Study On The Vibration And Noise Of The Press Section Of A Paper Machine

As modern pulp&paper making equipment tend to be higher speed,larger width,more complexity and higher degree of automation,the incurred structure vibration and noise becoming increasingly prominent.An appropriate control of these abnormality could improve the paper quality,reduce the number of equipment failures and improve the working environment.For this reason,research on structure vibration and noise is and will continue to be of great significance for papermaking enterprises.As one of the key components of paper machine,the press section,comprised of a complex roll pressure system,is very sensitive to vibration and liable to produce strong noise.Thus,it is of practical value to research on the intense vibration and noise of the press section.In this study,a finite element software ABAQUS is employed to build the finite element modeling of bearing-press roll system,including the three-dimensional structure modeling,bearing modeling by the springs with stiffness and damping characteristics,material and damping modeling with suitable characteristics,boundary condition and load modeling consistent with the actual situation.Firstly,modal analysis of the press roll is performed to investigate the dynamics.Hence,the natural frequency and modal shape are obtained.Modal analysis can effectively judge the weak areas of press roll in resonance,and it provides the reference for resonance prediction and failure diagnosis.Secondly,the unbalance response analysis of the press roll is carried out,and the amplitude-frequency response curve of the key points are obtained.Considering the design working speed of the press roll in this paper is 450m/min(the corresponding working frequency,1.667 Hz)and the response amplitude is relatively small,the press roll should have a long-term stability at this speed.The acoustic analysis of the press roll is also carried out.Acoustic model of press roll and field point mesh model are firstly established.Then the acoustic radiation analysis based on FEM and BEM is accomplished by acoustic software Virtual.lab acoustic using the result of the unbalance as the boundary condition.It shows that the intense sound pressure level mainly concentrates in the middle region of the field point mesh,reaching 85 dB at most of frequencies tested.Because such a strong sound pressure level exceeds the state-specified standard,it is necessary to decrease the noise of the press roll.The numerical simulation method is adopted in this paper to study the vibration and noise of press section of paper machine.By means of numerical simulation technology,amplitude response of press roll and noise distribution can be analyzed and thus the optimal design can be implemented,which can avoid the arbitrariness of the design work,can effectively save the cost and reduce the equipment design cycle.Furthermore,it has impact on speeding up the pace of the industrialization of the new equipment,it is therefore of very important realistic signifance.