High Precision CAE Analysis of Automotive Transaxle Oil Seal Leakage

The manufacturing industry today due to worldwide competition is focused on shorter development cycle. In this situation, computer aided education （CAE） technology as a tool for simultaneous achievement of quality, cost and delivery （QCD） plays an important role. The hardware-software environment surrounding CAE has evolved. Though technological problems have been understood and general solutions have been derived and reflected in the CAE analysis software, research findings that boost the credibility of CAE have still not been incorporated fully enough into the development of design process. The real technical mechanism issue is not precisely capture. Therefore, it is important to clarify the real cause in CAE results through CAE simulation in order to assure product reliability and assurance. It is the aim of this study to realize the prediction of design analysis process through understanding of unclear technical mechanism in abnormal occurrences with the utilization of CAE simulation. In other words, it is the aim of this study to focus on issue in automotive transaxle oil seal leakage to understand, grasp, and visualize the main cause through usage of CAE analysis process. It is understood that the point of contact and pump volume was related and this could contribute towards seals quality design. Plus, the utilization of CAE analysis in prediction phase to realized design development is also possible

Leakage performance of labyrinth seal for oil sealing of aero-engine

Experimental investigation has been done to evaluate the leakage performance of labyrinth seal for oil sealing on high-speed sealing test rig at different working and geometric parameters.Typical values of pressure ratio ranging from 1.0 to 2.0 were used and the rotating speed varied from 0 to 30,000 tpm.Dimensionless Taylor number was invited to response the effect of rotation.Oil was injected at the rate from 1.2 L/min to 2.8 L/min to check the sealing capacity.Leakage was measured at different seal configurations including sealing clearance,tooth tip thickness,pitch,teeth number,front inclined angle and oil-throwing angle.Different from gas sealing,the application of oil-throwing tooth in oil sealing attracted much interest as an obvious alternative to the conventional labyrinth seal.A blocking ring was captured during testing,which establishes understanding of underlying flow mechanisms in the clearance and plays an important role in oil sealing.There is a critical Taylor number at which the leakage coefficient drops drastically.After the critical Taylor number,a parabola rule appears.An optimal composition of tooth tip thickness,teeth number,oil-throwing angle and front inclined angle exists where the leakage performance behaves better.

Effects of n-3 polyunsaturated fatty acids from seal oils on nonalcoholic fatty liver disease associated with hyperlipidemia

AIM: To investigate the efficacy and safety of n-3 polyunsaturated fatty acids (PUFA) from seal oils for patients with nonalcoholic fatty liver disease (NAFLD) associated with hyperlipidemia. METHODS: One hundred and forty-four patients with NAFLD associated with hyperlipidemia were included in the 24-wk, randomized, controlled trial. The patients were randomized into two groups. Group A (n = 72) received recommended diet and 2 g n-3 PUFA from seal oils, three times a day. Group B (n = 72) received recommended diet and 2 g placebo, three times a day. Primary endpoints were fatty liver assessed by symptom scores, liver alanine aminotransferase (ALT) and serum lipid levels after 8, 12, 16, and 24 wk. Hepatic fat inf iltration was detected by ultrasonography at weeks 12 and 24 after treatment. RESULTS: A total of 134 patients (66 in group A, 68 in group B) were included in the study except for 10 patients who were excluded from the study. After 24 wk of treatment, no change was observed in body weight, fasting blood glucose (FBG), renal function and blood cells of these patients. Total symptom scores, ALT and triglyceride (TG) levels decreased more significantly in group A than in group B (P < 0.05). As expected, there was a tendency toward improvement in aspartate aminotransferase (AST), γ-glutamyltranspeptidase (GGT), and total cholesterol (TCHO) and high- density lipoprotein (HDL) cholesterol levels (P < 0.05) after administration in the two groups. However, no significant differences were found between the two groups. The values of low-density lipoprotein (LDL) were significantly improved in group A (P < 0.05), but no significant change was found in group B at different time points and after a 24-wk treatment. After treatment, complete fatty liver regression was observed in 19.70% (13/66) of the patients, and an overall reduction was found in 53.03% (35/66) of the patients in group A. In contrast, in group B, only f ive patients (7.35%, 5/68) achieved complete fatty liver regression (P = 0.04), whereas 24 patients (35.29%, 24/68) had a certain improvement in fatty liver (P = 0.04). No serious adverse events occurred in all the patients who completed the treatment. CONCLUSION: Our results indicate that n-3 PUFA from seal oils is safe and effi cacious for patients with NAFLD associated with hyperlipidemia and can improve their total symptom scores, ALT, serum lipid levels and normalization of ultrasonographic evidence. Further study is needed to confi rm these results.

Limitation of fault-sealing and its control on hydrocarbon accumulation——An example from the Laoyemiao Oilfi eld of the Nanpu Sag

Based on previous studies on the internal structures of fault belts, the fault belts in the Laoyemiao Oilfield of the Nanpu Sag can be divided into three units, a crushed zone, an upper induced fracture zone and a lower induced fracture zone according to the log response characteristics. The upper induced fracture zone is characterized by the development of pervasive fractures and has a poor sealing or non-sealing capability. It therefore can act as pathways for hydrocarbon migration. The lower induced fracture zone consists of fewer fractures and has limited sealing capability. The crushed zone has a good sealing capability comparable to mudstone and can thus prevent lateral migration of fluid. Through physical modeling and comparing laboratory data with calculated data of oil column heights of traps sealed by faults, it is concluded that the fault-sealing capability for oil and gas is limited. When the oil column height reaches a threshold, oil will spill over from the top of reservoir along the lower induced fracture zone under the action of buoyancy, and the size of reservoir will remain unchanged. Analysis of the formation mechanisms of the fault-sealed reservoirs in the Nanpu Sag indicated that the charging sequence of oil and gas in the reservoir was from lower formation to upper formation, with the fault playing an important role in oil and gas accumulation. The hydrocarbon potential in reverse fault-sealed traps is much better than that in the consequent fault-sealed traps. The reverse fault-sealed traps are favorable and preferred exploration targets.

Design and operation problems related to water curtain system forunderground water-sealed oil storage caverns

The underground water-sealed storage technique is critically important and generally accepted for the national energy strategy in China. Although several small underground water-sealed oil storage caverns have been built in China since the 1970s, there is still a lack of experience for large-volume underground storage in complicated geological conditions. The current design concept of water curtain system and the technical instruction for system operation have limitations in maintaining the stability of surrounding rock mass during the construction of the main storage caverns, as well as the long-term stability. Although several large-scale underground oil storage projects are under construction at present in China, the design concepts and construction methods, especially for the water curtain system, are mainly based on the ideal porosity medium flow theory and the experiences gained from the similar projects overseas. The storage projects currently constructed in China have the specific features such as huge scale, large depth, multiple-level arrangement, high seepage pressure, complicated geological conditions, and high in situ stresses, which are the challenging issues for the stability of the storage caverns. Based on years’ experiences obtained from the first large-scale （millions of cubic meters） underground water-sealed oil storage project in China, some design and operation problems related to water curtain system during project construction are discussed. The drawbacks and merits of the water curtain system are also presented. As an example, the conventional concept of “filling joints with water” is widely used in many cases, as a basic concept for the design of the water curtain system, but it is immature. In this paper, the advantages and disadvantages of the conventional concept are pointed out, with respect to the long-term stability as well as the safety of construction of storage caverns. Finally, new concepts and principles for design and construction of the underground water-sealed oil storage caverns are proposed.

Effect of Sealing Air on Oil Droplet and Oil Film Motions in Bearing Chamber

Beating chamber is one of important components that support aero-engine rotors and research on oil droplet and oil film motions is an important part of bearing chamber lubrication and heat transfer design. Consid- ering the pressure of sealing air is an important operating condition that affects the oil droplet and oil film mo- tions, the effect of sealing air pressure on airflow in bearing chamber is investigated in this paper firstly ; and then based on the air velocity and air/wall shear force, the oil droplet moving in core air, deposition of oil droplet im- pact on wall as well as velocity and thickness of oil film are analyzed secondly; the effect of sealing air pressure on oil droplet velocity and trajectory, deposition mass and momentum, as well as oil film velocity and thickness is discussed. The work presented in this paper is conducive to expose the oil/air two phase lubrication mechanism and has certain reference value to guide design of secondary air/oil system.

前卡式液压千斤顶往复密封摩擦生热分析

针对千斤顶内油膜摩擦生热问题,提出了一种基于前卡式液压千斤顶内活塞往复密封摩擦生热分析方法。首先,在摩擦生热热源条件下,利用计算流体力学(CFD)数值计算规则,根据活塞往复运动方程进行了用户自定义函数(UDF)编程;然后,结合油液黏温特性建立了千斤顶往复密封摩擦生热仿真计算模型,并给出了千斤顶活塞往复运动油膜摩擦生热建模分析方法;最后,分析了千斤顶油缸内摩擦阻力,并对千斤顶摩擦生热特性进行了仿真分析,得到了千斤顶内温度场分布,并把关键点温度仿真结果与试验数据进行了对比、分析。研究结果表明:前卡式液压千斤顶进行多次张拉工作时,其温度上升趋势和理论分析以及仿真数据基本吻合,在初次张拉工作时,温度上升速度较快;但是在张拉15次后,温度达到29℃左右时,后续温度上升趋势基本相同。前卡式液压千斤顶内温度场分布规律可以为液压千斤顶密封材料选取、结构改进和张拉系统油压表温度补偿提供理论和技术方面的支持。

油页岩循环床锅炉中温分离回输系统Loop Seal工作特性的研究

在目前世界上投入商业运行最大容量的 65t/h油页岩循环流化床锅炉上 ,进行了全尺寸的中温分离系统中LoopSeal型返料装置的工作特性热态试验 ,得到了油页岩循环流化床燃烧中温分离回输系统中LoopSeal型返料装置的运行参数、温度特性及其循环物料的颗粒特性和含碳量分布 。

稠油热采无机硅酸凝胶封窜剂的研究与应用

在稠油油藏热采过程中容易发生蒸汽地下窜流和地表汽窜,严重影响矿区产能,同时造成地面污染。以水玻璃与尿素为交联剂主体,通过与表面活性剂甘油三乙酸酯进行复配,研制了一种新型耐高温封窜剂。通过正交试验确定了最优封窜剂配方:60%水玻璃+4%尿素+0.2%甘油三乙酸酯+水;红外光谱(FTIR)及扫描电镜(SEM)分析发现,该体系中水玻璃通过一段时间的交联,形成单硅酸,后缩聚形成线性多聚硅酸,硅酸分子间相互作用发生缠结,形成的网状结构使得其稳定性较高,结构更稳定,有更好的耐温能力;实验室内填砂管性能评价结果表明,封窜剂段塞注入量为0.2 PV及候凝时间为5 d时,封堵率98.8%、突破压力梯度1.4 MPa/m、残余阻力系数83.32,经过21 PV 260℃的高温蒸汽冲刷后封堵率稳定在94%以上;现场试验结果表明,井F-109日产油从0.9 t增至5.5 t,含水率由89%降至50%,施工244 d,累计增油1122.4 t,F井区地面不再发生蒸汽窜漏,受地面窜漏影响的14口井恢复了正常注汽吞吐生产,累计增油15713.6 t,平均单井日注汽量100 m 3,注汽压力5.5 MPa。综合表明,该封窜剂体系具有良好的高温选择封堵性,对稠油热采高温蒸汽窜流的有效治理提供了理论指导和技术支撑。

基于似然函数筛选法的旋转轴唇形密封可靠性关键设计因素研究

基于油封的有限元和数值计算模型,分析油封的设计参数对其静态和动态密封可靠性的影响规律。将油封的初始安装过盈量、油侧唇角、空气侧唇角、腰厚、腰长、理论接触宽度、卡紧弹簧的弹性模量、油封主体橡胶的硬度8个设计参数的标准化数据作为输入向量,将油封唇口最大接触压力、泵吸率和摩擦扭矩的标准化数据作为输出向量,建立响应面模型,以输出向量方差得到各设计因素的似然函数值作为评判指标,确定各设计参数对油封密封可靠性的影响程度。结果表明:橡胶硬度、理论接触宽度、弹簧弹性模量、过盈量、腰长对油封动态密封可靠性的影响较显著,油封唇口最大接触压力对弹簧弹性模量、理论接触宽度、橡胶硬度、腰厚、油侧唇角较敏感。综合考虑旋转轴唇形油封的静态和动态可靠性,得到影响其可靠性的关键设计因素为理论接触宽度、弹簧弹性模量和橡胶硬度。

炼化企业挥发性有机化合物减排的探索与实践

炼化企业加工过程有组织、无组织排放的挥发性有机化合物(VOCs)量较大,对大气环境中的颗粒物、臭氧浓度等产生重大影响。A公司自“十三五”以来对VOCs减排进行了探索与实践,通过采取油气回收、储罐浮盘高效密封改造、呼吸阀改型升级、无组织排放改为有组织回收、VOCs焚烧、常态化泄漏检测与修复工作等多种减排措施,VOCs排放量已从2015年的4230 t下降到2022年的2157 t,降低比例达到49%,取得了显著的成效。

冲击荷载作用下花岗岩损伤与渗流特征演化规律

爆破振动是影响岩石构筑物稳定性和渗流特性的主要因素之一。本文针对爆破振动对地下水封油库围岩渗透性影响机制科学问题,结合霍普金森杆试验和岩石三轴渗流试验,开展了系统研究,分析了冲击荷载作用下花岗岩渗透性演化规律。通过现场获取典型花岗岩试样,并开展霍普金森压杆试验,研究了不同冲击速度和冲击循环次数下的花岗岩损伤演化规律;对于冲击损伤后的试样开展三轴渗流试验,研究了不同损伤量和水头差下花岗岩渗透性的演化规律。研究表明:花岗岩损伤量随冲击速度和冲击次数增大而增大。花岗岩破坏形态随损伤量增长依次经历无明显破坏(00.16)3个阶段。当损伤量小于0.16时,花岗岩破坏程度较低,花岗岩等效渗透系数小于1.4×10^(-9)cm·s^(-1)并随损伤量增长呈指数型缓慢增长。随着损伤量不断增长,花岗岩破碎明显,甚至出现贯通裂隙,此时花岗岩等效渗透系数以数量级为单位急剧增长。论文研究成果明确了冲击荷载作用下花岗岩损伤程度与地下水位对花岗岩渗透性的影响规律,可为研究爆破施工扰动对地下水封油库水封可靠性分析提供理论依据,并为类似工程提供参考。

辊压机用密封方案的优化选型分析

辊压机是水泥生产线上非常关键的设备之一,该设备的稳定工作决定了生产线能否正常运行,而影响辊压机正常工作的关键因素就是密封失效。本文根据以往辊压机密封的使用跟踪及相关文献资料,分析研究客户要求后,对现有的密封选型方案进行了总结归纳和优化,基本可以解决现有密封使用寿命短、更换不方便等问题,并且在一些用户的设备上也得到了验证。

水轮机组接力器锁锭系统改造优化设计分析

为解决传统水轮机组接力器锁锭系统存在的油液渗漏、操作不便、耗油量大、油缸上下腔窜油等问题,提出对现有结构采取以下措施进行整体改造优化设计:将控制阀组优化设计布置在油缸的上端盖上,采用通用型组合密封元件替代传统O形密封圈,并对油缸筒体、上缸盖、活塞杆进行了重新设计。设计改造完成后,系统结构更加紧凑,减少了管路数量,避开了对检修操作有妨碍的物体,方便设备的检修维护操作,同时降低了对环境造成污染的可能性,取得了较好的应用效果。

橡胶泊松比对等壁厚单螺杆泵举升性能影响的试验研究

为了研究橡胶泊松比对等壁厚单螺杆泵举升能力的影响,对其进行了有限元模拟和试验研究。首先,采用Workbench软件对等壁厚单螺杆泵进行了接触非线性仿真,研究了不同容腔压强下的压差载荷与其接触应力的关系,总结出了容腔间临界密封压力的计算方法,计算得到了不同橡胶泊松比下等壁厚单螺杆泵的临界密封压力,并使用Origin软件对其进行了多项式拟合;然后,分析了橡胶泊松比与容腔间临界密封压力的关系,根据等壁厚单螺杆泵内部油压传导规律,计算得到了不同橡胶泊松比下的螺杆泵扬程,并分析了两者间的关系;最后,为了验证等壁厚单螺杆泵接触非线性仿真结果的正确性,对该螺杆泵进行了水力特性试验。研究结果表明:容腔间接触应力随压差载荷的增大而近似呈线性增大,随容腔压强的增大而减小;容腔间的临界密封压力随容腔压强的增大而近似呈非线性减小;在容腔压强一定时,容腔间的临界密封压力随橡胶泊松比的增大而增大,泊松比越大其等壁厚单螺杆泵内部就越不易漏失;螺杆泵的扬程随橡胶泊松比的增大而呈非线性增大,且增长的速率越来越快;试验中,等壁厚螺杆泵所能达到的最大扬程为10.85 MPa,仿真结果与试验结果误差仅为3.2%。以上研究结果可为等壁厚单螺杆泵未来的研究提供借鉴参考。

大型油浸式电力变压器胶囊式储油柜运行维护

为解决因设计、制造、安装工艺不足或运行维护操作不规范导致的胶囊密封失效、油位计显示油位不准确等问题,从大型油浸式电力变压器胶囊式储油柜的密封运行维护、油位运行维护两方面进行探讨,分析了密封失效的常见原因和检查方法,提供了摆杆式指针油位计的标定方法,并给出相应的维护建议。

基于两相流的水封油库油气泄漏运移规律及控制措施

地下水封油库运行的关键是保持一定的水封厚度,为确定合适的水封厚度,基于气液两相流理论,采用有限元数值模拟方法,以我国某石油储备地下水封洞库为依托,模拟了地下水封石油洞库储油运行期油气的泄漏运移演变过程。结果表明:施工期不设置水幕系统情况下,洞室顶部出现了大面积的疏干区,造成后期无法储油;设置水幕系统情况下,洞库上方能够维持一定水封厚度,洞库周围岩层油气泄漏范围和泄漏量均与储油运行时间呈正幂函数关系;水封厚度越大油气泄漏范围和泄漏量越小,但过大的水封厚度会大大增加工程成本,所对应的案例在水封厚度为30 m时对油气泄漏控制最为经济合理,《地下水封石洞油库设计标准》推荐的水封厚度合理且有一定安全裕度。研究成果可为水封油库工程的设计及油气泄漏控制提供一定理论参考。

Study on Oil Cavity Number of Hydrostatic Guide Sleeve of Electro-hydraulic Servo Cylinder

The electro-hydraulic servo drive hydraulic cylinder has many unique advantages, such as fast response, high load stiffness, high control power, strong anti-eccentric load ability and so on, so it has been widely used in industrial control. Based on the guide sleeve of hydrostatic seal of hydraulic cylinder, the reasonable number of oil chamber of guide sleeve is studied in this paper. ICEM CFD software and FLUENT simulation software are used to calculate and analyze the number of different oil chambers of guide sleeve of hydrostatic seal. The temperature field of piston rod with different moving speed, different initial pressure of oil chamber and oil film under different number of oil chambers is analyzed. The relationship between the pressure field and temperature field provides a better basis for optimizing the design of hydrostatic guide sleeve and helps to improve the servo drive cylinder.

双端面机械密封在双螺杆原油泵上的应用

基于原油库拆建工程项目,对双螺杆原油泵原采用的单端面金属波纹管机械密封改造为新型的带泵效环的背靠背双端面机械密封,并配套冷却循环辅助系统,经现场工业考核,背靠背双端面机械密封在双螺杆原油泵上得到良好应用。结果表明,新改造的双端面机械密封彻底解决了原密封存在的摩擦副磨损严重、泄漏量大、使用寿命短等问题,实现了工艺介质的零泄漏并确保设备长周期安全稳定运行。

基于真三轴试验装置的岩石渗流密封方式改进及实验研究

国内现有的非常规油气储层的渗透性测试大多采用圆柱试样,通过假三轴试验装置进行测试,而真三轴条件下立方体试件棱边大多存在棱边串流与端面密封不严的缺陷。基于现有真三轴试验装置,以及大量的实验经验,针对现有的立方体试件单橡胶套渗流密封方式进行改进。介绍了嵌套式“上下密封套”结构特征,特别对棱边区的密封进行了设计,提出了密封套顶-底端面凹陷型内嵌“单孔网槽导流板”结构设计,并对顶部传压板的尺寸进行了讨论。对100 mm×100 mm×100 mm立方体煤样进行了真三轴渗流试验分析,得到了不同入口渗透压力真三轴围压条件下的渗透率。该密封方法的改进有助于提高科研单位及测试中心对原位地应力条件下非常规油气储层渗透性测试精度,并提高高端科研人才的实践创新能力与科研素养。