Gas Film Disturbance Characteristics Analysis of High-Speed and High-Pressure Dry Gas Seal

The dry gas seal（DGS） has been widely used in high parameters centrifugal compressor, but the intense vibrations of shafting, especially in high-speed condition, usually result in DGS＇s failure. So the DGS＇s ability of resisting outside interference has become a determining factor of the further development of centrifugal compressor. However, the systematic researches of which about gas film disturbance characteristics of high parameters DGS are very little. In order to study gas film disturbance characteristics of high-speed and high-pressure spiral groove dry gas seal（S-DGS） with a flexibly mounted stator, rotor axial runout and misalignment are taken into consideration, and the finite difference method and analytical method are used to analyze the influence of gas film thickness disturbance on sealing performance parameters, what＇s more, the effects of many key factors on gas film thickness disturbance are systematically investigated. The results show that, when sealed pressure is 10.1MPa and seal face average linear velocity is 107.3 m/s, gas film thickness disturbance has a significant effect on leakage rate, but has relatively litter effect on open force; Excessively large excitation amplitude or excessively high excitation frequency can lead to severe gas film thickness disturbance; And it is beneficial to assure a smaller gas film thickness disturbance when the stator material density is between 3.1 g/cm3 to 8.4 g/cm3; Ensuring sealing performance while minimizing support axial stiffness and support axial damping can help to improve dynamic tracking property of dry gas seal. The proposed research provides the instruction to optimize dynamic tracking property of the DGS.

Experimental Verification and Research for the Distortion in the Integrated Frequency Responses of the High-Pressure Sealed Cabin and Magnetic Field Sensor

Although magnetotelluric sounding method applied to the land is advanced, there are many difficulties when it is applied to marine environment, one of which is how to lay magnetic field sensors down to the seafloor to complete measurements. To protect the magnetic field sensors from intense erosion and high pressure, suitable high-pressure sealed cabins must be designed to load them. For the consideration of magnetic measurement and marine operation, the sealed pressure cabin should be nonmagnetic and transportable. Among all optional materials, LC4 super.hard aluminum alloy has the highest performance of price/quality ratio to make the sealed pressure cabin. However, it does not mean that the high-pressure sealed cabin made using LC4 will be perfect in performance. In fact, because of its weak magnetism, the pressure cabin made using LC4 has distorting effect on frequency responses of the magnetic field sensors sealed in it. This distorting effect does not affect the use of the magnetic field sensor, but if we want to eliminate its effect, we should study it by experimental measurements. In our experiment tests, frequency sweep magnetic field as excitation signal was used, and then responses of the magnetic field sensor before and after being loaded into the high-pressure sealed cabin were measured. Finally, normalized abnormal curves for the frequency responses were obtained, through which we could show how the high-pressure sealed cabin produces effects on the responses of the magnetic field sensor. Experimental results suggest that the response distortion induced by the sealed pressure cabin appears on mid- and high-frequency areas. Using experimental results as standardization data, the frequency responses collected from seafloor magnetotelluric measurements can be corrected to restore real information about the seafloor field source.

Effects of Four Types of Pre-swirls on the Leakage, Flow Field, and Fluid-Induced Force of the Rotary Straight-through Labyrinth Gas Seal

The labyrinth seal in turbomachinery is a key element that restricts leakage flow among rotor-stator clearances from high-pressure regions to low-pressure regions. The fluid-induced forces on the rotor from seals during machine operation must be accurately quantified to predict their dynamic behavior effectively. To understand the fluid-induced force characteristics of the labyrinth seal more fully, the effects of four types of pre-swirls on the leakage, flow field, and fluid-induced force of a rotary straight-through labyrinth gas seal (RSTLGS) were numerically investigated using the proposed steady computational fluid dynamics (CFD) method based on the three-dimensional models of the RSTLGS. The leakage, flow field, and fluid-induced force of the RSTLGS for six axial pre-swirl velocities, four radial preswirl angles, four circumferential positive pre-swirl angles, and four circumferential negative pre-swirl angles were computed under the same geometrical parameters and operational conditions. Mesh analysis ensures the accuracy of the present steady CFD method. The numerical results show that the four types of pre-swirls influence the leakage, flow field, and fluid-induced force of the RSTLGS. The axial pre-swirl velocity remarkably inhibits the fluid-induced force, and the circumferential positive pre-swirl angle and circumferential negative pre-swirl angle remarkably promote the fluid-induced force. The effects of the radial pre-swirl angle on the fluid-induced force are complicated, and the pressure forces and viscous forces show the maximum or minimum values at a specific radial pre-swirl angle. The pre-swirl has a negligible impact on the leakage. The four types of pre-swirls affect the leakage, flow field, and fluidinduced force of the RSTLGS to varying degrees. The pre-swirl is the influence factor affecting the leakage, flow field, and fluid-induced force of the RSTLGS. The conclusions will help to understand the fluid-induced force of labyrinth seals more fully, by providing helpful suggestions for engineering practices and a theoretical basis to analyze the fluid–structure interaction of the seal-rotor system in future research.

Development and Application of a Surface High-pressure Injection Device Using a Submersible Electric Pump

Injection recovery is an important measure for increasing the oil recovery rate of an oil field. One way is that centrifugal pumps or plunger pumps are used in an injection station to responsible for injection over a large area under the same pressure. This method is ineffective for low-permeability layers. For the oilfields in dispersed distribution in the marginal areas of Daqing, the low water-absorbing section needs an injection with a high delivery pressure and a low discharge capacity; another way is to install the submersible electric pump upside down, but because the submersible electric pump and the motor are underground, it is difficult for installation and maintenance. Introduced in this paper is the development and application of a surface high-pressure injection device with a submersible electric pump. Bysuccessful resolving some problems, such as the axial force of the submersible electric pump, sealing, level regulation of the pump, coaxiality and vibration, the device has the good points of running smoothly, moving easily, installation and maintains quickly and long period of running. This device can effectively solve the injection of the low water-absorbing section and of oilfields in dispersed locations. The recovery rate of oilfields is also enhanced.

Thermal-Mechanical Coupled FE Analysis for Rotary Shaft Seals

The aim of this paper is to model the steady-state condition of a rotary shaft seal (RSS) system. For this, an iterative thermal-mechanical algorithm was developed based on incremental finite element analyzes. The behavior of the seal’s rubber material was taken into account by a large-strain viscoelastic, so called generalized Maxwell model, based on Dynamic Mechanical Thermal Analyses (DMTA) and tensile measurements. The pre-loaded garter spring was modelled with a bilinear material model and the shaft was assumed to be linear elastic. The density, coefficient of thermal expansion and the thermal conductance of the materials were taken into consideration during simulation. The friction between the rotary shaft seal and the shaft was simplified and modelled as a constant parameter. The iterative algorithm was evaluated at two different times, right after assembly and 1 h after assembly, so that rubber material’s stress relaxation effects are also incorporated. The results show good correlation with the literature data, which state that the permissible temperature for NBR70 (nitrile butadiene rubber) material contacting with ~80 mm shaft diameter, rotating at 2600/min is 100°C. The results show 107°C and 104°C for the two iterations. The effect of friction induced temperature, changes the width of the contact area between the seal and the shaft, and significantly reduces the contact pressure.

结构参数对液压旋转接头密封性能的影响

为探究结构参数对液压旋转接头间隙密封性能的影响规律,分别以泄漏量和压力损失作为液压旋转接头的性能指标,研究密封有效长度、密封直径、密封间隙值3种主要结构参数对旋转接头性能的影响。采用正交试验与Fluent流体仿真相结合的方法,分析液压旋转接头间隙密封在不同结构参数下的泄漏量和压力损失情况。结果表明:3种结构参数对泄漏的影响程度由大到小依次为密封间隙值、密封有效长度、密封直径,对压力损失的影响程度由大到小依次为密封有效长度、密封直径、密封间隙值;密封间隙值大小对泄漏量影响非常显著,泄漏量随着间隙的增大呈指数增长关系,而间隙密封有效长度、环形密封直径对泄漏量无显著影响;密封有效长度对压力损失有极其显著影响,而密封直径和密封间隙值对压力损失没有显著影响;从整体上看密封间隙值、间隙密封直径、密封有效长度都大致与压力损失呈一次函数关系,且前两者与压力损失呈正相关关系,后者则与压力损失呈负相关关系。

不同粗糙度下织构处理前后端面密封表面的接触压力与摩擦性能分析

端面密封表面摩擦性能对叶片式液压摆动油缸的稳定运行有重大影响。对端面密封在不同粗糙度下、织构处理前后的接触压力与摩擦性能展开研究,综合分析粗糙度、织构化处理与端面密封摩擦性能的关系。将MATLAB与COMSOL相结合,建立端面密封有限元模型,仿真分析不同粗糙度、是否织构化处理等不同条件下的接触压力分布;结合对应摩擦实验获得端面密封摩擦力分布,并考虑叶片密封润滑模型,建立摆动油缸总摩擦力计算模型;最后通过摆动油缸实验,验证理论分析的准确性。结果表明:一定预压缩量下,接触压力随粗糙度的增大而增大;油润滑状态下,织构化表面摩擦性能优于未处理表面;所建立的总摩擦力计算模型可用于分析摆动油缸在不同粗糙度等条件下的摩擦性能。

冶金机械设备中旋转密封阀失效及修复研究

旋转密封阀作为干熄焦系统排焦部分的核心组成,影响着排焦部分的正常运行。为了提升旋转密封阀的密封性能,对密封阀常见的失效情况进行了说明,并从星型转子结构、润滑系统和轴承三个方面对密封阀的结构进行了优化设计,最后对结构优化后密封阀的密封性能进行验证。结果显示:在静态泄漏量的对比中,优化前后密封阀泄漏量的最大值分别为37.8 mL/h和32.4 mL/h,最小值分别为3.75 mL/h和2.55 mL/h;在静态泄漏量的对比中,优化前后密封阀泄漏量的最大值分别为24.8 mL/h和8.02 mL/h,最小值分别为23.1 mL/h和6.99 mL/h。结构优化后密封阀的密封性能更好,降低了设备出现故障的可能性,延长了使用年限。

回转窑在北方稀土矿焙烧中的使用和维护

内热式内衬回转窑是甘肃稀土新材料股份有限公司用于北方稀土矿(氟碳铈镧矿、独居矿)浓硫酸高温强化焙烧生产工艺最关键的设备之一,其维修成本占年度设备、设施检维修费用20%左右,回转窑的使用及维护重要性日益凸显。本文从稀土焙烧回转窑工作原理、主要运行参数、回转窑结构特点、常见问题及处理措施进行阐述,并结合日常维检修实例,对存在的问题进行分析论证,解决困扰生产的实际问题;最后结合“点检定修”原则,对回转窑的日常使用及维护要点着重进行阐述,并将一些好的使用、维护的经验进行分享,期望对相关设备使用单位有所裨益。

燃煤锅炉回转式空预器密封改造技术的研究与应用

回转式空预器的漏风改造已成为各火力发电厂节能挖潜的成熟选项。针对朔州热电有限公司2×350 MW超临界循环流化床锅炉自2020年初投产以来回转式空预器漏风率高达15%以上的现状,基于“双碳”目标下节能减排要求,三向密封结构研究、升级改造已迫在眉睫。通过#2锅炉回转式空预器滚动柔性接触式密封改造,将空预器在各种负荷下的漏风率降至6%以下,较好地解决了电流波动、扇形板磨损、冷端密封腐蚀等问题,显著提高了机组运行的安全可靠性和经济性。

回转式空气预热器异形复合密封装置动力学特性

回转式空气预热器(空预器)的漏风率影响着锅炉机组的经济效益,异形复合密封装置在克服空预器高漏风率缺陷中具有独特优势。为深入认识该密封装置的动力学特性,使其在推广应用时发挥最佳密封性能,基于弹塑性力学和理论力学,利用数值计算软件建立密封片-扇形板相互作用非线性动力学有限元模型,研究了异形复合密封片的动力学特性。结果表明:异形复合密封片的“合拢”“倾倒”复合形变可以增加其弹性和可靠性;密封片与扇形板动态相互作用时,密封片因发生振动而不会时刻与扇形板保持接触,合理增加密封片的刚度有利于减振降漏;密封片相对扇形板的运动速度对密封片的摩擦功耗有影响。研究结果为异形复合密封装置工程推广应用提供了一定参考。

ZP-205转盘润滑密封装置的改进与应用

转盘作为钻机的主要驱动装置之一,可为钻具提供持续的转矩、转速等,在钻井过程中发挥着重要作用。总结多年现场施工经验后发现,除安装误差等方面引起的转盘轴承磨损外,密封装置润滑效果不良也是导致轴承磨损的主要原因。因此,在不改变转盘主要结构和性能基础上,通过设计刚性材质的封闭式挡泥装置、改进固定方式等技术措施,形成一套改进型ZP-205转盘润滑密封装置。在现场应用过程中,该装置使油池内润滑油更换时间由2个月延长至6个月,轴承使用寿命延长25%以上,节约了润滑油使用量和转盘维修成本,缩短了钻进周期,创造了较好的经济效益。ZP-205转盘密封装置可广泛应用于ZJ15和ZJ30钻机,大庆油田目前有ZJ15和ZJ30钻机100部以上,全部配备该密封装置可以取得更好的经济效益和社会效益。

基于田口法和响应曲面法的旋转唇密封可靠性分析

基于有限元分析软件Abaqus建立旋转唇密封模型,计算得到其静态接触压力和径向变形影响系数矩阵,然后通过油封数值计算模型计算得到其泵吸率;在工况一定的情况下,分析理论接触宽度、前唇角、后唇角、过盈量、腰厚结构参数对密封性能的影响,并应用田口实验法进行正交试验设计,以信噪比作为衡量泵吸率稳定性的指标,得到影响密封可靠性的最佳参数组合;应用响应曲面分析,得到油封的极限状态方程,并通过蒙特卡洛法计算基于结构参数的油封可靠度。结果表明:各结构参数对泵吸率的影响排序依次是理论接触宽度、前唇角、后唇角、过盈量、腰厚;所研究油封的密封可靠度为0.999 87。

磁性液体密封耐压与启动力矩的影响因素研究

由于驱动电机的功率和力矩的限制,一些动密封场合对启动力矩有着明确的要求,相较于传统的密封导致启动力矩较大,磁性液体密封在启动力矩方面有更大的优势。但是在不同的环境中,磁性液体密封的启动力矩波动较大,无法达到某些极端密封场合对耐压和力矩的双重要求,从而限制了磁性液体密封在该类密封场合的应用。以温度为切入点,就磁性液体密封的耐压能力和启动力矩进行理论和实验研究,得到温度与磁性液体密封耐压能力和启动力矩的关系。结果表明:磁性液体密封的间隙越小,耐压能力越大;温度越低,最大耐压值越大,-40℃时最大耐压值为80℃时的5倍;启动力矩随压力的增加而逐渐减小;温度越低,启动力矩越大,-40℃时的启动力矩接近20℃时的5倍,并且在低温磁液用量对密封启动力矩的有明显影响。

密封面磨损对V形组合密封圈性能的影响

密封面磨损对V形组合密封圈的密封性能有显著影响。建立了V形组合密封圈的有限元模型,基于V形圈接触压力大的地方磨损较快且磨损较大的区域向空气侧移动的特点,在有限元仿真计算中通过修改V形圈的轮廓来表示V形组合密封圈不同的磨损状态,进而研究密封圈在不同磨损状态下的接触压力分布情况。考虑到V形组合密封圈变形与润滑油膜之间的耦合作用,基于弹性流体动压润滑理论,建立了V形组合密封圈弹流润滑数学模型。基于小变形理论,通过变形影响系数矩阵法得到V形组合密封圈在高压作用下的弹性变形,通过有限差分法求解了密封圈在工作过程中的油膜压力分布和厚度分布,分析了密封面磨损和粗糙度对组合密封圈润滑性能的影响。搭建了V形组合密封圈性能实验台,得到了在轻度和中度磨损状态下密封圈在不同电机转速下的摩擦扭矩和泄漏率,并将实验结果与仿真结果进行对比。结果表明:随着磨损加剧,靠近润滑油一侧油膜的压力和厚度增大;对于已经发生磨损的密封圈,粗糙度的提高会使其油膜压力增大;转速提高会使密封圈所受的摩擦扭矩和泄漏率增大。研究结果为提高V形组合密封圈的性能提供了参考。

旋转轴唇形密封的可持续设计研究

调研和确定旋转轴唇形密封的可持续标准,根据旋转轴唇形密封的具体结构和生产工艺,基于全生命周期评估(LCA)方法,通过定量和定性相结合的方法,计算和分析旋转轴唇形密封生命周期各阶段的能耗、碳排放、单位生产时间、成本等环境、社会和经济可持续指标,确定旋转轴唇形密封可持续改进策略:环境可持续侧重于使用阶段的能耗降低,社会可持续关注生产工艺创新,经济可持续聚焦于延寿设计。从延长使用寿命和优化运行时的摩擦状态2个方面,实施旋转轴唇形密封的可持续改进设计,分析宏观截面形状和尺寸、唇部的微观相貌、唇部材料对旋转轴唇形密封可持续性能的影响。结果表明:薄唇、微观织构和耐磨材料对降低旋转轴唇形密封的能耗和碳排放都具有积极作用,研究结果对提高旋转轴唇形密封的可持续性具有重要意义。

深中通道伶仃洋大桥主缆除湿防腐性能优化

为提高深中通道伶仃洋大桥主缆的除湿防腐性能,对该桥主缆除湿防腐措施及构造进行设计优化。通过对主缆内部不平衡的除湿过程进行分析,在传统转轮除湿技术的基础上,提出固定出口含湿量的冷凝除湿方式,干燥空气的制备从单一的转轮除湿优化为冷凝+转轮复合除湿,使主缆中相对湿度长时间维持稳定状态,保证其在高温高湿环境中的防腐耐久性。同时优化了防护构造,主缆缠丝区防护构造采用Z型缠丝+缠包带,非缠丝区索夹环缝密封采用卡槽+环形增强密封圈,直缝密封采用空心橡胶弹簧式密封条,螺杆紧固件采用整体式防水螺母密封,有效提高了主缆防护的气密性。

钢质颗粒输送装置旋叶及端部密封结构设计

颗粒输送机被广泛应用于石油、化工等多个行业。在粒子冲击钻井技术中,如何设计钢质颗粒输送装置,将固体粒子混杂在高压钻井液中,目前仍然存在挑战。文中优化设计了输送装置的旋叶及端部密封结构,并对关键部件进行强度校核,形成高压下钢质颗粒输送装置旋叶及端部密封结构的设计方案。该研究对于实现钢质颗粒在高压下的高效输送具有重要意义。

Design and development of the deep-rock in-situ condition-preserved coring calibration platform

To systematically validate and calibrate the theory and technology of the deep in-situ conditionpreserved coring, the in-situ conditions at different depths should be simulated, and the full-size coring tests should be carried out in this simulated environment. Therefore, a deep-rock in-situ conditionpreserved coring calibration platform was designed and developed. The self-tightening sealing structure and the quick-disassembly structure were designed on the basis of an innovative segmented nonuniformdiameter structure, which was a breakthrough from the traditional high-pressure vessel frame and was verified by finite element simulation and actual testing under extreme working conditions, respectively.To simulate the actual deep in-situ environment with a temperature of 150℃ and pressure of 140 MPa for a large Φ450 mm×H1400 mm core, temperature and pressure control systems were designed by coupling, and a pre-embedded high-pressure-resistant temperature sensor was designed. Finally, highprecision assembly automation, complex movement coordination of the coring device with the platform,and rotary dynamic sealing were achieved by utilizing the combination of adaptive cabin body servo control and an adaptive mechanical structure in a limited space, laying a solid foundation for the calibration of in-situ condition-preserved coring.

径向密封泄漏作用下喷射策略对柴油转子发动机燃烧过程的影响

为进一步提升柴油转子发动机的性能,对柴油转子发动机缸内燃烧过程进行了研究。此外,考虑到转子发动机在实际工作过程中难以避免的径向泄漏,建立了一种考虑径向密封泄漏的周边进气转子发动机三维动态计算模型,并对模型进行了验证。结合该计算模型,研究了柴油喷射时刻和喷射持续期对燃料分布及燃烧过程的影响。结果表明:当喷射时刻为上止点前80°曲轴转角且喷射持续期为50°曲轴转角时可获得较好的燃烧和排放特性。与原方案相比,缸内峰值压力提升了11.38%,碳烟和CO生成量分别降低了78.71%和92.72%,NO_(x)和CO_(2)生成量有所增加。