Overview
The Journal Bearing Apparatus consists of a journal (shaft) rotating inside a cylindrical bearing with oil lubrication, with circumferential pressure tapping holes connected to manometers or a pressure measurement system. As the shaft rotates, hydrodynamic oil film pressure is generated and its distribution around the bearing circumference can be measured. Students plot the circumferential and axial pressure distribution maps, determine minimum film thickness, Sommerfeld number, and friction coefficient, validating the Reynolds equation for hydrodynamic lubrication. The apparatus illustrates the fundamental mechanism by which hydrodynamic bearings support shaft loads without metal-to-metal contact in turbines, compressors, and large industrial machinery.
Specifications
| Journal diameter | 75 to 100 mm |
| Bearing length-to-diameter ratio | 0.5 to 1.5 |
| Shaft speed | 100 to 1500 RPM |
| Load | 0 to 2000 N (applied radially) |
| Oil | SAE 30 to SAE 60 |
| Pressure ports | 12 to 16 circumferential tappings |
| Manometers | multi-tube manometer board |
| Power supply | 220V AC, 50 Hz |