Simulation Analysis Of Vibration Characteristic Of Steam Turbine Rotor Under Fault Condition

As the major equipment in Equipment Manufacture Industry,Stream-turbine has been playing an important role in the power industry.Thus,whether the machine can keep normal state is directly related to the country's economic and social benefits.As the source of power,the security and stability of stream-turbine directly affect its life. Therefore,reducing fault of the stream,turbine and improving the reliability of it pose as the premise of the safe operation of the whole power system.Moreover,the turbine rotor is the core of the whole system,and vibration is commonly found when the stream-turbine turns out of order.Therefore,the research of vibration features of turbine rotor in fault state can provide basic data for the fault diagnosis,and it is of great significance for prolonging the life of stream-turbine and ensuring its safe and reliable operation.The 50MW steam-turbine rotor system was studied in this thesis.Based on multi-body dynamic theory,the virtual prototype of rotor was modeled.Besides, vibrating response law of imbalanced fault and rub-impact fault state at the rotor critical speed,were analyzed.Based on multi-body dynamic theory,virtual prototype of steam-turbine was modeled.The influence of stiffness,damping on the critical speed,relationship between amplitude and rotor critical speed were put forward as well as vibration characteristics in critical speed state.Finally,variable load was adopted to reduce intensity of vibration of rotor in the critical state.In order to simulate the response of rotor in the state of imbalance fault, imbalance mass block was added to build the virtual prototype.Vibration characteristics of rotor-bearing were discussed by adding up the imbalance block at different locations.Besides,spectrum was analyzed,which verified the weight of one octave vibration spectrum occupy the main component of annoying.Furthermore,the judgement of rotor imbalance mathematical model was discussed.In order to simulate the rub-impact fault state,triangle surging force was exerted at the journal to build the virtual prototype.Based on rub-impact theory,the orbit elliptical was shown in the thesis.In addition,the vibrating response of bearing and spindle in the state of rub were also involved,illustrating the sign of frequency spectrum of rotor in the state of fault,which was of great significance in investigating the mechanism of fault of the machine.The analysis of C50-8.83/0.98 turbine rotor vibration characteristics provides a basis for the feasibility of product design.