Abstract
Brush seal has excellent seal characteristics and has fantastic performance in many large machineries. At present, most of the research on brush seal systems concerns the analysis of normal system operation, this article aims to fill the gaps in exploring the misalignment fault of brush seal rotor systems. A new seal force model considering the axial deformation of bristles is proposed and combined with the excitation force caused by comprehensive misalignment faults, established a model under the coupling comprehensive misalignment faults and axial deformation of bristles. Analyze the system features such as motion bifurcation, Lyapunov exponent, axis trajectory, and Poincaré mapping to investigate the nonlinear characteristic. In addition, how the comprehensive misalignment affects the brush seal system is also studied. As the speed escalates, the system transitions through single-period, double-period, triple-period, and back to single-period before going into chaotic motion. With an increase in overall imbalance, the rotational speeds of periodic and chaotic motions converge, leading to the eventual disappearance of the triple-period motions. Comprehensive misalignment can lead to an earlier timing of chaos occurrence in the system. The increase in comprehensive misalignment results in a decrease in the speed at which chaos occurs and a more complex change in the system state. This study will provide a theoretical basis for the research and analysis of faults in seal system of rotating machinery.
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