流体微循环表面织构特性仿真分析研究

发布时间：2018-05-09 04:43

本文选题：表面织构 + 静压润滑　；参考：《武汉理工大学》2012年硕士论文

【摘要】：随着社会的发展,人们在设计机械系统时对环保与效率的要求越来越高,而零件的摩擦学性能对于提高整个机械系统的性能和使用寿命有着重要意义。与普通摩擦表面相比,具有适当织构形式的摩擦表面会有更好的流体循环特性和润滑特性,所以在表面织构理论在工程领域得到了广泛的应用。由于织构体表面分布有交错的网状沟槽,因而在润滑机理上建立准确的润滑模型具有很大的困难。本文针对液体润滑的基本特点,结合现有的织构表面润滑理论基础及实践经验,对其润滑机理做了初步探究,并在理论分析和仿真计算的基础上对不同的二维以及三维织构模型进行了探讨,并对四边形和六边形网状织构表面的动压特性进行了研究。本文首先建立了几种不同的二维织构模型以及四边形网状沟槽表面和六边形网状沟槽表面织构模型,阐述了微循环织构的几何特征及其流体动压润滑的基本工作原理。然后应用计算流体力学中的FLUENT软件进行迭代计算,成功地将其引入到表面织构微循环领域。表面织构动压特性的研究多采用简化的解析方法或数值解法,数值解法主要是有限元法和有限差分法,计算效率较低,而FLUENT软件采用的是近年发展非常迅速的有限体积法,计算效率和精度都很高。该软件对边界条件、计算模型、控制参数及网格质量方面都有严格要求。本文应用它对各种微循环织构体的压力场和速度场进行了仿真分析,得出了润滑液体在流场内部的压力分布云图、速度分布矢量图和重要截面上的压力散点图并计算出了在旋转壁面上形成的举升力。通过对云图和数据的分析,探讨了两种织构表面情况下产生不同结果的原因。分析表明,在具有相同深度的不同二维织构中,其表现出的动压特性随着倾角的增大有减小的趋势；而三维织构体中,六边形网状表面织构模型的微循环特性和润滑特性更好。最后,为了验证六边形网状织构模型的优越性,对不同进出口条件和不同润滑液体条件下的润滑性能进行了研究,结果表明,两种不同织构模型在相同条件下,六边形织构表面的润滑性能要优于四边形织构表面。
[Abstract]:With the development of society, environmental protection and efficiency are required more and more in the design of mechanical system, and the tribological performance of parts is of great significance to improve the performance and service life of the whole mechanical system. Compared with common friction surfaces, friction surfaces with proper texture form have better fluid circulation and lubricating properties, so the theory of surface texture has been widely used in engineering field. It is difficult to establish an accurate lubrication model on the lubrication mechanism because there are staggered mesh grooves on the surface of the texture. According to the basic characteristics of liquid lubrication, combined with the existing theoretical basis and practical experience of texture surface lubrication, this paper makes a preliminary study on its lubrication mechanism. On the basis of theoretical analysis and simulation, different two-dimensional and three-dimensional texture models are discussed, and the dynamic compression characteristics of quadrilateral and hexagonal reticulated textures are studied. In this paper, several different two-dimensional texture models and the surface texture models of quadrilateral and hexagonal reticulated grooves are established. The geometric characteristics of microcyclic textures and the basic working principle of hydrodynamic lubrication are described. Then the FLUENT software in computational fluid dynamics is applied to iterate calculation and it is successfully introduced into the field of surface texture microcirculation. The study of the dynamic pressure characteristics of surface texture mostly adopts simplified analytical method or numerical method. The numerical method is mainly finite element method and finite difference method, and the calculation efficiency is low. The FLUENT software uses the finite volume method, which has been developed very rapidly in recent years. The calculation efficiency and precision are very high. The software has strict requirements for boundary conditions, computational models, control parameters and mesh quality. In this paper, the pressure field and velocity field of various microcirculatory textures are simulated and analyzed, and the pressure distribution of lubricating liquid in the flow field is obtained. The velocity distribution vector diagram and the pressure scatter plot on the important section are calculated and the lift force formed on the rotating wall is calculated. Based on the analysis of cloud map and data, the causes of different results in the case of two kinds of texture surface are discussed. The analysis shows that the dynamic pressure characteristics of the two dimensional texture with the same depth decrease with the increase of the inclination angle, while the microcirculation and lubrication characteristics of the hexagonal reticulated surface texture model are better in the three dimensional texture. Finally, in order to verify the superiority of hexagonal mesh texture model, the lubricating properties of two different texture models under different inlet and outlet conditions and different lubricating liquid conditions are studied. The results show that the two different texture models are under the same conditions. The lubrication performance of hexagonal texture surface is better than that of quadrilateral texture surface.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH117

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