An Experimental Study Of Wheel Mass Unbalance Vibration Response Based On WS-ZHT3 Rotor Test Bed

Steam turbine is the core equipment of thermal power plant.The stability and reliability of its operation directly affect the safety and economy of thermal power plant.The unbalance of turbine rotor mass is one of the most important causes of turbine operation faults,which will cause a series of safety hidden troubles such as rubbing between the internal movement of the turbine,damage of steam seal and oil seal mechanism,bearing damage,and rotor bending,etc.,and in serious cases,will cause shutdown accidents.Therefore,the vibration response of turbine wheel mass imbalance is studied.The influence of life is of great significance.Paper based on WS-ZHT3 multi-function rotor test bench,the mass unbalance rotor model was established,by changing the wheel unbalance mass size,imbalance of two relative to the roulette centroid assumes the radial position and Angle,unbalanced quality wheel offset,to experimental measurement of vibration response,analysis the influence of different conditions on the rotor vibration response.The main research contents and results of this paper are as follows:(1)A single side dynamic balancing experiment was carried out for the wheel at the central point of the rotating shaft by the three-point trial-weight method.After adding the balance mass at the corresponding Angle of the wheel,the single-point and double-point unbalanced mass weighting experiment was carried out by the Bode diagram method.The results show that the critical speed decreases with the increase of the unbalance mass,and the amplitude at the critical speed(maximum amplitude)and each speed increases with the increase of the unbalance mass.The smaller the Angle between the two unbalanced masses with respect to the disc centroid,the smaller the critical rotation speed and the larger the amplitude.The larger the Angle between the two unbalanced masses with respect to the disc centroid,the larger the critical rotation speed and the smaller the amplitude.(2)By changing the wheel unbalance quality radial location,with axis of bird figure method,frequency spectrum analysis method and trajectory method for rotor respectively measured vibration response under various working conditions for experiments,in order to assure the accuracy of the experimental data,and introduces mathematical definition,sensitivity analysis of the critical speed of unbalanced radial position change quantity and quality of unbalanced quality sensitivity of roulette quality percentage changes.The results show that when the radial position of the unbalanced mass is fixed,the critical speed of the rotor decreases with the increase of the unbalanced mass.When the percentage of unbalanced mass is constant,the radial position of unbalanced mass on the disc is farther from the disc centroid,the critical speed of the rotor is smaller.The effect of the critical rotor speed affected by the change of the unbalanced mass of the wheel is much greater than that affected by the change of the radial position of the unbalanced mass.(3)A case of rotor vibration caused by unbalance mass in a thermal power plant is analyzed,and an experimental study is carried out on the dynamic balance treatment method of adding test weight at different measuring points in the case.The single-side dynamic balance experiment and single-point unbalance mass weighting experiment of the same wheel in different axial positions were carried out by three-point trial weight method.The theoretical calculation and finite element analysis were carried out based on each working condition of the rotor test platform,and the theoretical and experimental results were compared and analyzed.Results show that in three heavy single dynamic balance test experiment,the greater the roulette offset,the smaller the roulette need to add the balance quality,adding in the corresponding balance point of the corresponding balance quality does not completely eliminate the wheel unbalance,the greater the offset,the experimental measured critical speed and the theoretical calculation and finite element analysis result error is larger;The difference between the critical speed under the same vortex and that under the opposite vortex increases with the increase of the disk offset.The influence of the unbalance mass on the critical speed is greater when the wheel offset is larger.