高压喷射下自由射流和受限碰撞喷雾特性的试验研究

本利用激光纹影高速摄影技术，在常温定容弹装置上，研究了直喷式柴油机油泵－油嘴供油系统在喷油坟力为６０ＭＰａ～１００ＭＰａ时，喷孔直径，环境密度和壁面温度对自由射流和受限碰壁喷注的影响。     

加压条件下半焦燃烧特性的试验研究

热重分析法是了解煤热解和燃烧机理的有效工具。在自制的加压热重分析仪上，研究了压力（０．１ＭＰａ－０．９ＭＰａ）对煤热解后的半焦燃烧特性的影响，并对结果作了机理性分析。     

石油化工企业余热发电设备管理的体会

石油化工企业余热发电设备管理的体会洛阳石油化工总厂张捷在石油化工企业，需要大量使用各种等级的蒸汽，主要有３．５ＭＰａ、１．０ＭＰａ、０．３ＭＰａ等，而石化企业所属热电站的锅炉或装置加热炉、取热设备多以产１．０ＭＰａ或３．５ＭＰａ等级压力的蒸汽为主，其...     

伞喷喷注与 HL 喷注宏观特性的比较分析

本文采用了激光片光照明，对伞喷喷注与ＨＬ喷注高速照相，进行宏观特性对比分析研究。启喷压力２４．５ＭＰａ，高压容器背压分别是０．０９８ＭＰａ、０．９８ＭＰａ和１．９６ＭＰａ，一次喷油量２８．５ｍｇ，喷射频率８．３Ｈｚ。用分散率来评价喷注的分散特性，由摄影对比表明，在低背压时伞喷与ＨＬ喷注都呈空心锥状体，在高背压时ＨＬ喷注贯穿距离与伞状喷注相比增长２５％。     

废热锅炉蒸汽升压改造

介绍了７５２~＃硝酸废热锅炉蒸汽压力从２．４５ＭＰａ升压至３．８２ＭＰａ，并入３．８２ＭＰａ蒸汽管网，通过２~＃汽轮发电机组来进行多发电，既增加了运行调节手段，又合理利用了热能多发电，取得了较好的经济效益，对于在特定条件下的企业的节能挖潜改造，具有借鉴作用。     

供汽系统蒸汽降价损失与节能

供汽系统蒸汽降价损失与节能北京燕山石油化工公司聚酯厂蒲怀均１前言燕化公司聚酯厂ＷＧＺ６５／３９—６锅炉设计产汽参数为３．８２ＭＰａ、４５０℃，蒸发量为６５ｔ／ｈ，实际运行控制产汽参数为３．４３ＭＰａ、４３５℃。全厂用汽有三个等级，均由３．４３ＭＰａ、...     

球铁曲轴的BMP工艺

本文简述了球铁曲轴的强韧化新工艺──ＢＭＰ工艺，揭示了用这种工艺处理的１９５柴油机球铁曲轴的组织、应力分布，并进行了全面的性能测试。结果表明，ＢＭＰ工艺处理的曲轴轴颈及过渡圆角处的残余应力均较高，平均为４００ＭＰａ，是中频淬火曲轴的４倍。由于圆角处得到了强化，曲轴本体疲劳强度高达１７４ＭＰａ，实现了强度、韧性和耐磨性的优化结合。     

球铁曲轴的强韧化和性能

简述球铁曲轴的强韧化新工艺──ＢＭＰ工艺。揭示用这种工艺处理的１９５柴油机球铁曲轴的组织、应力分布，并进行全面的性能测试。结果表明，ＢＭＰ工艺处理的曲轴轴颈及过渡回角处的残余应力均较高，平均为４００ＭＰａ，是中频淬火曲轴的四倍，由于圆角处得到了强化，曲轴本体疲劳强度高达１７４ＭＰａ，实现了强度、韧性和耐磨性的优化结合。     

柴油机喷油泵柱塞偶件的保养

一些驾驶员、维修人员对柴油机喷油泵柱塞偶件的维修、保养不够重视，将柱塞套随意抽动，甚至将柱塞套零件相互更换，导致喷油泵柱塞偶件的使用寿命大大缩短，严重地影响了柴油机的工作效率。柴油机的喷油泵端压力一般在４０ＭＰａ以上，最高可超过１００ＭＰａ。柱塞与柱...     

电子控制柴油机蓄压式喷油系统的实验研究

作者对新型电子控制蓄压式喷油系统进行了实验。该系统利用一中等供油压力源，通过蓄压器和压力放大机构，在高速电磁阀的控制下，实现高压喷射。当供油压力为１０ＭＰａ时，最高喷射压力为８０ＭＰａ。通过该系统的实验，测量出其喷射特性和电磁阀的动态特性，从而能为该系统的评价、改型设计提供依据。     

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.     

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.     

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.     

液压系统常见的故障诊断及处理

任何工程机械式液压设备使用时出现故障是不可避免的。但是怎样确定故障的原因及找到好的解决方法,这是使用者最关心的问题。讲述了液压系统常见的故障及其排除方法。     

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.