Analysis of a Steam Turbine for Estimation of Coefficients of a Gas Bearing
DOI:
https://doi.org/10.46842/ipn.cien.v23n2a08Keywords:
rotodynamics, gas bearings, turbomachinery, porous graphiteAbstract
Current trends in modern turbomachinery design point towards oil-free operation, making use of green technologies. One of these is porous graphite gas bearings. The present work describes the development of a rotodynamic model of a steam turbine rotor capable of predicting free modal shapes up to the second mode at 181 Hz (10 kcpm). The rotordynamic analysis is complemented with a study of the dynamic characteristics (stiffness and damping) that the gas bearings must have so that the rotor-bearings system is considered as a critically damped system (according to the API standard 684). A direct stiffness of 31000 lbf/in and a direct damping of 32 lb-s/in are proposed. Results of this work are promising for the proper operation of the machine and are useful for the design of turbomachinery supported by porous graphite gas bearings.
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