Abstract

The influence of the heat transfer field on anomalous film formation under elastohydrodynamic lubrication (EHL) conditions was studied. Liquid lubricant film shapes between a transparent disc and steel ball friction pair were investigated by white light optical interferometry. The fatty alcohol 1-dodecanol was used as the representative lubricant to develop anomalous film shapes. A sapphire disc and glass disc, which have different thermal conductivities, were used as the transparent bounding surface. Experiments were performed wherein the applied load, sliding conditions and ambient temperature were varied. The temperature of the lubricant film was estimated by a simple model with the measured traction coefficient. The estimated temperature and maximum Hertzian pressure were compared with the phase diagram of 1-dodecanol obtained using a diamond anvil cell to investigate the phase state of the lubricant film. It was found that the anomalous film shape was stably formed in the solid-state regime of the phase diagram whereas the film exhibited unique characteristics such as the collapse behaviour in high sliding conditions and liquid-like behaviour of the traction with a remaining thickened film part in the liquid state regime.

Graphic Abstract

中文翻译：

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弹性流体动力润滑条件下传热场对异常润滑油膜形成的影响

摘要

研究了在弹性流体动力润滑 (EHL) 条件下传热场对异常薄膜形成的影响。通过白光光学干涉法研究了透明盘和钢球摩擦副之间的液体润滑剂膜形状。脂肪醇 1-十二烷醇用作代表性润滑剂以形成异常的膜形状。具有不同热导率的蓝宝石圆盘和玻璃圆盘被用作透明边界面。进行实验，其中施加的载荷、滑动条件和环境温度是变化的。润滑膜的温度通过一个简单的模型与测量的牵引系数进行估计。将估计的温度和最大赫兹压力与使用金刚石砧座获得的 1-十二醇的相图进行比较，以研究润滑膜的相状态。发现在相图的固态区域中，异常的薄膜形状稳定地形成，而薄膜表现出独特的特性，例如在高滑动条件下的坍塌行为和具有剩余增厚薄膜部分的牵引力的类液体行为在液态状态。

图形摘要