Experimental Research on Vibration Control for Rotor System of A Micro Turbojet Engine

摘要

The phenomenon of rotor-stator rubbing fault induced by rotor system instability was found frequently in ground operation of a new designed micro turbojet engine (MTE). In order to enhance rotor system stability and meet with the airworthiness standards of CS - E500 (a) and CS - E650 (e), a method was developed and was executed in experiments to confirm its validity. To use this method, three steps should be done, including balancing compressor impeller and turbine respectively; balancing rotor assembly components with compressor impeller, turbine and rotor shaft together; using dry friction damper designed intentionally for this rubbing fault to dissipate whirl energy from rotor vibration. Experiments were done to select optimum structure parameters of pads number and preloaded moment. And the results show that unbalance mass can be decreased into the least by balancing twice, and the most important is that dry friction damper can restrain abnormal rotor vibration and avoid rubbing fault. Furthermore, another factor, which will bring disaster impact to engine, was found that the failure of the bearing in turbine side because of too much thermal load was always tending to happen when the engine worked less than 60mins to make parts or engine ruined. By strengthening cooling fuel mass flow rate for the bearing, its life was extended obviously, but still did not meet with requirement. So, the main future work is to take down thermal load on bearing and solve the failure of turbine bearing to meet these airworthiness standards mentioned above. These experiences can be taken as references for MTE airworthiness design.