1Cr12Ni2W1Mo1V钢的补充试验

通过对１米叶片材料１Ｃｒ１２Ｎｉ２Ｗ１ｍｏ１Ｖ钢在提高强度等级后的力学性能补充试验,可以看出１Ｃｒ１２ＮｉＷ１Ｍｏ１Ｖ钢在１０１０℃油淬,在５７０℃回火处理后,其塑性,韧性完全能满足日立６００ＭＷ汽轮机末级４０英雨叶片材料１２％Ｃｒ－Ｎｉ－Ｍｏ－Ｖ钢的要求。     

30Cr2Ni4MoV转子钢室温裂纹扩展性能研究

研究了汽轮机转子钢３０Ｃｒ２Ｎｉ４ＭｏＶ在各种加载情况下的疲劳裂纹扩展性能，着重研究了频率，载荷比等试验控制量对对裂纹展展的影响，得到了３０Ｃｒ２Ｎｉ４ＭｏＶ转子钢纹扩展速率的一般关系式，这些关系式与试验数据吻合较好，便于实际应用。     

125MW汽轮机低压转子剩余寿命及安全风险研究

１２５ＭＷ汽轮机低压转子剩余寿命及安全风险研究余耀，王，王静飞１概述早期国产１２５ＭＷ汽轮机低压转子采用１７ＣｒＭｏ１Ｖ钢焊接转子，这种转于材料显然能满足结构强度的要求，但其断裂强度则较差，它的断口形貌转变温度ＦＡＴＴ达１－－１０ｔ，机组在正常运行时...     

600MW汽轮机转子疲劳寿命计算

采用电厂实际启、停机曲线对６００ＭＷ汽轮机组的高、中压转子分别进行了三维瞬态温度场及非线性应力场分析,并采用３０Ｃｒ１ＭｏＶ低周疲劳曲线对机组在实际启、停过程中的寿命损耗进行了估算。温度场及应力场的计算采用轴对称有限元法。     

疲劳短裂纹的试验和理论标定方法

利用交流电位法和边界元法，从实验和理论两方面对汽轮机转子材料３０Ｃｒ２ＭｏＶ钢进行了疲劳短裂纹扩展标定方法的研究。实验与理论对比表明，结果相当一致。     

锅炉用高强低合金钢材料的研制

一种新的用于燃烧锅炉的材料－低Ｃ－２．２５Ｃｒ－１．６Ｗ－Ｖ－Ｎｂ钢（ＨＣＭ２Ｓ）已研制出来。这种钢１００００小时外推蠕变断裂强度大约高于２．２５Ｃｒ－１Ｍｏ钢（Ｔ２２）１．８倍，几乎与改进的９Ｃｒ－１Ｍｏ钢（Ｔ９１）相同。这种极高的强度是用Ｗ代替Ｍｏ获得的。由于这种新研制钢的含碳量低，所以其焊接性能优于传统的Ｃｒ－Ｍｏ钢。较低的碳含量使得该钢焊前不可预热，焊后不用热处理。我们对这种新研制钢制成的     

12CrMoV钢厚板性能研究

本文通过对午阳钢铁公司生产的厚９０ｍｍ １２Ｃｒ１ＭｏＶ钢板各项性能试验，研究了１２Ｃｒ１ＭｏＶ钢厚板性能特性及作为锅炉用钢使用时应注意的问题。研究结果认为，１２Ｃｒ１ＭｏＶ钢厚板正火、回火状态５４０℃持久强度偏低达不到有关文献所推荐的性能指标。另外，１２Ｃｒ１ＭｏＶ钢厚板缺口敏感性高也是应注意的问题之一。     

某电厂高压主汽阀阀碟锈蚀分析

用物理、化学和能谱分析方法，对某电厂高压主汽阀阀碟及其套筒的锈蚀原因进行了研究和分析。结果表明，３０Ｃｒ１Ｍｏ１Ｖ钢和３０Ｃｒ２ＭｏＶ钢的抗氧化性能相当，电厂所用热蒸汽品质不符合标准。     

国产改良型9Cr—1Mo钢的焊接热裂纹敏感性研究

本研究采用可变拘速热裂纹试验方法研究阵产改良型９Ｃｒ－１Ｍｏ钢的焊接热裂纹敏感性，研究结果表明，尽管国产改良型９Ｃｒ－１Ｍｏ钢中的Ｓ、Ｐ含量很低，但采用较大焊接线能量进行焊接时，仍铁产生焊接热裂纹，并且其焊接热纹敏感性大于２－１／４Ｃｒ－１Ｍｏ、１２Ｃｒ１ＭｏＶ及１Ｃｒ１８Ｎｉ１９Ｔｉ这种常锅炉钢材，建议焊钢时，应采较小的线能量。     

30Cr1Mo1V钢转子锻件差异热处理工艺研究

用差异热处理的方法处理了３０Ｃｒ１Ｍｏ１Ｖ钢高、低压联合转子,使转子性能满足了设计要求,特别是低压侧的脆性转变温度ＦＡＴＴ５０降至工作温度以下。与原油冷工艺相比,差异热处理方法明显改善了转子的综合性能。     

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.     

Contents in Volume 23,2014

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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%.     

Performance assessment of some ice TES systems

In this paper, a performance assessment of four main types of ice storage techniques for space cooling purposes, namely ice slurry systems, ice-on-coil systems (both internal and external melt), and encapsulated ice systems is conducted. A detailed analysis, coupled with a case study based on the literature data, follows. The ice making techniques are compared on the basis of energy and exergy performance criteria including charging, discharging and storage efficiencies, which make up the ice storage and retrieval process. Losses due to heat leakage and irreversibilities from entropy generation are included. A vapor-compression refrigeration cycle with R134a as the working fluid provides the cooling load, while the analysis is performed in both a full storage and partial storage process, with comparisons between these two. In the case of full storage, the energy efficiencies associated with the charging and discharging processes are well over 98% in all cases, while the exergy efficiencies ranged from 46% to 76% for the charging cycle and 18% to 24% for the discharging cycle. For the partial storage systems, all energy and exergy efficiencies were slightly less than that for full storage, due to the increasing effect wall heat leakage has on the decreased storage volume and load. The results show that energy analyses alone do not provide much useful insight into system behavior, since the vast majority of losses in all processes are a result of entropy generation which results from system irreversibilities.     

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.     

Effect of co-cultivation of Chlamydomonas reinhardtii with Azotobacter chroococcum on hydrogen production

Chlamydomonas reinhardtii cc124 and Azotobacter chroococcum bacteria were co-cultured with a series of volume ratios and under a variety of light densities to determine the optimal culture conditions and to investigate the mechanism by which co-cultivation improves H₂ yield. The results demonstrated that the optimal culture conditions for the highest H₂ production of the combined system were a 1:40 vol ratio of bacterial cultures to algal cultures under 200 μE m^?2 s^?1. Under these conditions, the maximal H₂ yield was 255 μmol mg^?1 Chl, which was approximately 15.9-fold of the control. The reasons for the improvement in H₂ yield included decreased O₂ content, enhanced algal growth, and increased H₂ase activity and starch content of the combined system.     

Natural-gas fueled spark-ignition (SI) and compression-ignition (CI) engine performance and emissions

Natural gas is a fossil fuel that has been used and investigated extensively for use in spark-ignition (SI) and compression-ignition (CI) engines. Compared with conventional gasoline engines, SI engines using natural gas can run at higher compression ratios, thus producing higher thermal efficiencies but also increased nitrogen oxide (NO_x) emissions, while producing lower emissions of carbon dioxide (CO₂), unburned hydrocarbons (HC) and carbon monoxide (CO). These engines also produce relatively less power than gasoline-fueled engines because of the convergence of one or more of three factors: a reduction in volumetric efficiency due to natural-gas injection in the intake manifold; the lower stoichiometric fuel/air ratio of natural gas compared to gasoline; and the lower equivalence ratio at which these engines may be run in order to reduce NO_x emissions. High NO_x emissions, especially at high loads, reduce with exhaust gas recirculation (EGR). However, EGR rates above a maximum value result in misfire and erratic engine operation. Hydrogen gas addition increases this EGR threshold significantly. In addition, hydrogen increases the flame speed of the natural gas-hydrogen mixture. Power levels can be increased with supercharging or turbocharging and intercooling. Natural gas is used to power CI engines via the dual-fuel mode, where a high-cetane fuel is injected along with the natural gas in order to provide a source of ignition for the charge. Thermal efficiency levels compared with normal diesel-fueled CI-engine operation are generally maintained with dual-fuel operation, and smoke levels are reduced significantly. At the same time, lower NO_x and CO₂ emissions, as well as higher HC and CO emissions compared with normal CI-engine operation at low and intermediate loads are recorded. These trends are caused by the low charge temperature and increased ignition delay, resulting in low combustion temperatures. Another factor is insufficient penetration and distribution of the pilot fuel in the charge, resulting in a lack of ignition centers. EGR admission at low and intermediate loads increases combustion temperatures, lowering unburned HC and CO emissions. Larger pilot fuel quantities at these load levels and hydrogen gas addition can also help increase combustion efficiency. Power output is lower at certain conditions than diesel-fueled engines, for reasons similar to those affecting power output of SI engines. In both cases the power output can be maintained with direct injection. Overall, natural gas can be used in both engine types; however further refinement and optimization of engines and fuel-injection systems is needed.     

Controls on the Karaha–Telaga Bodas geothermal reservoir,Indonesia

Karaha–Telaga Bodas is a partially vapor-dominated, fracture-controlled geothermal system located adjacent to Galunggung Volcano in western Java, Indonesia. The geothermal system consists of: (1) a caprock, ranging from several hundred to 1600 m in thickness, and characterized by a steep, conductive temperature gradient and low permeability; (2) an underlying vapor-dominated zone that extends below sea level; and (3) a deep liquid-dominated zone with measured temperatures up to 353 °C. Heat is provided by a tabular granodiorite stock encountered at about 3 km depth. A structural analysis of the geothermal system shows that the effective base of the reservoir is controlled either by the boundary between brittle and ductile deformational regimes or by the closure and collapse of fractures within volcanic rocks located above the brittle/ductile transition. The base of the caprock is determined by the distribution of initially low-permeability lithologies above the reservoir; the extent of pervasive clay alteration that has significantly reduced primary rock permeabilities; the distribution of secondary minerals deposited by descending waters; and, locally, by a downward change from a strike-slip to an extensional stress regime. Fluid-producing zones are controlled by both matrix and fracture permeabilities. High matrix permeabilities are associated with lacustrine, pyroclastic, and epiclastic deposits. Productive fractures are those showing the greatest tendency to slip and dilate under the present-day stress conditions. Although the reservoir appears to be in pressure communication across its length, fluid, and gas chemistries vary laterally, suggesting the presence of isolated convection cells.     

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.