Stability experiments with hydrodynamic tilted-lobe journal bearings of various numbers of lobes and length-to-diameter ratios

Hydrodynamic journal bearing stability tests were conducted with 3.8 centimeter (1.5 in) diameter tilted-lobe bearings. The bearings had 3, 5, and 7 lobes and L/D ratios from 0.2 to 1.0. They were tested in water and MIL-L-7808G oil at 294 K (70 F) at speeds to 5, 400 rpm with zero load. Stability was not appreciably affected by the number of lobes and decreased with a decrease in L/D ratio. However, a three-tilted-lobe bearing with an offset factor of 0. 76 and an L/D of 0.5 was more stable than a three-centrally-lobed bearing with an offset factor of 0.50 and an L/D of 1.0. All data can be presented in terms of the parameter[Mbar](Γ*)1.4 = 9, where[Mbar]is the dimensionless mass parameter and Γ* is the optimized stability parameter. Presented at the 31st Annual Meeting in Philadelphia, Pennsylvania, May 10–13, 1976