Fluid-solid Interaction Model for Hydraulic Reciprocating O-ring Seals

Elastohydrodynamic lubrication characteristics of hydraulic reciprocating seals have significant effects on sealing and tribology performances of hydraulic actuators, especially in high parameter hydraulic systems. Only elastic deformations of hydraulic reciprocating seals were discussed, and hydrodynamic effects were neglected in many studies. The physical process of the fluid-solid interaction effect did not be clearly presented in the existing fluid-solid interaction models for hydraulic reciprocating O-ring seals, and few of these models had been simultaneously validated through experiments. By exploring the physical process of the fluid-solid interaction effect of the hydraulic reciprocating O-ring seal, a numerical fluid-solid interaction model consisting of fluid lubrication, contact mechanics, asperity contact and elastic deformation analyses is constructed with an iterative procedure. With the SRV friction and wear tester, the experiments are performed to investigate the elastohydrodynamic lubrication characteristics of the O-ring seal. The regularity of the friction coefficient varying with the speed of reciprocating motion is obtained in the mixed lubrication condition. The experimental result is used to validate the fluid-solid interaction model. Based on the model, The elastohydrodynamic lubrication characteristics of the hydraulic reciprocating O-ring seal are presented respectively in the dry friction, mixed lubrication and full film lubrication conditions, including of the contact pressure, film thickness, friction coefficient, liquid film pressure and viscous shear stress in the sealing zone. The proposed numerical fluid-solid interaction model can be effectively used to analyze the operation characteristics of the hydraulic reciprocating O-ring seal, and can also be widely used to study other hydraulic reciprocating seals.

Influence Analysis of Secondary O-ring Seals in Dynamic Behavior of Spiral Groove Gas Face Seals

The current research on secondary O-ring seals used in mechanical seals has begun to focus on their dynamic properties. However, detailed analysis of the dynamic properties of O-ring seals in spiral groove gas face seals is lacking. In particular a transient study and a difference analysis of steady-state and transient performance are imperative. In this paper, a case study is performed to gauge the effect of secondary O-ring seals on the dynamic behavior（steady-state performance and transient performance） of face seals. A numerical finite element method（FEM） model is developed for the dynamic analysis of spiral groove gas face seals with a flexibly mounted stator in the axial and angular modes. The rotor tilt angle, static stator tilt angle and O-ring damping are selected to investigate the effect of O-ring seals on face seals during stable running operation. The results show that the angular factor can be ignored to save time in the simulation under small damping or undamped conditions. However, large O-ring damping has an enormous effect on the angular phase difference of mated rings, affecting the steady-state performance of face seals and largely increasing the possibility of face contact that reduces the service life of face seals. A pressure drop fluctuation is carried out to analyze the effect of O-ring seals on the transient performance of face seals. The results show that face seals could remain stable without support stiffness and O-ring damping during normal stable operation but may enter a large-leakage state when confronting instantaneous fluctuations. The oscillation-amplitude shortening effect of O-ring damping on the axial mode is much greater than that on the angular modes and O-ring damping prefers to cater for axial motion at the cost of angular motion. This research proposes a detailed dynamic-property study of O-ring seals in spiral groove gas face seals, to assist in the design of face seals.

Experimental study on the failure factors of the O-ring for long-term working

The O-ring in the rotary dynamic sealing system of gas meters should have outstanding long-term sealing performance under the conditions of high and low temperature,which can ensure the safety of gas meters.In this paper,based on the O-ring sealing mechanism,taking the compression set as the main sealing index,a finite element simulation method is used to analyze the failure charac-teristics under different conditions according to the constitutive relation of nitrile rubber.Then,using the orthogonal test method for the O-ring sealing performance index,the main factors which affect the law of long-term test are analysed,and the orthogonal regression mathematical model that can predict the compression set is obtained.Finally,the O-ring is improved according to the model,and the test results show that the performance of the new O-rings with high and low temperature resistance is greatly improved and meets the expected target requirements.

Geopolymer-based modification of blasting sealing materials and optimization of blasting block size in coal seams of open pit mines

This research proposes the utilization of a geopolymer-based blasting sealing material to improve the profitability of coal sales and reduce the rate of coal fragmentation during blasting in open pit mines.The study first focused on optimizing the strength of the sealant material and reducing curing time.This was achieved by regulating the slag doping and sodium silicate solution modulus.The findings demonstrated that increasing slag content and improving the material resulted in an early rise in strength while increasing the modulus of the sodium silicate solution extended the curing time.The slag doping level was fixed at 80 g,and the sodium silicate solution modulus was set at 1.5.To achieve a strength of 3.12 MPa,the water/gel ratio was set at 0.5.The initial setting time was determined to be 33 min,meeting the required field test duration.Secondly,the strength requirements for field implementation were assessed by simulating the action time and force destruction process of the sealing material during blasting using ANSYS/LS-DYNA software.The results indicated that the modified material meets these requirements.Finally,the Shengli Open Pit Coal Mine served as the site for the field test.It was observed that the hole-sealing material’s hydration reaction created a laminated and flocculated gel inside it.This enhanced the density of the modified material.Additionally,the pregelatinized starch,functioning as an organic binder,filled the gaps between the gels,enhancing the cohesion and bonding coefficient of the material.Upon analyzing the post-blasting shooting effect diagram using the Split-Desktop software,it was determined that the utilization of the modified blast hole plugging material resulted in a decrease in the rate of coal fragmentation from 33.2%to 21.1%.This reduction exhibited a minimal error of 1.63%when compared to the field measurement,thereby providing further confirmation of the exceptional plugging capabilities of the modified material.This study significantly contributes to establishing a solid theoretical basis for enhancing the blasting efficiency of open pit mines and,in turn,enhancing their economic advantages.

Effect of nitrile butadiene rubber hardness on the sealing characteristics of hydraulic O-ring rod seals

The nitrile butadiene rubber(NBR)hardness effect on the sealing characteristics of hydraulic O-ring rod seals is analyzed based on a mixed lubrication elastohydrodynamic model.Parameterized studies are conducted to reveal the mechanism of the influence of rubber hardness on the static and dynamic behavior of seals.The optimized selections of rubber hardness are then investigated under different conditions.Results show that the low hardness seal is prone to stress concentration due to the extrusion effect under high pressure conditions;it is also more prone to leaking.A high hardness seal can better prevent leakage by reducing film thickness but it will cause large frictional power loss and increase the probability of wear failure.The choice of low hardness is recommended to reduce friction with the premise that leakage requirements are met.

高压电缆附件铅封缺陷超声检测定量方法

采用相控阵超声技术可以检测高压电缆终端铅封缺陷,为了解决常规的超声定量方法无法有效的检测和定量铅封缺陷的问题,提出了基于超声扇扫图像的高压电缆铅封缺陷定量检测方法,该方法以铅封缺陷纵波扇扫图像为对象并结合了阈值分割和腐蚀算法,能够实时的获取缺陷横截面积、缺陷高度等其他相关信息。首先,搭建了高压电缆终端铅封缺陷超声检测试验平台,对以孔洞、夹渣为代表的不同直径的铅封缺陷进行检测,其次,对采集的铅封超声扇扫图像进行阈值分割和腐蚀算法处理,进行缺陷定量分析,并与传统的-6 dB定量结果进行对比,最后讨论了不同直径缺陷对超声定量结果的影响。研究结果表明,相较于传统的-6 dB法,此方法测量的距离误差缩小了5%,缺陷尺寸精度提高了10%,正确率达到了85%以上,但当铅封缺陷直径增大时,缺陷测量误差也随之升高。该方法验证了采用相控阵超声技术可以高效、直观的检测和定量高压电缆铅封缺陷,为高压电缆铅封缺陷的工程应用提供了重要参考价值,有助于提高高压电缆终端铅封工艺质量,确保电网的运行安全。

基于结构变形理论的深海连接器O形圈密封性能研究

深海连接器是保证海洋装备能够正常运行的信号传输设备,而深海连接器的正常运行在很大程度上依赖于O形圈的密封性能。为此,对深海高压环境导致O形圈发生形变,从而严重影响O形圈的密封性能问题进行了研究。首先,基于结构变形理论,分析了环境压力对于密封结构变形和O形圈压缩量的影响变化;然后,基于有限元法建立了O形密封圈的非线性动密封模型,分析研究了模型网格划分对于模拟结果准确性的影响;接着,分析了结构变形与环境压力之间的关系曲线;最后,研究分析了材料性能、环境压力与密封结构尺寸对于动密封性能的影响。研究结果表明:当网格的实际值为47745,测定值为21685、37934、50707时,其模拟计算结果的误差值均小于2%;密封结构变形和O形圈压缩量的模拟值与理论值的曲线趋势基本一致;材料性能与环境压力的变化会影响动密封性能,在密封结构尺寸中,增大沟槽圆角半径可以增强O形圈的动密封性能。该研究结果可为深海高压环境下O形密封圈的设计与优化提供参考与理论支持。

三偏心蝶阀密封副空间模型及应用

正确设计阀座和密封圈的密封面加工尺寸,是三偏心蝶阀密封副(阀座和密封圈)经过加工后在关闭时能够严密配合且实现良好密封的前提。本文从三偏心蝶阀密封副的偏心结构特征和坐标转换的原理出发,建立密封面所在空间的斜圆锥面方程和密封副截面椭圆方程,通过该空间模型方程可以确定三偏心结构参数之间的相互关系。通过该空间模型方程,可以通过计算确定三偏心蝶阀密封面加工时测量尺寸的方法。此外,在阀座或密封圈偏离设计加工尺寸时,通过偏心结构参数之间的关系计算,快速得出相应需要单独设计的阀座或密封圈的加工测量尺寸。三偏心蝶阀密封副空间模型的建立在蝶阀产品现实设计加工过程中具有重要应用价值。

大型轴件的阻尼油封区表面银钎焊非等强修复

某大型42CrMo4+Ni+V轴件的阻尼油封区因故产生了表面损伤。为恢复受损区油封功能和几何尺寸,采用银钎焊工艺进行表面非等强修复。首先,制作模拟样棒,制定预焊接工艺规程,按照该规程进行了评定试验。对模拟样棒焊前焊后的相同部位进行了拉伸、冲击、硬度试验和金相组织观察。分析得出,热影响区范围约为2 mm,采用银钎焊修复对母材组织和力学性能的影响很小,用于表面损伤的非等强修复是可行的。最后,将该工艺成功用于大型轴件阻尼油封区表面损伤的实际修复。

采煤机摇臂浮动油封结构尺寸影响分析

介绍了采煤机摇臂浮动油封结构形式,对浮动油封使用处的结构进行分析,确定影响其结构尺寸的因素;对结构尺寸链及加工进行控制,从而达到满足尺寸公差要求;通过设置于滚筒联接套上的孔对安装后的浮动油封进行测量复核,从而避免浮动油封频繁漏油。

一种驱动电机用矩形橡胶密封系统的设计方法

本文以矩形橡胶密封圈和矩形密封槽的匹配设计作为研究对象,根据压缩率和填充率的范围要求,对矩形橡胶密封圈和密封槽尺寸进行匹配设计。同时,对于该密封系统在新能源汽车驱动电机环境的实际应用,在不同的环境温度时,对于不同的尺寸匹配结果,基于Ansys软件进行了热仿真,根据仿真结果发现,当环境温度在-40℃~160℃区间变化时,不同尺寸匹配情况下的压缩率和填充率都是随环境温度的升高而升高,但是依然满足密封系统的压缩率和填充率的范围要求。文章提出的根据压缩率和填充率范围要求,在温度变化的环境下,对矩形橡胶密封圈和矩形密封槽进行匹配设计,具有一定的工程指导意义。

大尺寸旋转密封技术在海上单点系泊输油领域的应用

本文根据海上单点系泊输油系统大尺寸旋转密封设计的影响因素,开展作业海域的气象水文条件对运动受力的影响,海洋温度、盐度环境和原油类型等对耐腐蚀性的要求分析,阐述了泛塞密封技术应用于海上单点系泊输油系统大尺寸旋转密封的设计、加工和试验的有关要求。

化工装置厂区防渗注浆关键技术研究

近几年来,国家对环境保护越来越重视,而化工装置厂区内危险源众多,如液氨、柴油、甲醇等,一旦泄露将对地下水资源和土壤等造成不可逆转的破坏,因此,对化工装置厂区进行防渗处理将是一种必然趋势。由于装置厂区建构筑物较多,特别是已建装置厂区,进行防渗处理时可采用的处理方法受限,强夯、土工铺膜、挤密桩等因为施工工艺的限制均不能进行施工,而注浆由于施工简单,作业面小,在调整钻孔注浆角度后可直接在装置下注浆,且注浆后防渗效果较好,能起到预期的防渗效果,因而化工装置厂区防渗注浆施工会在以后的施工中越来越被社会所认可并广泛采用,具有良好的发展趋势。此文通过对化工装置厂区内防渗注浆关键技术的研究,为今后类似的防渗注浆工程施工提供了理论依据和技术支持。

提高辊压机做功能力的影响因素分析

水泥工业广泛采用辊压机作为粉磨系统的预粉碎设备,辊压机的高效做功成为业内关注的重点,通过分析辊压机喂料阀及辊面、侧挡板间隙、辊缝、辊压机工作压力、中间仓和喂料溜子、V型选粉机、熟料粒径等对辊压机做功的影响,提出了优化改进措施,以保证辊压机料床挤压稳定运行,维持做功电流在额定电流的90%±5%,提高辊压机做功效率。

首山一矿综采工作面煤尘浓度-粒度分布规律研究

为了解决综采工作面粉尘污染严重且防治困难的问题,对首山一矿综采工作面粉尘颗粒浓度-粒度分布规律进行研究,并提出了尘源多级多维封闭雾化控除尘技术。结果表明:风流在采煤机滚筒处发生绕流及横移,风速最大达到2.5 m/s,在距采煤机约10 m处趋于平稳;在前滚筒中心下风侧9 m区域内形成高速风流带,平均风速超过2.0 m/s;在距移架10 m内的未移架区采空区形成长达38 m的高浓度粉尘带,浓度约1629~2257 mg/m^(3);前滚筒中心高度附近高浓度粉尘带长度达40 m,浓度约1590~2845 mg/m^(3);在人行道区域,粉尘颗粒粒径为0.25~10μm,对井下工作人员的呼吸造成巨大干扰。尘源多级多维封闭雾化控除尘技术应用后,现场呼尘平均降尘率为84.68%,总尘平均降尘率为88.52%。

弹性蓄能密封圈结构优化设计及验证

以OmniSeal 103A系列弹性蓄能密封圈为参考,提出密封夹套和与密封沟槽配合尺寸设计方法,并对弹性蓄能密封圈的结构进行优化,设计外唇面带有15°斜面的弹性蓄能密封圈JT1和外唇面为圆弧面的弹性蓄能密封圈JT2。设计实验从正反向摩擦力和密封性2个方面对两款弹性蓄能密封圈进行性能验证,并且与OmniSeal 103A系列中同规格密封圈性能进行对比。结果表明:JT1蓄能密封圈很大程度上提升了密封性能并且其抗摩擦性能也没有大幅下降,而JT2蓄能密封圈提升了抗摩擦性能,且密封性基本与OmniSeal蓄能密封圈相当。因此,JT1蓄能密封圈更适用于对密封性要求更高的场合,JT2蓄能密封圈更适用于对抗摩擦性要求更高的场合。

全通径双向硬密封蝶阀的设计与计算

为了克服现有浮动阀座双向硬密封蝶阀不能实现全通径的困难,本文提出了采用组合式阀体隐藏浮动阀座的全通径双向硬密封蝶阀技术方案,详细阐述了结构原理和设计原则,并结合DN1000的全通径双向硬密封蝶阀实例,对关键零部件浮动阀座的尺寸进行了详细计算。根据本文提出的阀门结构和计算方法而设计的全通径双向硬密封蝶阀,经过不同压力和不同口径的产品试验,均取得了满意的效果。

某核主泵机械密封低压泄漏率高根本原因分析

某核主泵机械密封发生多次低压泄漏率高事件,严重影响主泵安全稳定运行,通过机械密封解体检查,发现这多起机械密封故障是共模故障。本文对机械密封低压泄漏率高典型事件进行了根本原因分析并提出了机械密封改进建议,对机械密封静环导套进行修复,主系统泄漏量下降近一半,取得了良好效果。

O形密封圈尺寸视觉精密测量技术

针对现有O形密封圈尺寸测量方法的局限性,设计基于主动视觉的精密检测方法,并对快速自动调焦、亚像素边缘检测、边缘点拟合技术进行了研究。将快速自动调焦过程分为3个阶段,使用大步长和方差函数,结合灰度切割对比度增强与中值滤波,完成粗调焦;使用小步长和Tenengrad函数,完成细调焦;采用Brenner函数和微步距完成高灵敏度调焦.用Zernike矩算法对边缘点进行亚像素定位,并采用面积最小误差法拟合边缘点,求取O形密封圈的内径、外径.实验结果表明:本文方法经过16步搜索,在15 s内可自动完成调焦;与传统方法相比,通过亚像素提取,能将内外径测量结果达到微米级,满足O形密封圈测量需求.

重力对磁性液体密封性能的影响

磁性液体密封是磁性液体最重要最成熟的应用之一。通常,在分析磁性液体的密封性能时重力被忽略,但随着磁性液体应用的发展,有些工况重力会严重影响磁性液体密封的密封性能,甚至导致密封失效。本文通过实验研究了大直径大间隙的磁性液体密封的密封性能,分析了密封失效的原因,探讨了重力对密封性能的影响,提出了密封极限尺寸的概念。对于一般密封间隙的磁性液体密封,极限尺寸大约为1.57 m。随着密封间隙的增大,间隙里磁场的减弱,极限尺寸减小。