煤油泵轴尾机械密封副端面特性研究

发布时间：2018-04-06 21:30

本文选题：轴向柱塞泵　切入点：机械密封　出处：《哈尔滨工业大学》2017年硕士论文

【摘要】：机械密封是一种常见的动密封形式,作为液压元件中重要的基础组件,具有稳定、耐久、应用范围广的优点,因此被广泛应用在液压泵中。煤油介质轴向柱塞泵是航天液压系统中的关键动力元件,其可靠性与工作寿命对整个系统的稳定与安全有决定性影响,其轴尾处机械密封是柱塞泵抵抗内部高压煤油泄漏的重要装置,由于煤油的低粘度特性,机械密封副端面往往难以建立稳定的液膜,这会导致泵体发生泄漏超标与转矩超差问题,严重影响柱塞泵的工作寿命与可靠性。因此研究煤油泵机械密封副的泄漏与摩擦问题对保证柱塞泵正常运转,提高泵体性能有重要的现实意义。机械密封副的泄漏与摩擦问题主要受密封端面特性影响,本文选取重要的四组特性进行研究,即端面的应力变形特性、传热特性、液膜泄漏特性与摩擦磨损特性,从各特性对应的基础理论出发,建立研究模型,完成理论推导,得到影响泄漏与摩擦指标的参数间关系,通过结构与材料的多方位研究,来寻求降低泄漏量、提升摩擦性能的方法,并对机械密封进行了摩擦转矩的整泵测试。首先,给出了各特性分析的弹性力学模型、热力学模型、流体力学模型和基本磨损模型,得到端面径向位移、腔体流速、泄漏量与体积磨损度等关键参数的表达关系,为进一步研究作理论基础。其次,从机械密封专有的f G特性出发,利用仿真手段,依次得到了不同密封压差、不同腔体流速、不同配偶材料下的端面力变形、热变形,从而综合得到了不同参数控制下的液膜间隙形式,利用CFD软件对各间隙形式的泄漏量进行了计算,分析了结构与材料参数对泄漏量的影响,验证了泄漏指标。然后,分别选择具有代表性的3组端面软材料与硬材料,通过摩擦学试验得到了材料属性、端面粗糙度对摩擦系数、端面温升的影响;利用原子力显微镜(AFM)对试验前后的试件表面进行分析,通过统计学方法求解了单区域高度分布函数,得到了不同组合配对材料的单磨粒磨损体积与黏着磨损厚度。最后,总结得到的特性结果,加工多尺寸、材料的密封环,在煤油泵试验台上,对改进的整泵进行摩擦转矩试验,比较了不同轴向尺寸与配对材料对转矩的影响,对转矩指标进行了验证。
[Abstract]:Mechanical seal is a common type of dynamic seal. As an important basic component of hydraulic components, mechanical seal has the advantages of stability, durability and wide application, so it is widely used in hydraulic pump.Kerosene medium axial piston pump is a key power element in aerospace hydraulic system. Its reliability and working life have a decisive effect on the stability and safety of the whole system.Mechanical seal at shaft and tail is an important device for piston pump to resist internal high pressure kerosene leakage. Because of the low viscosity of kerosene, it is often difficult to establish stable liquid film on the end surface of mechanical seal pair.This will lead to excessive leakage and torque deviation of pump body, which seriously affects the working life and reliability of piston pump.Therefore, it is of great practical significance to study the leakage and friction of the mechanical seal pair of coal oil pump to ensure the normal operation of the piston pump and to improve the performance of the pump body.The leakage and friction of the mechanical seal pair are mainly affected by the seal end surface characteristics. In this paper, four important characteristics are selected to study, namely, the stress and deformation characteristics of the end face, heat transfer characteristics, liquid film leakage characteristics and friction and wear characteristics.Starting from the basic theory corresponding to each characteristic, the research model is established, the theoretical derivation is completed, and the relationship between the parameters affecting the leakage and friction index is obtained. Through the multi-directional study of the structure and the material, the leakage rate is reduced.The friction torque of the mechanical seal was tested by the whole pump.Firstly, the elastic mechanics model, thermodynamic model, hydrodynamic model and basic wear model are given, and the expression relations of the key parameters, such as the radial displacement of the end face, the velocity of the cavity, the leakage rate and the volume wear degree, are obtained.It is a theoretical basis for further research.Secondly, according to the special f / G characteristic of mechanical seal, by means of simulation, the different seal pressure difference, different chamber velocity, end face force deformation and thermal deformation under different spouse materials are obtained in turn.Thus, the liquid film clearance forms controlled by different parameters are synthetically obtained, the leakage volume of each gap form is calculated by using CFD software, the influence of structure and material parameters on the leakage rate is analyzed, and the leakage index is verified.Then, three groups of representative soft end materials and hard materials are selected, and the effects of material properties and end roughness on friction coefficient and end surface temperature rise are obtained by tribological test.Atomic force microscope (AFM) was used to analyze the surface of the specimen before and after the experiment. The single area height distribution function was solved by statistical method. The wear volume and thickness of the single abrasive particles of different combinations of matched materials were obtained.Finally, the characteristic results obtained are summarized. The friction torque test of the improved whole pump is carried out on the coal oil pump test-bed, and the effects of different axial dimensions and matched materials on the torque are compared.The torque index is verified.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH137.51

【相似文献】