CAJ | 학술논문

针对高压多级离心泵水润滑轴承—转子系统在启动瞬态过程中由于其轴颈的瞬态不稳定运动而带来启动时的安全、可靠和稳定性等问题，该文通过理论分析和试验来探索多级离心泵的启动瞬态轴心轨迹。首先以多级离心泵水润滑轴承—转子系统的有限元模型为基础，建立其在外激励作用下的动力学运动微分方程，并结合滑动轴承动特性系数的小参数算法，然后将以上建立的两类方程联立，建立高压多级离心泵水润滑轴承—转子系统的瞬态耦合动力学模型，并以此模型为基础结合平均加速度的Newmark β算法，通过MATLAB编程技术来耦合迭代数值求解得到水润滑轴承—转子系统在启动过渡阶段的瞬态轴心轨迹，最后利用前期设计研制的海水淡化高压泵结构专用水润滑轴承试验台对海水淡化高压泵水润滑轴承启动瞬态轴心轨迹进行试验研究。从计算和试验结果的总体变化趋势可以得知，在启动刚开始液膜形成的不稳定阶段，轴颈在瞬态液膜力的作用下呈上升且偏向旋转方向一侧运动；在启动阶段的后期随着转速的不断增加，轴颈呈小幅度“涡动”。该文提出的计算模型具有一定的理论和工程应用价值，为进一步改进万吨级海水淡化高压泵系统的启动性能提供了一定的研究基础。
침대고압다급리심빙수윤활축승—전자계통재계동순태과정중유우기축경적순태불은정운동이대래계동시적안전、가고화은정성등문제，해문통과이론분석화시험래탐색다급리심빙적계동순태축심궤적。수선이다급리심빙수윤활축승—전자계통적유한원모형위기출，건립기재외격려작용하적동역학운동미분방정，병결합활동축승동특성계수적소삼수산법，연후장이상건립적량류방정련립，건립고압다급리심빙수윤활축승—전자계통적순태우합동역학모형，병이차모형위기출결합평균가속도적Newmark β산법，통과MATLAB편정기술래우합질대수치구해득도수윤활축승—전자계통재계동과도계단적순태축심궤적，최후이용전기설계연제적해수담화고압빙결구전용수윤활축승시험태대해수담화고압빙수윤활축승계동순태축심궤적진행시험연구。종계산화시험결과적총체변화추세가이득지，재계동강개시액막형성적불은정계단，축경재순태액막력적작용하정상승차편향선전방향일측운동；재계동계단적후기수착전속적불단증가，축경정소폭도“와동”。해문제출적계산모형구유일정적이론화공정응용개치，위진일보개진만둔급해수담화고압빙계통적계동성능제공료일정적연구기출。
In view of water-lubricated bearing-rotor system’s safety, reliability and stability of the high-pressure multistage centrifugal pump in the process of start caused by the transient unsteady motion of journal, this paper explored the multistage centrifugal pump’s start-up and transient axis trajectory through the theoretical analysis and experimental research. First of all, on the basis of the finite element model of the multistage centrifugal pump’s water-lubricated bearing-rotor system, the differential equation of dynamic movement under the action of outer incentive was established;then we combine the previous dynamic equations of the high-pressure multistage centrifugal pump’s water-lubricated bearing-rotor system with the small parameter algorithm of solving the water-lubricated bearing’s dynamic characteristics, and establish the transient coupled dynamic model of high-pressure multistage centrifugal pump’s water lubricated bearing-rotor system. Based on this model and Newmark β algorithm, we can solve iteratively and numerically to gain the transient axis trajectory of the water-lubricated bearing-rotor system in the start-up phrase through the MATLAB programming techniques. Finally, we use the designed and developed special water-lubricated bearing test rig of desalination high-pressure pump to research the start-up and transient axis trajectory of desalination high-pressure pump’s water-lubricated bearing by experiments, and then compare the measurement results with theoretical calculation and analyze their similarities and differences. From the overall comparison results, in the beginning of start and in the unstable phrase of the liquid film formation, the journal presents upward movement and moves toward the direction of rotation movement under the action of transient liquid membrane force;in the later stages of the start-up phrase and as the rotational speed increasing, journal presents “whirling motion” under the small amplitude. In the process of the establishment of the theoretical model in this article, we assume that the mass eccentricity of discs such as impeller, balance disc and so on are the same, and also ignore the shaft’s mass eccentricity and the vibration of the outside world (such as the vibration of the machine run time, fluid pulsation);but these simplified or ignored factors exist in the actual experiments, and we also should consider the installation precision of sensors. So, the former axis trajectory is more smooth and the latter's is more cluttered. In conclusion, the overall trend of the transient axial trajectory in the startup phrase by measurement and the theoretical calculation are basically identical. So, the calculation model has a certain theoretical and engineering application value proposed in this paper, and provides a certain research base to further improve the starting performance of the 10 000 ton desalination high-pressure pump system.