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A deterministic mixed-elastohydrodynamic lubrication model and analysis of lip seal performance.

机译：确定性的混合弹性流体动力润滑模型和唇密封性能分析。

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摘要

Mixed-lubrication refers to the cases where the intervening fluid film between two solid surfaces of a tribological element is so thin that the asperities on the relatively moving surfaces interact. This happens when either the fluid film is not fully established or when it breaks down. It happens inevitably during the transients of startup and shutdown. As a consequence, the accumulated asperity contacts can change the geometry of the asperities, and damage to the rough surfaces may occur. Therefore, an in-depth study of mixed-lubrication problems would help to improve design and prevent failure.;In this thesis, a deterministic model for mixed-lubrication problems is developed. Several coupled processes are included in the model: transient hydrodynamic lubrication, cavitation, and rough surface contact. A simplified approach to determine the film rupture condition, when asperity contact occurs, is adopted to establish the link between micro-elastohydrodynamic lubrication and mixed-elastohydrodynamic lubrication. This model allows the identification of almost all the important parameters in a given mixed-lubrication problem, such as the load sharing between hydrodynamic and contact pressures, cavitation and contact areas, minimum and average film thickness, and the alteration of the rough surface pattern. Based on a mathematical analogy between transient lubrication and contact problems, a generalized formulation is derived;and a unique solution scheme is constructed to solve these two seemingly different types of problems. The computational efficiency is compared between this new scheme and some advanced iterative schemes, such as the SLOR and the ADI accelerated by the multi-grid method.;The above mixed-lubrication model is applied to the analysis of the rotary lip seal. Such seals are widely used in machines containing rotating shafts. They are usually protected from thermal and mechanical damage by a thin film of lubricant that separates the lip from the rotating shaft under steady-state conditions. However, under some transient conditions, the seals work in the mixed-lubrication regime. The implementation of the deterministic mixed-lubrication model in the performance analyses for rotary lip seals helps to better understand the sealing mechanism and extend the seal life. A new pumping mechanism, based on surface tilting, is introduced. A parametric study has been conducted for design improvement.
机译：混合润滑是指摩擦元件的两个固体表面之间的流体膜太薄而相对运动的表面上的凹凸相互作用的情况。当流体膜未完全建立或破裂时，就会发生这种情况。在启动和关闭的瞬态过程中不可避免地会发生这种情况。结果，累积的粗糙接触会改变粗糙的几何形状，并且可能会损坏粗糙表面。因此，对混合润滑问题的深入研究将有助于改进设计并防止出现故障。本论文建立了一种确定性的混合润滑问题模型。该模型包括几个耦合过程：瞬态流体动力润滑，气蚀和粗糙表面接触。当发生粗糙接触时，采用确定膜破裂状态的简化方法来建立微弹性流体动力润滑与混合弹性流体动力润滑之间的联系。该模型可以识别给定混合润滑问题中的几乎所有重要参数，例如流体动力和接触压力之间的负载分担，空化和接触面积，最小和平均膜厚以及粗糙表面图案的变化。基于瞬态润滑和接触问题之间的数学类比，推导了广义的公式；并构造了独特的解决方案来解决这两种看似不同的问题。比较了该新方案和一些先进的迭代方案（例如通过多网格方法加速的SLOR和ADI）的计算效率。上面的混合润滑模型用于旋转唇密封的分析。这种密封件广泛用于包含旋转轴的机器中。通常通过在稳态条件下将唇部与旋转轴分开的润滑剂薄膜保护它们免受热和机械损坏。但是，在某些瞬态条件下，密封件会在混合润滑状态下工作。确定性混合润滑模型在旋转唇形密封件性能分析中的实施有助于更好地了解密封机理并延长密封寿命。介绍了一种基于表面倾斜的新型抽气机构。已经进行了参数研究以改进设计。

著录项

  • 作者

    Shi, Fanghui.;

  • 作者单位

    Georgia Institute of Technology.;

  • 授予单位 Georgia Institute of Technology.;
  • 学科 Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 1999
  • 页码 183 p.
  • 总页数 183
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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