一种新型共轨蓄压柴油机电控单体喷油器

介绍了一种新型共轨蓄压式喷油规律可控的柴油机电控单体喷油器－－ＰＡＩＲＣＵＩ。这种喷油器基于蓄压式喷油器的工作原理,喷射过程受电控单元控制,喷油速率受喷油器内部结构参数的控制。其结构简单,喷油定时灵活可调,对油尖及管路的要求简单。ＰＡＩＲＣＵＩ还具备实现高效率低排放燃烧过程的特性：高的平均有效喷射压力、预喷射及快速断没一功能。喷油压力与发动机转速无关,但与发动机负荷有关。这些特性对改善发动机放和燃     

电控汽油机喷油器流量特性的试验研究

喷油器是电控燃油喷射发动机的核心部件,其流量精度直接影响着发动机的动力性、燃油经济性以及排放等。本文利用自主开发的一套单片机控制喷油系统,对K157FMI改装电喷摩托车汽油机所匹配的电磁式喷油器进行了流量特性标定试验,并对喷油器的喷油量进行了电压修正。     

船用柴油机蓄压式电控喷油器计量特性数字孪生才型研究

为实时准确地观测电控喷油器的喷油量,实现喷油过程的闭环控制,针对某船用柴油机蓄压式电控喷油器结构特征,根据其燃油流动过程和蓄压腔压力变化规律,利用理论机理计算与神经网络修正相结合的方法,建立了电控喷油器计量特性数字孪生模型。通过建立快速原型样机进行在线试验验证,对比喷油器计量特性数字孪生模型观测值与平台实测值。试验结果表明:当电控喷油器每循环喷油量大于1000 mm³时,喷油量计算误差在3%以内;当每循环喷油量小于1000 mm³时,喷油量计算误差在10%以内。     

船用柴油机蓄压式电控喷油器计量特性数字孪生模型研究

为实时准确地观测电控喷油器的喷油量,实现喷油过程的闭环控制,针对某船用柴油机蓄压式电控喷油器结构特征,根据其燃油流动过程和蓄压腔压力变化规律,利用理论机理计算与神经网络修正相结合的方法,建立了电控喷油器计量特性数字孪生模型。通过建立快速原型样机进行在线试验验证,对比喷油器计量特性数字孪生模型观测值与平台实测值。试验结果表明:当电控喷油器每循环喷油量大于1 000 mm~3时,喷油量计算误差在3%以内;当每循环喷油量小于1 000 mm~3时,喷油量计算误差在10%以内。     

无污染柴油机燃油电控喷射系统

无污染柴油机燃油电控喷射系统１前言通常燃油喷射系统（ＦＩＳ）必须满足如下要求：具有高压性能；控制喷射压力，控制喷射定时和喷油速率。一般在喷射过程中增加喷射压力是促使燃油液滴尺寸减小和改善燃烧状况并使炭烟排放降低。燃油液滴尺寸的减小在１００ＭＰａ的压力...     

双电磁阀增压喷油器喷油特性试验研究

近些年来,双电磁阀增压喷油器解决方案因其喷油规律可变,喷油器内部蓄压喷射的特性,在节油环保以及优良的发动机瞬态响应特性方面成为未来喷油器研究的热点,也代表喷油器的发展方向。针对双电磁阀增压喷油器,研究了双电磁阀协同工作时多种喷油规律的实现方法,并进行了试验验证,以期获得不同的喷油控制效果。最后,通过比较增压与非增压喷射喷油量的差异,分析并确定了增压喷油器的压力放大倍数。     

GD-1高压共轨燃油喷射系统的应用研究

将GD-1高压共轨电控燃油喷射系统配备在YC6112ZLQ发动机上,通过一系列调整喷油参数的试验,探讨了喷油压力、喷油正时和预喷射对发动机性能和废气排放的影响规律.根据这些规律,对喷油参数在所有工况范围内进行匹配标定,并将标定后的共轨系统用于YC6112ZLQ柴油机.研究表明GD-1高压共轨电控燃油喷射系统在控制喷油参数方面有很大的灵活性,对降低废气排放和改善发动机的性能有很大潜力.     

船用中速柴油机电控燃油喷射系统匹配

针对4190船用中速柴油机,提出由电控组合泵替代传统机械泵,利用AMESim软件建立电控组合泵燃油喷射系统模型,确定试验用凸轮型线、喷孔直径、油泵柱塞直径、高压油管长度等参数。通过发动机台架试验研究凸轮工作段位置、喷油器伸出高度、喷孔直径及供油提前角对柴油机经济性和排放的影响。研究结果表明:凸轮工段位置影响喷油规律,从而影响经济性和排放;喷油器伸出高度减小会导致经济性变差;喷孔直径越小,最低燃油耗的供油提前角越大;减小喷孔直径,燃油喷射压力提高,有利于降低燃油消耗率和NOx排放,但小喷孔直径的喷油持续期长,后燃增加,效率下降且CO排放增加。     

GD-1燃油喷射系统喷油参数对发动机性能的影响

摘将GD-1高压共轨电控燃油喷射系统用于常规直喷式柴油机，采用不同喷油参数(喷油规律、喷油压力和喷油定时)对发动机的性能进行研究。试验结果表明，预喷射不仅可以改善冷起动性能和降低冷起动时白烟的排放，在高负荷时也可以降低烟度的排放；喷油压力的提高和喷油定时的提前改善了发动机的性能和排放。     

节流孔板对电控喷油器性能影响的试验研究

使用EFS喷射试验台,测量电控喷油器在匹配不同参数的节流孔板后所表现小的喷油特性,并加以分析.结果表明:节流孔板是电控共轨喷油器的重要构成部分,既控制着喷油嘴针阀的开启速度,又控制着喷油率的形状.因此,合理优化节流孔板参数,对改进喷油器的喷射性能、改善发动机燃烧状况、降低排放等具有重大意义.     

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

<正>~~     

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.     

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%.     

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.     

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.     

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.     

Exergetic evaluation of 5 biowastes-to-biofuels routes via gasification

This paper presents the exergy analysis results for the production of several biofuels, i.e., SNG (synthetic natural gas), methanol, Fischer–Tropsch fuels, hydrogen, as well as heat and electricity, from several biowastes generated in the Dutch province of Friesland, selected as one of the typical European regions. Biowastes have been classified in 5 virtual streams according to their ultimate and proximate analysis. All production chains have been modeled in Aspen Plus in order to analyze their technical performance. The common steps for all the production chains are: pre-treatment, gasification, gas cleaning, water–gas-shift reactions, catalytic reactors, final gas separation and upgrading. Optionally a gas turbine and steam turbines are used to produce heat and electricity from unconverted gas and heat removal, respectively. The results show that, in terms of mass conversion, methanol production seems to be the most efficient process for all the biowastes. SNG synthesis is preferred when exergetic efficiency is the objective parameter, but hydrogen process is more efficient when the performance is analyzed by means of the 1st Law of Thermodynamics. The main exergy losses account for the gasification section, except in the electricity and heat production chain, where the combined cycle is less efficient.     

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.