Coupling Simulation And Experimental Study On Piezoelectrc Micro-jet Device For Bearing Lubrication

With the development of space technology in our country,more and more spacecraft have been launched into space.At the same time,the frequency of launching spacecraft has gradually increased.Half of spacecraft amount have been launched in the last ten years.However,every launch costs a lot.So,how to prolong the service life of spacecraft has become the research hotspot in the international.In recent decades,the service life of electronic components has been greatly improved,but the mechanical failure of spacecraft is still a keypoint that limited the service life of spacecraft.Because of the deterioration of lubricating oil,bearing will gradually serious wear which will cause mechanical failure of spacecraft.The development of lubrication technology will taking a long time,so many researchers have put their attention into the study of supplementary lubrication device.Supplementary lubrication device can be divided into active supplement lubricating device and passive supplement lubricating device,in which the structure of passive supplement lubricating device is simple but with small storage capacity,and the delivery rate is hard to control.Because of the large storage capacity of oil and strong controllability,the active supplementary device has gradually become the research hotspot.Piezoelectric micro-jet device has the advantages of quick response,tiny injection droplets,high controllability,no impact on lubricating oil,and strong resistance to electromagnetic interference.Therefore,it can be used as an active supplementary lubrication solution for bearings.In this paper,the present research situation of micro-jet device at home and abroad is introduced and analyzed.Then,an embedded piezoelectric micro-jet lubrication device is designed to solve the problem of active replenishment lubrication of spacecraft bearings.The structure of piezoelectric micro-jet device has the advantages of small size and compact,and can employed universally to the structure of bearing system.Cantilever piezoelectric vibrator structure is adopted in the design of micro-jet device in order to reduce the stiffness of piezoelectric vibrator.So this type of piezoelectric vibrator can improve the jet performance.This paper also designs an experimental platform for bearing micro-redundancy lubrication test.The experimental platform has small system error,can be used to improve the convenience of the experiment.The measuring principle of the experimental platform is to measure the lubrication state of the bearing by measuring the friction torque between the vibration and the ring of the bearing.In this paper,ANSYS has been used to complete the coupling numerical simulation of the piezoelectric micro-jet device.And the working mode and the optimum working frequency of the piezoelectric vibrator are obtained.ANSYS fluid solid interaction simulation and FLUENT two-phase flow simulation are used to co-simulate the lubrication injection process of micro-jet device under the excitation signal.The simulation method is used to study the influence of different excitation conditions and fluid properties on the jet performance of micro-jet device.Under the excitation of single pulse signal,this paper has experimentally analyzed the effects of excitation signal and fluid properties on the jet performance.The feasibility of the micro-jet device and the reliability of the simulation result are verified by the experience.The feasibility of using piezoelectric micro-jet device as active lubrication for bearings,has been tested by the bearing micro-redundancy test platform.Under different signal excitation conditions and bearing conditions,this paper has also analyzed the pulse numbers bearing required for reaching a micro-redundant lubrication state by experience.