Rotor-bearing systems supported on squeeze film dampers (SFDs) show large amplitude vibratory motions when traversing critical speeds. At these operating conditions air is drawn into the damper thin film clearance generating a bubbly mixture with the lubricant and producing SFD forces not readily predictable with currently available analysis. A continuum model is proposed for describing the motion of a bubbly fluid in an open ended SFD operating with circular centered journal orbits. Computed predictions for peak-peak dynamic pressures and fluid film forces agree reasonably well with experimental measurements conducted on a SFD test rig operating with a controlled air in oil mixture. The bubbly flow model provides an initial procedure towards the reliable design of SFDs in actual operating conditions. [S0742-4787(00)02601-1]

Issue Section:
Technical Papers
Keywords:
lubrication, bubbles, rotors, machine bearings, film flow, damping, vibrations, air
Topics:
Dampers, Lubricants, Pressure, Fluids, Bearings, Clearances (Engineering), Rotors, Bubbles, Fluid films, Bubbly flow
1.
Diaz
,
S.
, and
San Andre´s
,
L.
,
1998
, “
Measurements of Pressure in a Squeeze Film Damper with an Air/Oil Bubbly Mixture
,”
STLE Tribol. Trans.
,
41
, No.
2
, pp.
282
–
288
.
2.
Diaz, S., and San Andre´s, L., 1998, “Reduction of the Dynamic Load Capacity in a Squeeze Film Damper Operating with a Bubbly Lubricant,” ASME Paper 98-GT-109, accepted for publication at ASME J. Gas Turbines Power.
3.
Diaz, S., and San Andre´s, L., 1998, “Effects of Bubbly Flow on the Dynamic Pressure Fields of a Test Squeeze Film Damper,” 1998 ASME Fluids Engineering Division Summer Meeting, Washington, DC, June, Paper FEDSM98-5070.
4.
Diaz, S., and San Andre´s, L., 1999, “A Method for Identification of Bearing Force Coefficients and its Application to a Squeeze Film Damper with a Bubbly Lubricant,” presented at STLE Annual Meeting, Nevada, May (STLE Preprint 99-AM-5).
5.
Diaz, S., and San Andre´s, L., 1999, “Air Entrainment vs. Lubricant Vaporization in Squeeze Film Dampers,” ASME Paper 99-GT-187, accepted for publication at ASME J. Gas Turbines Power.
6.
Zeidan, F., San Andre´s, L., and Vance, J. M., 1996, “Design and Application of Squeeze Film Dampers in Rotating Machinery,” Proc. of the 25th Turbomachinery Symposium, Texas A&M University, Sept., pp. 169–188.
7.
Diaz, S., 1999, “The Effects of Air Entrainment on the Forced Performance of Squeeze Film Dampers: Experiments and Analysis,” Ph.D. dissertation, Department of Mechanical Engineering, Texas A&M University, May.
8.
Atkin
,
R. J.
, and
Craine
,
R. E.
,
1976
, “
Continuum Theories of Mixtures: Basic Theory and Historical Development
,”
Quarter. J. Mech. Appl. Math.
,
29
, pp.
209
–
244
.
9.
Bowen, R. M., 1976, “Theory of Mixtures,” Continuum Mechanics III, A. C. Eringen, ed., Academic Press, N. Y.
10.
Rajagopal, K. R., and Tao, L., 1995, “Mechanics of Mixtures,” Series on Advances in Mathematics for Applied Sciences, Vol. 35, World Scientific, Singapore.
11.
Tao, L., and Rajagopal, K. R., 1997, “Flows of Bubbly Liquids,” J. Appl. Mech. Eng. (to appear).
12.
Taylor, G. I., 1932, “The Viscosity of a Fluid Containing Small Drops of Another Fluid,” Proceedings of the Royal Society, Series A138, pp. 41–48.
13.
Chamniprasart
,
K.
,
Al-Sharif
,
A.
,
Rajagopal
,
K. R.
, and
Szeri
,
A. Z.
,
1993
, “
Lubrication with Binary Mixtures: Bubbly Oil
,”
ASME J. Tribol.
,
115
, pp.
253
–
260
.
14.
Feng
,
N. S.
, and
Hahn
,
E. J.
,
1986
, “
Density and Viscosity Models for Two-Phase Homogeneous Hydrodynamic Damper Fluids
,”
ASLE Trans.
,
29
, pp.
361
–
369
.
15.
Pinkus, O., 1990, Thermal Aspects of Fluid Film Tribology, ASME Press, New York, pp. 317–326.
16.
Hayward, A. T., 1961, “The Viscosity of Bubbly Oil,” N.E.L. Fluids Report No. 99, National Engineering Laboratory, UK.
17.
San Andre´s
,
L.
, and
Vance
,
J. M.
,
1986
, “
Effects of Fluid Inertia and Turbulence on the Force Coefficients for Squeeze Film Dampers
,”
ASME J. Eng. Gas Turbines Power
,
108
, pp.
332
–
339
.
Copyright © 2000
 by ASME
You do not currently have access to this content.