Analysis Of Fluid-Structure Coupling Of Rotor With The Crack

The centrifuge machine can be regarded as indispensable equipment in the field of nuclear industry.The core component of the centrifuge consists of a high-speed rotor system,whose vibration performance has exerted a direct influence on the centrifuge machine's performance,structural integrity,and functional reliability.By using finite element analysis method for modal analysis of the rotor,modal frequencies and vibration modes can be obtained,so the possibility of the occurrence of the rotor dynamic interference with other components can be predicted,thus it can avoid resonance by making a reasonable design of the rotor structure.Vibration of rotor system caused by excessive of unbalance is very harmful,because it can reduce mechanical efficiency,and some parts are easy to fatigue,wear and be shorten of life.The rotor system under crack state may cause a lot of serious problems when it undergoes a high speed rotation procedure.This kind of phenomenon undercuts the safety of the rotor structure system and further could make the entire system go failure.Nowadays most structure industrial businesses have increasingly high demand of the rotating units regard strength and working life.It is of great importance analyzing the working performance of the high speed rotation shell structure under crack condition.The rotor unit of the centrifugal machine works at a high speed rotation under the vacuum condition.When the shell of the centrifugal machine is broken and the air leakage takes place,a flow field outside the rotor unit is formed.The interaction between air from the flow field and the rotor unit also known as the fluid-structure coupling,is inevitable.Practice and evidence in the actual working condition has proved that fluid-structure coupling effects the dynamic performance of the rotor system at varying degrees.This kind of influence reaches its high value under the high rotation speed condition.This paper uses finite element software ANSYS to establish the rotor system in which the core unit rotor system of the centrifugal machine is treated as the research object.Then the critical speed of rotation is calculated based on the practical condition and the transient response analysis of the unbalanced rotor is established.The vibrate condition of the rotor when it starts out is observed and the conterforce on the bearing is calculated.This paper is based on Workbench to load the interaction between fluid and rotor onto the rotor.Therefore the modal distribution of the rotor components under the pretention condition can be achieved and the wet modal calculations of the rotor component are also obtained.To sum up we obtain the wet modal of the rotor system under the pretention condition and the next step is to provide a reference basis for further analyzing the rotor dynamic behavior and improving the structural performance.Differences of stress intensities of the crack under the vacuum condition and the normal fluid condition have been made and so did the natural frequency under two different conditions to support evidence using in the actual engineering application.