Experimental Study on Frictional and Sealing Performances of Packing Rings in an Oil-free Gas Compressor

To enhance the reliability and to extend service life of packing rings,tribological and sealing performances are investigated based on the experimental results.Friction force,leakage rate and power consumption of three materials of pressure packing seals are measured in a refitted vertical gas compressor.The rings are made of common filled polytetrafluroethylene(Filled PTFE),PTFE reinforced with 30% mass fraction carbon fiber(30%CF+PTFE),and carbon-carbon composites infiltrated with PTFE(C/C+PTFE),respectively.It is found that packing rings will periodically vibrate with the periodic vibration of pressure packing after the travel direction of motion abruptly turns to the reverse direction.Furthermore,the amplitude of vibration slows down with the increasing crank angle.Approximate value of friction force is available by multiple-point fast Fourier transformation(FFT) employed to process the experimental results by reducing the impact of vibration to a great extent.Of three materials of rings employed in experiments,Filled PTFE presents minimal leakage rate accompanied with maximum power consumption.And 30%CF+PTFE exhibits minimum friction power and moderate leakage rate.As for C/C+PTFE,its high mechanical and thermal properties are favorable factors to enhance the ability of operating under high pressure and velocity and to improve the wear resistance.Unfortunately,this also leads to a large leakage rate.Comprehensive consideration should be taken into to evaluate the availability,reliability and service life for a type of packing ring under dry running conditions.

Synthesis and mechanism of environmentally friendly high temperature and high salt resistant lubricants

With the exploration and development of deep and ultra-deep oil and gas,high torque and high friction during the drilling of deep and ultra-deep wells become one of the key issues affecting drilling safety and drilling speed.Meanwhile,the high temperature and high salt problem in deep formations is prominent,which poses a major challenge to the lubricity of drilling fluids under high temperature and high salt.This paper reports an organic borate ester SOP as an environmentally friendly drilling fluid lubricant.The performance evaluation results show that when 1%lubricant SOP is added to the fresh water-based mud,the lubrication coefficient decreases from 0.631 to 0.046,and the reduction rate of lubrication coefficient is 92.7%.Under the conditions of 210℃ and 30%NaCl,the reduction rate of lubricating coefficient of the base slurry with 1%SOP was still remain 81.5%.After adding 1%SOP,the wear volume decreased by 94.11%compared with the base slurry.The contact resistance experiment during the friction process shows that SOP can form a thick adsorption film on the friction surface under high temperature and high salt conditions,thus effectively reducing the friction resistance.Molecular dynamics simulation shows that lubricant SOP can be physically adsorbed on the surface of drilling tool and borehole wall through hydrogen bond and van der Waals force.XPS analysis further shows that SOP adsorbs on the friction surface and reacts with metal atoms on the friction surface to form a chemically reactive film.Therefore,under high temperature and high salt conditions,the synergistic effect of physical adsorption film and chemical reaction film effectively reduces the frictional resistance and wear of the friction surface.In addition,SOP is non-toxic and easy to degrade.Therefore,SOP is a highly effective and environmentally friendly lubricant in high temperature and high salt drilling fluid.

温度对组合型织构油封密封性能的影响

耦合流体力学、变形分析、接触力学、能量守恒方程和黏温黏压方程,建立具有表面组合型织构油封的密封区域混合润滑数值模型,研究温度对表面组合型织构油封密封性能的影响;通过有限差分法对数值方程离散求解,得到不同表面织构油封唇口的温度分布及不同转速下油封唇口的最高温度,对比分析温升对油封泵吸率、油膜厚度、摩擦扭矩等密封性能的影响。结果表明:油封最高温度位于唇尖处,无织构油封最高温度略高于织构油封,随着转速的增加,油封最高温度也都随之增加;织构的存在会引起油封泵吸率的增加和平均油膜厚度变大;随着温度的升高,油封泵吸率、摩擦扭矩、油膜厚度都会逐渐减小,油封密封性能明显下降,温度升高至一定程度,油封泵吸率会变为负值。

Cooling and lubrication techniques in grinding:A state-of-the-art review,applications,and sustainability assessment

Grinding technology is an essential manufacturing operation,in particular,when a component with a superfinishing and an ultra-resolution is yearned.Meeting the required strict quality checklist with maintaining a high level of productivity and sustainability is a substantive issue.The recent paper outlines the lubrication and cooling technologies and mediums that are used for grinding.Furthermore,it provides a basis for a critical assessment of the different lubrication/cooling techniques in terms of machining outputs,environmental impact,hygiene effect,etc.Meanwhile,the paper put light on the sustainability of different cooling/lubrication strategies.The sustainability of machining aims to get the product with the best accuracy and surface quality,minimum energy consumption,low environmental impact,reasonable economy,and minimum effect on worker’s health.The paper revealed that despite some cooling/lubrication mediums like mineral oils and semisynthetic,afford sufficient lubrication or cooling,they have a significant negative impact on the environment and public health.On the other hand,emulsions can overcome environmental problems but the economy and the energy consumption during grinding are still a matter of concern.Biodegradable and vegetable oils are considered eco-friendly oils,but they suffer from a lack of thermal stability which affects their ability of efficiently cooling.Using the cooling medium with the lowest amount can achieve the goal of the economy but it may be reflected negatively on the machinability.Furthermore,cryogenic lubrication doesn’t provide sufficient lubrication to reduce friction and hence energy consumption.The research described in the paper is such a comprehensive compilation of knowledge regarding the machinability and machining performance under different cooling and lubrication systems that it will aid the next generation of scientists in identifying current advancements as well as potential future directions of research on ecological aspects of machining for sustainability.

某型市域车齿轮箱接地侧迷宫密封结构优化

针对某型市域车齿轮箱润滑油发黑问题,文章结合油样检测、齿轮箱拆解检查,以及接地侧流场仿真计算等进行原因分析,并通过台架故障复现试验进行确认。采取减小迷宫间隙、优化碳粉排放结构等措施对迷宫密封结构进行优化,并进行了仿真分析、台架试验和线路试验对比,结果显示优化后的迷宫密封结构可有效抑制碳粉进入齿轮箱内部。

SI Engine Fueled with Gasoline, CNG and CNG-HHO Blend: Comparative Evaluation of Performance, Emission and Lubrication Oil Deterioration

Hydroxy gas (HHO) is one of the potential alternative fuels for spark ignition (SI) engine,notably due to simultaneous increase in engine performance and reduction in exhaust emissions.However,impact of HHO gas on lubrication oil for longer periods of engine operation has not yet been studied.Current study focuses on investigation of the effect of gasoline,CNG and CNG-HHO blend on lubrication oil deterioration along with engine performance and emissions in SI engine.HHO unit produces HHO gas at 4.72 L/min by using 6 g/L of KOH in the aqueous solution.CNG was supplied to the test engine at a pressure of 0.11 MPa using an electronically controlled solenoid valve.Engine tests were carried out at different speeds at 80%open throttle condition and various performance parameters such as brake power (BP),brake specific fuel consumption(BSFC),brake thermal efficiency (BTE),exhaust gas temperature and exhaust emissions (HC,CO_(2),CO and NO_(x))were investigated.In addition,various lubrication oil samples were extracted over 120 h of engine running while topping for drain out volume and samples were analyzed as per ASTM standards.CNG-HHO blend exhibited better performance i.e.,15.4%increase in average BP in comparison to CNG,however,15.1%decrease was observed when compared to gasoline.CNG-HHO outperformed gasoline and CNG in the case of HC,CO_(2),CO and brake specific fuel consumption (31.1%decrease in comparison to gasoline).On the other hand,CNG-HHO produced higher average NO_(x) (12.9%) when compared to CNG only.Furthermore,lubrication oil condition(kinematic viscosity,water contents,flash point and total base number (TBN)),wear debris (Iron (Fe),Aluminum(Al),Copper (Cu),Chromium (Cr)) and additives depletion (Zinc (Zn),Calcium (Ca)) presented a significant degradation in the case of CNG-HHO blend as compared to gasoline and CNG.Lubrication oil analyses illustrated 19.6%,12.8%and 14.2%decrease in average viscosity,flash point and TBN for CNG-HHO blend respectively.However,average water contents,Fe,Al and Cu mass concentration appeared 2.7%,25×10^(-6),19×10^(-6),and 22×10^(-6) in lubrication oil for CNG-HHO respectively.

Experimental study of oil mist characteristics generated from minimum quantity lubrication and flood cooling

The use of metalworking fluids during machining can generate oil mist and endanger the health of workers.In order to study the characteristics and emission laws of oil mist generated by machining,this study constructed a test bench to simulate the turning process.Parameters affecting the oil mist generated in the minimum quantity lubrication(MQL)mode and flood cooling mode were studied by means of single-factor experiments,and the formation mechanisms of oil mist were analyzed.The results show that the oil mist generated by the MQL system has two main sources,the initial escape of oil mist into the air and the evaporation/condensation of oil mist.The centrifugation has almost no effect on oil mist formation in the MQL mode.The mass concentration of oil mist generated by the MQL system is proportional to the cutting oil flow rate.When the work-piece is at room temperature,increasing the air supply pressure and nozzle distance,increases the oil mist mass concentration.For the flood cooling mode,the concentration of centrifugal aerosol is linearly and positively correlated with the relative centrifugal force generated by the work-piece,and the coefficient of determination(R 2)is above 0.97.The oil mist mass concentrations in MQL mode is 8.33 mg/m^(3)~305.88 mg/m^(3).The MMD and SMD are 0.74μm to 4.42μm and 0.31μm to 2.14μm,respectively.The oil mist mass concentrations in flood cooling mode is 0.2 mg/m^(3)~22.42 mg/m^(3).The MMD and SMD are 1.81μm to 6.58μm and 0.45μm to 5.13μm,respectively.

Utilizing an auxiliary portable lube oil heating system in Aliabad Katoul-Iran V94.2 gas turbine during standstill mode:a case study

In a gas turbine power plant,the lubrication oil must be hot enough for the turbine start-up where the unit is in standstill mode.Currently,the strategy to heat the lubrication oil of ANSALDO V94.2 gas turbine power plant is operating the units in turning gear mode or interval mode.However,these strategies cause to suffering the power plant from high power consumption rate and aging.In this study,an auxiliary portable heating system was added to the unit 5 of the MAPNA built MGT-70(an Iranian version of V94.2)Aliabad Katoul-Iran power plant for increasing the lube oil temperature.Irreversibility,cost-effectiveness,and availability of the proposed heating system are studied by the concepts of exergy,economy,and reliability analyses,respectively.The result of the exergy analysis shows that by using the auxiliary portable lube oil heating system the exergy destruction decreases about 94.7%and 92.6%in comparison with turning gear mode and interval mode,respectively.The result of the economic analysis shows that the auxiliary portable heating system consumes less power rather than turning gear mode.Moreover,it is a cost-effective system which has no penalty and no non-profit production.Finally,the reliability analysis shows that the auxiliary portable lube oil heating system is a reliable tool during its lifetime.

润滑条件下旋转轴唇形密封件磨损分析

将全局网络重构的有限元方法与润滑条件下的数值计算模型相结合,分析油封在润滑条件下的磨损过程中,唇口轮廓、接触压力、最大接触压力、泵吸率和摩擦扭矩等密封性能参数的变化趋势。模拟结果表明:油封磨损可以分为2个阶段,第一阶段为初期磨损阶段,该阶段唇口的磨损速率较大,最大接触压力也呈现较大的下降趋势;第二阶段为稳定磨损阶段,该阶段磨损速率较小,磨损量也较小,最大接触压力变化趋势趋于平缓;唇口轮廓的磨损程度随着磨损时间的增加而逐渐趋于平缓,并且空气侧的磨损程度比油侧更为严重;泵吸率呈现出先下降后上升的变化趋势,说明磨损会导致的唇尖材料损失,会引起油封密封性能的不稳定;摩擦扭矩由于受磨损导致的径向力和润滑油剪切作用相互变化的叠加影响,呈现上升的趋势。

变截面密封圈温度场及密封性能分析

为研究不同工况下变截面密封圈密封特性及润滑油膜温度场与黏温特性的关系,根据变截面密封圈密封机制,建立润滑油膜三维数值计算模型,考虑黏温特性和流体内摩擦效应,采用FLUENT和MATLAB软件,研究变截面密封圈润滑油膜在实际工况下的密封特性以及温度特性。结果表明:考虑黏温特性和在定黏度2种情况下所得结果差距明显,表明黏温特性对密封特性的影响不可忽略;油膜最高温度区域均处于外界环境侧,并随工况的改变而移动;油膜最高温度值随转速增加而升高,随密封压力增加而降低,但转速的影响大于其他工况参数;随润滑油温度升高,考虑黏温特性时油膜最高温度值随之增加,而定黏度时呈先减后增的趋势;泄漏量均随转速、密封压力和润滑油温度的增加而增大,但密封压力的影响最大。

抽油机减速箱自润滑双级油封总成的研制与应用

减速箱作为机械采油过程中的重要生产设备,长期在野外运行,由于箱体内压力高、回油槽堵塞、油封刃口与轴套发生干磨导致密封失效等原因易造成减速箱各部位发生漏油,成为生产过程中设备管理的一大顽疾,困扰油井的正常生产。针对以上问题,研制了减速箱双级油封总成,增加减速箱轴承密封级数,实现自润滑功能,解决了减速箱在轴承端盖部位漏油问题。现场124台抽油机减速箱成功应用后,达到了时率增产、降低油耗、杜绝污染等目的,累计创效154.54万元,延长减速箱输入轴和输出轴密封周期2~3倍,取得了降本增效和环保效益的双赢。

不同黏度润滑油与冷却水温度对发动机性能影响研究

润滑油对发动机的强化程度、缸内燃烧压力、发动机经济性和排放性能有显著影响。随着排放标准的日益严格和发动机技术的不断发展,柴油机爆发压力不断提高,有必要重新认识润滑油对柴油机经济性和排放性能的影响。在一台满足国六排放标准的重型柴油机上进行了外特性和负荷特性试验,研究了15W-40和5W-30两种黏度等级的润滑油与冷却水温度对发动机性能的影响。结果表明:对于外特性试验,使用小黏度的5W-30润滑油,燃油消耗率比使用大黏度的15W-40润滑油最多高1.76%;使用两种润滑油的最大功率相同,最大转矩、最高爆发压力有微小差异。对于负荷特性试验,发动机在低转速下,使用5W-30润滑油的燃油消耗率比使用15W-40润滑油低,最多低1.14%;在中等转速下,中高负荷时,与使用15W-40润滑油相比,使用5W-30润滑油的燃油消耗率有时略高,有时略低,存在一定的波动性;在高转速下,使用5W-30润滑油的燃油消耗率比使用15W-40润滑油低,最多低0.36%。在全工况范围内,使用15W-40润滑油的THC排放均低于使用5W-30润滑油;中高负荷时,随着转速的升高,使用15W-40润滑油的THC排放比使用5W-30润滑油低更多。总体上,两种润滑油对碳烟排放的影响差异较小。两种润滑油对NO_(x)和CO排放基本没有影响。在低冷却水温度下,使用两种润滑油的节油效果差异很小;随着冷却水温度的升高,使用5W-30润滑油的节油效果更明显。

ZJ119型卷接机组平准器的改进设计

为解决ZJ119型卷接机组在长时间运行后,平准器部位出现润滑油渗漏的问题,对平准器的劈刀盘传动轴和刷丝轮座进行了优化设计,提高了设备的密封性。以常德卷烟厂的“芙蓉王(硬黄)”牌卷烟为研究对象,对改进前后的ZJ119型卷接机组进行对比测试,结果表明:改进后平准器的劈刀盘处渗油次数由0.75次/周降到0,平准器刷丝轮处渗油次数由1.5次/周减少到0。该方法有效预防了润滑油的渗漏。

高速齿轮喷油润滑流场及冷却性能研究

为探究齿轮传动过程中喷油润滑冷却特性以及确定最佳喷油位置,本文以一对外啮合直齿轮为研究对象,根据齿轮传动功率损失,建立了齿轮喷油润滑流场和温度场耦合计算模型,采用流热耦合数值计算方法以及动网格技术对齿轮喷油润滑工况进行了瞬态仿真分析,得到了各喷油位置下润滑液分布情况以及齿轮本体温度分布情况,从而确定最佳喷油位置。

主给水泵组润滑油水分超标原因分析与处理

主给水泵属于核电厂二回路的关键重要设备,其功能是从除氧器通过高压加热器给水系统连续向蒸汽发生器供水。某核电厂曾发生多台主给水泵组润滑油系统水分超标的问题,从可能漏入水份的各个部件开展分析排查,依据漏入水分的分析结果、以及泵轴承解体情况,确认泄漏点来源于压力级泵自由端机封。对同厂家同类型主给水泵的使用情况调研,确认了压力级泵机封与轴承间泵壳密闭设计不合理。借助有限元分析方法进行计算分析,制定了泵壳优化方案,通过在泵壳体开呼吸孔手段进行了故障处理。泵组重新投运后连续多次对润滑油取样确认缺陷已消除。通过主给水泵润滑油系统进水故障处理的过程,探索出了一系列针对同类型主给水泵润滑油进水的排查方法,对泵壳开呼吸孔的优化手段也为类似高温泵泵壳的设计改进提供了重要的借鉴。

基于移动粒子半隐式方法的油冷电驱系统润滑特性分析

为研究油冷电驱系统的润滑特性,分析了某油冷电驱系统的飞溅润滑特性和极端姿态下低速润滑不良现象,并针对强制润滑和油泵吸空现象进行了分析。结果表明:低速润滑不良、高速润滑良好是飞溅润滑的主要特性,随倾角增大,上坡工况流量逐渐下降,下坡工况相反,左倾20°时无飞溅润滑效果并存在吸油口吸空现象,右倾20°时低速搅油效果差,左、右倾工况下飞溅润滑油量表现相反;强制润滑可综合考虑电机和减速器的流量需求和比例;油泵吸空将导致强制润滑失效,解决吸空问题需同时考虑效率的降低。

西马克夹送辊双唇密封冷却方式改进

西马克高速线材轧机夹送辊双唇密封冷却方式不当,生产过程中双唇密封损坏严重,使用周期缩短。易造成夹送辊进水,润滑站油品乳化,影响设备稳定使用周期。结合现场实际运行情况对夹送辊八字板进行改进,增加了冷却环,引入压缩空气进行高效冷却,能起到密封作用,双唇密封的寿命由改进前的3 d延长到15 d,满足生产现场使用要求。

基于AMESim的汽车电驱动总成冷却润滑系统仿真分析

应用AMESim软件对某新能源电驱动总成冷却润滑系统进行仿真,设计了冷却润滑系统仿真模型,对冷却润滑系统的压力特性与流量分配分析进行了动态仿真。通过仿真和试验验证,得到较为可靠的电驱动总成冷却润滑系统的一维仿真模型,对冷却润滑系统元器件选型、流量分配设计等具有前期指导意义。

对称平衡活塞往复压缩机有油润滑的填料函应用研究

对称平衡活塞往复压缩机的有油润滑填料函是各个密封件的组合体,其主要有冷却、润滑、密封、泄露的气体排放功能,任何一环出现问题就会导致填料故障;在高压、高温、有毒、易燃、易爆的环境下,一旦填料泄漏易发生火灾和爆炸,生产中的有毒有害气体就会对周围的人身造成伤害,对周围的环境造成破坏,这就要求在机组维护保养时一定要保证装配和维修的质量,其重点阐述应用在整体机组GE DPC 2803/04系列、GE分体机CFA系列、RAM系列、WH系列、ARIEL JG系列等活塞杆的填料函和密封环,并分析其系统原理、密封环原理、密封环结构、密封环种类、填料函拆卸、装配注意事项、填料函失效原因排查等。

行星减速器的温度升高试验

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