机械密封空化效应的数值计算方法与实验研究
发布时间:2018-07-24 08:58
【摘要】:对于介质为液体的机械端面密封,受密封环端面形貌的影响,在密封间隙局部会产生低压区,当压力低于工作温度下液体的饱和蒸汽压时,液体将发生汽化,形成气泡,即发生了空化。为了分析密封的性能,必须考虑可能出现的空化现象。 对此,本课题提出了考虑空化效应的自由网格有限元算法,能够适应任意端面构型的机械端面密封的计算,并给出一种非常规的有限元推导过程,能够直接获得求解域边界的流量,特别适合机械密封的性能分析计算。该算法被证明高效稳定,具有较高的可靠性,且推导过程严谨清晰,利于进一步扩展。 同时,基于MATLAB开发了一整套求解计算的程序,给出了完整的实现过程。该程序被证明具有适用性强、求解效率高等优点。程序采用模块化设计,便于进行二次开发,预置了5种密封端面结构以及2种边界条件的求解模块,引入了COMSOL Multiphysics软件,通过API调用能够实现多种功能,利于该程序向“流-固-热”耦合分析进行扩展。对比了两种空化边界条件的计算,得知对于空化程度较高的模型,,JFO边界条件的计算结果的可信度明显高于雷诺边界。而且预置的JFO边界条件的计算模块求解效率很高,求解时间甚至小于雷诺边界条件,从而使JFO边界条件能够得到更广泛的应用。另外,提出了一种新的斜直线槽密封结构,利用计算程序进行了性能分析。 进一步的,设计了一套全新的特殊的密封实验台,采用开放式设计,并采用透明材料制作其中一个密封环,因此能够对密封间隙内的流体进行直接观测,并且能够测量相关的性能参数。实验证明斜直线槽密封在实验的工况下发生了明显的空化现象,空泡形状与JFO边界条件的计算结果十分吻合,显示出JFO边界条件的优势及必要性。
[Abstract]:For the mechanical end seal with liquid medium, due to the shape of the end surface of the seal ring, there will be a low pressure area in the seal clearance. When the pressure is below the saturated vapor pressure of the liquid at the working temperature, the liquid will vaporize and form a bubble. Cavitation occurs. In order to analyze the performance of seal, the cavitation phenomenon that may occur must be considered. In this paper, a free mesh finite element algorithm considering cavitation effect is proposed, which can be used for the calculation of mechanical end seal with arbitrary end configuration, and an unconventional finite element derivation process is given. The flow rate of the boundary can be obtained directly, which is especially suitable for the performance analysis of mechanical seals. The algorithm is proved to be efficient and stable with high reliability, and the derivation process is precise and clear, which is conducive to further expansion. At the same time, a whole set of program based on MATLAB is developed, and the complete realization process is given. The program has been proved to have strong applicability and high efficiency. The program is designed by modularization, which is convenient for secondary development. Five kinds of sealing end structure and two kinds of boundary conditions are preset. COMSOL Multiphysics software is introduced, and many functions can be realized by calling API. This program can be extended to the "fluid-solid-thermal" coupling analysis. By comparing the calculation results of two kinds of cavitation boundary conditions, it is found that the computational results of JFO boundary conditions with higher cavitation degree are more reliable than those with Reynolds boundary conditions. Moreover, the calculation module of preset JFO boundary condition is very efficient, and the solution time is even smaller than that of Reynolds boundary condition, so that the JFO boundary condition can be applied more widely. In addition, a new structure of oblique straight groove seal is proposed, and the performance is analyzed by computer program. Furthermore, a new set of special sealing test rig is designed, which is open design, and one of the sealing rings is made of transparent material, so that the fluid in the seal clearance can be observed directly. And can measure the related performance parameters. The experimental results show that the cavitation of oblique straight groove seal is obvious under the experimental condition, and the cavitation shape is in good agreement with the calculation result of JFO boundary condition, which shows the advantage and necessity of JFO boundary condition.
【学位授予单位】:清华大学
【学位级别】:硕士
【学位授予年份】:2011
【分类号】:TH136;O241.82
本文编号:2140872
[Abstract]:For the mechanical end seal with liquid medium, due to the shape of the end surface of the seal ring, there will be a low pressure area in the seal clearance. When the pressure is below the saturated vapor pressure of the liquid at the working temperature, the liquid will vaporize and form a bubble. Cavitation occurs. In order to analyze the performance of seal, the cavitation phenomenon that may occur must be considered. In this paper, a free mesh finite element algorithm considering cavitation effect is proposed, which can be used for the calculation of mechanical end seal with arbitrary end configuration, and an unconventional finite element derivation process is given. The flow rate of the boundary can be obtained directly, which is especially suitable for the performance analysis of mechanical seals. The algorithm is proved to be efficient and stable with high reliability, and the derivation process is precise and clear, which is conducive to further expansion. At the same time, a whole set of program based on MATLAB is developed, and the complete realization process is given. The program has been proved to have strong applicability and high efficiency. The program is designed by modularization, which is convenient for secondary development. Five kinds of sealing end structure and two kinds of boundary conditions are preset. COMSOL Multiphysics software is introduced, and many functions can be realized by calling API. This program can be extended to the "fluid-solid-thermal" coupling analysis. By comparing the calculation results of two kinds of cavitation boundary conditions, it is found that the computational results of JFO boundary conditions with higher cavitation degree are more reliable than those with Reynolds boundary conditions. Moreover, the calculation module of preset JFO boundary condition is very efficient, and the solution time is even smaller than that of Reynolds boundary condition, so that the JFO boundary condition can be applied more widely. In addition, a new structure of oblique straight groove seal is proposed, and the performance is analyzed by computer program. Furthermore, a new set of special sealing test rig is designed, which is open design, and one of the sealing rings is made of transparent material, so that the fluid in the seal clearance can be observed directly. And can measure the related performance parameters. The experimental results show that the cavitation of oblique straight groove seal is obvious under the experimental condition, and the cavitation shape is in good agreement with the calculation result of JFO boundary condition, which shows the advantage and necessity of JFO boundary condition.
【学位授予单位】:清华大学
【学位级别】:硕士
【学位授予年份】:2011
【分类号】:TH136;O241.82
【参考文献】
相关期刊论文 前10条
1 袁世先,薛晓虎,杨惠霞;机械端面密封的动压效应[J];工程机械;2003年09期
2 郑海泉;陈汝灼;;机械密封机理的探讨[J];北京化工学院学报;1981年02期
3 顾伯勤,蒋小文,孙见君,陈晔;机械密封技术最新进展[J];化工进展;2003年11期
4 赵中;彭旭东;盛颂恩;白少先;李纪云;;多孔扇形分布端面机械密封性能的数值分析[J];化工学报;2009年04期
5 于新奇,蔡仁良;激光加工多孔端面机械密封的动压分析[J];华东理工大学学报;2004年04期
6 王美华,董勋,黄步玉;机械密封的研究现状及研究方向[J];机械设计与研究;1993年03期
7 王晓雪;刘莹;李京浩;黄伟峰;王玉明;;核主泵用动静压波度机械密封机理[J];机械工程学报;2010年24期
8 宋鹏云,陈匡民,董宗玉,吴旨玉;液体润滑螺旋槽机械密封性能的数值分析[J];昆明理工大学学报;2000年03期
9 彭建,鄢新华,左孝桐,隋德生,张达夫;上游泵送密封研究[J];流体机械;1998年02期
10 顾永泉;机械密封的空化和空化边界确定[J];流体机械;1998年12期
本文编号:2140872
本文链接:https://www.wllwen.com/kejilunwen/jixiegongcheng/2140872.html