Presentation on theme: "Analysis of Various Parameters Associated with Oil Lubricated Journal Bearings By: Paul Wolfinger."— Presentation transcript:
1 Analysis of Various Parameters Associated with Oil Lubricated Journal Bearings By: Paul Wolfinger
2 BackgroundIn marine bearing lubrication, the rotating shaft inside the bearing is in the presence of oil, which generates a wedge between the two due to the dynamics of the fluid. The fluid generally adheres to each body and must shear in order to accommodate the relative motion.Fluid film thickness between the bearing surface and rotor provides lubrication, of which one can determine a velocity and temperature profile.
3 Project PurposeThis project evaluates full journal bearings, which completely surround the shaft journal to show relationships between diameter and RPM.Four full journal bearing types are evaluated in COMSOL at four different conditions to trade-off bearing stability and capability to handle load:Plain journalElliptical journalPressure dam journalOffset/lobe journal
4 Validation of COMSOLReynolds equation with Sommerfeld solultion used to validate COMSOLPetroff’s Equation to compare cases
7 Conditions for Evaluation of Each Bearing in COMSOL CaseABCDBearing Radius (m)0.250.50Rotor Radius (m)0.240.48Rotational Speed (rad/sec)104.7209.4Offset in X-dir (m)0.003Offset in Y-dir (m)Eccentricity (m)Radial Clearance (m)0.010.02Eccentricity Ratio0.0000.4240.212
12 Summary of Case A and B Case A Case B Bearing Plain Elliptical Pressure DamOffset/LobeMax Pressure (kPa)4.3636.7348.7640.82Min Pressure (kPa)-5.49-56.77-22.39-30.94Max Temperature (K)305.64305.59305.57305.73Case BBearingPlainEllipticalPressure DamOffset/LobeMax Pressure (kPa)104.98106.13107.9266.24Min Pressure (kPa)-89.62Max Temperature (K)306.69305.73306.98306.10
13 Summary of Case C and D Case C Case D Bearing Plain Elliptical Pressure DamOffset/LobeMax Pressure (kPa)190.74245.79249.13159.57Min Pressure (kPa)Max Temperature (K)305.29305.24305.33Case DBearingPlainEllipticalPressure DamOffset/LobeMax Pressure (kPa)701.241,217.2763.42575.86Min Pressure (kPa)-1,651.7Max Temperature (K)305.51305.30305.66305.59