Fm. Dejongh et Pg. Morton, THE SYNCHRONOUS INSTABILITY OF A COMPRESSOR ROTOR DUE TO BEARING JOURNAL DIFFERENTIAL HEATING, Journal of engineering for gas turbines and power, 118(4), 1996, pp. 816-823
The paper describes a synchronous vibration instability problem encoun
tered on a centrifugal compressor with oil-lubricated bearings. The pr
oblem was solved by modification of the compressor rotor; however, the
root cause was not completely understood at that time. A possible exp
lanation was based on a theory that suggested differential heating of
the bearing journals. II rt as decided to verify this theory by experi
ments. Therefore a rest rotor,vas designed with identical rotor dynami
c characteristics to those of the compressor rotor. To fill a gap in t
he published research on bearing thermohydrodynamics, an experimental
technique was devised to measure the surface temperature variations ar
ound one of the journals of this rotor. The dependence of significant
temperature differentials across the journal upon its orbit was confir
med.