往复活塞式压缩机缓冲罐强度及模态分析研究

发布时间：2018-09-10 10:59

【摘要】：目前,天然气已成为影响国民生计的重要战略资源,随着其普及范围的增加,国家对天然气压缩设备的安全稳定提出了更高的要求。在天然气压缩领域,往复活塞式压缩机因其热效率高、适应压力范围广、造价低廉等优点在天然气增压集输、采气、注气、轻烃回收和脱硫增压等方面得到广泛的使用。缓冲罐是减小气流脉动最常用的结构,它对改善往复活塞式压缩机气路系统的振动起到了重要的作用。缓冲罐长期处在高压、机组振动等工作环境中,如果发生开裂失效,泄漏的高压易爆天然气将威胁到现场使用人员的安全。同时,压缩机大多工作在野外,导致压缩机维修不便,长时间的停运往往造成严重的经济损失。因此,缓冲罐的安全可靠就显得尤其重要。本文通过对一常用的往复活塞式压缩机缓冲罐进行强度及模态分析研究,找到了结构的薄弱部位以及结构的模态参数识别方法,通过补强设计提高了缓冲罐的强度,通过分析结构共振研究可能的失效原因,从而为采取措施避免失效提供了参考。主要开展了以下几个方面的工作： (1)通过综述国内外往复式压缩机安全可靠问题以及缓冲罐强度分析研究的现状,确定本文所采用的有限元计算方法和压力容器安全评价标准来进行缓冲罐强度计算与校核。具体利用Workbench静力分析模块进行了结构静力强度分析,找到了缓冲罐在不同工况下的应力应变规律与结构薄弱部位。 (2)对增加补强圈后的缓冲罐进行静强度计算与校核,同时对补强圈结构不同尺寸进行正交试验研究,并得出了补强圈尺寸对缓冲罐结构应力峰值的影响规律。 (3)利用Workbench的模态分析模块对缓冲罐结构进行了有无预应力状态下的模态分析,通过模态分析得到了缓冲罐的固有频率、模态振型和模态应力参数,验证了静力分析时得出的结构薄弱部位结论。然后利用缓冲罐流固耦合分析的计算结果进行了预应力下的模态分析,研究了工作参数对结构模态参数的影响。(4)进行了模态测试试验,得到了缓冲罐的试验固有频率及模态振型,通过对比有限元的模态结果,对有限元分析方法进行了验证。通过上述研究成果,可以更合理的设计缓冲罐补强圈结构尺寸,从而尽可能的提高缓冲罐的安全系数,避免在复杂振动环境中的意外失效。模态分析得出的结果为工程设计人员与现场使用人员提供了安全指导,从而为提高其可靠性,以及防止发生意外失效提供了有价值的参考。
[Abstract]:At present, natural gas has become an important strategic resource affecting the livelihood of the people. With the increase of its popularization scope, the country has put forward higher requirements for the safety and stability of natural gas compression equipment. In the field of natural gas compression, reciprocating piston compressors are widely used in natural gas pressurization and transportation, gas production, gas injection, light hydrocarbon recovery and desulfurization and pressurization because of their high thermal efficiency, wide range of adaptive pressure and low cost. Buffer tank is the most commonly used structure to reduce the flow pulsation. It plays an important role in improving the vibration of reciprocating piston compressor system. The buffer tank is in the working environment of high pressure and unit vibration for a long time. If cracking and failure occur, the leaking high pressure explosive natural gas will threaten the safety of the personnel in the field. At the same time, the compressor mostly works in the field, which leads to the inconvenience of compressor maintenance, and the long time outage often results in serious economic losses. Therefore, the safety and reliability of the buffer tank is particularly important. Through the strength and modal analysis of a commonly used reciprocating piston compressor buffer tank, the weak part of the structure and the modal parameter identification method are found, and the strength of the buffer tank is improved by reinforcement design. By analyzing the possible failure causes of structural resonance, this paper provides a reference for taking measures to avoid failure. The main works are as follows: (1) through summarizing the safety and reliability problems of reciprocating compressors at home and abroad and the present situation of strength analysis of buffer tanks, The finite element method and the safety evaluation standard of pressure vessel are adopted to calculate and check the strength of buffer tank. The static strength analysis of the structure is carried out by using the Workbench static analysis module, and the stress-strain law and the weak part of the structure of the buffer tank under different working conditions are found. (2) the static strength calculation and checking of the buffer tank after adding the reinforcing ring are carried out. At the same time, the orthogonal test was carried out to study the different dimensions of the reinforcing ring structure. The influence of the reinforcement ring size on the peak stress of the buffer tank structure is obtained. (3) the modal analysis of the buffer tank structure with or without prestress is carried out by using the modal analysis module of Workbench. Through modal analysis, the natural frequency, modal mode and modal stress parameters of the buffer tank are obtained, and the conclusion of the weak part of the structure obtained in static analysis is verified. Then the modal analysis under prestress is carried out by using the results of fluid-solid coupling analysis of buffer tank, and the influence of working parameters on modal parameters of the structure is studied. (4) Modal test is carried out. The experimental natural frequencies and modal modes of the buffer tank are obtained. The finite element analysis method is verified by comparing the modal results of the finite element method. Through the above research results, the structural dimensions of the reinforcement ring of the buffer tank can be designed more reasonably, so as to increase the safety factor of the buffer tank as much as possible and avoid accidental failure in the complex vibration environment. The results of modal analysis provide safety guidance for engineering designers and field users, thus providing a valuable reference for improving their reliability and preventing accidental failure.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE974

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