低黏度柴油发动机润滑油性能研究

根据国六排放法规对柴油发动机的发展和润滑油的性能要求开发了低黏度柴油发动机润滑油.选用10W40和5W30柴机油进行发动机台架试验,并通过发动机台架试验和整车道路试验重点考察了5W30对发动机节能和整车耐久性的影响.试验结果表明:采用低黏度柴油发动机润滑油可以提高柴油发动机的燃油经济性.     

固体颗粒对低黏度介质润滑特性的影响

基于水-固两相单流体模型,研究润滑过程中的固体颗粒对低黏度润滑介质的影响。以无限宽楔形滑块为计算模型,推导出特定假设条件下考虑惯性力和界面滑移的低黏度介质润滑的雷诺方程,并通过不同条件下雷诺方程的求解,探讨固体颗粒含量对低黏度介质润滑特性的影响。结果表明:在对低黏度介质润滑特性进行研究时,需考虑其惯性力和界面滑移影响;固体颗粒的存在一定程度上增大润滑膜的压力和承载能力,颗粒含量越大,承载能力越大,但颗粒含量对润滑膜整体的压力分布状态几乎不会产生影响;惯性力增大固体颗粒对润滑介质的影响程度,而界面滑移减小固体颗粒对润滑介质承载能力的影响,发生滑移时,颗粒基本不影响润滑膜的承载能力。     

Compressibility of Lubricants at High Pressures

Results from a high pressure chamber, recently developed at Lund Institute of Technology, are presented. The compressibility variation with the pressure of five different lubricants is investigated for pressures up to 2.7 GPa. The density variation for each lubricant is presented as a curve fit. The results show that at high pressures when the lubricant has solidified, the density varies linearly with the pressure. It is also concluded that the Dowson-Higginson relationship may be inaccurate when describing the density variation for some lubricants, especially at higher pressures.     

New Method of Measuring Permanent Viscosity Loss of Polymer-Containing Lubricants

An ultrahigh shear rate viscometer (USV) was used to measure the viscosity of polymer solutions. It was found that some polymer solutions in base oil, including those used as engine oil viscosity modifiers, show permanent viscosity loss when subjected to very high shear rates above 10⁶ s^?1. The USV was modified to automatically carry out a series of viscosity measurements on the same test lubricant sample. This enabled the accumulation of permanent viscosity loss to be measured over successive strain cycles.

As expected, permanent viscosity loss increased with both strain rate and molecular weight. When carried out at 5 × 10⁶ s^?1 and 100°C, the test was more severe than the Kurt Orbahn test because samples of lubricants subjected to the latter underwent further shear thinning in the USV.

The USV test appears to be a rapid and convenient way to quantify the permanent viscosity loss of polymer-containing lubricants for engine use, and a protocol to assess permanent viscosity loss (PVL) and permanent shear stability index (PSSI) based on viscosity measurements at 10⁶ s^?1 before and after shear thinning is outlined.

The study also shows that it is important to take into account possible permanent viscosity loss when measuring the viscosity of polymer solutions in very high shear rate viscometers such as the USV. This can be done by minimizing the amount of shear to which the lubricant is subjected or by taking successive measurements and subtracting the permanent viscosity loss taking place in each of the first few strain rate cycles.     

傅立叶变换红外光谱快速测定润滑油碱值

提出了利用傅立叶变换红外光谱快速测定润滑油碱值的方法,介绍了其原理及分析过程.该方法与国家标准方法相比,具有速度快、环保且化学试剂用量小、精密度高,操作方便等特点,适用于常规、快速分析.研究结果表明所建方法与国家标准方法的测定结果之间具有很好的一致性,测定结果的相对标准偏差小于5%.     

润滑油粘度对单盘柔性转子振动特性影响的实验

采用INV1612型单盘柔性转子实验台,通过改变负重盘的位置和润滑油膜的性质进行了大量实验。结果显示,在转子的轴向中心位置有周向均匀负重时,临界转速和最大振幅出现峰值;增大润滑油运动粘度,可降低转子的最大振幅,提高临界转速;随着润滑油高温粘性指数增大,转子的最大振幅减小,临界转速近似不变;低温粘性指数对转子振动特性影响的规律较不明显,还有待进一步研究。实验结果为研究影响转子系统稳定性因素提供了依据。     

低温多效蒸馏海水淡化蒸发器腐蚀研究

低温多效蒸馏海水淡化技术由于操作温度低、传热性能优良,正在被广泛应用和研究。针对国内不同工程的低温多效蒸馏海水淡化工程蒸发器壳体的腐蚀情况,在实验室条件下进行了相关材料的腐蚀模拟试验,利用成分和显微组织分析手段研究介质条件、工作环境等因素对蒸发器的腐蚀影响,提出了海水淡化装置在设计、制造及运行等方面控制腐蚀的具体措施及优化方向。     

环境友好润滑油碱值测定方法研究

建立了一种采用含破乳剂的水溶液作为萃取剂、以反滴定为基础的润滑油碱值测定方法。这种方法使用环境友好的化学试剂,不会对环境和人造成伤害。滴定是在水溶液中进行的,终点易于判定。研究结果表明所建方法与国家标准方法的测定结果之间具有很好的一致性,测定结果的相对标准偏差小于4%。     

低温多效海水淡化热力计算研究

根据低温多效海水淡化(MED)系统的工作原理,系统建立了带有热力蒸汽压缩器(TVC)的低温多效海水淡化数学模型.利用Visual Basic语言编制了低温多效海水淡化系统热力计算程序,通过与实际工程项目技术参数对比,验证了计算程序的正确性.     

Determination of the Ester Composition of Neopentyl Polyol Ester Lubricants

Because of the increasing use of the neopentyl polyol esters as lubricants, an analytical method capable of giving detailed information concerning the composition of these complex ester mixtures is desirable. Methods of gas-liquid chromatography and thin-layer chromatography have been applied in the successful development if such an analytical method. By direct programmed temperature gas chromatography of the lubricants, the components are separated according to volatility; in most cases resolution is adequate for semi-quantitative analysis. Gas-liquid chromatographic analysis of the free acids produced by hydrolysis of the sample reveals the acyl composition. The parent polyols are determined by programmed temperature gas chromatography of their valerate esters. A semi-preparative thin-layer chromatographic method permits the isolation of the three main ester types, trimethylol propane, pentaerythritol, and dipentaerythritol, for further analysis. A combination of these analytical methods permits a detailed study of the changes in composition which occur in these lubricants during service.     

采用双螺杆压缩机的机械蒸汽再压缩污水处理系统试验研究

对国内自主研发的采用双螺杆压缩机的60 t/d双效机械蒸汽压缩(Mechanical vapor compression,MVC)采油污水处理系统进行调试及变工况试验研究,分析压缩机转速、一效进水温度和二效出水循环量对系统产水量及产水能耗的影响,为系统优化设计及市场化提供参考。研究表明,系统能稳定运行,在60 t/d原料水处理量下,系统产水量约为1.03 t/h,每吨水处理能耗为35 k W·h;双螺杆压缩机工作过程喷入的冷却水水质需要满足一定要求,避免转子及机壳表面结垢发生故障;随压缩机转速升高,系统产水量升高,产水能耗存在最低值,即压缩机转速及系统运行工况存在最优匹配关系;系统产水量及产水能耗随一效进水温度升高而分别升高和降低,且这种规律不受压缩机转速影响;随着二效出水循环量的升高,系统产水量逐渐升高,升高幅值随一效入口温度升高而降低。     

Desorption Kinetics of Polyether Lubricants from Surfaces

Desorption or evaporation is one of the mechanisms for loss of perfluoropolyalkylether (PFPE) lubricants from the surfaces of data storage media. One approach to minimizing PFPE loss to desorption is the use of lubricants with increasing molecular weight or increasing average chain length. In order to understand the effects of chain length on the lubricant evaporation kinetics we have studied the desorption kinetics of monolayer films of oligomeric ethers with varying chain length adsorbed on the surface of graphite. The desorption pre-exponents, v, and desorption barriers, E _des , have been measured for poly(ethylene glycol) dimethyl ethers, CH₃O(CH₂CH₂O) _m CH₃, with m=1,2,3,4,8 and 10. These are models for the PFPE known as Fomblin Z, which has a structure CF₃O(CF₂CF₂O) _x (CF₂O) _y CF₃. The results show that the desorption pre-exponents are independent of chain length and have an average value of v=10^18.7±0.3 s^–1. The E _des for the poly(ethylene glycol) dimethyl ethers vary non-linearly with chain length and can be fit with a power law expression of the form E _des =a+bN , where N is the total number of atoms in the oligomer backbone (N=3m+3) and the scaling exponent has a value of 1/2. This non-linear dependence of E _des on chain length has also been observed in recent studies of the desorption kinetics of straight chain alkanes from graphite. A desorption mechanism is described that explains the non-linearity of E _des for the poly(ethylene glycol) dimethyl ethers. The implication for the lifetime of lubricants on data storage media is that the long chain PFPE lubricants desorb more rapidly than one might expect based on simple linear scaling of the E _des of lower molecular weight PFPEs.     

常顶挥发线波纹管膨胀节失效分析

通过对失效膨胀节的磁性检查、金相分析、断口形貌分析、腐蚀产物能谱分析、X射线衍射分析等检验 ,认为该膨胀节失效是由硫化氢导致的应力腐蚀开裂 ,并对其腐蚀环境因素、应力因素和材料因素进行阐述 ,并提出了预防建议     

低噪声密封轴承润滑脂选用及机理分析(续前)

2．2 典型低噪声密封轴承润滑脂的流变性和胶体性能 使用动态离心分油试验机、表观粘度试验机、流动压力测试仪和电子扫描显微镜等试验装置对选定的润滑脂进行试验分析。从众多的润滑脂噪声试验研究中，标定润滑脂流变性和胶体安定性的下列试验数据对轴承的振动性能产生重要的影     

Study on Mechanism of Hydrogen Generation from Lubricants

To establish fundamental countermeasures for hydrogen embrittlement that occurs to several kinds of bearings, the mechanism of hydrogen generation from lubricants was studied. Sliding tests were conducted, and the amount of hydrogen generated from several kinds of lubricants during sliding was measured. It is concluded that the lubricant is decomposed and hydrogen is generated through a catalytic reaction with the fresh steel surface. The amount of hydrogen generated from each lubricant depends on its lubricity, not on its chemical structure. It is also confirmed that the lubricant with the larger wear brings more generated hydrogen into steel. Based on the above mechanism of hydrogen generation, methods of inhibiting hydrogen brittle flaking with additives were investigated. It is clarified that the addition of corrosion inhibitors that form a passive state film on the steel surface effectively inhibits generation of hydrogen from lubricants and penetration of hydrogen into steel.

     

Development and Application of a Novel Quantum-Chemical Molecular-Dynamics Method for Degradation Dynamics of Organic Lubricants Under High Temperatures and Pressures

The dynamics of the degradation process of a monoester (ethyl acetate) at reaction temperatures was clarified for the first time by a novel tight-binding, quantum-chemical, molecular-dynamics method with initial parameters that are determined completely on the basis of first-principles calculations. It was confirmed that the proposed method can calculate the structure, electronic states and total energy of a monoester and its fragments as accurately as the density-functional calculations, while the CPU time of the new method is over 5000 times faster than that of the density-functional calculations. In the case of the acetic ester molecule, the -hydrogen which is located at the ethanol group was cleaved quickly. Compared to it, -hydrogen was cleaved more slowly than -hydrogen. Each atom expressed cleavage and association with repetition. As a whole, degradation phenomena were observed in this simulation. This observation agrees with experimental data.     

基于光化学气相发生的重金属痕量分析方法的介绍

光化学气相发生作为原子光谱的样品引入方式,是近年来重金属痕量分析领域新兴的研究热点。相比传统的化学发生方法,光化学发生的仪器简单,仅需一个紫外（UV）光源和低分子量的醇、醛、有机酸（甲酸、乙酸、丙酸、丁酸等）作为还原剂,是更绿色环保的分析方法。本文从光化学发生机理,气相发生装置,发生试剂优化,以及光化学发生的应用领域等方面,介绍了基于光化学气相发生的重金属痕量分析方法。     

低噪声密封轴承润滑脂选用及机理分析

对轴承行业主要使用的低噪声密封轴承润滑脂现状进行评述，并在此基础上利用动态离心分油试验机、表观粘度试验机、流动压力测试仪、速度型和加速度型轴承振动测量仪等仪器，进一步分析了润滑脂对密封轴承振动噪声性能的影响因素及其机理。     

润滑油酸值测定结果影响因素的分析

润滑油的酸值和酸度是表明油品中含有机酸性物质的重要指标。根据酸值的大小,可以判断油品中所含酸性物质的量,油品中的酸性物质的数量随着原料与油品的精制、清洗处理的程度而变化。因而准确测定润滑油中酸值对生产装置具有非常重要的现实意义。润滑油的酸值测定一般借鉴GB264--83石油产品酸值测定法。现从测定的方法原理入手,探讨了影响测定结果准确度与精密度的因素。     

酸化油甲酯环氧化合成环境友好润滑油的研究

以植物废弃油脂为原料,通过酯化反应合成了酸化油甲酯,并采用环氧化新型工艺使酸化油甲酯中的不饱和键饱和,大大改善了其氧化稳定性.考察了酸化油甲酯环氧化改性前后的流变学性能和摩擦学性能,并对其润滑时的磨斑表面形貌进行了分析.结果表明,酸化油甲酯改性前后均具有较好的黏温性能和润滑性能,通过对磨斑形貌进行分析发现,由环氧化改性酸化油甲酯润滑的钢球磨斑表面光滑,磨痕浅且尺寸较小,优于酸化油甲酯.