Development Of A Measurement And Control System Of The Sliding Bearing Test Bench For The Fuel Pump

Sliding bearing is a key component in aircraft engine fuel pump, its wear directly affects the service life of the fuel pump. In order to provide scientific test data for design and application of sliding bearing, the test bench is needed to simulate the actual working conditions and working environment of sliding bearing. In the given working conditions of bearing speed, load and lubrication, the performance parameters of the sliding bearing are measured and the sliding bearing performance is evaluatd.The measurement and control system is an important part of the sliding bearing test bench, also is a fundamental guarantee of sliding bearing performance test. In order to control the test bearing working speed and bearing load, and to realize multi-parameter measurement, a measurement and control system for a multi-functional sliding bearing test rig is developed. In this paper, the main research work is as follows:(1) The overall structure of the measurement and control system design.According to the sliding bearing test content and basic requirements, through the type selection of a main control computer, the sensors, the measurement instruments and the sub-system control modules, the distributed computer measurement and control system was constructed. A control network was formed using the RS-485serial communication interface, combined the host computer and the power transmission control system, oil temperature control system and load control system. The motor speed and bearing load were set by the operation panel or software. The measured parameters, such as speed, torque, fuel inlet and outlet pressure, fuel temperature, fuel flow rate, loading were measured and displayed, and switching of control mode (automatic and manual) was achieved.(2) Measurement and control system software development.Based on hardware platform composed of industrial control computer (IPC) and high-speed data acquisition card, using virtual instrument technology, the measurement and control system software was developed in LabVIEW programming environment. The real-time measurement of sliding bearing oil film thickness, axial and circumferential pressure, bearing temperature was realized. The corresponding distribution curves were ploted and locus of journal center was calculatd. The functions of data storage, database management, time domain waveform display of data and historical records playback were realized.(3) Design of hydraulic loading control system.The hardware of hydraulic loading control system and PLC control software were designed based on Siemens S7-200series PLC. The touch screen control module software was design using EV5000configuration software. Through the position measurement and oil pressure measurement, the control of the loading lever position and closed loop control of bearing load were realized. After completing the development of the loading system, the control accuracy, stability and safety of the loading system were examined though a series of loading test.(4) The actual test verification.Through a lot of trials with different speed and different load, and the actual sliding bearing, the functions and the work reliability of the measurement and control system were assessed and evaluated. The results show that, the change process of the various sliding bearing parameters can be turly reflected by the measured data, and the requirements of sliding bearing characteristic test can be completely satisfied by the test rig measurement and control system.In the process of measurement and control system development, through combining data acquisition technology, serial communication technology, PLC application technology and frequency converter technology, the sliding bearing test bed for the fuel pump has the modernized breath. The system has friendly human-computer interaction interface, convenient operation, high test efficiency, a powerful tool for studying lubrication performance of the journal bearing in a shaft-sliding bearing system at different speed and different load is provided.