泵用螺旋槽干气密封技术研究

发布时间：2018-05-14 13:01

本文选题：螺旋槽干气密封 + FLUENT　；参考：《南京林业大学》2012年硕士论文

【摘要】：螺旋槽干气密封是一种新型的非接触式机械密封，与传统的机械密封相比，具有低泄漏、低磨损、低功耗以及长寿命、氋可靠性等优点。本文通过UG建立螺旋槽模型，通过GAMBIT划分网格，将网格导入FLUENT软件分析螺旋槽干气密封性能。同时，本文中还建立了螺旋槽干气密封端面间气体流动过程物理模型，采用有限体积法对控制方程进行离散，编制了有限体积计算程序，对控制方程进行了数值求解。对比两种计算方式结果的差异，并且以FLUENT计算结果为基准，探讨了槽形几何参数对密封性能的影响，利用正交试验原理考察了各个参数对螺旋槽干气密封性能影响的显著性。对实验室已有机械密封试验机进行改装，为干气密封试验研究奠定基础。本文的主要工作及结论如下： (1)用UG软件建立了单个周期气膜模型，用GAMBTI软件划分网格，通过手动划分网格，解决了气膜的厚度微尺度和径向、周向宏观尺度的矛盾。通过逐步加密网格来解决由于网格密度问题引起的较大误差，将误差控制在合理范围内。通过FLUENT计算出气膜的压力分布云图，观察发现在槽根处由于密封坝的阻挡，气体在槽根处受到压缩形成一个氋压区，，最终形成开启力。 (2)在一定假设的基础上，根据可压Navier-Stokes方程、连续性方程和气体状态方程，推导出了等温状态下螺旋槽干气密封端面间可压缩流体动力润滑控制方程。通过有限体积法对控制方程进行离散。由于有限体积法对于规则网格有较高的精度，在离散过程采用坐标变换法将不规则网格转换为方形网格。通过数值计算得到各个离散点的压力分布，由气膜压力分布计算了螺旋槽干气密封的主要性能参数-开启力、端面摩擦力、摩擦功耗、轴向刚度以及泄漏量。 (3)开展了 FLUENT软件模拟结果和数值计算结果比较研究，表明端面槽形几何参数适宜的取值范围为：18°a25°，10jAm/j;15jAm,2.5jAm/jo4|j,m,0.5^0.7,0.4y0.6,10iVg18。通过正交试验分析表明：螺旋角、槽深、槽长坝长比对泄漏量的影响特别显著，膜厚、槽台宽比对泄漏量的影响不显著；螺旋角、膜厚对轴向刚度的影响特别显著，槽长坝长比对轴向刚度的影响显著，槽深、槽台宽比对轴向刚度影响不显著。两种计算结果存在一定的差异，这些差异由计算中的误差和网格划分密度引起。 (4)从公知技术中了解到现有的机械密封试验机还存在一些缺点，本文对干气密封试验机结构进行改进设计，主要解决了三个问题：1.解决了单悬臂轴、单对密封式机械密封试验装置轴向力的问题；2.解决了双悬臂轴式机械密封试验装置的复杂结构问题；3.解决了单悬臂轴、两对密封式机械密封试验装置弹簧压缩量调节不均衡问题。
[Abstract]:Spiral groove dry gas seal is a new type of non-contact mechanical seal. Compared with the traditional mechanical seal, it has the advantages of low leakage, low wear, low power consumption, long life, reliability and so on. In this paper, the helical groove model is established by UG, and the mesh is meshed by GAMBIT. The mesh is imported into FLUENT software to analyze the performance of spiral groove dry gas seal. At the same time, the physical model of gas flow between the end surfaces of spiral groove dry gas seal is established, the control equation is discretized by finite volume method, the finite volume calculation program is compiled, and the control equation is solved numerically. The difference between the results of the two calculation methods is compared and the effect of the geometric parameters of the groove on the seal performance is discussed based on the results of FLUENT. The significance of the influence of the parameters on the performance of the spiral groove dry gas seal is investigated by using the principle of orthogonal test. The mechanical seal testing machine has been refitted to lay the foundation for dry gas seal test. The main work and conclusions are as follows: 1) the single periodic film model is established by UG software, and the grid is divided by GAMBTI software, and the contradiction between micro scale and radial scale and circumferential macroscopic scale of film thickness is solved by manually dividing the mesh. The larger error caused by the mesh density problem is solved by gradually encrypting the mesh, and the error is controlled within a reasonable range. The pressure distribution of the gas film is calculated by FLUENT. It is found that the gas is compressed at the root of the groove to form a pressure zone due to the barrier of the sealing dam at the root of the groove, and finally the opening force is formed. On the basis of certain assumptions, the compressible hydrodynamic lubrication governing equations between the end surfaces of spiral groove dry gas seals under isothermal condition are derived according to compressible Navier-Stokes equation, continuity equation and gas state equation. The governing equations are discretized by finite volume method. Due to the high accuracy of the finite volume method for regular meshes, the coordinate transformation method is used to transform irregular meshes into square meshes in the discrete process. The pressure distribution of each discrete point is obtained by numerical calculation, and the main performance parameters of spiral groove dry gas seal are calculated from the film pressure distribution-opening force, end surface friction force, friction power consumption, axial stiffness and leakage volume. (3) A comparative study between the simulation results of FLUENT software and the results of numerical calculation shows that the suitable range of geometric parameters of the end face grooves is: 18 掳a 25 掳10 J Amr / J 15J Amg 2.5 j Amjo4 JM 0. 5 ^ 0. 7 0. 4 y0. 6 / 10 iVg18. The results of orthogonal test show that the effects of spiral angle, groove depth, length ratio of channel length dam on leakage volume are particularly significant, film thickness and slot width ratio have no significant effect on leakage volume, spiral angle and film thickness have significant effects on axial stiffness. The influence of length ratio on axial stiffness is significant, but the influence of groove depth and platform width ratio on axial stiffness is not significant. There are some differences between the two results, which are caused by the error in calculation and the density of mesh division. In this paper, the structure of dry gas seal testing machine has been improved and designed, which mainly solves three problems: 1. The problem of axial force of single cantilever shaft and single pair sealing mechanical seal test device is solved. The complex structure problem of double cantilever shaft mechanical seal test device is solved. The problem of unbalance adjustment of spring compression of single cantilever shaft and two pairs of sealed mechanical seal test device is solved.
【学位授予单位】：南京林业大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH136

【参考文献】