Study On Active Balancing Technology And Its Application To Rotating Machinery

In the modern process industries, such as chemical engineering, power plant, astronavigation and metallurgy etc., rotor system often can not be in normal working condition because of vibration induced by the unbalance or the other accident caused by vibration. It is quite often for the machinery to have to be stopped and accepted dynamic balance, but it will lead to great economic loss. So, it is necessary to develop and spread on-line active balancing technology in the modern indurtries.Structure of each component in the electromagnetic active balancing autuator is firsyly analysized in this paper. The structure, counterweight principle and balancing principle of the key component--counterweight disk are studied, and then self-lock principle and deblocking motion principle are clarified. Combining with specific dimension of the rotating ring, maximum angular acceleration for the counterweight disk and calculation method of the impulse value generated by controller are studied, on which loop flow of electromagnetic active balancing system and calculation method of rotating angel for the counterweight disk during balancing are formatted.Single-plane self-correction controlling algorithm based on the influence coefficient method for electromagnetic active balancing device is also studied in this paper. In order to cancel the contradiction between vibration control convergence rate and instant maximum vibration value, convergence error factorε_?, scaling factorsη_? andη_? are employed to modify the value ofα_? andβ_? on-line; Supervisory strategy for the electromagnetic on-line active balancing is put forward. Upper limit e_? and below limit e_? for turning on and turning off the active balancing system are introduced, which can avoid turning on and turning off the active balancing system blindly. Aiming at correct and false initial value of the influence coefficient, contrast simulations among balancing process rates of conventional influence coefficient method, fixed parameter and time-varying parameter influence coefficient method are carried out on the Jeffcott rotor system. Simulation results indicate superiority of time-varying parameter influence coefficient method.On the base of the theoretic study above, experimental and engineering application study of electromagnetic active balancing system are carried out in this paper.Contrast experiments between double planes and single plane active balancing are carried out on the test rig with flexible bending rotor. Test results indicate that when passing the first critical speed, rotor vibration response can be decreased approximately by 80% and 93% by using single plane and double planes active balancing devices.Electromagnetic active balancing experiments arc fulfilled on the large-scale vertical hypergravity machine. Test result of decreasing stable vibration indicates that vibration response can be decreased from 154．96μm to 15．73μm, and vibration response decreases by more than 89．8%. Test result of decreasing instant vibration indicates that vibration response can be decreased from 30．4μm to 9．86μm through only one active adjustment in 4．9 seconds.Aiming at vibration problem of one centrifugal compressor with tail, engineering application study of electromagnetic active balancing system is carried out. Modified scheme for the high pressure cylinder rotor is put forward. Simulation results reveal that original response at the tail is approximately 2．5 times the response for the modified rotor. Through simulation calculations, installation schemes for the electromagnetic active balancing device with maximum balancing capacity of 2500g·mm placed near the left coupling hub and right bearing block are presented, and installation drawing for the electromagnetic active balancing device is also designed. Aiming at inactivation problem for aluminum counterweight disk in the electromagnetic active balancing test under the centrifugal compressor operating speed, solution is brought forward that material of counterweight disk is changed from aluminum into steel. Simulations and experiments reveal that maximum deformation value in Y direction is decreased to 500 microns below for the steel counterweight disk with balancing capacity of 2500g·mm under centrifugal compressor operating speed, assuring counterweight disk relatively regular revolution around the rotor shaft. Furthermore, relation map among counterweight disk balancing capacity, diameter and operating speed is calculated and summarized under the material of aluminum and steel. The relation map provides theoretical base for safe design method and engineering application of the counterweight disk.Aiming at vibration problem in the engineering because of deposition on the fume turbine, it is studied to adopt electromagnetic active balancing technology. Finite element model for the fume turbine is established, and balancing effects of four single-plane and three double-plane balancing schemes are calculated. On the base of dimension measurement on-site. electromagnetic and hydraulic balancing schemes are put forward and installation drawings are also designed. Simulation test rig for the fume turbine is designed and constructed. establishing the foundation for the contrast experiments of electromagnetic double-plane and hydraulic single-plane balancing programs.Finally, structure and control algorithm of hydraulic balancing system are analysized and tested in this paper. Design and installation method for the balancing head in hydraulic balancing system are advanced, and strength of the balancing head is checked: Calculation method of maximum balancing capacity for balancing head with three chambers is studied, on the base of optimizing computation for the number of balancing chambers in the balancing head; A kind of hydraulic balancing control algorithm--chamber by chamber optimization method is put forward. Simulation results on the Jeffcott rotor system indicate that chamber by chamber optimization method can reduce rotor vibration level fast and effectively, in spite of the unbalance at any angle; Hydraulic active balancing experiments are carried out on the drilling machine. Test results indicate that vibration response can be decreased from 975μm/s to 25μm/s below after 9 times of liquid injections in 12 seconds.