1. A test rig for evaluation of thrust foil bearings and/or face seals
2013 NEW Proposal to TRC
A test rig for evaluation of thrust foil bearings and/or face seals
Luis San Andrés
Mast-Childs Professor
May 2013

2. USET Thrust Bearing Test Rig
USET research program ( )
$ k
Test rig: $288.5 k
Radial
Bearings
Test Thrust
Bearing 6 12
inch
Rotor 2
4 in

3. Objective & Tasks (2005-2008) Test rig funded by USET (AF) program
Design & construction of thrust bearing test rig.
Measurements of axial clearance, load, pocket pressures, and flow rates in a water hybrid thrust bearing.
Prediction of performance from tool XLHYDROTHRUST and comparisons to test data.

4. Thrust Bearing Test Rig – Cross Section
Airbuffer Seals
Radial Hydrostatic Bearings
Aerostatic Bearings
shaker
Thrust Load mechanism
Rotor Assembly
Test Thrust Bearing
Slave Thrust Bearing
2 in
4 in
or FACE SEAL

5. Schematic test rig: thrust and radial bearings as mechanical elements with stiffness and damping
Test element: thrust bearing or face seal

6. TEST RESULTS & PREDICTIONS
Water supply pressure=250 psig (17.2 bar)
7.5 krpm
17.5 krpm
Axial clearances are weak functions of rotor speed – hydrostatic effect mainly
Predictions agree well with test data, best at highest load (400 lbf)
XLHYDROTHRUST predictions
TB clearance vs. axial load: 7.5, 12.5 & 17.5 krpm

7. Work in
Dr. Sangshin Park (Visiting Scholar)
Test rig modified to operate with air lubricated bearings.
Flexure pivot hydrostatic/hydrodynamic air bearings designed and manufactured ($7.5 k)

8. Proposed work Complete revamping test rig: install instrumentation and
Year I
Complete revamping test rig: install instrumentation and
TRC member provides face seal or thrust foil bearing for testing OR acquire thrust bearing.
Install bearing and measure drag torque and film thickness vs. applied axial load at increasing shaft speeds.
Max speed: 30 kprm
Seal or Bearing OD: 3 inch
Compare measurements to predictions from TB or SGFace seal codes. 8

9. TRC Budget
Year I
Year III
Support for graduate student (20 h/week) x $ 2,050 x 12 months
$ 24,600
Fringe benefits (0.6%) and medical insurance ($185/month)
$ 2,368
Tuition & fees three semesters ($362/credit hour)
$ 8,686
Other (manufacture TB and contribute to purchase ADRE system)
$ 8,346
Total Cost:
$ 44,00
TRC members wish to verify/validate predictive tools for hydrodynamic thrust bearings and face seals. 9 9

10. Questions (?) 10

11. Components of Motor Drive System
SKF Precision/Gilman Technologies
Spindle Motor Drive (D45985)
22KW (30 30,000 RPM
Constant torque 0 – 30,000 RPM (62 lb-in torque)
Digital closed-loop speed control with LabView interface
Water chiller
All subsequent required hardware and software
Coupling Corp. of America (CCA), Custom Coupling
- FLEXXOR Twin-diaphragm or Quill shaft design with Anderson Locking hub(s)
30,000 RPM Maximum speed rating
825 lb-in max. continuous torque
+/ inch Axial Travel allowance (> 8X req’d.)
Low axial spring rate ( lb/0.001 inches)
Weight: 2.1 – 3.5 lbs.
Inertia (Ip): 2.6 – 5.3 lb-in^2

12. Test Rig Operation STATIC LOAD TESTS
Thrust and radial bearings lubricated with water at 91F (~32 C)
Open water lines and SET supply pressure into radial bearings (100 psig)
Supply pressure to gas bearings supporting axial load arm (100 psig)
SET supply pressure into thrust bearings: 50, 100, 150, 200, 250 psig
SET thrust bearings at nominal clearance (3 mil)
Shaker applies axial load – increasing & decreasing
MEASURE rotor axial displacements (clearances) at test & slave bearings, RECORD flow rates (in & out), pocket pressures, supply and discharge P&T’s
SET rotor speed (max 25 krpm): 7.5, 10.5, 17.5 krpm

13. Test Rig Instrumentation
Rotor lateral radial motions: 2 x 2 (X,Y) eddy current sensors:
Rotor collar axial and tilt motions at test & slave thrust bearings
2 x 3 (120 deg) (Z) eddy current sensors:
Thrust Force with strain gauge load cell & stinger connected to shaker. Torque mechanism not active.
Turbine flow meters in supply lines to water radial bearings, and
test thrust bearing INLET and OUTLET at ID
Three (3) strain-gauge pressure sensors for measurement of (2) pocket and (1) land pressures in test thrust bearing.
Thermocouples: inlet & outlet of test thrust bearing
Pressure gauges: supply and discharge of test thrust bearing
Tachometer: rotor speed LABVIEW® DAQ system and control

14. ORIGINAL Flexure Pivot Tilting Pad Hybrid Bearings
Material: 330 Bearing Bronze
Wire-EDM manufacturing
Modeled using
XLHYDROJET

15. ORIGINAL Thrust Hybrid Bearings
Thrust bearings
Material 660 Bearing bronze
Inner diameter: inch Outer diameter: inch
Axial clearance mil (nominal 3 mil)
EIGHT (8) Pockets:
Mean Diameter: inch
radial length: 0.32 inch
Arc length: 20 degrees
Depth: inch
Pocket/wetted area ratio = 19%
Orifice size: inch
Axial injection at r=1.08 inch
Test bearing
Slave bearing
FLUID WATER

16. Thrust Bearing Test Rig – Cross Section
Test Thrust
Bearing
Slave Thrust
Bearing
Hydraulic shaker delivers axial load to TB housing
Journal
Bearings
Hydrostatic
Air Bearings
Coupling
stinger
Rotor
Max Supply pressure: 250 psi, Top speed=25 krpm 5
10 inch
Thrust
Shaft
Test
Bearing
Cover
Journal
Bearing
Housing
Slave
Bearing
Housing
Two flexure pivot hydrostatic/hydrodynamic bearings support rotor
Double Thrust Bearing (TB) configuration – face to face
Air bearings support test TB housing (friction free axial motion)

17. Thrust Bearing Test Rig – Exploded View