Study On Balancing Optimization Method Of Flexible Rotor Considering Multiple Speeds

Rotating machinery is the main power equipment in many industries,and the key to ensure its safe and stable operation is to maintain a good balance of the core rotor system.For the flexible rotor of rotating machinery,the least squares influence coefficient method(LSM)through multiple planes,multiple measuring points,and multi-speeds cannot exclude the possibility that the value of residual vibration is too large.Therfore,further optimization is needed.Additionally,the traditional balancing techniques require repeated restarts of the rotor with trial weight.In contrast,balancing methods without trial weight can save much time and cost.However,the balancing of the flexible rotor without trial weight needs to be further optimized.With consideration of the problems mentioned above,we have carried out many works.(1)A balancing method of flexible rotors combined with dual-objective optimization(DOM)based on genetic algorithm(GA)is proposed and studied.The aim of this combined method is to over come the shortcomings of LSM.The first optimization takes the sum of squares of residual vibrations in multi-speeds as the objective function,and GA is used to perform global searches of the objective function to obtain a set of optimized correction weights based on the current population.A second optimization run is then performed by minimizing the maximum value of the residual vibration of the rotor.Each correction weight from a solution of the first optimization is brought into the equation that represents the residual vibration,to finally obtain an optimal correction weight.The validity of the proposed method is verified by simulations and experiments related to a double-disc rotor-bearing system.The results show the DOM provides a more effective balancing strategy than the one obtained from using GA and classical LSM.(2)Combining the DOM and the inverse problem theory,a dual-objective optimization for balancing the flexible rotor without trial weight is proposed.The dynamic model of the rotor is established based on the finite element technology,and the optimized objective function is constructed through the inverse problem theory.The maximum value of the residual vibrations and the difference between the predicted unbalance responses and the measured values is taken as the objective function.Then the balancing of a flexible rotor is optimized without trial weight.The simulations and experiments related to the three-disc rotor system show that the DOM is also applicable for the balancing of the flexible rotor without trial weight and can achieve a good balancing effect(3)Based on the proposed balancing optimization method,a software used for balancing optimization of the rotor installed on a rotating machine is developed.The software has been further developed and optimized on the basis of the influence coefficient method(ICM).It is planned to be applied to the on-site balancing of the rotor system in rotating machines to achieve better balancing effect and higher balancing efficiency.