Session: 23-14: Seal Turbomachinery Applications II

Submission Number: 178039

Rotordynamic Effects of Balance Piston Seal Eccentricity and Surface Roughness Using Transient Computation Fluid Dynamic Analysis 

In rotating machinery, such as centrifugal compressors and turbines, the fluid forces acting on the rotor from components such as labyrinth seals, balance piston seals, and impellers can affect rotordynamic stability and must be accounted for to ensure that the rotor has been sufficiently designed. Other influences on stability can include running eccentricity and abradable coatings, both in the elevated surface roughness and the increased clearance as the seals wear in. In this study, the balance piston seal of an eight-stage natural gas centrifugal compressor was evaluated at near-surge conditions using transient computational fluid dynamic (CFD) simulations to predict the rotordynamic force coefficients. The balance piston seal, consisting of two labyrinth seals in-series, each with upstream swirl brake vanes, was modeled with worn-in grooves from an abradable rotor surface coating. A multi-frequency whirling motion was used to reduce the computational time by superimposing several whirling frequencies, which reduced the required number of simulations. The predicted forces and prescribed multi-frequency mesh motion were used to calculate the impedance matrices of each labyrinth seal for two surface roughness and three eccentricity cases to evaluate the influence of the surface roughness of the abradable coating and measured eccentricity of the compressor. Additionally, the rotordynamic coefficients of the labyrinth seals were compared to bulk-flow predictions.

Presenting Author: Jeffrey Moore Southwest Research Institute

Presenting Author Biography: Dr. Jeffrey Moore is an Institute Engineer in the Machinery Section at Southwest Research Institute in San Antonio, TX. He holds a B.S., M.S., and Ph.D. in Mechanical Engineering from Texas A&M University. His professional experience over the last 30 years includes engineering and management responsibilities related to centrifugal compressors and gas turbines at Solar Turbines Inc. in San Diego, CA, Dresser-Rand (now Siemens Energy) in Olean, NY, and Southwest Research Institute in San Antonio, TX. His interests include advanced power cycles and compression methods, rotordynamics, seals and bearings, computational fluid dynamics, finite element analysis, machine design, controls, aerodynamics, and oxy-combustion. He has authored over 40 technical papers related to turbomachinery and has four patents issued. Dr. Moore has held positions as the Vanguard Chair of the Structures and Dynamics Committee and Chair of Oil and Gas Committee for IGTI Turbo Expo. He has also served as the Associate Editor for the Journal of Tribology and a member of the IGTI sCO2 Committee, Turbomachinery Symposium Advisory Committee, the IFToMM International Rotordynamics Conference Committee, and the API 616 and 684 Task Forces.

Authors:

Mark Anguiano Southwest Research Institute
Chris Kulhanek Southwest Research Institute
Jeffrey Moore Southwest Research Institute
David Ransom Siemens Energy
Daniel Wolbert Siemens Energy
Roman Mensing Siemens Energy