Session: Poster Session

Paper Number: 162890

Effect of Plugged Orifices on Hybrid Journal Bearing Performance in Rocket Engine Turbopumps 

This study investigates the impact of plugged orifices on the static load performance of hybrid journal bearings, which are critical components in liquid rocket engine turbopumps. Wear debris in the fluid supply line can clog the orifices responsible for supplying hydrostatic pressure, leading to unpredictable performance degradation and jeopardizing the turbopump system's stability. To assess this risk, a hybrid journal bearing operating with liquid oxygen is modeled, incorporating the Reynolds equation for turbulent flow and accounting for bearing geometry, including orifice diameter and recess volume. This model enables accurate prediction of bearing characteristics, such as load capacity, stiffness, and damping, under various plugged orifice configurations. Analysis reveals that while a plugged orifice moderately reduces the overall flow rate, the location of the blockage significantly influences the bearing's load capacity and stiffness. When the plugged orifice is located within ±90° of the applied load direction, load capacity and direct stiffness decrease. Conversely, when the angle exceeds ±90°, these parameters tend to increase. This finding highlights the importance of orifice location relative to the load vector in determining the bearing's response to blockage. Furthermore, the study reveals the potential for increased instability due to plugged orifices, particularly when their location aligns with specific angles relative to the load direction. This instability can manifest as increased cross-coupled stiffness and damping, potentially causing undesirable vibrations and even bearing failure. This research provides valuable insights for engineers seeking to optimize bearing design and mitigate the risks associated with plugged orifices in demanding aerospace applications.

Presenting Author: Hyunsung Jung Hanyang University

Presenting Author Biography: Graduate Research Assistant at Hanyang University

Authors:

Hyunsung Jung Hanyang University
Keun Ryu Hanyang University