静压干气密封微尺度气膜刚度的变分计算及优化

发布时间：2018-06-11 15:25

本文选题：变分方程 + 有限元法　；参考：《兰州理工大学》2017年硕士论文

【摘要】：目前,一种发展比较迅速其在高速旋转设备使用上备受青睐的动密封即为干气密封。在工程实践应用上,条件范围拓宽到主轴处于低转速下,如搅拌器等。干气密封在高速形成动压的理论过程不能得以实现,工程问题突显出需要一种适用低转速下的密封理论来指导解决工程实践中出现的问题。本论文依据流体力学和气体润滑,结合静压干气密封的边界条件,推导出了气体雷诺方程,依据静压干气密封的基本工作原理和结构参数,应用伽辽金法对方程进行化简得到变分方程,由密封腔中密封气膜所处的边界条件,使用有限元法和超松弛迭代对离散化的变分方程进行求解。得出在静环密封端面上压力分布,在轴向上,从静环密封端面到动环密封端面方向上,压力呈现抛物线型递减趋势。在静环密封端面径向上,由节流孔处向内径和外径出逐渐降低,在节流孔处出现压力最高峰。再通过热平衡分析和模型简化,建立了静压干气密封三维稳态柱坐标下无内热源的固体导热微分方程。应用ANSYS软件建立静压干气密封动、静环力变形、温度场及热力耦合变形有限元分析模型,并对密封环力变形分析,温度场进行求解及热力耦合变形下的计算。得出了只考虑力变形情况下,动、静环的变形云图和变形量。密封端面的温度场分析和热力耦合变形情况下的动、静环的变形云图和变形量。根据稳态下计算出来的静环端面压力分布,考虑热力耦合下静环端面的变形,从而影响气膜刚度。计算得出在不同工况下,不同的节流孔特性参数及端面参数对密封稳定性的影响,及不同工况下的泄漏量及摩擦功耗。最后获得静压干气密封端面微尺度气膜位移的优化结构。
[Abstract]:At present, a kind of dynamic seal, which is very popular in the use of high speed rotating equipment, is called dry gas seal. In engineering practice, the range of conditions is widened to the spindle at low speed, such as agitator. The theoretical process of dry gas seal forming dynamic pressure at high speed can not be realized. Engineering problems highlight the need for a kind of sealing theory suitable for low rotational speed to guide and solve the problems in engineering practice. Based on hydrodynamics, gas lubrication and boundary conditions of hydrostatic dry gas seal, the gas Reynolds equation is deduced in this paper, and the basic working principle and structure parameters of hydrostatic dry gas seal are discussed. The Galerkin method is used to simplify the equation to obtain the variational equation. The discrete variational equation is solved by finite element method and overrelaxation iteration according to the boundary conditions of the sealing film in the sealing chamber. The pressure distribution on the end face of the static ring seal is obtained, and the pressure decreases in the direction of the axial direction from the end face of the static ring seal to the end face of the moving ring seal. In the radial direction of the end face of the static ring seal, the internal diameter and the outer diameter gradually decrease from the orifice to the orifice, and the pressure peak occurs at the throttle hole. By means of thermal equilibrium analysis and model simplification, the differential equation of solid heat conduction without internal heat source is established under the three-dimensional steady cylinder coordinates of hydrostatic dry gas seal. The finite element analysis model of static pressure dry gas seal dynamic, static ring force deformation, temperature field and thermo-mechanical coupling deformation is established by using ANSYS software, and the analysis of seal ring force deformation, the solution of temperature field and the calculation of thermal coupling deformation are carried out. The deformation cloud figure and deformation quantity of moving and static ring are obtained only considering force deformation. The temperature field analysis of the seal end face and the deformation cloud diagram and deformation quantity of the dynamic and static ring under the condition of coupled thermal deformation. According to the pressure distribution of static ring end surface calculated under steady state, considering the deformation of static ring end surface under thermal coupling, the film stiffness is affected. The effects of different characteristic parameters of throttle hole and end face on the seal stability, leakage and friction power consumption under different working conditions were calculated. Finally, the optimized structure of micro-scale gas film displacement on the end face of hydrostatic dry gas seal is obtained.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH136

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