Abstract: It is hard to measure the oil film thickness in aero-engine bearing chamber. According to the basic principle of the pulse reflection method,software and hardware of an ultrasonic measurement system for measuring the oil film thickness in bearing chamber,are established. The hardware system mainly consists of signal acquisition card,probe,delay block and the corresponding cables. Functions as setting of measurement parameter,real-time display of measurement waveforms,post-processing and so on are included in measurement software. Then ultrasonic measurement system is applied on the eight kinds of oil film thicknesses at static conditions. Comparison between experimental data with calculated values shows that the maximum error is less than 5% at the former seven conditions except the eighth measurement error being 6.9%,meeting the actual requirements. Finally,dynamic film thickness of the wall is measured with this measurement system. Signal quality of the dynamic measurement is analyzed. And also,analysis among different oil film thickness with the same oil flow and different rotation rate is conducted. It is concluded that this measurement system can measure the oil film thickness on bearing chamber wall in relative high accuracy.

Key words: Oil film thickness；Ultrasonic measurement system；Static measurement；Dynamic measurement

摘要： 针对轴承腔壁面油膜厚度难测的问题,根据脉冲反射法的基本原理,建立了用于测量轴承腔内壁面油膜厚度的超声波测量系统。测量系统主要包括硬件系统和软件系统两大部分,硬件系统主要由数据采集卡、探头、延迟块和相应的电缆等组成；软件系统功能主要有测量参数的设置、测量波形的实时显示、后处理等功能。然后,用所开发的测量系统测量静态条件下八种不同厚度的油膜,并将实验结果与计算值进行对比,第八种油膜厚度下相对误差为6.9%,其余七种情况油膜厚度的相对误差均在5%以下,满足工程实践要求。最后,进行油膜厚度动态测量实验,获得相同流量、不同转速下轴承腔壁面的油膜厚度,经过动态测量的信号品质分析和油膜厚度变化规律分析,该测量系统能在较高精度的要求下完成轴承腔壁面油膜厚度的测量。

关键词: 油膜厚度；超声测量系统；静态测量；动态测量