新型乳化柴油喷雾特性的试验研究

通过定容弹模拟乳化柴油喷雾形成的全过程,采用高速摄影记录了不同喷油压力、喷油背压以及喷油脉宽下乳化柴油喷雾的形成过程,从喷雾锥角、贯穿距以及锋面速度3个方面对乳化柴油的喷雾特性进行了试验研究,结果表明：乳化柴油的喷雾特性与柴油基本一致,喷油压力对乳化柴油喷雾锥角和贯穿距的影响较大,喷雾背压和喷油脉宽对乳化柴油喷雾贯穿距的影响较大,喷油压力、喷雾背压和喷油脉宽对乳化柴油喷雾锋面速度的影响均较小,较高的喷油压力、较短喷油脉宽有利于乳化柴油的雾化。     

立体传质塔板CTST喷射性能实验研究

立体喷射型塔板的喷射状况对气液两相接触面积有重要影响。本文利用直径570mm的实验塔,采用高速摄像仪对CTST的喷射过程进行了研究,并基于不稳定波动理论建立了液滴群平均粒径的计算模型。结果表明：喷射孔气速是影响喷射锥角的主要因素,随着喷射孔气速的增加喷射锥角逐渐增大,当喷射孔气速超过7.5 m/s左右时,喷射锥角较为恒定,其数值稳定在55°左右。随着气速的增加喷射孔处液膜速度显著增大,而液体流量增加时液膜速度稍有减小,越靠近喷射孔顶端液膜速度越大。喷射区域内液滴的分布密度接近于Rosin-Rammler分布,在喷射锥角[20o, 40o]范围内的液滴数量比较集中,随着气速和液体流量的增大,液滴分布密度逐渐趋于均匀。液滴群平均粒径随气速的增加而减小,随液量的增加略有增大。正常工作范围内的液滴群平均粒径范围为1.0~2.5 mm。     

基于CFD的自进式喷嘴参数优化

为了有效穿透井眼污染带，扩大泄油面积，提高油藏采收率，最终实现增产增注的目的。通过建立喷嘴三维模型，采用Fluent软件进行模拟，研究自进式喷头在不同前后喷嘴直径、前后喷嘴角度下的流场特性，利用流场中速度的分布规律结合公式计算出反冲力、破岩力、推进力的变化趋势。结果表明:随着后喷射角直径和前喷射角角度的增大，反冲力、推进力增大，破岩力减小；随着前喷射角直径和后喷射角度的增大，反冲力和推进力减小，破岩力增大。最终得到喷嘴的匹配方案，为实际生产提供了可靠依据。     

汽车新能源及润滑油的发展

汽车新能源主要有替代燃料和电能,其研发异常活跃,并开始用于公交和出租等车辆,有望成为今后的发展主流。随着石油资源的日益紧张,新能源的发展备受关注,减轻了对石油产品的依赖程度。燃料的变化还引起了发动机润滑油性能要求的改变,出现了醇燃料发动机油和燃气发动机油。文章对气体燃料和醇燃料等代用燃料的性能和使用现状进行了概述,并对未来发展趋势进行了描述,认为电动汽车及混合动力汽车将越来越多地投入使用,替代燃料的比例也会增长,发动机油将随着替代燃料的使用而进一步的发展。     

装有微处理器的双燃料发动机控制系统

为CATERPILAR 3208自然吸气发动机以天然气为燃料并利用柴油喷射引燃方式运行而研制的微处理器控制系统已经成功。这个系统的设计指标是在双燃料运行时,维持较高的峰值压力和较高的压力升高比。系统输入参数有发动机速度、负荷和进气温度。柴油替代量最高大约是85％。装设该系统的发动机通过了性能、过度过程、稳定性等一系列试验并且完成了优化性能的双燃料调整策略。     

长输管道加热炉燃料调整经济性分析

为了节约燃料油,从技术方案、经济效益及环境影响等方面对长输管道加热炉燃料调整的不同方式进行分析。使用原煤或使用水煤浆替代燃油后,通过合理的环保技术措施,可以使污染物的排放控制在排放标准之内;使用天然气替代燃油,由于天然气的燃料特性和燃烧技术的成熟,对环境的影响具有积极的意义。     

预测21世纪运输燃料的组成

21世纪，替代燃料技术将起重要作用，而用汽油和醇为燃料的燃料电池技术最终将能解决提高行车利润，降低废气排放量的问题。目前采用的新配方燃料与未来燃料电池燃料组成相吻合。21世纪仍要使用汽、柴油，特别是新配方燃料。它们的代表是美国加州汽油和瑞典一级柴油。但是能再用多久，还是未知数。为保证高质量的大气环境，将大力控制公路运输方面的废气排放量。预计21世纪前半期，炼油工业将能提供高氢组分的替代燃料。而汽车制造业则应制造出使用该种燃料的新型发动机。到21世纪后半期，炼油工业已能从原油和天然气生产数量大、质量高的“…     

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LNG是一种比CNG更清洁、高效的优质能源。LNG作为车用燃料比CNG具有两大显优点：一是储罐自重轻，一次行驶里程长；二是优化了发动机性能，延长了发动机寿命。章介绍的我国改装成功的第一辆LNG-汽油电控喷射两用燃料汽车就是在保留原车供油系统不变的前提下增加了一套车载LNG燃料供给系统。后由LNG车用储罐、调压阀、汽化器、减压调压阀、步进电机及ECU控制系统、混合器及安全系统等组成。经试车表明，该车电控燃料转换过渡平稳，经济性、动力性均较好：速度在100km/h以下行驶，使用LNG燃料与使用汽油时动力相同；最高时速达到140km／h时，动力性仍然平稳。     

GE航空公司测试100%Gevo公司生产的醇制喷气燃料

正GE航空公司已开始使用100%Gevo公司的源于可再生醇的喷气燃料(ATJ)测试喷气发动机燃烧室部件。这是美国联邦航空管理局(FAA)持续减少能源、排放和噪音计划(CLEEN)的一部分。CLEEN计划是FAA与GE航空公司等航空业界领先企业合作在加速新型飞机、发动机技术的开发以及推进可持续替代喷气燃料方面的主要环保举措。具体而言,这一测试旨在用生物基替代产品替代更多的石油基喷气燃料。生物基烃类燃料具有与石油基燃料     

顺丁橡胶长链支化度的表征

建立了以凝胶渗透色谱(GPC)数据与稀溶液特性粘度数据相结合，测定顺丁橡胶长链支化度的方法。用沉淀分级法对顺丁橡胶样品分级后，以各分级样的流体力学体积对GPC淋出体积所确定的lg J—Ve曲线与窄分布聚苯乙烯标样的普适校正线基本重合，证明采用普适校正技术测定顺丁橡胶的各种平均相对分子质量和长链支化度是可行的。测定了顺丁橡胶样品的相对分子质量分布和长链支化度，讨论了影响测定结果的因素，并考察了样品中凝胶含量与支化度的关系。     

Effects of Blending Long-Chain Alcohols with Jet Fuel on the Macroscopic Spray Characteristics

Long-chain alcohols were considered to be promising alternative fuels and fuel additives. This study was aimed at figuring out the influences of blending long-chain alcohols with jet fuel on the macroscopic spray characteristic. n-Butanol and n-pentanol were chosen as tested alternative fuels. A common-rail injection system was used to create high-pressure injection conditions. The Schlieren imaging system was used to capture spray processes. Results showed that with the addition of long-chain alcohols, the spray tip penetration and the peak spray tip velocity increased, whereas the spray cone angle and the spray area decreased. Comparisons between those macroscopic spray characteristics of AKB blends and AKP blends were also conducted. Compared to AKB blends, AKP blends showed similar spray tip penetration, larger peak tip velocity, smaller spray cone angle, and smaller spray area.     

结构及操作参数对旋流器切向速度场的影响——液-液水力旋流器速度场研究之二

利用多普勒激光测速仪,结合流体力学理论,试验分析了双锥体水力旋流器结构和操作参数对切向速度场的影响。试验分析表明,大锥段和小锥段切向速度分布规律基本相同,均由准自由涡和准强制涡构成,分界面半径ｒｍ没有变化;随着小锥角θ的增加,准自由涡区缩小,准强制涡区扩大,速度梯度增加会加大液滴的乳化程度;随入口流量增加,切向速度增大,经拟合得出大锥段和小锥段的最大切向速度均为入口流量的４９４倍;分流比加大,分界面半径基本不变,最大切向速度增加。指出合理选择小锥角θ,控制操作参数如入口流量Ｑｉ和分流比Ｆ,可得到较好的分离效果。     

IGNITION DELAY AND SOOT EMISSION CHARACTERISTICS OF METHANOL-DIESEL FUEL BLENDS

Alcohols, as alternative fuels, may contribute to the solution of environmental and economical problems to a certain extend. But, they seem to have little chances to be directly used in Diesel engines because of their low cetane number. However, as blended fuels with diesel fuel they have places on the application area. In this study, the effect of the compression ratio on ignition delay and soot emission for methanol-diesel fuel blends with various blending ratios is investigated on an ASTM-CFR engine and the results are compared with baseline diesel fuel. Longer ignition delays and less soot emissions have been obtained for blend fuels as compared to diesel fuel.     

Investigation of performance and emission characteristics of waste cooking oil as biodiesel in a diesel engine

Biodiesel is one of the most popular prospective alternative fuels and can be obtained from a variety of sources. Waste frying oil is one such source along with the various raw vegetable oils. However, some specific technical treatments are required to improve certain fuel properties such as viscosity and calorific value of the biodiesel being obtained from waste cooking oil methyl ester (WCOME). Various treatments are applied depending on the source and therefore the composition of the cooking oil. This research investigated the performance of WCOME as an alternative biofuel in a four-stroke direct injection diesel engine. An 8-mode test was undertaken with diesel fuel and five WCOME blends. The best compromise blend in terms of performance and emissions was identified. Results showed that energy utilization factors of the blends were similar within the range of the operational parameters (speed, load and WCOME content). Increasing biodiesel content produced slightly more smoke and NOx for a great majority of test points, while the CO and THC emissions were lower.     

Effect of waste cooking-oil biodiesel on performance and exhaust emissions of a diesel engine

The ever increase in global energy demand, consumption of depletable fossil fuels, exhaust emissions and global warming, all these led to search about alternative fuels. Biodiesel was produced from waste cooking-oil by transesterification process. Blends of waste cooking-oil biodiesel and diesel oil were prepared in volume percentages of 10, 20 and 30% as B10, B20 and B30. Biodiesel blends have ASTM standards of physical and chemical characterization near to diesel fuel. Diesel engine performance and exhaust emissions were studied experimentally for burning waste cooking-oil blend with diesel fuel. This experimental was applied on a diesel engine at different engine loads from zero to full load. Thermal efficiencies for waste cooking-oil biodiesel blends were lower than diesel oil. Specific fuel consumptions of biodieselblends were higher than diesel fuel. Higher exhaust gas temperatures were recorded for biodiesel blends compared to diesel oil. CO₂ emissions for waste cooking-oil biodiesel blends were higher than diesel oil. CO, smoke opacity and HC emissions for biodiesel blends were lower than diesel fuel. NO_x emissions for biodiesel blends were higher than diesel fuel.     

旋流器轴向速度分布规律——液-液水力旋流器速度场研究之三

用多普勒激光测速仪并加入频移装置,提高了对双锥体结构水力旋流器轴向速度场的测试精度、测试结果和分析研究表明,旋流器的轴向速度场以零轴向速度包络面为界分为内外两个旋流区,外旋流区的流体边旋转边向底流流动,最终从底流口排出;内旋流区的流体则边旋转边向溢流口流动,最终从溢流口排出。双锥水力旋流器的零轴向速度包络面为一柱锥联合面,其柱面直径Ｄｖ是溢流口直径Ｄｕ的２５倍左右,锥面的锥顶角约为１４°,锥顶在小锥段内部。     

IGNITION DELAY AND SOOT EMISSION CHARACTERISTICS OF METHANOL-DIESEL FUEL BLENDS

ABSTRACT

Alcohols, as alternative fuels, may contribute to the solution of environmental and economical problems to a certain extend. But, they seem to have little chances to be directly used in Diesel engines because of their low cetane number. However, as blended fuels with diesel fuel they have places on the application area. In this study, the effect of the compression ratio on ignition delay and soot emission for methanol-diesel fuel blends with various blending ratios is investigated on an ASTM-CFR engine and the results are compared with baseline diesel fuel. Longer ignition delays and less soot emissions have been obtained for blend fuels as compared to diesel fuel.     

Study on the characteristics of palm oil–biodiesel–diesel fuel blend

Palm oil/palm oil methyl esters are blends with diesel fuel, the blends were characterized as an alternative fuels for diesel engines. Density, kinematic viscosity, and flash point were estimated according to ASTM as key fuel properties. Palm oil and palm oil biodiesel were blended with diesel. The properties of both blends were estimated. The results showed that the fuel properties of the blends were very close to that of diesel till 30% unless other characteristics are within the limits. The experimental data were correlated as a function of the volume fraction of oil/biodiesel in the blend. Different correlations were developed to predict the properties of the oil/bio-oil-diesel blends based on our experimental results. The developed correlations were validated by comparing the correlation prediction with experimental data in literature. A good agreement was found between modeled equations prediction and experimental data in literature. The developed equations can be used as a guide for determining the best blending mixture to be used for diesel engines.