Identification methods and test results for tilting pad and fixed geometry journal bearing dynamic coefficients – A review

摘要: Fluid film journal bearings (FFBs) are used to support high-speed rotors in turbomachinery which often operate above the rotor first bending critical speed. The FFBs provide both lateral and dynamic coefficients: stiffness, damping, mass terms, related machine vibrations. Detailed numerical values of bearing characteristics necessary for proper design operation rotating machinery. methods identification fluid static characteristics, particularly coefficients, from measured data, obtained different measurement systems, is reviewed. Many tests have been performed validate a number theoretical models, including classical Reynolds isoviscous model. More advanced models include thermohydrodynamic (THD), thermoelastohydrodynamic (TEHD) approaches. also turbulence effects important as speeds continue increase. range data no longer includes current operational conditions. various approaches problem discussed, force excitation incremental loading, sinusoidal, pseudorandom, impulse, known/additional unbalance, non-contact excitation. Also discussed. Data processing time frequency domains presented. Methods evaluating uncertainty on overall coefficient confidence levels In this review, relative strengths weaknesses presented, developments trends improving measurements documented. Future improvement