共查询到17条相似文献,搜索用时 171 毫秒
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金属垫片密封泄漏模型试验研究 总被引:2,自引:0,他引:2
建立了气体通过金属垫片的泄漏模型.对常温下金属平垫片密封性能进行了试验研究,研究了压紧应力、介质压力和表面形貌对密封性能的影响.试验表明,泄漏率随分形维数、压紧应力和尺度系数的变化规律与理论模型的描述基本一致,泄漏率的理论计算值与试验结果吻合较好,表明建立的金属垫片泄漏模型是合理的.建立的泄漏率计算公式将泄漏率、压紧应力、介质压力和密封表面分形参数联系在一起,因而使以最大允许泄漏率为准则的金属垫片密封连接设计以及紧密性评价成为可能. 相似文献
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垫片密封泄漏模型研究 总被引:4,自引:0,他引:4
本文讨论了现有垫片密封模型及其泄漏率计算方法,对非石棉垫片及柔性石墨增强垫片进行了密封性能试验研究,确定了多孔介质模型泄漏率公式中的常数。这一工作为现行规范中的密封设计主要由依据连接结构强度的设计方法发展为以最大泄漏率为设计准则的密封连接的“紧密性设计”提供了理论依据。 相似文献
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高温螺栓法兰连接的紧密性评价方法 总被引:9,自引:1,他引:9
提出了高温螺栓法兰连接的紧密性概念;试验研究了柔性石墨填充缠绕式垫片、金属冲齿板柔性石墨复合垫片和金属包覆垫片的压缩回弹性能、蠕变性能和基本密封性能;通过试验数据的回归分析得到了垫片高温性能表达式;将试验得到的垫片变形特性和泄漏特性统一于螺栓法兰连接中进行系统分析,建立了紧密性评价方法。该方法不仅可对在役螺栓法兰连接的泄漏状况作出评价,而且为密封连接的设计、新型垫片的开发以及垫片性能的评价提供了借鉴。 相似文献
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基于紧密度要求的法兰优化设计 总被引:4,自引:0,他引:4
传统的法兰设计准则依据强度失效判据,不能定量估计法兰接头的紧密性,本文采用密封设计准则,通过实验测定试验垫片的PVRC垫片系数:a=0.39,Gs=0.012MPa和Gb=4.57MPa,并在此基础上,得到该垫片在各级紧密度参数Tp下的最佳垫片装配应力(Sga)opt与垫片应力变化量ΔS的关系,从而计算法兰接头的最佳预紧螺栓载荷。 相似文献
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非金属垫片螺栓法兰连接寿命评价 总被引:2,自引:0,他引:2
分析非金属垫片密封的时效特性,考虑高温条件下材料退化和垫片载荷松弛过程对密封性能的影响,依据多孔介质理论,建立非金属垫片密封的时效泄漏模型.将螺栓法兰连接系统寿命划分为密封寿命和部件寿命.提出密封寿命试验方法,在考虑垫片泄漏特性变化的基础上,基于指标泄漏率分析螺栓法兰连接系统密封寿命;基于蠕变和疲劳损伤准则分析高温螺栓的剩余寿命,探讨螺栓法兰连接系统的密封寿命和各部件寿命之间的关系.建立螺栓法兰连接系统的寿命预测最弱环模型,将垫片的变形特性和泄漏特性统一于螺栓法兰连接系统中进行研究,提出基于指标泄漏率和结构完整性的螺栓法兰连接系统寿命评价方法. 相似文献
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金属垫片接触应力分布解析算法 总被引:1,自引:1,他引:0
金属垫片密封是压力容器和管道中常见的密封形式,其失效极少是因强度不足引起的,泄漏是连接系统失效的主要原因.在真实螺栓法兰金属垫片连接结构中,垫片的局部接触应力对螺栓法兰连接结构密封性能的影响较垫片的平均压紧应力更大.笔者在Warters法的基础上,考虑了操作压力的影响,对法兰变形进行理论分析,推导了法兰偏转角的计算公式.根据法兰偏转角和金属垫片力学性能,提出了金属垫片接触应力分布的解析算法.解析计算得到的平均应力与数值模拟结果较为接近,但垫片外缘的最大应力小于数值模拟值,金属垫片接触应力的解析计算方法可作为一种保守的工程算法,可用于真实螺栓法兰金属垫片连接结构的设计. 相似文献
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金属垫片密封研究进展 总被引:7,自引:2,他引:7
介绍了金属平垫、椭侧垫、八角垫、“O”形环、双锥环、透镜垫等金属垫片密封的国内外研究进展,提出了金属垫片密封机理和泄漏模型研究以及垫片密封比压的确定是值得重视的研究课题。 相似文献
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不锈钢柔性石墨缠绕垫片基本性能研究 总被引:3,自引:0,他引:3
对不锈钢柔性石墨缠绕垫片进行了常温机械性能和密封性能的试验研究,找出了垫片常温密封的基本规律,提出了较好地表征该垫片压缩回弹特性、应力松弛特性和基本密封特性的公式,通过试验数据的回归分析,得到公式中的各系数,为螺栓法兰垫片连接的紧密性分析和密封件的工程选用提供了依据。 相似文献
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垫片密封设计的工程方法 总被引:1,自引:0,他引:1
迄今为止,螺栓法兰连接的设计都是为强度为依据的,并没有考虑连接是否紧密,本提出了表征垫片高温性能的基本方程和垫片密封性能实验数据的修正方法,在考虑工况,介质特性对连接性能影响的基础上,建立了基于最大允许泄漏率的垫片密封连接设计方法。 相似文献
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J. Arghavani M. Derenne L. Marchand 《The International Journal of Advanced Manufacturing Technology》2001,18(1):67-78
The paper presents the concept for and the implementation of a fuzzy logic approach in the selection of gaskets, for their
sealing performance, based on system requirements. Gasket sealing performance is complex, owing to numerous parameters affecting
the gasket sealability. A fuzzy decision support system (FDSS) and its application to the selection of sets of optimal parameters
for the joint connections are described. The FDSS is based on the compositional rules of inference, which take into consideration
the fact that many unknown parameters have an influence on the gasket sealing performance. The paper outlines the complex
nature of gaskets, justifying the need for a predictive system capable of dealing with vague information and providing precise
results. It also presents a new methodology for proper gasket selection for a given set of operating conditions, e.g. applied
load, gas pressure, and leakage rate. 相似文献
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J. Arghavani M. Derenne L. Marchand 《The International Journal of Advanced Manufacturing Technology》2003,21(10-11):713-732
The effect of surface characteristics on compressive stress and leakage rate in gasketed flanged joints is discussed qualitatively and quantitatively based on experimental verifications. The sensitivity of the sealing phenomenon to the sealing surface characteristics, gas pressure and stress level is presented. Sealing surfaces produced with grinding, turning and milling procedures of different roughness values were the subject of the tests with three types of gasket, namely, PTFE (polytetrafluoroethylene), graphite, and spiral wound. The experimental results indicated that the roughness value Ra (average arithmetic height) has no effect on the sealing performance of the gasket, except for the ground type sealing surfaces. The platen (flange) surface forms were found to be the determining factor on the leakage rate and flow regime for gasketed flanged joints. It is shown that the surface characteristics have no effect on the leakage rate and on the gasket performance for the PTFE gasket at high stress levels. However, at low stress levels the rougher ground and milled sealing surfaces having radial channels on the surface produce larger leakage rates. The effect of surface characteristics, stress level, and gas pressure was more evident on the graphite and spiral wound gasket types, at both low and high stress levels. It is also shown that the leakage rate follows an exponential law as a factor of surface stress and gas pressure, for all sealing surface characteristics and gasket types. While there is little difference in the leakage rate for the PTFE gasket when the gasket stress level is increased by a factor of two, from S3 to S5, a substantial leakage rate reduction by a ratio of 17.5 times was observed for the graphite and spiral wound gaskets for most sealing surfaces. On the other hand, when increasing the helium gas pressure from 200 to 800 p.s.i., the leakage rate increased by 5 times for the PTFE, and up to10 times for the graphite and the spiral wound gaskets. It was determined that while molecular flow regimes can be achieved for the PTFE gasket for all sealing surfaces, the two other gasket types provided laminar flow under the same operating conditions. 相似文献