空气静压止推轴承跨缝静承载特性的研究

发布时间：2018-03-01 03:34

本文关键词： 气体静压止推轴承狭缝 k-ε湍流模型静特性　出处：《哈尔滨工业大学》2012年硕士论文　论文类型：学位论文

【摘要】：由于气体静压轴承具有精度高、结构简单、摩擦阻力小和寿命长等优点，使其在高速和精密工程、微电子技术、医疗器械和空间技术等领域有着广泛的应用。特别在航空航天领域中，采用卫星控制系统全物理仿真气浮台来模拟航天器各自由度的运动并加以控制，以深化对航天器的研究。这种仿真气浮台就是依靠空气在气体静压止推轴承和支承平台之间形成一定压力下的气膜使气浮台浮起。然而由于高精度大平面气浮支撑台体加工难度大，，目前工程上由多块小平台拼接而成，这就使得大平面气浮台难免存在缝隙。故本文将研究气浮轴承过缝时承载性能，分析轴承过缝时静特性的影响因素，为大平面气浮台所需空气静压轴承的研究与设计奠定基础。由于狭缝的影响，使得气浮轴承过缝时气膜中心的流场特性发生变化，本文首先从理论上分析气体在流道中可能发生的节流形式，继而分析影响气浮轴承静特性的因素，包括供气压力、气膜厚度、进气孔直径与数目、狭缝的结构与位置等。目前工程上应用的气体静压止推轴承主要为6孔环形分布和12孔双排环形分布的两种形式，故本文采用基于有限体积法的FLUENT软件分别建立6孔和12孔环形供气静压轴承跨一字缝时的仿真模型，将k-ε湍流模型引入到气体静压轴承的数值模拟中，针对理想气体研究气体静压轴承跨缝时的静特性。首先分析了6孔气浮轴承不过缝与过三种不同缝位置时的静承载力和入口流量，分析缝位置对轴承静特性的影响。继而针对轴承中心过缝的情况，研究气膜厚度、进气孔直径、进气孔数目、供气压力、狭缝宽度和狭缝深度对轴承的静承载力、静刚度和入口流量三个特性的影响规律，指出提高6孔气浮轴承跨缝时静特性的方法。接下来，本文对12孔双排交错分布静压止推轴承进行仿真计算，分析中心过缝的两种形式的静承载力和入口流量，并与无缝时进行对比，继而针对其中一种狭缝情况，分析气膜厚度和供气压力对轴承跨缝时静特性的影响规律，并和6孔轴承进行了对比，指出狭缝对12孔双排交错分布气体静压止推轴承的影响程度要小于6孔静压轴承。最后搭建实验台，通过试验方法研究6孔静压止推轴承跨缝时的静承载力受供气压力和气膜厚度的影响规律。并将实验结果与仿真结果进行对比分析，验证仿真结果的准确性。本文的研究结果给出气体静压轴承在大平面气浮台上过一字缝时的静特性指标及提高相应静特性的方法。为进一步研究气浮轴承在大平面气浮台上移动时的承载性能奠定了基础。
[Abstract]:Because of the advantages of high precision, simple structure, small friction resistance and long life, the aerostatic bearing is used in high speed and precision engineering, microelectronics technology, etc. Especially in the field of aerospace, satellite control system is used to simulate the motion and control of the various degrees of freedom of the spacecraft. In order to deepen the research on spacecraft, the simulated air floatation platform is based on the air film formed between the aerostatic thrust bearing and the supporting platform to make the platform float. However, because of the high precision large plane air floating support. It is difficult to process the brace body. At present, engineering is made up of several small platforms, which makes it inevitable that there are gaps in the large plane air bearing platform. Therefore, this paper will study the bearing capacity of the air bearing when it is overslit, and analyze the influence factors of the static characteristics of the bearing when it is oversevered. It lays a foundation for the research and design of aerostatic bearing for large plane air flotation platform. Because of the influence of slit, the flow field characteristics of the gas film center change when the air bearing passes through the slot. In this paper, the possible throttling form of the gas in the flow channel is analyzed theoretically, and then the factors influencing the static characteristics of the air bearing are analyzed. Including gas supply pressure, film thickness, intake hole diameter and number, slit structure and location, etc. At present, the aerostatic thrust bearing used in engineering mainly consists of two types: 6-hole annular distribution and 12-hole double-row annular distribution. Therefore, the FLUENT software based on the finite volume method is used to establish the simulation model of the annular hydrostatic bearing with 6 holes and 12 holes respectively, and the k- 蔚 turbulence model is introduced into the numerical simulation of the aerostatic bearing. In this paper, the static characteristics of gas hydrostatic bearings with cross joints are studied. Firstly, the static bearing capacity and inlet flow rate of six holes bearing with different joints and three different joints are analyzed. This paper analyzes the influence of joint position on the static characteristics of bearing, and then studies the static bearing capacity of bearing by the thickness of gas film, the diameter of intake hole, the number of inlet pores, the pressure of air supply, the width of slit and the depth of slit in the center of bearing. The influence of static stiffness and inlet flow rate on static characteristics is discussed, and the method of improving static characteristics of 6-hole air-bearing is pointed out. Then, the paper simulates the 12-hole double-row staggered static thrust bearing. This paper analyzes the static bearing capacity and inlet flow rate of two types of central seam, and compares them with the seamless ones, and then analyzes the influence of film thickness and air supply pressure on the static characteristics of the bearing when it is across the seam, aiming at one of the slit conditions. Compared with 6-hole bearing, it is pointed out that the influence of slit on 12-hole double-row staggered aerostatic thrust bearing is less than that of 6-hole hydrostatic bearing. Finally, a test bench is built to study the influence of air supply pressure and film thickness on the static bearing capacity of a 6-hole static thrust bearing when it crosses the cracks. The experimental results are compared with the simulation results, and the experimental results are compared with those of the simulation results. The accuracy of the simulation results is verified. The static characteristic index and the method of improving the corresponding static characteristic of the aerostatic bearing passing through a word slot on the large plane air floatation table are given in this paper. In order to further study the air bearing in Daping, the method of improving the static characteristic of the aerostatic bearing is given in this paper. The bearing capacity of the surface air floatation platform when moving laid the foundation.
【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】：2012
【分类号】：TH133.3

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