Ps. Keogh et Pg. Morton, JOURNAL BEARING DIFFERENTIAL HEATING EVALUATION WITH INFLUENCE ON ROTOR DYNAMIC BEHAVIOR, Proceedings - Royal Society. Mathematical and physical sciences, 441(1913), 1993, pp. 527-548
The nature of differential heating across the journal of a hydrodynami
cally lubricated bearing has been investigated theoretically and an as
sessment made of the local thermal bend in the rotor at the bearing lo
cation. The energy balance for the system is time dependent and involv
es a stationary bearing component, an oscillating lubricant film, and
a rotating, orbiting section of journal. Thermohydrodynamic solutions
are developed which allow for temporal and spatial periodic variations
of bearing, lubricant and journal temperatures. The influence of a sy
nchronous journal orbit on the temperature distribution throughout the
system is discussed. In particular, the relation between any prescrib
ed orbit and the steady state temperature differential across the jour
nal, resulting in steady state rotor bending, is established. The role
played by such thermal bending in the onset of unstable synchronous w
hirl in the rotors of high-speed machines is outlined.