| With large capacity generators gradually become the mainstream of development, thelength of the last stage turbine blades is increasing, resulting in lower natural frequencies ofthe blade itself, that make the coupled vibration of the shaft and turbine’s blade in last stagebecome possible. It is particularly necessary to analyses the relationship of blade bendingvibration and shaft torsional vibration. Purely theoretical analysis is lacking in guidingsignificance for practical unit. Therefore, it is important to study the coupled vibration ofthe shaft and turbine’s blade in last stage, and put up test bed to experiment. In this paper,,designing cascades and to reach the purpose of testing the coupled vibration between bladesand shaft by the existing test bed in the laboratoryFirst, study the existing bed in the laboratory, and get its torsional vibration modeshapes and natural frequencies, on this basis, design a reasonable structure cascade structure.Analyzing for individual blades, no cascade rotor and cascade rotor, study their torsionalvibration deformation curve and torsional vibration frequency, and get the conclusion thatinstalling cascades will make the rotor’s natural frequency rising.Secondly, by applying short-circuit fault incentive in the generator rotor, analyses thedisplacement deformation of no cascades rotor, cascades rotor and blades, and analyses thestress of journals, blade’s roots and midpoint. And get the conclusion that installingcascades will make the rotor’s natural frequency rising, and make the torsional vibrationamplitude falls.Finally, based on preliminary calculations, design the cascades, shafting torsionalvibration measurement, blade vibration measurement, and fault simulation device. Lay thefoundation for putting up test bed. |
