Theoretical and Experimental Dynamic Characteristics of a Highly Preloaded Three-Lobe Journal Bearing

Abstract

The predicted performunce of a three-lobe journal bearing with a and slope of the coeflcients vs. Sommerfeld number match well. D k preload factor of 0.75 is compared with the measured performance. agreement in coeflcient magnitude by as much as 100% is seen at Operating eccentricity and dynamic coeflcients versus Sommerfeld high Sommerfeld numbers, although there is general agreement in the number are compared for three shaft speeds and various steady loads. trend for predicted coeflcients vs. Sommerfeld number. Numerical results are based on a model which solves the Rtynoldc equation and allows for a variety of thermal effects including cir-WORDS cumferential and mss-~ilm viscosity and temperature variation. The linearized coeflciats are experimentally determined by an average Hydrodynamic Bearings, Journal Bearings, ~u l t i -k b e magnitude and phase method using synchronous, sinusoidal exciBearings, Hydrodynamic Lubrication tations. Comparisons of journal position show good agreement (within 9.5 %) for Somme$eld numbers below 0.7 and increasing disagreement (30 % or greater) at higher Sommerfeld numbers. Agreement in journal position improves as load and shaft speed increase. At Sommerfeld numbers less than 0.4 to 0.7, agreement between the numm'cal and experimental dynamic coeflcients is very good, typically within the uncertainty of the measured data. The magnitude

A Review on Application of Dynamic Parameters of Journal Bearing for Vibration and Condition Monitoring

“…The uncertainty analysis was based on subsequent bearing identification experiments, including 2-axial groove bearings [57,58]; other studies of the 3-lobe bearing include testing of the linearity assumption the effect of load orientation on coefficients [59,60], three independent shaft orbits and the orbits resulting in the lowest uncertainty were used to identify bearing coefficients for a 3-lobe journal bearing with 0.75 preload [61,62] and five-pad tilting pad bearings [63][64][65][66]. The five-pad tilting pad tests have included the effect of pad pivot friction [63] and varying preload [64] on identified bearing coefficients.…”

Identification Methods and Test Results for Tilting Pad and Fixed Geometry Journal Bearing Dynamic Coefficients – A Review

“…The optimal points in shaft orbits to extract the bearing parameters were addressed, which are related to numerical conditioning. The uncertainty analysis was used on subsequent bearing identification experiments, including 2-axial groove bearings [31,32], 3 lobe bearings [7,8,17,30], and five-pad tilting pad bearings [46,47,63,69]. Typical uncertainties in identified bearing coefficients were 3-20 percent, depending on the experiment.…”

“…The experimental methods were improved by selecting orbits that improved the numerical condition of the matrix inversion required for the identification method. Three independent shaft orbits were produced, and the orbits resulting in the lowest uncertainty were used to identify bearing coefficients for a 3-lobe journal bearing with 0.75 preload [17,30]. Other studies of the 3-lobe bearing include testing of the linearity assumption the effect of load orientation on coefficients [7,8].…”

Effect of couple stress parameter on steady-state and dynamic characteristics of three-lobe journal bearing operating on TiO2 nanolubricant

“…The experimental and theoretical dynamic coefficients for multilobe bearing were compared by Kostrzewsky et al. 9 For dynamic analysis of multilobe bearings, Dargaiah et al. 10 applied theoretical outcome of Shang and Dien 6 and evaluated the stiffness and damping coefficients of grooved multilobe bearings.…”