机节能方法与变频技术合理应用研究

为了充分发挥变频技术在抽油机节能方面的潜能,大范围地推广变频技术在油田上的应用。本文从多角度阐述了变频技术在抽油机节能方面的巨大优势以及一些常用油田节能方法的局限性,结合交流调速理论总结出变频技术应用存在的一些缺陷。最后,提出一种合理可靠易实行的抽油机变频节能技术。通过理论分析、现场试验表明上述技术可以有效地解决变频技术应用中出现的不足。     

促进IGCC发电技术在我国发展的建议

本文对当今洁净煤技术之一的整体煤气化联合循环的系统进行了介绍,分析了该技术的主要优点、存在的主要问题,介绍了发达国家在该技术领域的发展趋势和当前的主要工程实践。分析认为,当前在节能减排压力日渐增大的前提下,相对超超临界等发电技术而言,IGCC作为可预见的高效发电技术,在碳减排技术环节具有强大的优势。因此,当前大力发展IGCC技术是我国电力工业必然选择。通过分析,本文同时对我国发展该技术提出了建议。     

煤矿掘进技术及安全生产管理探讨

煤矿企业的发展与掘进技术息息相关,先进的掘进技术可以在很大程度上保证煤矿开采的高效和安全进行。随着煤矿开采强度进一步增大,对煤矿掘进技术要求更高,因此,在保证安全的前提下,实现煤矿的高效掘进非常重要。具体分析了煤矿中常见的掘进技术,主要有钻爆技术、掘锚机组一体化技术、光面爆破技术、深孔爆破技术等。在施工的过程中需要关注安全生产管理工作,采取一系列措施确保煤矿掘进顺利推进。     

可持续建筑设计中的技术策略研究

文中阐述了被动式技术、主动式技术、高技术、低技术在建筑可持续设计中的适用性和价值意义,以及四种技术策略的特性、优势、不足和应用前景,并对这四种技术策略在可持续架构下的关系进行了分析,最后归纳出建筑设计走可持续之路所需要的五个技术系统,即可持续建筑的技术策略体系。设计依赖于技术,技术需要被设计,未来的可持续建筑必然越来越需要系统技术的策略支持。     

先进测量技术在船用柴油机制造中的应用分析

针对我国船用柴油机制造中先进测量技术相对薄弱的现状;对先进测量技术,如三坐标扫描测量技术、关节臂测量技术、激光跟踪测量技术、激光干涉测量技术,以及在机测量技术在船用柴油机制造中的应用进行了介绍和分析,并提出了相应的建议。     

我国火电机组技术发展方向探讨

分析了目前我国火电机组技术同国外先进技术的差距。在安全经济运行技术、大型超临界火电机组技术、洁净煤发电技术、燃煤火电厂脱硫脱硝技术等新技术方面 ,结合国外先进技术 ,对我国今后火电机组技术的发展提出了建议。发展方向就是不断引进、吸收国外先进技术 ,使我国的电力工业上一个新的台阶。     

紫外成像检测技术在电力设备放电检测上的应用

紫外检测作为高压电气设备放电的一种在线检测技术,目前已在我国得到了越来越多的应用和推广。阐述了紫外成像检测技术的工作原理及技术特点,并与传统的预防性试验、红外检测技术作了详细比较。结合具体实例,对紫外成像检测技术在输变电设备上的实际应用作了详细分析,并一一分析了影响紫外成像检测结果准确度的因素。在此基础上,指出了紫外成像检测技术在实际应用中尚需解决的问题,并明确了该技术今后的发展方向。     

物探技术在煤矿地质探测中的应用研究

近些年来,物探技术在探测煤矿地质情况中广泛应用,并取得了十分可观的效果。一方面,在煤矿井下地质勘测过程中应用物探技术可以提升勘测的效率、准确性和精确度;另一方面,应用物探技术可以正确指引煤矿井下作业,促使井下施工进程的顺利进行。首先对物探技术在煤矿地质探测中的重要性进行了系统阐述;其次图文并茂地分析了煤矿地质探测中常用的三种物探技术,分别是地震勘探技术、无线电坑透技术和电法勘探技术,这三种技术各有特色,都能够满足中国煤矿企业的地质探测需求;最后从两个方面阐述了煤矿地质探测中物探技术的应用,分别是探测煤矿地质构造和防治水害。物探技术可以很好地应用于地质勘测中,希望此次研究可以为提升物探技术在地质勘测中的应用效果及效率提供些许参考。     

大容量锅炉尾部烟道空气动力场研究

阐述了北方农村秸秆高效利用技术研究的重要意义;对各种秸秆高效利用技术进行了分析,指出了它们推广应用的技术关键。秸秆固化成型技术在近期已经具备一定推广应用条件。秸秆成型燃料燃烧特性艮好,且便于储存和运输。秸秆成型加工可以作为秸秆燃料的预处理技术,为各种秸秆的高效利用技术特别是直接燃烧技术准备原料。秸秆成型机技术已有较大进步,进一步研究需要在降低能耗和提高成产率方面开展。     

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.     

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。     

Contents in Volume 23,2014

<正>~~     

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.