Stability of water-lubricated bearing rotor system of seawater desalination high-pressure pump and energy recovery integrated machine
In order to ensure the safe and operational stability of seawater desalination high-pressure pump and energy recovery integrated machine,the stability of water-lubricated rotor system with in-clined journal was studied.Based on hydrodynamic lubrication theory,a 32 dynamic coefficient model considering four degrees of freedom by using difference method and perturbation method was estab-lished.At the same time,the rotor dynamic equation was solved,and the effects of the dynamic and static characteristics of the bearing under different eccentricities,tilt angles and loads were analyzed.The hydrodynamic lubrication effect caused by the water film in the ring gap on the stability of the rotor was also studied.The characteristic equation was solved,and the stability of the rotor was analyzed by the real part of the eigenvalue.The results show that the tilt motion has a significant impact on the sta-bility of the rotor.The increase of eccentricity and tilt angle under four degrees of freedom increases 32 dynamic characteristic coefficients to varying degrees,which reduces the displacement caused by rotor whirl during operation and increases bearing capacity.In addition,the hydrodynamic lubrication effect of the water film in the gap between the mouth ring has a non-negligible impact on the stability of the rotor,which can reduce the displacement response of the rotor to 1/3 of the original and the time to achieve stable operation to 1/3 of the original.The study finds that the limit speed of the integrated ma-chine rotor is between 40000-45000 r/min.If the speed exceeds this limit,the characteristic value of the positive real part appears in the system,which can lead to instability.The limit speed of the rotor can be increased by increasing the width of the mouth ring and reducing the thickness of the water film gap of the mouth ring and intermembrane space gap.
water-lubricated rotorfour degrees of freedomdynamic and static characteristicsstabilityaxis trajectory
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