Experimental study of ultrasonic measurement of oil film thickness in bearing chamber wall

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.