Analysis Of The Vibration And Fatigue Life Of The Air-cooled Device Of The Diesel

In order to safely shutdown the nuclear power plant reactor in emergency circumstances,an emergency power supply system must be equipped.The emergency diesel generator set is the most widely used emergency power supply system,in which the safe and reliable operation of the air cooled radiator component plays the significant role.Based on ensuring the normal vibration characteristic,the reliability of the air cooled radiator and its key parts must be considered.In this paper,the wind turbine equipment of an emergency diesel generator unit air cooling radiator components in a nuclear power plant was taken as the research object,a steady experimental test apparatus was design and established.The vibration characteristics of the equipment were investigated via the experiment and numerical simulation.Consequently,the assessment on stresses and fatigue life of various parts in this equipment was studied.Main contents are as follows:(1)Based on the finite element method,the model to calculate the wind machine equipment was established,and the experimental apparatus was constructed.Through the calculation and experimental test,natural frequency and vibration mode characteristics of the equipment were obtained.The vibration characteristics of the daily operation of the fan equipment were analyzed,and the result reveals that the excessive vibration problem is caused by the resonance of the forced vibration.(2)On the basis of modeling and experimental analysis,the reinforcement optimization scheme for the problem of excessive vibration was proposed,and numerical calculation and experiment of the wind turbine equipment were applied.The result shows that the natural frequency of the non driving end of the device is avoided with the working frequency of the motor and the problem of vibration is solved.(3)Based on the virtual prototyping technology,the rigid flexible coupling model of the wind turbine equipment was set up by using the multi-body dynamics method,and the structure of the stress distribution was observed.By comparing the results before and after the reinforcement,it is found that the stress concentration position is as same as the actual fracture position.The maximum stress of supporting rods,wheel hub and other parts are definitely improved after reinforcement.Therefore,the strengthened vibration can be weakened,the stress concentration degree can be reduced.(4)The fatigue life of various components of fan equipment was conducted by using the nominal stress and finite element methods.The calculation results indicate the coincidence between the place of the smallest fatigue life and the crack in the actual engineering.Compared with the stress concentration parts,the calculation results play a certain reference value for the management and monitoring of equipment in nuclear powers.