DESIGN ON STOP SEAL FOR PROCESS THICK LIQUID PUMP

The using situation at present is summarized about the scal for process thick liquid pump. It is reasonable that sealing scheme is composed of secondary impeller and centrifugal block stop seal. Main formulas are deduced and some problems are pointed out on design and calculation of centrifugal block stop seal.

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.

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relation- ship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.

Stress and thickness calculation of a bolted flat cover with double metal sealing rings

The design of a bolted flat cover is extremely important for the structural integrity of pressure vessels.The present design codes provide the thickness calculation equations for a bolted flat cover with single metal gasket.However,the rules for a bolted flat cover with double metal sealing rings are not developed to date.In the study,a new thickness calculation equation for the bolted flat cover with double metal sealing rings is proposed.First,the theoretical stress solution for bolted flat cover with the double metal sealing rings is obtained,based on the theory of simply supported circular plate and then verified using the results from finite element analyses.The results indicate that the influence of double metal sealing ring on the stress of the flat cover is more serious compared to single metal gasket.Second,a more accurate and reasonable equation is proposed to calculate the thickness of bolted flat cover with double metal sealing rings based on the derived theoretical equations of maximum stress.Finally,the influence of linear load and the spacing between rings on the thickness are discussed.Subsequently,a few suggestions are provided to design low-pressure or atmosphere pressure vessels.The study provides a theoretical foundation to develop design codes of pressure vessels in nuclear reactors.

高压自紧式聚酰亚胺垫片密封性能影响因素分析及结构优化

为了解决液体火箭发动机在异常工况下的密封失效问题,建立了发动机充气阀阀芯密封结构的有限元模型,分析了密封结构参数、加工误差及卡滞偏斜对充气阀阀芯密封性能的影响,并进行了试验验证。结果表明:综合考虑可加工性、密封效果,圆阀座是充气阀的首选结构;在不同圆角半径下,圆角半径在0.35~0.45 mm范围内使用效果最佳;平面度偏差及卡滞偏斜在0~0.07 mm范围内对密封效果和使用寿命几乎没有影响。本研究可为航天军工用高精密密封的设计和优化提供参考,有助于提高我国高精密密封的技术水平。

斯特林机帽式密封性能分析及回归参数优化设计

为改善斯特林机活塞杆帽式密封性能,首先采用数值仿真分析了5 MPa工质压力下其静、动态力学特性,从而获取了O型圈内径尺寸L_(N)、C型环径向壁厚T和装配过盈量S这3个关键结构参数对密封性能的影响规律。在此基础上,利用回归设计法以配伍面最大接触压力平稳且密封可靠为优化目标,对密封结构的上述3个关键参数进行优化设计以确定其最佳匹配方案,最后通过密封试验台验证了本文优化设计方法的准确性和普适性。结果表明:活塞杆与C型环密封面中间区域上最大接触压力随L_(N)和S的增大而增大,但随T的增大而减小;通过估计回归系数和方差分析(ANOVA)发现,L_(N)对密封性能影响最为显著、S次之、T影响最小;L_(N)和T、L_(N)和S交互项对响应显著,而T和S交互项对响应不显著;当L_(N)为13.745 mm、T为0.40 mm和S为0.020 mm时,优化密封件对应的正行程最大接触压力为9.01 MPa、回程为9.75 MPa,较工程在用密封件(L_(N)=13.780 mm、T=0.50 mm、S=0 mm)最大接触压力分别降低了14.7%和25.5%。实验进一步验证了优化密封件的密封性能和使用寿命均优于工程在用密封件,并且在不同工质压力下优化密封件的接触压力均匀性更好,减摩延寿效果显著,充分证明本文性能分析与优化设计方法准确有效。

被动式封隔器的国产化研发

通过对被动式封隔器结构组成、工作原理和主要功能的研究,提出国产化研发方案。对被动式封隔器的主要部件进行力学性能理论分析和仿真模拟,并针对被动式封隔器在实际运行中存在的问题进行优化设计。改进后的国产被动式封隔器顺利通过多项原型试验,并获得法国船级社(BV)审查认证。试验结果表明,国产化研发的被动式封隔器各项性能均达到设计和使用要求。被动式封隔器的成功研制及其国产化为有效降低工程项目成本、提高行业核心竞争力打下坚实基础。

止浆塞外塞胶料的设计及优化

设计一种新型具有密封和排气功能的止浆塞,采用有限元方法对止浆塞的实际工作状态进行数值模拟分析,对外塞胶料进行优化。结果表明:随着止浆塞外塞胶料的硬度的减小,止浆塞的密封性能提高;综合考虑密封性能和成本,确定止浆塞外塞采用邵尔A型硬度为40度的天然橡胶胶料。

基于生产过程的多规格不锈钢管自动封箱装置设计

针对6种不同规格的不锈钢管和企业对产品的包装需求,为实现3~6箱/min的自动包装效率,设计了一种自动封箱装置,该装置由夹箱机构、纸箱拍齐装置、折箱装置、顶升机构和机架5部分组成,通过分析每个机构的结构特点和工作原理,阐述了夹箱机构、纸箱拍齐装置、折箱装置的运动过程,重点分析了折箱机构中针对不同规格的不锈钢管如何设计其短边折箱机构及其主要技术参数的计算方法。实践证明:该封箱装置结构设计合理,整体运行稳定可靠,产品包装速度达到生产要求,减少了单条生产线所需要工人的数量,改变了传统的人工包装方式,提高了生产效率,降低了生产成本,具有较好的推广价值。

斯特林机活塞杆帽式密封泄漏率预测及其优化设计

斯特林机活塞杆帽式密封处总有微量气体泄漏,但目前大多数研究是通过分析密封面接触载荷而开展的。为探究干摩擦状态下帽式密封泄漏问题,基于分形理论从微观角度对密封面形貌进行表征,结合环形轴向缝隙流体流动模型建立帽式密封泄漏分形模型。通过试验验证泄漏模型的准确性。根据已验证模型对泄漏率影响因素进行交互分析,获取工况条件对不同粗糙度密封面泄漏率的影响规律,并提出使用遗传算法对特定工况下的C型环密封表面形貌与O型圈的预压缩率进行最优匹配。结果表明:泄漏率随着O型圈的预压缩率增大而下降,随着工质压力及活塞杆速度的增大而增大,且密封面越粗糙时泄漏率变化幅度越大;当密封表面粗糙度增大时泄漏率增大,但密封面形貌越粗糙时,增大接触载荷泄漏率更易减小;最终确定当斯特林机的工质压力P1=5 MPa,活塞杆运动速度V=1 m/s时,应匹配密封面粗糙度Ra=0.27μm的改性聚四氟乙烯C型环,并设定O型圈的预压缩率W=23.13%,帽式密封泄漏率将会达到最低。所建泄漏模型可提前为密封件的选择做出决策,而优化设计方法可为后续密封件表面粗糙度的确定和加工方法的选择提供指导。

大腔体陶瓷封装中平行缝焊的密封可靠性设计

随着平行缝焊腔体尺寸的增大,尤其在中温共烧陶瓷封装和薄型高温共烧陶瓷封装中,常常存在平行缝焊的密封成品率相对较低和气密性可靠性相对较差的问题。通过分析氧化铝陶瓷封装的密封失效原因,提出优化平行缝焊可伐焊框和盖板的结构设计来提升密封可靠性。以采用FC-CPGA570封装形式的某型DSP电路为例进行仿真和验证,通过降低钎焊残余热应力、增加缓冲结构、采用盖板轻量化设计,实现了很好的密封成品率及好的密封可靠性,为同类产品乃至低温共烧陶瓷封装的气密性设计、可靠性提升提供参考。

高黏疏水抑冰雾封层材料设计和性能评价

为解决南方秋冬季道路被动抑冰滞后和效率低等问题,研发了主动型高黏疏水抑冰雾封层材料。通过正交理论设计、层次模型分析法进行综合性能评价,确定了增黏剂、疏水剂的最佳用量,采用多性能试验评价了路用性能和抑冰性能,确定了抑冰剂的最佳用量。研究结果表明:相比于乳化沥青基材,综合设计得到的最佳掺量高黏疏水雾封层材料的黏聚性和疏水性分别提升了55.7%、144.3%。抑冰剂掺量为9%~12%时,雾封层材料储存稳定性较好,最佳洒布量为0.06 g/cm^(2)时,固化性能和抗滑性能明显提升,达到最佳平衡状态。抑冰剂掺量与电导率呈显著线性相关,多次浸水循环后,高黏疏水抑冰雾封层材料具有缓释持久性。最佳抑冰剂掺量为9%时,雾封层材料抗凝冰效果达到最佳。

深水半潜式生产平台电缆密封贯穿装置的设计研究

深水半潜式生产平台电缆密封贯穿装置的设计至关重要,相比以往的常规钻采平台、上部模块等设计要求更高。本文通过深水半潜式生产平台“深海一号”的建造设计经验,对深水半潜式生产平台电缆密封贯穿装置的设计有关注意事项进行总结,对指导深水半潜式生产平台电缆密封贯穿装置的设计有重要参考意义。

液压控制阀密封圈顺序强脱注塑模具设计

对液压控制阀密封圈塑件进行了结构工艺性及成型工艺性分析,该产品为环状结构,内部有环状U型凹槽,无法实现内抽芯,针对塑件无法实现内抽芯的难题,创新设计了具有顺序顶出脱模机构,该机构的核心部件嵌在型芯固定板和成型套管固定板之间,借助推杆的动力完成顺序强制脱模,设计巧妙、机构紧凑,具有创新性。根据塑件的外观及尺寸精度要求、对浇口位置进行分析,确定采用潜伏式浇口,设计的顺序顶出脱模注塑模具包括:分型面设计、杯冷式的单循环浇注系统设计、成型零件设计等;设计了液压控制阀密封圈潜伏式浇口顺序脱模机构注塑模具装配图及成型零件图;详细介绍了顺序脱模机构的工作过程及模具工作原理。实践证明,模具结构具有创新性,对回转体强制脱模类的模具设计提供参考。

“印”文化符号在食品包装设计中的应用研究

为研究印文化符号在食品包装设计中的应用价值,文章首先对印文化符号的人文价值及美学品质进行分析,探讨印文化符号在食品包装设计中的作用,从形、意、神三个角度探讨印文化符号在食品包装设计中的设计策略。最后得出结论,即印文化符号在食品包装设计中的具体应用,能够强化人们自身的身份认同,提高包装的审美趣味和文化意蕴,期望此研究能为食品包装设计提供创意启示,以丰富延续传统文化的未来方案,形成文化自信的积淀与传承,促进食品经济的发展。

高空台流量管新型篦齿密封特性分析及结构优化设计

针对高空台流量管与导流盆连接结构减小气体泄漏、避免出现反向进气压力过大导致结冰的设计要求,开展不同内径流量管新型篦齿密封特性及结构参数优化研究。建立了高空台新型流量管篦齿密封结构有限元模型,并开展了新型流量管篦齿密封结构泄漏特性实验研究。基于数值模拟与试验,研究了流量管内径对密封性能的影响规律。根据Box-Behnken响应面设计法,选取不同流量管内径下的密封间隙、控制口数量以及孔型出口数量为优化参数,进行新型篦齿密封结构参数优化设计研究。结果表明:仿真泄漏量与试验值相比最大误差不超过7%,证明了本文仿真模型的有效性;当结构内径由1 m增大到3 m,密封泄漏量由0.021 kg/s逐渐增加到0.162 kg/s,增幅高达671.4%;内径1 m,2 m和3 m篦齿密封结构经优化后,最大流速分别减小了16.1%,14.3%和9.7%,泄漏量分别降低50.74%,98.50%和97.52%。本文研究为高空台新型流量管篦齿密封结构优化设计提供了有效方法,也为流量管尺寸规范化设计提供了技术支撑。

煤矿井下三段式自动封孔器结构设计

针对传统封孔器自动化程度低和现有自动封孔器安全性低、封孔器下放与注料不连续等问题,分析了自动封孔器的功能需求与安全需求,提出三段式自动封孔器方案。设计了封孔器同轴接扣机构、钻孔封堵机构、自动注料流道和动密封机构等关键机构。制作样机并开展了室内封孔实验。实验显示,钻孔封堵机构可自动封堵模拟钻孔,封孔料可自动注入模拟钻孔中完成封孔,三段式自动封孔器方案合理,具有可行性。

薄壁管材特殊螺纹接头密封性能研究

为了解决薄壁管材特殊螺纹接头在油田频繁出现高压泄漏的问题,采用有限元和实物试验相结合的方式,研究分析了薄壁管材特殊螺纹接头台肩厚度、螺纹过盈量和密封面结构等关键参数对接头密封性能的影响。结果表明,增大台肩厚度、降低螺纹过盈、设计锥/锥密封结构可大幅提高接头密封接触压力积分值,能够较好解决薄壁特殊螺纹油套管密封性能不足而导致的高压泄漏问题。根据该思路设计出常用规格的薄壁特殊螺纹套管,经实物试验验证,薄壁套管接头抗粘扣性能优异,密封性能达到了100%等管体,能够有效解决薄壁特殊螺纹接头上扣不稳定及高压漏失问题。

某型飞机螺旋桨动密封结构设计及仿真

变桨距螺旋桨是涡轮螺旋桨飞机的重要组成部分,其动密封系统性能直接影响着飞机运行的效率及安全。因此,开展螺旋桨桨根动密封系统的设计与研究具有重要工程实际意义。该文针对螺旋桨变桨距时的往复摆转运动特点,设计出一种橡塑组合密封结构,并采用数值仿真和试验测量相结合的手段,对该组合密封系统开展研究。最终的数值仿真和试验测试表明,所设计的橡塑组合密封系统符合螺旋桨动密封系统的使用要求,未产生泄漏情况,可有效提升螺旋桨密封系统的可靠性,具有重要的工程指导价值。