Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Numerical Simulation of Gas and Liquid Seals for Rotordynamic Coefficients Calculations using Open Source Software
Submission Author:
Franco Barbi , SP
Co-Authors:
Franco Barbi, João Marcelo Vedovotto, Aldemir Ap Cavalini Jr, Aristeu Silveira Neto, Raphael Timbó
Presenter: Franco Barbi
doi://10.26678/ABCM.COBEM2023.COB2023-0849
Abstract
Gas seals are used in compressors and turbines to suppress fluid leakage while enabling shaft rotation through multiple regions at different pressure levels. There are many types of seals: plain, labyrinth, hole pattern, honeycomb; each one with its performance and geometric characteristics. Turbomachinery in the Gas & Oil industry operates at severe conditions due to productivity requirements. In many cases, elevated rotation frequencies are desired but often limited by equipment's vibrational stability. Therefore, it is crucial to understand the rotordynamic behavior of these machines and how each component affects the system in order to enhance design quality and optimize maintenance activity. During operation of seals, fluid dynamic forces interacting with rotor's and stator's surfaces contribute to rotordynamic coefficients and its evaluation based on modeling is of great interest. Models based on the bulk-flow theory have the advantage of low processing costs but its simplification hypothesis can be limiting, especially for seals with complex geometry. Such models can be improved with results obtained from models that solve the complete set of constitutive equations for fluid flows, i. e., mass conservation, Newton's Second Law of motion and energy conservation. Despite the elevated computational capacity required, the rapid advance of hardware technology and numerical methods is enabling the usage of Computational Fluid Dynamics (CFD) to investigate the phenomena present in seal's flows and improve rotordynamic coefficient calculations. The aim of this research work is to evaluate the application of the open-source CFD library OpenFOAM base solvers in the calculation of rotordynamic coefficients in plain seals with compressible flows. Results are explored for different rotational shaft velocity and different outlet total pressure. Comparisons with literature data obtained from experiments, with CFD/open-source, CFD/commercial, bulk-flow based models are also presented, contributing with the discussion of the advantages and drawbacks when using the method.
Keywords
Plain Seal, rotordynamic coefficients, OpenFOAM
