Running on an ultra-thin dynamic oil film, the slipper bearing in an aviation fuel piston pump is vulnerable to lubrication failure. To improve lubrication performance, the slipper surface is often grooved. However, the eventual lubrication effects remain challenging to judge qualitatively due to inaccessible measurement of oil film thickness distribution during pump operation. Eddy current sensors have been attempted, but they inevitably damage the oil film itself, and the tribo-pair test bench or incomplete pump used cannot simulate the complete working performance of a real pump. Addressing this issue, an ultrasonic-based method is investigated for online monitoring of the oil film thickness in a grooved slipper bearing. Firstly, the influence of groove texture on acoustic reflection is investigated by dividing the acoustic echoes into that from the top and bottom of the grooved surface, respectively. On this basis, a reflection coefficient extraction method fusing the reference signal and reflected signals at the top and bottom of the grooved surface is proposed, which can accurately extract the reflection coefficient and thus calculate the oil film thickness. Secondly, the finite element simulation is carried out to reveal the universal effects of the groove structure on the classical calculation method. The theoretical validity of the proposed reflection coefficient extraction method is verified by finite element simulation and experiment. A real aviation fuel piston pump is adopted for experimental validation, which is thoroughly performed under various operating conditions. The ultrasound measurement method shows promising results that are consistent with the theoretical calculations.

中文翻译：

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超声波反射测量航空燃油活塞泵滑靴轴承中的油膜厚度


航空燃油活塞泵中的滑动轴承在超薄动态油膜上运行，很容易出现润滑故障。为了提高润滑性能，滑靴表面常开槽。然而，由于泵运行期间无法测量油膜厚度分布，因此最终的润滑效果仍然难以定性判断。涡流传感器已经尝试过，但它们不可避免地会损坏油膜本身，并且使用的摩擦副试验台或不完整的泵无法模拟真实泵的完整工作性能。为了解决这个问题，研究了一种基于超声波的方法来在线监测沟槽滑动轴承中的油膜厚度。首先，通过将声回波分为来自凹槽表面的顶部和底部的回波，研究凹槽纹理对声反射的影响。在此基础上，提出了一种融合参考信号和凹槽表面顶部和底部反射信号的反射系数提取方法，可以准确提取反射系数，从而计算出油膜厚度。其次，进行有限元模拟，揭示沟槽结构对经典计算方法的普遍影响。通过有限元仿真和实验验证了所提出的反射系数提取方法的理论有效性。采用真实的航空燃油活塞泵进行实验验证，在各种工况下进行了彻底的实验验证。超声测量方法显示出与理论计算一致的有希望的结果。