Research On Off-line Dynamic Balance Method Of High-speed Flexible Rotor

Dynamic balancing is a very important step in the process of rotor processing and manufacturing.After a long development,according to the time position of the balancing process in the rotor production to application,it is divided into offline balancing: balancing during rotor processing and production;on-site balancing: balancing the rotor after the product assembly is completed;online balancing: balancing during the rotor operation.The three types of dynamic balancing correspond to the removal of the rotor’s own imbalance,the imbalance brought about during assembly,and the imbalance generated during operation.The residual imbalance in the front of the three types of dynamic balancing steps will increase the difficulty of the later steps.Traditional off-line dynamic balancing needs to determine several balance planes from the rotor,and new eccentric mass is introduced into the balance planes to suppress the whole vibration amplitude of the rotor.This method has a good balancing effect for rotors with small aspect ratios and high stiffness.As the rotor develops towards high speed and high aspect ratio,multiple balance planes are required for the offline dynamic balancing of the rotor.This type of rotor requires multiple trial weight measurements to calculate the required counterweight on multiple balance planes.At this time,the balancing process of traditional dynamic balancing is complex and inefficient.In this thesis,a new off-line dynamic balancing method is proposed.By continuously measuring the rotor vibration displacement and phase in the axial direction,the vibration information of the whole shaft length of the rotor is obtained,and the eccentric mass of the whole shaft length of the rotor is obtained by designing a circular iterative procedure to inverse solve.In this thesis,simulation analysis of three different eccentric mass distributions is carried out for the inverse solution calculation.The finite element software participates in the inverse calculation process,and the eccentric mass obtained is the nodal eccentric mass.In the continuous balancing process,the eccentric mass of the node needs to be converted into the continuous eccentric mass.And distinguish the machined surface and unmachined surface of the rotor,and make corresponding adjustments.For the rotor with non-machinable surfaces,the thesis calculates the residual eccentric mass and makes a difference in the original eccentric mass to obtain the required removal amount for dynamic balancing.Finally,an experimental bench is designed to experimentally validate the proposed offline dynamic balancing method.The rotor is divided into 100 nodes along the rotor axial direction,and the rotor vibration is detected by laser displacement sensor at each node position,and the rotor phase is recorded at the same time.The vibration measurement experiments with and without counterweight are carried out,and the data processing is carried out.The difference of amplitude and phase of sinusoidal curve formed by vibration displacement of each node in the two groups of data is compared,and the feasibility of the proposed off-line dynamic balance method is verified.