有利于齿轮组装式压缩机转子稳定的一种密封结构——叶轮端面密封

A Type of Seal with Effectively Increasing Rotor Instability of Integrally Geared Compressor——Impeller End Seal

随着齿轮组装式压缩机的高参数化发展方向,转子系统的稳定性问题越来越明显,甚至成为制约离心压缩机设计的关键。常规提高转子稳定性的手段:增加转子的刚性,随之而来可能由于转子的临界转速过高,与工作转速之间的隔离裕度不能满足相关标准的要求;密封采用反旋流技术,但效果有限。与传统的迷宫密封相比,叶轮端面密封可以大大降低气流失稳力的大小。叶轮端面密封通过改变密封的布置形式,由轴向变为径向,消除了气流对于转子的失稳作用力,提高了转子的稳定性。本文中提到了某二氧化碳机组,分别采用迷宫密封和端面密封,经计算,端面密封的交叉耦合刚度仅为迷宫密封的10%左右(交叉耦合刚度可表征气流失稳力的大小),转子也由失稳转子变为稳定转子。

With the high parameter development of integrally geared compressor, stability of rotor-bearing-seal system is more and more serious, and becomes the key problem.The common ways of increasing stability are to increase the shaft stiffness and choose the anti-swirl technology.With increasing the shaft stiffness, critical speed will increase and the separate margin becomes small which cannot meet the requirements of relevant standards.The effective of anti-swirl technology is limited.Comparing with traditional labyrinth seal, end seal can greatly decrease the instability force.Through the change of seal arrangement, from axial to radial direction, it has diminished the instability force, and increased the stability of rotor system.A carbon dioxide integrally geared compressor is designed with labyrinth and end seal in the paper.Cross-coupled stiffness of end seal is only 10% of labyrinth seal(cross-coupling stiffness can represent the instability force),and compressor changes from instability to stability rotor.