Nonlinear dynamics of reverse osmosis high pressure high speed centrifugal pumps.

High-pressure pump rotors are critical components in a wide range of industrial and mechanical systems, including turbomachinery, hydraulic systems, and aviation engines. This study presents a dynamic model for a single-stage high-speed high-pressure centrifugal pump supported by hydrodynamic journal and thrust bearings. The model is based on a rigid rotor framework and incorporates the coupling effects between the journal and thrust bearings. The influence of key bearing parameters is systematically investigated, with particular attention given to the impact of introducing a central groove in the left bearing. Furthermore, the analysis explores the effects of integrating a third central journal into the system which acts also as rear wear ring. The study also examines the role of bearing boundary conditions, which can be regulated through auxiliary lines, and evaluates the influence of unbalance forces on system performance. The results demonstrate that boundary conditions significantly affect the load-carrying capacity and stability of the bearings, potentially leading to bearing failure if not properly managed. Additionally, while a coupling effect between the journal and thrust bearings is observed, its influence is found to be relatively minor in the context of the rigid rotor model employed in this analysis. The findings of this study provide valuable insights for the design and optimization of high-speed centrifugal pumps, offering a deeper understanding of the dynamic interactions and operational constraints inherent in such systems.