| The centrifugal pump is a commonly used energy exchange equipment,which has been widely used in energy,chemical,aerospace,transportation and other fields.The performance of the centrifugal pump determines the continuity,stability and safety of the entire industrial production system.In order to meet the requirements of pressure balance and sealing,there are a large number of circulating seal structures represented by seal ring rings and balance drums in centrifugal pumps.Such seal structures have an important influence on the delivery efficiency and operational stability of centrifugal pumps.In this paper,the labyrinth seal ring is used as the research object.The lattice Boltzmann method(LBM)is used to calculate the internal flow field of the labyrinth seal under the liquid phase conditions.The equivalent dynamic characteristics were studied.The seal-rotor test device was built to measure the axis trajectory of the rotor in the labyrinth seal.Specific analysis contents include:(1)Using LBM to solve the labyrinth seal flow field in liquid phase,a high-precision labyrinth seal performance calculation method based on D2Q9 particle velocity discrete model and les-smagorinsky model was constructed,and a numerical simulation program was written based on the method.The flow characteristics of labyrinth sealing medium were obtained by LBM and CFD simulation of flow field by finite volume method.The flow field in the sealing groove was composed of large vortices at the center and small vortices at the bottom of both sides of the groove.Comparing the results of the two simulation methods with the experimental results,it is found that LBM has better computational accuracy.(2)The Euler-Euler two-fluid model was used to study the sealing performance and equivalent dynamic characteristics of the labyrinth seal under solid-liquid two-phase conditions The pressure difference,speed,and The effect of particle volume fraction and vortex direction on the sealing performance and equivalent dynamic characteristics of the labyrinth seal found that the circumferential flow of the sealing medium is uneven,and the flow velocity is negatively correlated with the gap size in the axial direction Then there will be periodic changes.The increase in inlet pressure and particle volume fraction leads to an increase in leakage,but it can play a role in improving the stability of the rotor system.When the rotor speed increases,the leakage of the labyrinth seal will decrease,and the leakage will decrease to a greater extent when the vortex is negative.The increase of the rotor speed will also increase the instability coefficient of the rotor system,which is not conducive to the stability of the rotor system.The instability coefficient during negative vortex is an order of magnitude greater than that during positive vortex,indicating that the negative vortex will damage the stable operation of the rotor.(3)By building a seal-rotor test device,the axis of the labyrinth seal rotor is measured,and the test results are compared with the simulation results of the rotor vibration response calculation program to verify the labyrinth seal under solid-liquid two-phase flow conditions The effectiveness of numerical simulation methods.The analysis and test results show that the change of the rotor axis trajectory is the result of the coupling effect of various factors such as the imbalance of the rotor mass and the force of the sealing medium on the rotor.Increasing the inlet pressure can suppress the rotor vibration.The increase in rotational speed has two sides,on the one hand,it will increase the force of the sealing medium on the rotor to suppress the rotor vibration,on the other hand,it will amplify the effect of mass imbalance and enhance the rotor vibration. |
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