1544. Synchronous and subsynchronous vibration under the combined effect of bearings and seals: numerical simulation and its experimental validation
1544. Synchronous and subsynchronous vibration under the combined effect of bearings and seals: numerical simulation and its experimental validation
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发表时间：
2015
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通讯作者：
Wanfu Zhang;Jiangang Yang;Chun Li;R. Dai;A. Yang;Wanfu Zhang;Jiangang Yang;Li Chun;R. Dai;A. Yang
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作者：
Wanfu Zhang;Jiangang Yang;Chun Li;R. Dai;A. Yang;Wanfu Zhang;Jiangang Yang;Li Chun;R. Dai;A. Yang
为了研究轴承与迷宫密封的联合作用对转子-轴承-密封系统动力学特性的影响机理，建立了迷宫密封的三维计算流体动力学（CFD）模型。计算了不同转速下迷宫密封的动特性系数。结果表明，随着转速的增加，交叉耦合系数的绝对值增大，而直接耦合系数的绝对值略有减小。进口处的正预紧力会加剧交叉耦合系数的增大和直接耦合系数的减小。负的预刺激表现出相反的效果。进一步建立了有限元模型。结果表明，迷宫式密封由于其阻尼作用，对转子在共振区的同步响应有很大影响。对于其他速度，它有轻微的影响。迷宫式密封会增加转子-轴承-密封系统的不稳定性。当考虑密封力时，次同步振动显著增加。在入口处引入负压可普遍提高系统的稳定性。结果还表明，迷宫密封的不利影响可以通过使用合适的轴承来补偿。可以设计适当的轴承配置，以降低密封引起的转子动力学不稳定性的风险。最后进行了实验测试，结果表明与数值模拟吻合良好。
A three-dimensional computational fluid dynamics (CFD) model of a labyrinth seal was established in order to investigate the influence mechanism of combined effects between bearings and labyrinth seals on the dynamic characteristics of the rotor-bearing-seal system. The dynamic coefficients of the labyrinth seal for various rotating speeds were calculated. Results show that the absolute values of cross-coupled coefficients increase with the increasing rotating speed, while the absolute values of direct coefficients decrease slightly. The positive preswirl at the inlet tends to intensify the increase of cross-coupled coefficients and the decrease of direct coefficients. The negative preswirl shows the opposite effect. A finite element model was further setup. Results show that the labyrinth seal has a large influence on the synchronous response of rotor in the resonant region due to its damping effect. For other speeds, it has a minor effect. The labyrinth seal may promote the instability of the rotor-bearing-seal system. The subsynchronous vibration increases significantly when the seal force is taken into account. The system stability can be generally enhanced by introducing the negative preswirl at the inlet. Results also show that the detrimental influence of the labyrinth seal can be compensated by using suitable bearings. A proper bearing configuration can be designed to reduce the risks of rotordynamic instabilities due to seals. An experimental test was finally performed, and it shows good agreements with the numerical simulation.