Dynamic Optimization And Experimental Study Of Spiral Seal For Nuclear Power Charge Pump

Spiral seals are widely used in rotating machinery suc h as high-speed centrifuges,nuclear power and space installations due to their good sealing performance.At present,most of the domestic and foreign experts and scholars' optimization research on the spiral seal stays only on the spiral seal structure itself.However,as the charge pump develops in the direction of high performance,large flow rate and high speed,the flow velocity and pressure difference of its internal fluid continue to increase.The large and fluid force on the rotor bearings also continues to increase,causing the problems of vibration noise and stability inside the pump body to become more and more prominent.The study of the sealing structure alone cannot meet the design requirements of modern pump units.In order to ensure the stable and safe operation of the supercharge pump,this dissertation has carried out the research work on the spiral seal from the perspective of the rotor-bearingspiral system.The main research contents are as follows:(1)The establishment of a spiral seal fluid analysis model for a nuclear power charge pump.Pro / Enginee was used to establish the three-dimensional model of the spiral seal.CFD ICEM was used to mesh the three-dimensional model.Then the independence of the mesh was verified to determine the mesh model.The transient problem of moving grid analysis is analyzed,and the research method of dynamic characteristics of spiral seal in this paper is determined,that is,the moving grid transient calculation method.(2)The leakage characteristics of the spiral seal of the nuclear power charging pump were analyzed.In order to provide a theoretical basis for the research of the rotor-bearing-seal system,this paper uses CFD software to numerically simulate the effect of different structural parameters and operati ng parameters on the spiral seal,and obtains the spiral angle,relative groove depth,and rotor speed on the spiral seal.The influence of the leakage characteristics and the speed on the force of the rotor.(3)In view of the current insufficient research on nonlinear dynamics analysis of spiral dense applications in large systems,this paper establishes and analyzes the nonlinear dynamics model of the rotor-bearing-spiral seal system.First,the oil film force model of the system is analyzed and explained.Based on the dynamic characteristics of the system,a two-way analysis equation of the rotor-bearing system is established.The numerical method is used to study the influence of the axial and lateral forces on the model vibration,and then derived.Transverse-axis bidirectional vibration model,and the self-programmed program is used to solve the dynamic coefficients of the bidirectional coupling model of the rotor-bearing system;Secondly,on this basis,a dynamic model of the rotor-bearing-spiral seal system is established,and the influence of different sealing structure parameters on the dynamic characteristics of the rotor-bearing-seal system is studied;Finally,according to the conclusions of the study,the entire sealed system is optimized for vibration reduction.(4)Design and build a test bed for sealing leakage characteristics and dynamic characteristics to verify the conclusions.Based on the function principle of the experimental bench,a test plan was formulated and the data processing method was deduced.Two kinds of spiral seals with different spiral angles were selected for experiments.The accuracy of the conclusions obtained in the previous experiments was verified through experiments,and the numerical analysis results were further modified,provide theoretical guidance for the optimization of spiral seal dynamics in the future.